@article{CestnikPikovskij2022,
  author    = {Cestnik, Rok and Pikovskij, Arkadij},
  title     = {Exact finite-dimensional reduction for a population of noisy oscillators and its link to Ott-Antonsen and Watanabe-Strogatz theories},
  series = {Chaos : an interdisciplinary journal of nonlinear science},
  volume    = {32},
  journal   = {Chaos : an interdisciplinary journal of nonlinear science},
  number    = {11},
  publisher = {AIP},
  address   = {Melville},
  issn      = {1054-1500},
  doi       = {10.1063/5.0106171},
  pages     = {15},
  year      = {2022},
  abstract  = {Populations of globally coupled phase oscillators are described in the thermodynamic limit by kinetic equations for the distribution densities or, equivalently, by infinite hierarchies of equations for the order parameters. Ott and Antonsen [Chaos 18, 037113 (2008)] have found an invariant finite-dimensional subspace on which the dynamics is described by one complex variable per population. For oscillators with Cauchy distributed frequencies or for those driven by Cauchy white noise, this subspace is weakly stable and, thus, describes the asymptotic dynamics. Here, we report on an exact finite-dimensional reduction of the dynamics outside of the Ott-Antonsen subspace. We show that the evolution from generic initial states can be reduced to that of three complex variables, plus a constant function. For identical noise-free oscillators, this reduction corresponds to the Watanabe-Strogatz system of equations [Watanabe and Strogatz, Phys. Rev. Lett. 70, 2391 (1993)]. We discuss how the reduced system can be used to explore the transient dynamics of perturbed ensembles. Published under an exclusive license by AIP Publishing.},
  language  = {en}
}
@article{ZeiskeSandbergKurpiersetal.2022,
  author    = {Zeiske, Stefan and Sandberg, Oskar J. and Kurpiers, Jona and Shoaee, Safa and Meredith, Paul and Armin, Ardalan},
  title     = {Probing charge generation efficiency in thin-film solar cells by integral-mode transient charge extraction},
  series = {ACS photonics},
  volume    = {9},
  journal   = {ACS photonics},
  number    = {4},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {2330-4022},
  doi       = {10.1021/acsphotonics.1c01532},
  pages     = {1188 -- 1195},
  year      = {2022},
  abstract  = {The photogeneration of free charges in light-harvesting devices is a multistep process, which can be challenging to probe due to the complexity of contributing energetic states and the competitive character of different driving mechanisms. In this contribution, we advance a technique, integral-mode transient charge extraction (ITCE), to probe these processes in thin-film solar cells. ITCE combines capacitance measurements with the integral-mode time-of-flight method in the low intensity regime of sandwich-type thin-film devices and allows for the sensitive determination of photogenerated charge-carrier densities. We verify the theoretical framework of our method by drift-diffusion simulations and demonstrate the applicability of ITCE to organic and perovskite semiconductor-based thin-film solar cells. Furthermore, we examine the field dependence of charge generation efficiency and find our ITCE results to be in excellent agreement with those obtained via time-delayed collection field measurements conducted on the same devices.},
  language  = {en}
}
@article{IlićPetkovićPoppenhaegerHosseini2022,
  author    = {Ilić Petković, Nikoleta and Poppenh{\"a}ger, Katja and Hosseini, Seyede Marzieh},
  title     = {Tidal star-planet interaction and its observed impact on stellar activity in planet-hosting wide binary systems},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {513},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {3},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/stac861},
  pages     = {4380 -- 4404},
  year      = {2022},
  abstract  = {Tidal interaction between an exoplanet and its host star is a possible pathway to transfer angular momentum between the planetary orbit and the stellar spin. In cases where the planetary orbital period is shorter than the stellar rotation period, this may lead to angular momentum being transferred into the star's rotation, possibly counteracting the intrinsic stellar spin-down induced by magnetic braking. Observationally, detecting altered rotational states of single, cool field stars is challenging, as precise ages for such stars are rarely available. Here we present an empirical investigation of the rotation and magnetic activity of a sample of planet-hosting stars that are accompanied by wide stellar companions. Without needing knowledge about the absolute ages of the stars, we test for relative differences in activity and rotation of the planet hosts and their co-eval companions, using X-ray observations to measure the stellar activity levels. Employing three different tidal interaction models, we find that host stars with planets that are expected to tidally interact display elevated activity levels compared to their companion stars. We also find that those activity levels agree with the observed rotational periods for the host stars along the usual rotation-activity relationships, implying that the effect is indeed caused by a tidal interaction and not a purely magnetic interaction that would be expected to affect the stellar activity, but not necessarily the rotation. We conclude that massive, close-in planets have an impact on the stellar rotational evolution, while the smaller, more distant planets do not have a significant influence.},
  language  = {en}
}
@article{OsterFritschUlbrichtetal.2022,
  author    = {Oster, Simon and Fritsch, Tobias and Ulbricht, Alexander and Mohr, Gunther and Bruno, Giovanni and Maierhofer, Christiane and Altenburg, Simon},
  title     = {On the registration of thermographic in situ monitoring data and computed tomography reference data in the scope of defect prediction in laser powder bed fusion},
  series = {Metals : open access journal},
  volume    = {12},
  journal   = {Metals : open access journal},
  number    = {6},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2075-4701},
  doi       = {10.3390/met12060947},
  pages     = {21},
  year      = {2022},
  abstract  = {The detection of internal irregularities is crucial for quality assessment in metal-based additive manufacturing (AM) technologies such as laser powder bed fusion (L-PBF). The utilization of in-process thermography as an in situ monitoring tool in combination with post-process X-ray micro computed tomography (XCT) as a reference technique has shown great potential for this aim. Due to the small irregularity dimensions, a precise registration of the datasets is necessary as a requirement for correlation. In this study, the registration of thermography and XCT reference datasets of a cylindric specimen containing keyhole pores is carried out for the development of a porosity prediction model. The considered datasets show variations in shape, data type and dimensionality, especially due to shrinkage and material elevation effects present in the manufactured part. Since the resulting deformations are challenging for registration, a novel preprocessing methodology is introduced that involves an adaptive volume adjustment algorithm which is based on the porosity distribution in the specimen. Thus, the implementation of a simple three-dimensional image-to-image registration is enabled. The results demonstrate the influence of the part deformation on the resulting porosity location and the importance of registration in terms of irregularity prediction.},
  language  = {en}
}
@article{SunSandbergNeheretal.2022,
  author    = {Sun, Bowen and Sandberg, Oskar and Neher, Dieter and Armin, Ardalan and Shoaee, Safa},
  title     = {Wave optics of differential absorption spectroscopy in thick-junction organic solar cells},
  series = {Physical review applied / The American Physical Society},
  volume    = {17},
  journal   = {Physical review applied / The American Physical Society},
  number    = {5},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {2331-7019},
  doi       = {10.1103/PhysRevApplied.17.054016},
  pages     = {12},
  year      = {2022},
  abstract  = {Differential absorption spectroscopy techniques serve as powerful techniques to study the excited species in organic solar cells. However, it has always been challenging to employ these techniques for characterizing thick-junction organic solar cells, especially when a reflective top contact is involved. In this work, we present a detailed and systematic study on how a combination of the presence of the interference effect and a nonuniform charge-distribution profile, severely manipulates experimental spectra and the decay dynamics. Furthermore, we provide a practical methodology to correct these optical artifacts in differential absorption spectroscopies. The results and the proposed correction method generally apply to all kinds of differential absorption spectroscopy techniques and various thin-film systems, such as organics, perovskites, kesterites, and two-dimensional materials. Notably, it is found that the shape of differential absorption spectra can be strongly distorted, starting from 150-nm active-layer thickness; this matches the thickness range of thick-junction organic solar cells and most perovskite solar cells and needs to be carefully considered in experiments. In addition, the decay dynamics of differential absorption spectra is found to be disturbed by optical artifacts under certain conditions. With the help of the proposed correction formalism, differential spectra and the decay dynamics can be characterized on the full device of thin-film solar cells in transmission mode and yield accurate and reliable results to provide design rules for further progress.},
  language  = {en}
}
@article{DoerriesChechkinMetzler2022,
  author    = {Doerries, Timo J. and Chechkin, Aleksei V. and Metzler, Ralf},
  title     = {Apparent anomalous diffusion and non-Gaussian distributions in a simple mobile-immobile transport model with Poissonian switching},
  series = {Interface : journal of the Royal Society},
  volume    = {19},
  journal   = {Interface : journal of the Royal Society},
  number    = {192},
  publisher = {Royal Society},
  address   = {London},
  issn      = {1742-5689},
  doi       = {10.1098/rsif.2022.0233},
  pages     = {14},
  year      = {2022},
  abstract  = {We analyse mobile-immobile transport of particles that switch between the mobile and immobile phases with finite rates. Despite this seemingly simple assumption of Poissonian switching, we unveil a rich transport dynamics including significant transient anomalous diffusion and non-Gaussian displacement distributions. Our discussion is based on experimental parameters for tau proteins in neuronal cells, but the results obtained here are expected to be of relevance for a broad class of processes in complex systems. Specifically, we obtain that, when the mean binding time is significantly longer than the mean mobile time, transient anomalous diffusion is observed at short and intermediate time scales, with a strong dependence on the fraction of initially mobile and immobile particles. We unveil a Laplace distribution of particle displacements at relevant intermediate time scales. For any initial fraction of mobile particles, the respective mean squared displacement (MSD) displays a plateau. Moreover, we demonstrate a short-time cubic time dependence of the MSD for immobile tracers when initially all particles are immobile.},
  language  = {en}
}
@article{NematiHenkelAnders2022,
  author    = {Nemati, Somayyeh and Henkel, Carsten and Anders, Janet},
  title     = {Coupling function from bath density of states},
  series = {epl : a letters journal exploring the frontiers of physics},
  volume    = {139},
  journal   = {epl : a letters journal exploring the frontiers of physics},
  number    = {3},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0295-5075},
  doi       = {10.1209/0295-5075/ac7b42},
  pages     = {7},
  year      = {2022},
  abstract  = {Modelling of an open quantum system requires knowledge of parameters that specify how it couples to its environment. However, beyond relaxation rates, realistic parameters for specific environments and materials are rarely known. Here we present a method of inferring the coupling between a generic system and its bosonic (e.g., phononic) environment from the experimentally measurable density of states (DOS). With it we confirm that the DOS of the well-known Debye model for three-dimensional solids is physically equivalent to choosing an Ohmic bath. We further match a real phonon DOS to a series of Lorentzian coupling functions, allowing us to determine coupling parameters for gold, yttrium iron garnet (YIG) and iron as examples. The results illustrate how to obtain material-specific dynamical properties, such as memory kernels. The proposed method opens the door to more accurate modelling of relaxation dynamics, for example for phonon-dominated spin damping in magnetic materials.},
  language  = {en}
}
@article{Poppenhaeger2022,
  author    = {Poppenh{\"a}ger, Katja},
  title     = {Helium absorption in exoplanet atmospheres is connected to stellar coronal abundances},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {512},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {2},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0035-8711},
  doi       = {10.1093/mnras/stac507},
  pages     = {1751 -- 1764},
  year      = {2022},
  abstract  = {Transit observations in the helium triplet around 10 830 Angstrom are a successful tool to study exoplanetary atmospheres and their mass loss. Forming those lines requires ionization and recombination of helium in the exoplanetary atmosphere. This ionization is caused by stellar photons at extreme ultraviolet (EUV) wavelengths; however, no currently active telescopes can observe this part of the stellar spectrum. The relevant part of the stellar EUV spectrum consists of individual emission lines, many of them being formed by iron at coronal temperatures. The stellar iron abundance in the corona is often observed to be depleted for high-activity low-mass stars due to the first ionization potential (FIP) effect. I show that stars with high versus low coronal iron abundances follow different scaling laws that tie together their X-ray emission and the narrow-band EUV flux that causes helium ionization. I also show that the stellar iron to oxygen abundance ratio in the corona can be measured reasonably well from X-ray CCD spectra, yielding similar results to high-resolution X-ray observations. Taking coronal iron abundance into account, the currently observed large scatter in the relationship of EUV irradiation with exoplanetary helium transit depths can be reduced, improving the target selection criteria for exoplanet transmission spectroscopy. In particular, previously puzzling non-detections of helium for Neptunic exoplanets are now in line with expectations from the revised scaling laws.},
  language  = {en}
}
@article{MallonnPoppenhaegerGranzeretal.2022,
  author    = {Mallonn, Matthias and Poppenh{\"a}ger, Katja and Granzer, Thomas and Weber, Michael and Strassmeier, Klaus G.},
  title     = {Detection capability of ground-based meter-sized telescopes for shallow exoplanet transits},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {657},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361/202140599},
  pages     = {10},
  year      = {2022},
  abstract  = {Meter-sized ground-based telescopes are frequently used today for the follow-up of extrasolar planet candidates. While the transit signal of a Jupiter-sized object can typically be detected to a high level of confidence with small telescope apertures as well, the shallow transit dips of planets with the size of Neptune and smaller are more challenging to reveal. We employ new observational data to illustrate the photometric follow-up capabilities of meter-sized telescopes for shallow exoplanet transits. We describe in detail the capability of distinguishing the photometric signal of an exoplanet transit from an underlying trend in the light curve. The transit depths of the six targets we observed, Kepler-94b, Kepler-63b, K2-100b, K2-138b, K2-138c, and K2-138e, range from 3.9 ppt down to 0.3 ppt. For five targets of this sample, we provide the first ground-based photometric follow-up. The timing of three targets is precisely known from previous observations, and the timing of the other three targets is uncertain and we aim to constrain it. We detect or rule out the transit features significantly in single observations for the targets that show transits of 1.3 ppt or deeper. The shallower transit depths of two targets of 0.6 and 0.8 ppt were detected tentatively in single light curves, and were detected significantly by repeated observations. Only for the target of the shallowest transit depth of 0.3 ppt were we unable to draw a significant conclusion despite combining five individual light curves. An injection-recovery test on our real data shows that we detect transits of 1.3 ppt depth significantly in single light curves if the transit is fully covered, including out-of-transit data toward both sides, in some cases down to 0.7 ppt depth. For Kepler-94b, Kepler-63b, and K2-100b, we were able to verify the ephemeris. In the case of K2-138c with a 0.6 ppt deep transit, we were able to refine it, and in the case of K2-138e, we ruled out the transit in the time interval of more than ±1.5 σ of its current literature ephemeris.},
  language  = {en}
}
@article{FischerAndersSaalfrank2022,
  author    = {Fischer, Eric Wolfgang and Anders, Janet and Saalfrank, Peter},
  title     = {Cavity-altered thermal isomerization rates and dynamical resonant localization in vibro-polaritonic chemistry},
  series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  volume    = {156},
  journal   = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  number    = {15},
  publisher = {American Institute of Physics},
  address   = {Melville, NY},
  issn      = {0021-9606},
  doi       = {10.1063/5.0076434},
  pages     = {16},
  year      = {2022},
  abstract  = {It has been experimentally demonstrated that reaction rates for molecules embedded in microfluidic optical cavities are altered when compared to rates observed under "ordinary" reaction conditions. However, precise mechanisms of how strong coupling of an optical cavity mode to molecular vibrations affects the reactivity and how resonance behavior emerges are still under dispute. In the present work, we approach these mechanistic issues from the perspective of a thermal model reaction, the inversion of ammonia along the umbrella mode, in the presence of a single-cavity mode of varying frequency and coupling strength. A topological analysis of the related cavity Born-Oppenheimer potential energy surface in combination with quantum mechanical and transition state theory rate calculations reveals two quantum effects, leading to decelerated reaction rates in qualitative agreement with experiments: the stiffening of quantized modes perpendicular to the reaction path at the transition state, which reduces the number of thermally accessible reaction channels, and the broadening of the barrier region, which attenuates tunneling. We find these two effects to be very robust in a fluctuating environment, causing statistical variations of potential parameters, such as the barrier height. Furthermore, by solving the time-dependent Schrodinger equation in the vibrational strong coupling regime, we identify a resonance behavior, in qualitative agreement with experimental and earlier theoretical work. The latter manifests as reduced reaction probability when the cavity frequency omega(c) is tuned resonant to a molecular reactant frequency. We find this effect to be based on the dynamical localization of the vibro-polaritonic wavepacket in the reactant well.},
  language  = {en}
}
@article{WangZhangYanetal.2022,
  author    = {Wang, Feipeng and Zhang, Zheng and Yan, Yuyang and Shen, Zijia and Wang, Qiang and Gerhard, Reimund},
  title     = {Surface reconstruction on electro-spun PVA/PVP nanofibers by water evaporation},
  series = {Nanomaterials},
  volume    = {12},
  journal   = {Nanomaterials},
  number    = {5},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2079-4991},
  doi       = {10.3390/nano12050797},
  pages     = {7},
  year      = {2022},
  abstract  = {Tailoring the secondary surface morphology of electro-spun nanofibers has been highly desired, as such delicate structures equip nanofibers with distinct functions. Here, we report a simple strategy to directly reconstruct the surface of polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) nanofibers by water evaporation. The roughness and diameter of the nanofibers depend on the temperature during vacuum drying. Surface changes of the nanofibers from smooth to rough were observed at 55 degrees C, with a significant drop in nanofiber diameter. We attribute the formation of the secondary surface morphology to the intermolecular forces in the water vapor, including capillary and the compression forces, on the basis of the results from the Fourier-transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy. The strategy is universally effective for various electro-spun polymer nanofibers, thus opening up avenues toward more detailed and sophisticated structure design and implementation for nanofibers.},
  language  = {en}
}
@article{ToenjesKori2022,
  author    = {T{\"o}njes, Ralf and Kori, Hiroshi},
  title     = {Phase and frequency linear response theory for hyperbolic chaotic oscillators},
  series = {Chaos : an interdisciplinary journal of nonlinear science},
  volume    = {32},
  journal   = {Chaos : an interdisciplinary journal of nonlinear science},
  number    = {4},
  publisher = {AIP Publishing},
  address   = {Melville},
  issn      = {1054-1500},
  doi       = {10.1063/5.0064519},
  pages     = {13},
  year      = {2022},
  abstract  = {We formulate a linear phase and frequency response theory for hyperbolic flows, which generalizes phase response theory for autonomous limit cycle oscillators to hyperbolic chaotic dynamics. The theory is based on a shadowing conjecture, stating the existence of a perturbed trajectory shadowing every unperturbed trajectory on the system attractor for any small enough perturbation of arbitrary duration and a corresponding unique time isomorphism, which we identify as phase such that phase shifts between the unperturbed trajectory and its perturbed shadow are well defined. The phase sensitivity function is the solution of an adjoint linear equation and can be used to estimate the average change of phase velocity to small time dependent or independent perturbations. These changes in frequency are experimentally accessible, giving a convenient way to define and measure phase response curves for chaotic oscillators. The shadowing trajectory and the phase can be constructed explicitly in the tangent space of an unperturbed trajectory using co-variant Lyapunov vectors. It can also be used to identify the limits of the regime of linear response.},
  language  = {en}
}
@article{WulffMientusNowaketal.2022,
  author    = {Wulff, Peter and Mientus, Lukas and Nowak, Anna and Borowski, Andreas},
  title     = {Utilizing a pretrained language model (BERT) to classify preservice physics teachers' written reflections},
  series = {International journal of artificial intelligence in education},
  journal   = {International journal of artificial intelligence in education},
  number    = {33},
  publisher = {Springer},
  address   = {New York},
  issn      = {1560-4292},
  doi       = {10.1007/s40593-022-00290-6},
  pages     = {439 -- 466},
  year      = {2022},
  abstract  = {Computer-based analysis of preservice teachers' written reflections could enable educational scholars to design personalized and scalable intervention measures to support reflective writing. Algorithms and technologies in the domain of research related to artificial intelligence have been found to be useful in many tasks related to reflective writing analytics such as classification of text segments. However, mostly shallow learning algorithms have been employed so far. This study explores to what extent deep learning approaches can improve classification performance for segments of written reflections. To do so, a pretrained language model (BERT) was utilized to classify segments of preservice physics teachers' written reflections according to elements in a reflection-supporting model. Since BERT has been found to advance performance in many tasks, it was hypothesized to enhance classification performance for written reflections as well. We also compared the performance of BERT with other deep learning architectures and examined conditions for best performance. We found that BERT outperformed the other deep learning architectures and previously reported performances with shallow learning algorithms for classification of segments of reflective writing. BERT starts to outperform the other models when trained on about 20 to 30\% of the training data. Furthermore, attribution analyses for inputs yielded insights into important features for BERT's classification decisions. Our study indicates that pretrained language models such as BERT can boost performance for language-related tasks in educational contexts such as classification.},
  language  = {en}
}
@article{ZhaoYanLiuetal.2022,
  author    = {Zhao, Siqi Q. and Yan, Huirong and Liu, Terry Z. and Liu, Mingzhe and Wang, Huizi},
  title     = {Multispacecraft analysis of the properties of magnetohydrodynamic fluctuations in Sub-Alfvenic solar wind turbulence at 1 au},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {937},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  number    = {2},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.3847/1538-4357/ac822e},
  pages     = {14},
  year      = {2022},
  abstract  = {We present observations of three-dimensional magnetic power spectra in wavevector space to investigate the anisotropy and scalings of sub-Alfvenic solar wind turbulence at magnetohydrodynamic (MHD) scale using the Magnetospheric Multiscale spacecraft. The magnetic power distributions are organized in a new coordinate determined by wavevectors ((kappa) over cap) and background magnetic field ((b) over cap (0)) in Fourier space. This study utilizes two approaches to determine wavevectors: the singular value decomposition method and multispacecraft timing analysis. The combination of the two methods allows an examination of the properties of magnetic field fluctuations in terms of mode compositions without any spatiotemporal hypothesis. Observations show that fluctuations (delta B-perpendicular to 1) in the direction perpendicular to (kappa) over cap and (b) over cap (0) prominently cascade perpendicular to (b) over cap (0), and such anisotropy increases with wavenumbers. The reduced power spectra of 6.8 11 follow Goldreich-Sridhar scalings: (P) over cap (k(perpendicular to)) proportional to k(perpendicular to)(-5/3) and (P) over cap (k(parallel to)) proportional to k(parallel to)(-2). In contrast, fluctuations within the (k) over cap(b) over cap (0) plane show isotropic behaviors: perpendicular power distributions are approximately the same as parallel distributions. The reduced power spectra of fluctuations within the (k) over cap(b) over cap (0) plane follow the scalings (P) over cap (k(perpendicular to)) proportional to k(perpendicular to)(-3/2) and (P) over cap (k(parallel to)) proportional to k(parallel to)(-3/2). Comparing frequency-wavevector spectra with theoretical dispersion relations of MHD modes, we find that delta B-perpendicular to 1 are probably associated with Alfven modes. On the other hand, magnetic field fluctuations within the (k) over cap(b) over cap (0) plane more likely originate from fast modes based on their isotropic behaviors. The observations of anisotropy and scalings of different magnetic field components are consistent with the predictions of current compressible MHD theory. Moreover, for the Alfvenic component, the ratio of cascading time to the wave period is found to be a factor of a few, consistent with critical balance in the strong turbulence regime. These results are valuable for further studies of energy compositions of plasma turbulence and their effects on energetic particle transport.},
  language  = {en}
}
@article{KliemSeehafer2022,
  author    = {Kliem, Bernhard and Seehafer, Norbert},
  title     = {Helicity shedding by flux rope ejection},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {659},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361/202142422},
  pages     = {9},
  year      = {2022},
  abstract  = {We quantitatively address the conjecture that magnetic helicity must be shed from the Sun by eruptions launching coronal mass ejections in order to limit its accumulation in each hemisphere. By varying the ratio of guide and strapping field and the flux rope twist in a parametric simulation study of flux rope ejection from approximately marginally stable force-free equilibria, different ratios of self- and mutual helicity are set and the onset of the torus or helical kink instability is obtained. The helicity shed is found to vary over a broad range from a minor to a major part of the initial helicity, with self helicity being largely or completely shed and mutual helicity, which makes up the larger part of the initial helicity, being shed only partly. Torus-unstable configurations with subcritical twist and without a guide field shed up to about two-thirds of the initial helicity, while a highly twisted, kink-unstable configuration sheds only about one-quarter. The parametric study also yields stable force-free flux rope equilibria up to a total flux-normalized helicity of 0.25, with a ratio of self- to total helicity of 0.32 and a ratio of flux rope to external poloidal flux of 0.94. These results numerically demonstrate the conjecture of helicity shedding by coronal mass ejections and provide a first account of its parametric dependence. Both self- and mutual helicity are shed significantly; this reduces the total initial helicity by a fraction of ∼0.4--0.65 for typical source region parameters.},
  language  = {en}
}
@article{FosterPoppenhaegerIlićPetkovićetal.2022,
  author    = {Foster, Mary Grace and Poppenh{\"a}ger, Katja and Ilić Petković, Nikoleta and Schwope, Axel},
  title     = {Exoplanet X-ray irradiation and evaporation rates with eROSITA},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {661},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361/202141097},
  pages     = {11},
  year      = {2022},
  abstract  = {High-energy irradiation is a driver for atmospheric evaporation and mass loss in exoplanets. This work is based on data from eROSITA, the soft X-ray instrument on board the Spectrum Roentgen Gamma mission, as well as on archival data from other missions. We aim to characterise the high-energy environment of known exoplanets and estimate their mass-loss rates. We use X-ray source catalogues from eROSITA, XMM-Newton, Chandra, and ROSAT to derive X-ray luminosities of exoplanet host stars in the 0.2-2 keV energy band with an underlying coronal, that is, optically thin thermal spectrum. We present a catalogue of stellar X-ray and EUV luminosities, exoplanetary X-ray and EUV irradiation fluxes, and estimated mass-loss rates for a total of 287 exoplanets, 96 of which are characterised for the first time based on new eROSITA detections. We identify 14 first-time X-ray detections of transiting exoplanets that are subject to irradiation levels known to cause observable evaporation signatures in other exoplanets. This makes them suitable targets for follow-up observations.},
  language  = {en}
}
@article{TockhornSutterCruzBournazouetal.2022,
  author    = {Tockhorn, Philipp and Sutter, Johannes and Cruz Bournazou, Alexandros and Wagner, Philipp and J{\"a}ger, Klaus and Yoo, Danbi and Lang, Felix and Grischek, Max and Li, Bor and Li, Jinzhao and Shargaieva, Oleksandra and Unger, Eva and Al-Ashouri, Amran and K{\"o}hnen, Eike and Stolterfoht, Martin and Neher, Dieter and Schlatmann, Rutger and Rech, Bernd and Stannowski, Bernd and Albrecht, Steve and Becker, Christiane},
  title     = {Nano-optical designs for high-efficiency monolithic perovskite-silicon tandem solar cells},
  series = {Nature nanotechnology},
  volume    = {17},
  journal   = {Nature nanotechnology},
  number    = {11},
  publisher = {Nature Publishing Group},
  address   = {London [u.a.]},
  issn      = {1748-3387},
  doi       = {10.1038/s41565-022-01228-8},
  pages     = {1214 -- 1221},
  year      = {2022},
  abstract  = {Designing gentle sinusoidal nanotextures enables the realization of high-efficiency perovskite-silicon solar cells <br /> Perovskite-silicon tandem solar cells offer the possibility of overcoming the power conversion efficiency limit of conventional silicon solar cells. Various textured tandem devices have been presented aiming at improved optical performance, but optimizing film growth on surface-textured wafers remains challenging. Here we present perovskite-silicon tandem solar cells with periodic nanotextures that offer various advantages without compromising the material quality of solution-processed perovskite layers. We show a reduction in reflection losses in comparison to planar tandems, with the new devices being less sensitive to deviations from optimum layer thicknesses. The nanotextures also enable a greatly increased fabrication yield from 50\% to 95\%. Moreover, the open-circuit voltage is improved by 15 mV due to the enhanced optoelectronic properties of the perovskite top cell. Our optically advanced rear reflector with a dielectric buffer layer results in reduced parasitic absorption at near-infrared wavelengths. As a result, we demonstrate a certified power conversion efficiency of 29.80\%.},
  language  = {en}
}
@article{WalkerBoyntonShpritsetal.2022,
  author    = {Walker, Simon N. and Boynton, Richard J. and Shprits, Yuri and Balikhin, Michael A. and Drozdov, Alexander},
  title     = {Forecast of the energetic electron environment of the radiation belts},
  series = {Space Weather: The International Journal of Research and Applications},
  volume    = {20},
  journal   = {Space Weather: The International Journal of Research and Applications},
  number    = {12},
  publisher = {American Geophysical Union},
  address   = {Washington},
  issn      = {1542-7390},
  doi       = {10.1029/2022SW003124},
  pages     = {21},
  year      = {2022},
  abstract  = {Different modeling methodologies possess different strengths and weakness. For instance, data based models may provide superior accuracy but have a limited spatial coverage while physics based models may provide lower accuracy but provide greater spatial coverage. This study investigates the coupling of a data based model of the electron fluxes at geostationary orbit (GEO) with a numerical model of the radiation belt region to improve the resulting forecasts/pastcasts of electron fluxes over the whole radiation belt region. In particular, two coupling methods are investigated. The first assumes an average value for L* for GEO, namely LGEO* L-GEO* = 6.2. The second uses a value of L* that varies with geomagnetic activity, quantified using the Kp index. As the terrestrial magnetic field responds to variations in geomagnetic activity, the value of L* will vary for a specific location. In this coupling method, the value of L* is calculated using the Kp driven Tsyganenko 89c magnetic field model for field line tracing. It is shown that this addition can result in changes in the initialization of the parameters at the Versatile Electron Radiation Belt model outer boundary. Model outputs are compared to Van Allen Probes MagEIS measurements of the electron fluxes in the inner magnetosphere for the March 2015 geomagnetic storm. It is found that the fixed LGEO* L-GEO* coupling method produces a more realistic forecast.},
  language  = {en}
}
@article{LewensteinCirauquiAngelGarciaMarchetal.2022,
  author    = {Lewenstein, Maciej and Cirauqui, David and Angel Garcia-March, Miguel and Corominas, Guillem Guigo and Grzybowski, Przemyslaw and Saavedra, Jose R. M. and Wilkens, Martin and Wehr, Jan},
  title     = {Haake-Lewenstein-Wilkens approach to spin-glasses revisited},
  series = {Journal of physics : A, Mathematical and theoretical},
  volume    = {55},
  journal   = {Journal of physics : A, Mathematical and theoretical},
  number    = {45},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1751-8113},
  doi       = {10.1088/1751-8121/ac9d10},
  pages     = {20},
  year      = {2022},
  abstract  = {We revisit the Haake-Lewenstein-Wilkens approach to Edwards-Anderson (EA) model of Ising spin glass (SG) (Haake et al 1985 Phys. Rev. Lett. 55 2606). This approach consists in evaluation and analysis of the probability distribution of configurations of two replicas of the system, averaged over quenched disorder. This probability distribution generates squares of thermal copies of spin variables from the two copies of the systems, averaged over disorder, that is the terms that enter the standard definition of the original EA order parameter, qEA 0 0},
  language  = {en}
}
@article{RamanVenkatesanWuebbenhorstGerhard2022,
  author    = {Raman Venkatesan, Thulasinath and W{\"u}bbenhorst, Michael and Gerhard, Reimund},
  title     = {Structure-property relationships in three-phase relaxor-ferroelectric terpolymers},
  series = {Ferroelectrics},
  volume    = {586},
  journal   = {Ferroelectrics},
  number    = {1},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0015-0193},
  doi       = {10.1080/00150193.2021.2014260},
  pages     = {60 -- 81},
  year      = {2022},
  abstract  = {Poly(vinylidenefluoride-trifluoroethylene)-based (P(VDF-TrFE)-based) terpolymers represent a new class of electroactive polymer materials that are relaxor-ferroelectric (RF) polymers and that offer unique and attractive property combinations in comparison with conventional ferroelectric polymers. The RF state is achieved by introducing a fluorine-containing termonomer as a "defect" into the ferroelectric P(VDF-TrFE) copolymer, which reduces the interaction between the VDF/TrFE dipoles. The resulting terpolymer exhibits a low Curie transition temperature and small remanent and coercive fields yielding a slim hysteresis loop that is typical for RF materials. Though the macroscopic behavior is similar to RF ceramics, the mechanisms of relaxor ferroelectricity in semi-crystalline polymers are different and not fully understood yet. Structure-property relationships play an important role in RF terpolymers, as they govern the final RF properties. Hence, a review of important characteristics, previous studies and relevant developments of P(VDF-TrFE)-based terfluoropolymers with either chlorofluoroethylene (CFE) or chlorotrifluoroethylene (CTFE) as the termonomer is deemed useful. The role of the termonomer and of its composition, as well as the effects of the processing conditions on the semi-crystalline structure which in turn affects the final RF properties are discussed in detail. In addition, the presence of noteworthy transition(s) in the mid-temperature range and the influence of preparation conditions on those transitions are reviewed. A better understanding of the fundamental aspects affecting the semi-crystalline structures will help to elucidate the nature of RF activity in VDF-based terpolymers and also help to further improve their applications-relevant electroactive properties.},
  language  = {en}
}
@article{SmirnovShpritsAllisonetal.2022,
  author    = {Smirnov, Artem and Shprits, Yuri and Allison, Hayley and Aseev, Nikita and Drozdov, Alexander and Kollmann, Peter and Wang, Dedong and Saikin, Anthony},
  title     = {An empirical model of the equatorial electron pitch angle distributions in earth's outer radiation belt},
  series = {Space Weather: the International Journal of Research and Applications},
  volume    = {20},
  journal   = {Space Weather: the International Journal of Research and Applications},
  number    = {9},
  publisher = {American Geophysical Union},
  address   = {Washington, DC},
  issn      = {1542-7390},
  doi       = {10.1029/2022SW003053},
  pages     = {17},
  year      = {2022},
  abstract  = {In this study, we present an empirical model of the equatorial electron pitch angle distributions (PADs) in the outer radiation belt based on the full data set collected by the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes in 2012-2019. The PADs are fitted with a combination of the first, third and fifth sine harmonics. The resulting equation resolves all PAD types found in the outer radiation belt (pancake, flat-top, butterfly and cap PADs) and can be analytically integrated to derive omnidirectional flux. We introduce a two-step modeling procedure that for the first time ensures a continuous dependence on L, magnetic local time and activity, parametrized by the solar wind dynamic pressure. We propose two methods to reconstruct equatorial electron flux using the model. The first approach requires two uni-directional flux observations and is applicable to low-PA data. The second method can be used to reconstruct the full equatorial PADs from a single uni- or omnidirectional measurement at off-equatorial latitudes. The model can be used for converting the long-term data sets of electron fluxes to phase space density in terms of adiabatic invariants, for physics-based modeling in the form of boundary conditions, and for data assimilation purposes.},
  language  = {en}
}
@article{DebPopovaJaffresetal.2022,
  author    = {Deb, Marwan and Popova, Elena and Jaffr{\`e}s, Henri-Yves and Keller, Niels and Bargheer, Matias},
  title     = {Polarization-dependent subpicosecond demagnetization in iron garnets},
  series = {Physical review : B, covering condensed matter and materials physics},
  volume    = {106},
  journal   = {Physical review : B, covering condensed matter and materials physics},
  number    = {18},
  publisher = {American Institute of Physics, American Physical Society},
  address   = {Woodbury, NY},
  issn      = {2469-9950},
  doi       = {10.1103/PhysRevB.106.184416},
  pages     = {7},
  year      = {2022},
  abstract  = {Controlling the magnetization dynamics at the fastest speed is a major issue of fundamental condensed matter physics and its applications for data storage and processing technologies. It requires a deep understanding of the interactions between the degrees of freedom in solids, such as spin, electron, and lattice as well as their responses to external stimuli. In this paper, we systematically investigate the fluence dependence of ultrafast magnetization dynamics induced by below-bandgap ultrashort laser pulses in the ferrimagnetic insulators BixY3-xFe5O12 with 1 xBi 3. We demonstrate subpicosecond demagnetization dynamics in this material followed by a very slow remagnetization process. We prove that this demagnetization results from an ultrafast heating of iron garnets by two-photon absorption (TPA), suggesting a phonon-magnon thermalization time of 0.6 ps. We explain the slow remagnetization timescale by the low phonon heat conductivity in garnets. Additionally, we show that the amplitudes of the demagnetization, optical change, and lattice strain can be manipulated by changing the ellipticity of the pump pulses. We explain this phenomenon considering the TPA circular dichroism. These findings open exciting prospects for ultrafast manipulation of spin, charge, and lattice dynamics in magnetic insulators by ultrafast nonlinear optics.},
  language  = {en}
}
@article{PietzschNiskanenVazdaCruzetal.2022,
  author    = {Pietzsch, Annette and Niskanen, Johannes and Vaz da Cruz, Vinicius and B{\"u}chner, Robby and Eckert, Sebastian and Fondell, Mattis and Jay, Raphael Martin and Lu, Xingye and McNally, Daniel and Schmitt, Thorsten and F{\"o}hlisch, Alexander},
  title     = {Cuts through the manifold of molecular H2O potential energy surfaces in liquid water at ambient conditions},
  series = {Proceedings of the National Academy of Sciences of the United States of America},
  volume    = {119},
  journal   = {Proceedings of the National Academy of Sciences of the United States of America},
  number    = {28},
  publisher = {National Acad. of Sciences},
  address   = {Washington, DC},
  issn      = {1091-6490},
  doi       = {10.1073/pnas.2118101119},
  pages     = {6},
  year      = {2022},
  abstract  = {The fluctuating hydrogen bridge bonded network of liquid water at ambient conditions entails a varied ensemble of the underlying constituting H2O molecular moieties. This is mirrored in a manifold of the H2O molecular potentials. Subnatural line width resonant inelastic X-ray scattering allowed us to quantify the manifold of molecular potential energy surfaces along the H2O symmetric normal mode and the local asymmetric O-H bond coordinate up to 1 and 1.5 angstrom, respectively. The comparison of the single H2O molecular potentials and spectroscopic signatures with the ambient conditions liquid phase H2O molecular potentials is done on various levels. In the gas phase, first principles, Morse potentials, and stepwise harmonic potential reconstruction have been employed and benchmarked. In the liquid phase the determination of the potential energy manifold along the local asymmetric O-H bond coordinate from resonant inelastic X-ray scattering via the bound state oxygen ls to 4a(1) resonance is treated within these frameworks. The potential energy surface manifold along the symmetric stretch from resonant inelastic X-ray scattering via the oxygen 1 s to 2b(2) resonance is based on stepwise harmonic reconstruction. We find in liquid water at ambient conditions H2O molecular potentials ranging from the weak interaction limit to strongly distorted potentials which are put into perspective to established parameters, i.e., intermolecular O-H, H-H, and O-O correlation lengths from neutron scattering.},
  language  = {en}
}
@article{DebPopovaJaffresetal.2022,
  author    = {Deb, Marwan and Popova, Elena and Jaffr{\`e}s, Henri-Yves and Keller, Niels and Bargheer, Matias},
  title     = {Controlling high-frequency spin-wave dynamics using double-pulse laser excitation},
  series = {Physical review applied},
  volume    = {18},
  journal   = {Physical review applied},
  number    = {4},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {2331-7019},
  doi       = {10.1103/PhysRevApplied.18.044001},
  pages     = {7},
  year      = {2022},
  abstract  = {Manipulating spin waves is highly required for the development of innovative data transport and processing technologies. Recently, the possibility of triggering high-frequency standing spin waves in magnetic insulators using femtosecond laser pulses was discovered, raising the question about how one can manipulate their dynamics. Here we explore this question by investigating the ultrafast magnetiza-tion and spin-wave dynamics induced by double-pulse laser excitation. We demonstrate a suppression or enhancement of the amplitudes of the standing spin waves by precisely tuning the time delay between the two pulses. The results can be understood as the constructive or destructive interference of the spin waves induced by the first and second laser pulses. Our findings open exciting perspectives towards generating single-mode standing spin waves that combine high frequency with large amplitude and low magnetic damping.},
  language  = {en}
}
@article{PoelkingBenduhnSpoltoreetal.2022,
  author    = {Poelking, Carl and Benduhn, Johannes and Spoltore, Donato and Schwarze, Martin and Roland, Steffen and Piersimoni, Fortunato and Neher, Dieter and Leo, Karl and Vandewal, Koen and Andrienko, Denis},
  title     = {Open-circuit voltage of organic solar cells},
  series = {Communications physics},
  volume    = {5},
  journal   = {Communications physics},
  number    = {1},
  publisher = {Nature portfolio},
  address   = {Berlin},
  issn      = {2399-3650},
  doi       = {10.1038/s42005-022-01084-x},
  pages     = {7},
  year      = {2022},
  abstract  = {Organic photovoltaics (PV) is an energy-harvesting technology that offers many advantages, such as flexibility, low weight and cost, as well as environmentally benign materials and manufacturing techniques. Despite growth of power conversion efficiencies to around 19 \% in the last years, organic PVs still lag behind inorganic PV technologies, mainly due to high losses in open-circuit voltage. Understanding and improving open circuit voltage in organic solar cells is challenging, as it is controlled by the properties of a donor-acceptor interface where the optical excitations are separated into charge carriers. Here, we provide an electrostatic model of a rough donor-acceptor interface and test it experimentally on small molecule PV materials systems. The model provides concise relationships between the open-circuit voltage, photovoltaic gap, charge-transfer state energy, and interfacial morphology. In particular, we show that the electrostatic bias generated across the interface reduces the photovoltaic gap. This negative influence on open-circuit voltage can, however, be circumvented by adjusting the morphology of the donor-acceptor interface. Organic solar cells, despite their high power conversion efficiencies, suffer from open circuit voltage losses making them less appealing in terms of applications. Here, the authors, supported with experimental data on small molecule photovoltaic cells, relate open circuit voltage to photovoltaic gap, charge-transfer state energy, and donor-acceptor interfacial morphology.},
  language  = {en}
}
@article{KoelschDietrichUjevicetal.2022,
  author    = {K{\"o}lsch, Maximilian and Dietrich, Tim and Ujevic, Maximiliano and Br{\"u}gmann, Bernd},
  title     = {Investigating the mass-ratio dependence of the prompt-collapse threshold with numerical-relativity simulations},
  series = {Physical review : D, Particles, fields, gravitation, and cosmology},
  volume    = {106},
  journal   = {Physical review : D, Particles, fields, gravitation, and cosmology},
  number    = {4},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {2470-0010},
  doi       = {10.1103/PhysRevD.106.044026},
  pages     = {27},
  year      = {2022},
  abstract  = {The next observing runs of advanced gravitational-wave detectors will lead to a variety of binary neutron star detections and numerous possibilities for multimessenger observations of binary neutron star systems. In this context a clear understanding of the merger process and the possibility of prompt black hole formation after merger is important, as the amount of ejected material strongly depends on the merger dynamics. These dynamics are primarily affected by the total mass of the binary, however, the mass ratio also influences the postmerger evolution. To determine the effect of the mass ratio, we investigate the parameter space around the prompt-collapse threshold with a new set of fully relativistic simulations. The simulations cover three equations of state and seven mass ratios in the range of 1.0 <= q <= 1.75, with five to seven simulations of binary systems of different total mass in each case. The threshold mass is determined through an empirical relation based on the collapse time, which allows us to investigate effects of the mass ratio on the threshold mass and also on the properties of the remnant system. Furthermore, we model effects of mass ratio and equation of state on tidal parameters of threshold configurations.},
  language  = {en}
}
@article{SchaffenrothPelisoliBarlowetal.2022,
  author    = {Schaffenroth, Veronika and Pelisoli, Ingrid and Barlow, Brad N. and Geier, Stephan and Kupfer, Thomas},
  title     = {Hot subdwarfs in close binaries observed from space I.},
  series = {Astronomy and astrophysics : an international weekly journal},
  volume    = {666},
  journal   = {Astronomy and astrophysics : an international weekly journal},
  publisher = {EDP Sciences},
  address   = {Les Ulis},
  issn      = {0004-6361},
  doi       = {10.1051/0004-6361/202244214},
  pages     = {19},
  year      = {2022},
  abstract  = {Context: About a third of the hot subdwarfs of spectral type B (sdBs), which are mostly core-helium-burning objects on the extreme horizontal branch, are found in close binaries with cool, low-mass stellar, substellar, or white dwarf companions. They can show light variations due to di fferent phenomena. Aims: Many hot subdwarfs now have space-based light curves with a high signal-to-noise ratio available. We used light curves from the Transiting Exoplanet Survey Satellite and the K2 space mission to look for more sdB binaries. Their light curves can be used to study the hot subdwarf primaries and their companions, and obtained orbital, atmospheric, and absolute parameters for those systems, when combined with other analysis methods. Methods: By classifying the light variations and combining these with the fit of the spectral energy distribution, the distance derived by the parallaxes obtained by Gaia, and the atmospheric parameters, mainly from the literature, we could derive the nature of the primaries and secondaries in 122 (75\%) of the known sdB binaries and 82 newly found reflection e ffect systems. We derived absolute masses, radii, and luminosities for a total of 39 hot subdwarfs with cool, low-mass companions, as well 29 known and newly found sdBs with white dwarf companions. Results: The mass distribution of hot subdwarfs with cool, low-mass stellar and substellar companions, di ffers from those with white dwarf companions, implying they come from di fferent populations. By comparing the period and minimum companion mass distributions, we find that the reflection e ffect systems all have M dwarf or brown dwarf companions, and that there seem to be several di fferent populations of hot subdwarfs with white dwarf binaries - one with white dwarf minimum masses around 0.4 M-circle dot, one with longer periods and minimum companion masses up to 0.6 M-circle dot, and at the shortest period, another with white dwarf minimum masses around 0.8 M-circle dot. We also derive the first orbital period distribution for hot subdwarfs with cool, low-mass stellar or substellar systems selected from light variations instead of radial velocity variations. It shows a narrower period distribution, from 1.5 h to 35 h, compared to the distribution of hot subdwarfs with white dwarfs, which ranges from 1 h to 30 days. These period distributions can be used to constrain the previous common-envelope phase.},
  language  = {en}
}
@article{AdolfsHoqueShprits2022,
  author    = {Adolfs, Marjolijn and Hoque, Mohammed Mainul and Shprits, Yuri},
  title     = {Storm-time relative total electron content modelling using machine learning techniques},
  series = {Remote sensing},
  volume    = {14},
  journal   = {Remote sensing},
  number    = {23},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2072-4292},
  doi       = {10.3390/rs14236155},
  pages     = {17},
  year      = {2022},
  abstract  = {Accurately predicting total electron content (TEC) during geomagnetic storms is still a challenging task for ionospheric models. In this work, a neural-network (NN)-based model is proposed which predicts relative TEC with respect to the preceding 27-day median TEC, during storm time for the European region (with longitudes 30 degrees W-50 degrees E and latitudes 32.5 degrees N-70 degrees N). The 27-day median TEC (referred to as median TEC), latitude, longitude, universal time, storm time, solar radio flux index F10.7, global storm index SYM-H and geomagnetic activity index Hp30 are used as inputs and the output of the network is the relative TEC. The relative TEC can be converted to the actual TEC knowing the median TEC. The median TEC is calculated at each grid point over the European region considering data from the last 27 days before the storm using global ionosphere maps (GIMs) from international GNSS service (IGS) sources. A storm event is defined when the storm time disturbance index Dst drops below 50 nanotesla. The model was trained with storm-time relative TEC data from the time period of 1998 until 2019 (2015 is excluded) and contains 365 storms. Unseen storm data from 33 storm events during 2015 and 2020 were used to test the model. The UQRG GIMs were used because of their high temporal resolution (15 min) compared to other products from different analysis centers. The NN-based model predictions show the seasonal behavior of the storms including positive and negative storm phases during winter and summer, respectively, and show a mixture of both phases during equinoxes. The model's performance was also compared with the Neustrelitz TEC model (NTCM) and the NN-based quiet-time TEC model, both developed at the German Aerospace Agency (DLR). The storm model has a root mean squared error (RMSE) of 3.38 TEC units (TECU), which is an improvement by 1.87 TECU compared to the NTCM, where an RMSE of 5.25 TECU was found. This improvement corresponds to a performance increase by 35.6\%. The storm-time model outperforms the quiet-time model by 1.34 TECU, which corresponds to a performance increase by 28.4\% from 4.72 to 3.38 TECU. The quiet-time model was trained with Carrington averaged TEC and, therefore, is ideal to be used as an input instead of the GIM derived 27-day median. We found an improvement by 0.8 TECU which corresponds to a performance increase by 17\% from 4.72 to 3.92 TECU for the storm-time model using the quiet-time-model predicted TEC as an input compared to solely using the quiet-time model.},
  language  = {en}
}
@article{MoldenhawerMorenoSchindleretal.2022,
  author    = {Moldenhawer, Ted and Moreno, Eduardo and Schindler, Daniel and Flemming, Sven and Holschneider, Matthias and Huisinga, Wilhelm and Alonso, Sergio and Beta, Carsten},
  title     = {Spontaneous transitions between amoeboid and keratocyte-like modes of migration},
  series = {Frontiers in Cell and Developmental Biology},
  volume    = {10},
  journal   = {Frontiers in Cell and Developmental Biology},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2296-634X},
  doi       = {10.3389/fcell.2022.898351},
  pages     = {13},
  year      = {2022},
  abstract  = {The motility of adherent eukaryotic cells is driven by the dynamics of the actin cytoskeleton. Despite the common force-generating actin machinery, different cell types often show diverse modes of locomotion that differ in their shape dynamics, speed, and persistence of motion. Recently, experiments in Dictyostelium discoideum have revealed that different motility modes can be induced in this model organism, depending on genetic modifications, developmental conditions, and synthetic changes of intracellular signaling. Here, we report experimental evidence that in a mutated D. discoideum cell line with increased Ras activity, switches between two distinct migratory modes, the amoeboid and fan-shaped type of locomotion, can even spontaneously occur within the same cell. We observed and characterized repeated and reversible switchings between the two modes of locomotion, suggesting that they are distinct behavioral traits that coexist within the same cell. We adapted an established phenomenological motility model that combines a reaction-diffusion system for the intracellular dynamics with a dynamic phase field to account for our experimental findings.},
  language  = {en}
}
@article{MorenoGrossmannBetaetal.2022,
  author    = {Moreno, Eduardo and Großmann, Robert and Beta, Carsten and Alonso, Sergio},
  title     = {From single to collective motion of social amoebae},
  series = {Frontiers in physics},
  volume    = {9},
  journal   = {Frontiers in physics},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2296-424X},
  doi       = {10.3389/fphy.2021.750187},
  pages     = {17},
  year      = {2022},
  abstract  = {The coupling of the internal mechanisms of cell polarization to cell shape deformations and subsequent cell crawling poses many interdisciplinary scientific challenges. Several mathematical approaches have been proposed to model the coupling of both processes, where one of the most successful methods relies on a phase field that encodes the morphology of the cell, together with the integration of partial differential equations that account for the polarization mechanism inside the cell domain as defined by the phase field. This approach has been previously employed to model the motion of single cells of the social amoeba Dictyostelium discoideum, a widely used model organism to study actin-driven motility and chemotaxis of eukaryotic cells. Besides single cell motility, Dictyostelium discoideum is also well-known for its collective behavior. Here, we extend the previously introduced model for single cell motility to describe the collective motion of large populations of interacting amoebae by including repulsive interactions between the cells. We performed numerical simulations of this model, first characterizing the motion of single cells in terms of their polarity and velocity vectors. We then systematically studied the collisions between two cells that provided the basic interaction scenarios also observed in larger ensembles of interacting amoebae. Finally, the relevance of the cell density was analyzed, revealing a systematic decrease of the motility with density, associated with the formation of transient cell clusters that emerge in this system even though our model does not include any attractive interactions between cells. This model is a prototypical active matter system for the investigation of the emergent collective dynamics of deformable, self-driven cells with a highly complex, nonlinear coupling of cell shape deformations, self-propulsion and repulsive cell-cell interactions. Understanding these self-organization processes of cells like their autonomous aggregation is of high relevance as collective amoeboid motility is part of wound healing, embryonic morphogenesis or pathological processes like the spreading of metastatic cancer cells.},
  language  = {en}
}
@article{KranjcHorvatWienerSchmelingetal.2022,
  author    = {Kranjc Horvat, Anja and Wiener, Jeff and Schmeling, Sascha and Borowski, Andreas},
  title     = {Learning goals of professional development programs at science research institutions},
  series = {Journal of science teacher education : the official journal of the Association for the Education of Teachers in Science},
  volume    = {33},
  journal   = {Journal of science teacher education : the official journal of the Association for the Education of Teachers in Science},
  number    = {1},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {1046-560X},
  doi       = {10.1080/1046560X.2021.1905330},
  pages     = {32 -- 54},
  year      = {2022},
  abstract  = {Effective professional development programs (PDPs) rely on well-defined goals. However, recent studies on PDPs have not explored the goals from a multi-stakeholder perspective. This study identifies the most important learning goals of PDPs at science research institutions as perceived by four groups of stakeholders, namely teachers, education researchers, government representatives, and research scientists. Altogether, over 100 stakeholders from 42 countries involved in PDPs at science research institutions in Europe and North America participated in a three-round Delphi study. In the first round, the stakeholders provided their opinions on what they thought the learning goals of PDPs should be through an open-ended questionnaire. In the second and third rounds, the stakeholders assessed the importance of the learning goals that emerged from the first round by rating and ranking them, respectively. The outcome of the study is a hierarchical list of the ten most important learning goals of PDPs at particle physics laboratories. The stakeholders identified enhancing teachers' knowledge of scientific concepts and models and enhancing their knowledge of the curricula as the most important learning goals. Furthermore, the results show strong agreement between all the stakeholder groups regarding the defined learning goals. Indeed, all groups ranked the learning goals by their perceived importance almost identically. These outcomes could help policymakers establish more specific policies for PDPs. Additionally, they provide PDP practitioners at science research institutions with a solid base for future research and planning endeavors.},
  language  = {en}
}
@article{VinodCherstvyMetzleretal.2022,
  author    = {Vinod, Deepak and Cherstvy, Andrey G. and Metzler, Ralf and Sokolov, Igor M.},
  title     = {Time-averaging and nonergodicity of reset geometric Brownian motion with drift},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {106},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  number    = {3},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {2470-0045},
  doi       = {10.1103/PhysRevE.106.034137},
  pages     = {36},
  year      = {2022},
  abstract  = {How do near-bankruptcy events in the past affect the dynamics of stock-market prices in the future? Specifically, what are the long-time properties of a time-local exponential growth of stock-market prices under the influence of stochastically occurring economic crashes? Here, we derive the ensemble- and time-averaged properties of the respective "economic" or geometric Brownian motion (GBM) with a nonzero drift exposed to a Poissonian constant-rate price-restarting process of "resetting." We examine-based both on thorough analytical calculations and on findings from systematic stochastic computer simulations-the general situation of reset GBM with a nonzero [positive] drift and for all special cases emerging for varying parameters of drift, volatility, and reset rate in the model. We derive and summarize all short- and long-time dependencies for the mean-squared displacement (MSD), the variance, and the mean time-averaged MSD (TAMSD) of the process of Poisson-reset GBM under the conditions of both rare and frequent resetting. We consider three main regions of model parameters and categorize the crossovers between different functional behaviors of the statistical quantifiers of this process. The analytical relations are fully supported by the results of computer simulations. In particular, we obtain that Poisson-reset GBM is a nonergodic stochastic process, with generally MSD(Delta) not equal TAMSD(Delta) and Variance(Delta) not equal TAMSD(Delta) at short lag times Delta and for long trajectory lengths T. We investigate the behavior of the ergodicity-breaking parameter in each of the three regions of parameters and examine its dependence on the rate of reset at Delta/T << 1. Applications of these theoretical results to the analysis of prices of reset-containing options are pertinent.},
  language  = {en}
}
@article{SecklerMetzler2022,
  author    = {Seckler, Henrik and Metzler, Ralf},
  title     = {Bayesian deep learning for error estimation in the analysis of anomalous diffusion},
  series = {Nature Communications},
  volume    = {13},
  journal   = {Nature Communications},
  number    = {1},
  publisher = {Nature portfolio},
  address   = {Berlin},
  issn      = {2041-1723},
  doi       = {10.1038/s41467-022-34305-6},
  pages     = {13},
  year      = {2022},
  abstract  = {Modern single-particle-tracking techniques produce extensive time-series of diffusive motion in a wide variety of systems, from single-molecule motion in living-cells to movement ecology. The quest is to decipher the physical mechanisms encoded in the data and thus to better understand the probed systems. We here augment recently proposed machine-learning techniques for decoding anomalous-diffusion data to include an uncertainty estimate in addition to the predicted output. To avoid the Black-Box-Problem a Bayesian-Deep-Learning technique named Stochastic-Weight-Averaging-Gaussian is used to train models for both the classification of the diffusion model and the regression of the anomalous diffusion exponent of single-particle-trajectories. Evaluating their performance, we find that these models can achieve a well-calibrated error estimate while maintaining high prediction accuracies. In the analysis of the output uncertainty predictions we relate these to properties of the underlying diffusion models, thus providing insights into the learning process of the machine and the relevance of the output. <br /> Diffusive motions in complex environments such as living biological cells or soft matter systems can be analyzed with single-particle-tracking approaches, where accuracy of output may vary. The authors involve a machine-learning technique for decoding anomalous-diffusion data and provide an uncertainty estimate together with predicted output.},
  language  = {en}
}
@phdthesis{Kotz2022,
  author    = {Kotz, Maximilian},
  title     = {The economic costs of climate change},
  school      = {Universit{\"a}t Potsdam},
  pages     = {279},
  year      = {2022},
  language  = {en}
}
@article{AndersSaitHorsley2022,
  author    = {Anders, Janet and Sait, Connor R. J. and Horsley, Simon A. R.},
  title     = {Quantum Brownian motion for magnets},
  series = {New journal of physics : the open-access journal for physics},
  volume    = {24},
  journal   = {New journal of physics : the open-access journal for physics},
  number    = {3},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/ac4ef2},
  pages     = {21},
  year      = {2022},
  abstract  = {Spin precession in magnetic materials is commonly modelled with the classical phenomenological Landau-Lifshitz-Gilbert (LLG) equation. Based on a quantized three-dimensional spin + environment Hamiltonian, we here derive a spin operator equation of motion that describes precession and includes a general form of damping that consistently accounts for memory, coloured noise and quantum statistics. The LLG equation is recovered as its classical, Ohmic approximation. We further introduce resonant Lorentzian system-reservoir couplings that allow a systematic comparison of dynamics between Ohmic and non-Ohmic regimes. Finally, we simulate the full non-Markovian dynamics of a spin in the semi-classical limit. At low temperatures, our numerical results demonstrate a characteristic reduction and flattening of the steady state spin alignment with an external field, caused by the quantum statistics of the environment. The results provide a powerful framework to explore general three-dimensional dissipation in quantum thermodynamics.},
  language  = {en}
}
@phdthesis{Schlemm2022,
  author    = {Schlemm, Tanja},
  title     = {The marine ice cliff instability of the Antarctic ice sheet},
  doi       = {10.25932/publishup-58633},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-586333},
  school      = {Universit{\"a}t Potsdam},
  pages     = {107},
  year      = {2022},
  abstract  = {The Antarctic ice sheet is the largest freshwater reservoir worldwide. If it were to melt completely, global sea levels would rise by about 58 m. Calculation of projections of the Antarctic contribution to sea level rise under global warming conditions is an ongoing effort which yields large ranges in predictions. Among the reasons for this are uncertainties related to the physics of ice sheet modeling. These uncertainties include two processes that could lead to runaway ice retreat: the Marine Ice Sheet Instability (MISI), which causes rapid grounding line retreat on retrograde bedrock, and the Marine Ice Cliff Instability (MICI), in which tall ice cliffs become unstable and calve off, exposing even taller ice cliffs. In my thesis, I investigated both marine instabilities (MISI and MICI) using the Parallel Ice Sheet Model (PISM), with a focus on MICI.},
  language  = {en}
}
@article{MauRosenblum2022,
  author    = {Mau, Erik Thomas Klaus and Rosenblum, Michael},
  title     = {Optimizing charge-balanced pulse stimulation for desynchronization},
  series = {Chaos : an interdisciplinary journal of nonlinear science},
  volume    = {32},
  journal   = {Chaos : an interdisciplinary journal of nonlinear science},
  number    = {1},
  publisher = {AIP},
  address   = {Melville},
  issn      = {1054-1500},
  doi       = {10.1063/5.0070036},
  pages     = {15},
  year      = {2022},
  abstract  = {Collective synchronization in a large population of self-sustained units appears both in natural and engineered systems. Sometimes this effect is in demand, while in some cases, it is undesirable, which calls for control techniques. In this paper, we focus on pulsatile control, with the goal to either increase or decrease the level of synchrony. We quantify this level by the entropy of the phase distribution. Motivated by possible applications in neuroscience, we consider pulses of a realistic shape. Exploiting the noisy Kuramoto-Winfree model, we search for the optimal pulse profile and the optimal stimulation phase. For this purpose, we derive an expression for the change of the phase distribution entropy due to the stimulus. We relate this change to the properties of individual units characterized by generally different natural frequencies and phase response curves and the population's state. We verify the general result by analyzing a two-frequency population model and demonstrating a good agreement of the theory and numerical simulations.},
  language  = {en}
}
@article{FosterPoppenhaeger2022,
  author    = {Foster, Grace and Poppenh{\"a}ger, Katja},
  title     = {Identifying interesting planetary systems for future X-ray observations},
  series = {Astronomische Nachrichten = Astronomical notes},
  volume    = {343},
  journal   = {Astronomische Nachrichten = Astronomical notes},
  number    = {4},
  publisher = {Wiley-VCH},
  address   = {Berlin},
  issn      = {1521-3994},
  doi       = {10.1002/asna.20220007},
  pages     = {7},
  year      = {2022},
  abstract  = {X-ray observations of star-planet systems are important to grow our understanding of exoplanets; these observations allow for studies of photoevaporation of the exoplanetary atmosphere, and in some cases even estimations of the size of the outer planetary atmosphere. The German-Russian eROSITA instrument onboard the SRG (Spectrum Roentgen Gamma) mission is performing the first all-sky X-ray survey since the 1990s, and provides X-ray fluxes and spectra of exoplanet host stars over a much larger volume than was accessible before. Using new eROSITA data as well as archival data from XMM-Newton, Chandra, and ROSAT, we estimate mass-loss rates of exoplanets under an energy-limited escape scenario and identify several exoplanets with strong X-ray irradiation and expected mass loss that are amenable to follow-up observations at other wavelengths. We model sample spectra using a toy model of an exoplanetary atmosphere to predict what exoplanet transit observations with future X-ray missions such as Athena will look like and estimate the observable X-ray transmission spectrum for a typical hot Jupiter-type exoplanet.},
  language  = {en}
}
@article{IlinPoppenhaegerAlvaradoGomez2022,
  author    = {Ilin, Ekaterina and Poppenh{\"a}ger, Katja and Alvarado-G{\´o}mez, Juli{\´a}n David},
  title     = {Localizing flares to understand stellar magnetic fields and space weather in exo-systems},
  series = {Astronomische Nachrichten = Astronomical notes},
  volume    = {343},
  journal   = {Astronomische Nachrichten = Astronomical notes},
  number    = {4},
  publisher = {Berlin},
  address   = {Wiley-VCH},
  issn      = {1521-3994},
  doi       = {10.1002/asna.20210111},
  pages     = {7},
  year      = {2022},
  abstract  = {Stars are uniform spheres, but only to first order. The way in which stellar rotation and magnetism break this symmetry places important observational constraints on stellar magnetic fields, and factors in the assessment of the impact of stellar activity on exoplanet atmospheres. The spatial distribution of flares on the solar surface is well known to be nonuniform, but elusive on other stars. We briefly review the techniques available to recover the loci of stellar flares, and highlight a new method that enables systematic flare localization directly from optical light curves. We provide an estimate of the number of flares we may be able to localize with the Transiting Exoplanet Survey Satellite, and show that it is consistent with the results obtained from the first full sky scan of the mission. We suggest that nonuniform flare latitude distributions need to be taken into account in accurate assessments of exoplanet habitability.},
  language  = {en}
}
@article{Omel'chenkoLaing2022,
  author    = {Omel'chenko, Oleh and Laing, Carlo R.},
  title     = {Collective states in a ring network of theta neurons},
  series = {Proceedings of the Royal Society of London. Series A, Mathematical, physical and engineering sciences},
  volume    = {478},
  journal   = {Proceedings of the Royal Society of London. Series A, Mathematical, physical and engineering sciences},
  number    = {2259},
  publisher = {Royal Society},
  address   = {London},
  issn      = {1364-5021},
  doi       = {10.1098/rspa.2021.0817},
  pages     = {23},
  year      = {2022},
  abstract  = {We consider a ring network of theta neurons with non-local homogeneous coupling. We analyse the corresponding continuum evolution equation, analytically describing all possible steady states and their stability. By considering a number of different parameter sets, we determine the typical bifurcation scenarios of the network, and put on a rigorous footing some previously observed numerical results.},
  language  = {en}
}
@misc{YeZhangWarbyetal.2022,
  author    = {Ye, Fangyuan and Zhang, Shuo and Warby, Jonathan and Wu, Jiawei and Gutierrez-Partida, Emilio and Lang, Felix and Shah, Sahil and Saglamkaya, Elifnaz and Sun, Bowen and Zu, Fengshuo and Shoaee, Safa and Wang, Haifeng and Stiller, Burkhard and Neher, Dieter and Zhu, Wei-Hong and Stolterfoht, Martin and Wu, Yongzhen},
  title     = {Overcoming C₆₀-induced interfacial recombination in inverted perovskite solar cells by electron-transporting carborane},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1317},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-58770},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-587705},
  pages     = {12},
  year      = {2022},
  abstract  = {Inverted perovskite solar cells still suffer from significant non-radiative recombination losses at the perovskite surface and across the perovskite/C₆₀ interface, limiting the future development of perovskite-based single- and multi-junction photovoltaics. Therefore, more effective inter- or transport layers are urgently required. To tackle these recombination losses, we introduce ortho-carborane as an interlayer material that has a spherical molecular structure and a three-dimensional aromaticity. Based on a variety of experimental techniques, we show that ortho-carborane decorated with phenylamino groups effectively passivates the perovskite surface and essentially eliminates the non-radiative recombination loss across the perovskite/C₆₀ interface with high thermal stability. We further demonstrate the potential of carborane as an electron transport material, facilitating electron extraction while blocking holes from the interface. The resulting inverted perovskite solar cells deliver a power conversion efficiency of over 23\% with a low non-radiative voltage loss of 110 mV, and retain >97\% of the initial efficiency after 400 h of maximum power point tracking. Overall, the designed carborane based interlayer simultaneously enables passivation, electron-transport and hole-blocking and paves the way toward more efficient and stable perovskite solar cells.},
  language  = {en}
}
@article{YeZhangWarbyetal.2022,
  author    = {Ye, Fangyuan and Zhang, Shuo and Warby, Jonathan and Wu, Jiawei and Gutierrez-Partida, Emilio and Lang, Felix and Shah, Sahil and Saglamkaya, Elifnaz and Sun, Bowen and Zu, Fengshuo and Shoai, Safa and Wang, Haifeng and Stiller, Burkhard and Neher, Dieter and Zhu, Wei-Hong and Stolterfoht, Martin and Wu, Yongzhen},
  title     = {Overcoming C₆₀-induced interfacial recombination in inverted perovskite solar cells by electron-transporting carborane},
  series = {Nature Communications},
  volume    = {13},
  journal   = {Nature Communications},
  number    = {1},
  publisher = {Springer Nature},
  address   = {London},
  issn      = {2041-1723},
  doi       = {10.1038/s41467-022-34203-x},
  pages     = {12},
  year      = {2022},
  abstract  = {Inverted perovskite solar cells still suffer from significant non-radiative recombination losses at the perovskite surface and across the perovskite/C₆₀ interface, limiting the future development of perovskite-based single- and multi-junction photovoltaics. Therefore, more effective inter- or transport layers are urgently required. To tackle these recombination losses, we introduce ortho-carborane as an interlayer material that has a spherical molecular structure and a three-dimensional aromaticity. Based on a variety of experimental techniques, we show that ortho-carborane decorated with phenylamino groups effectively passivates the perovskite surface and essentially eliminates the non-radiative recombination loss across the perovskite/C₆₀ interface with high thermal stability. We further demonstrate the potential of carborane as an electron transport material, facilitating electron extraction while blocking holes from the interface. The resulting inverted perovskite solar cells deliver a power conversion efficiency of over 23\% with a low non-radiative voltage loss of 110 mV, and retain >97\% of the initial efficiency after 400 h of maximum power point tracking. Overall, the designed carborane based interlayer simultaneously enables passivation, electron-transport and hole-blocking and paves the way toward more efficient and stable perovskite solar cells.},
  language  = {en}
}
@article{LopezdeGuerenuKurganovaKlierHaubitzetal.2022,
  author    = {L{\´o}pez de Guere{\~n}u Kurganova, Anna and Klier, Dennis Tobias and Haubitz, Toni and Kumke, Michael Uwe},
  title     = {Influence of Gd3+ doping concentration on the properties of Na(Y,Gd)F-4},
  series = {Photochemical \& photobiological sciences / European Society for Photobiology},
  volume    = {21},
  journal   = {Photochemical \& photobiological sciences / European Society for Photobiology},
  number    = {2},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {1474-905X},
  doi       = {10.1007/s43630-021-00161-4},
  pages     = {235 -- 245},
  year      = {2022},
  abstract  = {We present a systematic study on the properties of Na(Y,Gd)F-4-based upconverting nanoparticles (UCNP) doped with 18\% Yb3+, 2\% Tm3+, and the influence of Gd3+ (10-50 mol\% Gd3+). UCNP were synthesized via the solvothermal method and had a range of diameters within 13 and 50 nm. Structural and photophysical changes were monitored for the UCNP samples after a 24-month incubation period in dry phase and further redispersion. Structural characterization was performed by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as dynamic light scattering (DLS), and the upconversion luminescence (UCL) studies were executed at various temperatures (from 4 to 295 K) using time-resolved and steady-state spectroscopy. An increase in the hexagonal lattice phase with the increase of Gd3+ content was found, although the cubic phase was prevalent in most samples. The Tm3+-luminescence intensity as well as the Tm3+-luminescence decay times peaked at the Gd3+ concentration of 30 mol\%. Although the general upconverting luminescence properties of the nanoparticles were preserved, the 24-month incubation period lead to irreversible agglomeration of the UCNP and changes in luminescence band ratios and lifetimes.},
  language  = {en}
}
@misc{SecklerMetzler2022,
  author    = {Seckler, Henrik and Metzler, Ralf},
  title     = {Bayesian deep learning for error estimation in the analysis of anomalous diffusion},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1314},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-58602},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-586025},
  pages     = {13},
  year      = {2022},
  abstract  = {Sprache Englisch Modern single-particle-tracking techniques produce extensive time-series of diffusive motion in a wide variety of systems, from single-molecule motion in living-cells to movement ecology. The quest is to decipher the physical mechanisms encoded in the data and thus to better understand the probed systems. We here augment recently proposed machine-learning techniques for decoding anomalous-diffusion data to include an uncertainty estimate in addition to the predicted output. To avoid the Black-Box-Problem a Bayesian-Deep-Learning technique named Stochastic-Weight-Averaging-Gaussian is used to train models for both the classification of the diffusionmodel and the regression of the anomalous diffusion exponent of single-particle-trajectories. Evaluating their performance, we find that these models can achieve a wellcalibrated error estimate while maintaining high prediction accuracies. In the analysis of the output uncertainty predictions we relate these to properties of the underlying diffusion models, thus providing insights into the learning process of the machine and the relevance of the output.},
  language  = {en}
}
@article{SecklerMetzler2022,
  author    = {Seckler, Henrik and Metzler, Ralf},
  title     = {Bayesian deep learning for error estimation in the analysis of anomalous diffusion},
  series = {Nature Communnications},
  volume    = {13},
  journal   = {Nature Communnications},
  publisher = {Nature Publishing Group UK},
  address   = {London},
  issn      = {2041-1723},
  doi       = {10.1038/s41467-022-34305-6},
  pages     = {13},
  year      = {2022},
  abstract  = {Modern single-particle-tracking techniques produce extensive time-series of diffusive motion in a wide variety of systems, from single-molecule motion in living-cells to movement ecology. The quest is to decipher the physical mechanisms encoded in the data and thus to better understand the probed systems. We here augment recently proposed machine-learning techniques for decoding anomalous-diffusion data to include an uncertainty estimate in addition to the predicted output. To avoid the Black-Box-Problem a Bayesian-Deep-Learning technique named Stochastic-Weight-Averaging-Gaussian is used to train models for both the classification of the diffusionmodel and the regression of the anomalous diffusion exponent of single-particle-trajectories. Evaluating their performance, we find that these models can achieve a wellcalibrated error estimate while maintaining high prediction accuracies. In the analysis of the output uncertainty predictions we relate these to properties of the underlying diffusion models, thus providing insights into the learning process of the machine and the relevance of the output.},
  language  = {en}
}
@article{Fritsch2022,
  author    = {Fritsch, Daniel},
  title     = {Revisiting the Cu-Zn disorder in kesterite type Cu2ZnSnSe4 employing a novel approach to hybrid functional calculations},
  series = {Applied Sciences : open access journal},
  volume    = {12},
  journal   = {Applied Sciences : open access journal},
  number    = {5},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2076-3417},
  doi       = {10.3390/app12052576},
  pages     = {10},
  year      = {2022},
  abstract  = {In recent years, the search for more efficient and environmentally friendly materials to be employed in the next generation of thin film solar cell devices has seen a shift towards hybrid halide perovskites and chalcogenide materials crystallising in the kesterite crystal structure. Prime examples for the latter are Cu2ZnSnS4, Cu2ZnSnSe4, and their solid solution Cu2ZnSn(SxSe1-x)(4), where actual devices already demonstrated power conversion efficiencies of about 13 \%. However, in their naturally occurring kesterite crystal structure, the so-called Cu-Zn disorder plays an important role and impacts the structural, electronic, and optical properties. To understand the influence of Cu-Zn disorder, we perform first-principles calculations based on density functional theory combined with special quasirandom structures to accurately model the cation disorder. Since the electronic band gaps and derived optical properties are severely underestimated by (semi)local exchange and correlation functionals, supplementary hybrid functional calculations have been performed. Concerning the latter, we additionally employ a recently devised technique to speed up structural relaxations for hybrid functional calculations. Our calculations show that the Cu-Zn disorder leads to a slight increase in the unit cell volume compared to the conventional kesterite structure showing full cation order, and that the band gap gets reduced by about 0.2 eV, which is in very good agreement with earlier experimental and theoretical findings. Our detailed results on structural, electronic, and optical properties will be discussed with respect to available experimental data, and will provide further insights into the atomistic origin of the disorder-induced band gap lowering in these promising kesterite type materials.},
  language  = {en}
}
@misc{SposiniKrapfMarinarietal.2022,
  author    = {Sposini, Vittoria and Krapf, Diego and Marinari, Enzo and Sunyer, Raimon and Ritort, Felix and Taheri, Fereydoon and Selhuber-Unkel, Christine and Benelli, Rebecca and Weiss, Matthias and Metzler, Ralf and Oshanin, Gleb},
  title     = {Towards a robust criterion of anomalous diffusion},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1313},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-58596},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-585967},
  pages     = {10},
  year      = {2022},
  abstract  = {Anomalous-diffusion, the departure of the spreading dynamics of diffusing particles from the traditional law of Brownian-motion, is a signature feature of a large number of complex soft-matter and biological systems. Anomalous-diffusion emerges due to a variety of physical mechanisms, e.g., trapping interactions or the viscoelasticity of the environment. However, sometimes systems dynamics are erroneously claimed to be anomalous, despite the fact that the true motion is Brownian—or vice versa. This ambiguity in establishing whether the dynamics as normal or anomalous can have far-reaching consequences, e.g., in predictions for reaction- or relaxation-laws. Demonstrating that a system exhibits normal- or anomalous-diffusion is highly desirable for a vast host of applications. Here, we present a criterion for anomalous-diffusion based on the method of power-spectral analysis of single trajectories. The robustness of this criterion is studied for trajectories of fractional-Brownian-motion, a ubiquitous stochastic process for the description of anomalous-diffusion, in the presence of two types of measurement errors. In particular, we find that our criterion is very robust for subdiffusion. Various tests on surrogate data in absence or presence of additional positional noise demonstrate the efficacy of this method in practical contexts. Finally, we provide a proof-of-concept based on diverse experiments exhibiting both normal and anomalous-diffusion.},
  language  = {en}
}
@article{SposiniKrapfMarinarietal.2022,
  author    = {Sposini, Vittoria and Krapf, Diego and Marinari, Enzo and Sunyer, Raimon and Ritort, Felix and Taheri, Fereydoon and Selhuber-Unkel, Christine and Benelli, Rebecca and Weiss, Matthias and Metzler, Ralf and Oshanin, Gleb},
  title     = {Towards a robust criterion of anomalous diffusion},
  series = {Communications Physics},
  volume    = {5},
  journal   = {Communications Physics},
  publisher = {Springer Nature},
  address   = {London},
  issn      = {2399-3650},
  doi       = {10.1038/s42005-022-01079-8},
  pages     = {10},
  year      = {2022},
  abstract  = {Anomalous-diffusion, the departure of the spreading dynamics of diffusing particles from the traditional law of Brownian-motion, is a signature feature of a large number of complex soft-matter and biological systems. Anomalous-diffusion emerges due to a variety of physical mechanisms, e.g., trapping interactions or the viscoelasticity of the environment. However, sometimes systems dynamics are erroneously claimed to be anomalous, despite the fact that the true motion is Brownian—or vice versa. This ambiguity in establishing whether the dynamics as normal or anomalous can have far-reaching consequences, e.g., in predictions for reaction- or relaxation-laws. Demonstrating that a system exhibits normal- or anomalous-diffusion is highly desirable for a vast host of applications. Here, we present a criterion for anomalous-diffusion based on the method of power-spectral analysis of single trajectories. The robustness of this criterion is studied for trajectories of fractional-Brownian-motion, a ubiquitous stochastic process for the description of anomalous-diffusion, in the presence of two types of measurement errors. In particular, we find that our criterion is very robust for subdiffusion. Various tests on surrogate data in absence or presence of additional positional noise demonstrate the efficacy of this method in practical contexts. Finally, we provide a proof-of-concept based on diverse experiments exhibiting both normal and anomalous-diffusion.},
  language  = {en}
}
@misc{MayerLeverPicconietal.2022,
  author    = {Mayer, Dennis and Lever, Fabiano and Picconi, David and Metje, Jan and Ališauskas, Skirmantas and Calegari, Francesca and D{\"u}sterer, Stefan and Ehlert, Christopher and Feifel, Raimund and Niebuhr, Mario and Manschwetus, Bastian and Kuhlmann, Marion and Mazza, Tommaso and Robinson, Matthew Scott and Squibb, Richard James and Trabattoni, Andrea and Wallner, M{\aa}ns and Saalfrank, Peter and Wolf, Thomas J. A. and G{\"u}hr, Markus},
  title     = {Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1301},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-57744},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-577442},
  pages     = {9},
  year      = {2022},
  abstract  = {The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220-250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.},
  language  = {en}
}
@article{MayerLeverPicconietal.2022,
  author    = {Mayer, Dennis and Lever, Fabiano and Picconi, David and Metje, Jan and Ališauskas, Skirmantas and Calegari, Francesca and D{\"u}sterer, Stefan and Ehlert, Christopher and Feifel, Raimund and Niebuhr, Mario and Manschwetus, Bastian and Kuhlmann, Marion and Mazza, Tommaso and Robinson, Matthew Scott and Squibb, Richard James and Trabattoni, Andrea and Wallner, M{\aa}ns and Saalfrank, Peter and Wolf, Thomas J. A. and G{\"u}hr, Markus},
  title     = {Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy},
  series = {Nature Communications},
  volume    = {13},
  journal   = {Nature Communications},
  publisher = {Springer Nature},
  address   = {Berlin},
  issn      = {2041-1723},
  doi       = {10.1038/s41467-021-27908-y},
  pages     = {9},
  year      = {2022},
  abstract  = {The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220-250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.},
  language  = {en}
}