TY - JOUR A1 - Markötter, Henning A1 - Sintschuk, Michael A1 - Britzke, Ricardo A1 - Dayani, Shahabeddin A1 - Bruno, Giovanni T1 - Upgraded imaging capabilities at the BAMline (BESSY II) JF - Journal of synchrotron radiation N2 - The BAMline at the BESSY II synchrotron X-ray source has enabled research for more than 20 years in widely spread research fields such as materials science, biology, cultural heritage and medicine. As a nondestructive characterization method, synchrotron X-ray imaging, especially tomography, plays a particularly important role in structural characterization. A recent upgrade of key equipment of the BAMline widens its imaging capabilities: shorter scan acquisition times are now possible, in situ and op erando studies can now be routinely performed, and different energy spectra can easily be set up. In fact, the upgraded double-multilayer monochromator brings full flexibility by yielding different energy spectra to optimize flux and energy resolution as desired. The upgraded detector (based on an sCMOS camera) also allows exploiting the higher flux with reduced readout times. Furthermore, an installed slip ring allows the sample stage to continuously rotate. The latter feature enables tomographic observation of processes occurring in the time scale of a few seconds. KW - synchrotron radiation KW - computed tomography KW - double-multilayer monochromators KW - pink beams KW - X-ray optics Y1 - 2022 U6 - https://doi.org/10.1107/S1600577522007342 SN - 1600-5775 VL - 29 IS - 5 SP - 1292 EP - 1298 PB - International Union of Crystallography CY - Chester ER - TY - JOUR A1 - Rosenblum, Michael A1 - Pikovsky, Arkady T1 - Inferring connectivity of an oscillatory network via the phase dynamics reconstruction JF - Frontiers in network physiology N2 - We review an approach for reconstructing oscillatory networks’ undirected and directed connectivity from data. The technique relies on inferring the phase dynamics model. The central assumption is that we observe the outputs of all network nodes. We distinguish between two cases. In the first one, the observed signals represent smooth oscillations, while in the second one, the data are pulse-like and can be viewed as point processes. For the first case, we discuss estimating the true phase from a scalar signal, exploiting the protophase-to-phase transformation. With the phases at hand, pairwise and triplet synchronization indices can characterize the undirected connectivity. Next, we demonstrate how to infer the general form of the coupling functions for two or three oscillators and how to use these functions to quantify the directional links. We proceed with a different treatment of networks with more than three nodes. We discuss the difference between the structural and effective phase connectivity that emerges due to high-order terms in the coupling functions. For the second case of point-process data, we use the instants of spikes to infer the phase dynamics model in the Winfree form directly. This way, we obtain the network’s coupling matrix in the first approximation in the coupling strength. KW - oscillations KW - network KW - connectivity KW - data analysis KW - phase reduction Y1 - 2023 U6 - https://doi.org/10.3389/fnetp.2023.1298228 SN - 2674-0109 VL - 3 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Cestnik, Rok A1 - Mau, Erik T. K. A1 - Rosenblum, Michael T1 - Inferring oscillator's phase and amplitude response from a scalar signal exploiting test stimulation JF - New journal of physics : the open-access journal for physics N2 - The phase sensitivity curve or phase response curve (PRC) quantifies the oscillator's reaction to stimulation at a specific phase and is a primary characteristic of a self-sustained oscillatory unit. Knowledge of this curve yields a phase dynamics description of the oscillator for arbitrary weak forcing. Similar, though much less studied characteristic, is the amplitude response that can be defined either using an ad hoc approach to amplitude estimation or via the isostable variables. Here, we discuss the problem of the phase and amplitude response inference from observations using test stimulation. Although PRC determination for noise-free neuronal-like oscillators perturbed by narrow pulses is a well-known task, the general case remains a challenging problem. Even more challenging is the inference of the amplitude response. This characteristic is crucial, e.g. for controlling the amplitude of the collective mode in a network of interacting units-a task relevant to neuroscience. Here, we compare the performance of different techniques suitable for inferring the phase and amplitude response, particularly with application to macroscopic oscillators. We suggest improvements to these techniques, e.g. demonstrating how to obtain the PRC in case of stimuli of arbitrary shape. Our main result is a novel technique denoted by IPID-1, based on the direct reconstruction of the Winfree equation and the analogous first-order equation for isostable dynamics. The technique works for signals with or without well-pronounced marker events and pulses of arbitrary shape; in particular, we consider charge-balanced pulses typical in neuroscience applications. Moreover, this technique is superior for noisy and high-dimensional systems. Additionally, we describe an error measure that can be computed solely from data and complements any inference technique. KW - phase response KW - amplitude response KW - phase-isostable reduction KW - inference Y1 - 2022 U6 - https://doi.org/10.1088/1367-2630/aca70a SN - 1367-2630 VL - 24 IS - 12 PB - Dt. Physikalische Ges., IOP CY - Bad Honnef, London ER - TY - JOUR A1 - Zhelavskaya, Irina A1 - Aseev, Nikita A1 - Shprits, Yuri T1 - A combined neural network‐ and physics‐based approach for modeling plasmasphere dynamics JF - JGR / AGU, American Geographical Union. Space Physics N2 - Abstract In recent years, feedforward neural networks (NNs) have been successfully applied to reconstruct global plasmasphere dynamics in the equatorial plane. These neural network‐based models capture the large‐scale dynamics of the plasmasphere, such as plume formation and erosion of the plasmasphere on the nightside. However, their performance depends strongly on the availability of training data. When the data coverage is limited or non‐existent, as occurs during geomagnetic storms, the performance of NNs significantly decreases, as networks inherently cannot learn from the limited number of examples. This limitation can be overcome by employing physics‐based modeling during strong geomagnetic storms. Physics‐based models show a stable performance during periods of disturbed geomagnetic activity if they are correctly initialized and configured. In this study, we illustrate how to combine the neural network‐ and physics‐based models of the plasmasphere in an optimal way by using data assimilation. The proposed approach utilizes advantages of both neural network‐ and physics‐based modeling and produces global plasma density reconstructions for both quiet and disturbed geomagnetic activity, including extreme geomagnetic storms. We validate the models quantitatively by comparing their output to the in‐situ density measurements from RBSP‐A for an 18‐month out‐of‐sample period from June 30, 2016 to January 01, 2018 and computing performance metrics. To validate the global density reconstructions qualitatively, we compare them to the IMAGE EUV images of the He+ particle distribution in the Earth's plasmasphere for a number of events in the past, including the Halloween storm in 2003. KW - data assimilation KW - Kalman filter KW - machine learning KW - neural networks KW - plasmasphere KW - plasma density Y1 - 2021 U6 - https://doi.org/10.1029/2020JA028077 SN - 2169-9380 SN - 2169-9402 VL - 126 IS - 3 PB - Wiley CY - Hoboken, NJ ER - TY - JOUR A1 - Durand, Gael A1 - van den Broeke, Michiel R. A1 - Le Cozannet, Goneri A1 - Edwards, Tamsin L. A1 - Holland, Paul R. A1 - Jourdain, Nicolas C. A1 - Marzeion, Ben A1 - Mottram, Ruth A1 - Nicholls, Robert J. A1 - Pattyn, Frank A1 - Paul, Frank A1 - Slangen, Aimee B. A. A1 - Winkelmann, Ricarda A1 - Burgard, Clara A1 - van Calcar, Caroline J. A1 - Barre, Jean-Baptiste A1 - Bataille, Amelie A1 - Chapuis, Anne T1 - Sea-Level rise: from global perspectives to local services JF - Frontiers in Marine Science N2 - Coastal areas are highly diverse, ecologically rich, regions of key socio-economic activity, and are particularly sensitive to sea-level change. Over most of the 20th century, global mean sea level has risen mainly due to warming and subsequent expansion of the upper ocean layers as well as the melting of glaciers and ice caps. Over the last three decades, increased mass loss of the Greenland and Antarctic ice sheets has also started to contribute significantly to contemporary sea-level rise. The future mass loss of the two ice sheets, which combined represent a sea-level rise potential of similar to 65 m, constitutes the main source of uncertainty in long-term (centennial to millennial) sea-level rise projections. Improved knowledge of the magnitude and rate of future sea-level change is therefore of utmost importance. Moreover, sea level does not change uniformly across the globe and can differ greatly at both regional and local scales. The most appropriate and feasible sea level mitigation and adaptation measures in coastal regions strongly depend on local land use and associated risk aversion. Here, we advocate that addressing the problem of future sea-level rise and its impacts requires (i) bringing together a transdisciplinary scientific community, from climate and cryospheric scientists to coastal impact specialists, and (ii) interacting closely and iteratively with users and local stakeholders to co-design and co-build coastal climate services, including addressing the high-end risks. KW - sea-level rise KW - Antarctic KW - Greenland KW - glaciers KW - local impact Y1 - 2022 U6 - https://doi.org/10.3389/fmars.2021.709595 SN - 2296-7745 VL - 8 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Kretzschmar, Mirjam E. A1 - Ashby, Ben A1 - Fearon, Elizabeth A1 - Overton, Christopher E. A1 - Panovska-Griffiths, Jasmina A1 - Pellis, Lorenzo A1 - Quaife, Matthew A1 - Rozhnova, Ganna A1 - Scarabel, Francesca A1 - Stage, Helena B. A1 - Swallow, Ben A1 - Thompson, Robin N. A1 - Tildesley, Michael J. A1 - Villela, Daniel Campos T1 - Challenges for modelling interventions for future pandemics JF - Epidemics N2 - Mathematical modelling and statistical inference provide a framework to evaluate different non-pharmaceutical and pharmaceutical interventions for the control of epidemics that has been widely used during the COVID-19 pandemic. In this paper, lessons learned from this and previous epidemics are used to highlight the challenges for future pandemic control. We consider the availability and use of data, as well as the need for correct parameterisation and calibration for different model frameworks. We discuss challenges that arise in describing and distinguishing between different interventions, within different modelling structures, and allowing both within and between host dynamics. We also highlight challenges in modelling the health economic and political aspects of interventions. Given the diversity of these challenges, a broad variety of interdisciplinary expertise is needed to address them, combining mathematical knowledge with biological and social insights, and including health economics and communication skills. Addressing these challenges for the future requires strong cross disciplinary collaboration together with close communication between scientists and policy makers. KW - Mathematical models KW - Pandemics KW - Pharmaceutical interventions KW - Non-pharmaceutical interventions KW - Policy support Y1 - 2022 U6 - https://doi.org/10.1016/j.epidem.2022.100546 SN - 1755-4365 SN - 1878-0067 VL - 38 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Anders, Friedrich A1 - Khalatyan, Arman A1 - Queiroz, Anna B. A. A1 - Chiappini, Cristina A1 - Ardèvol, Judith A1 - Casamiquela, Laia A1 - Figueras, Francesca A1 - Jiménez-Arranz, Óscar A1 - Jordi, Carme A1 - Monguio, Maria A1 - Romero-Gómez, Merce A1 - Altamirano, Diego A1 - Antoja, Teresa A1 - Assaad, R. A1 - Cantat-Gaudin, Tristan A1 - Castro-Ginard, Alfred A1 - Enke, Harry A1 - Girardi, Léo A1 - Guiglion, Guillaume A1 - Khan, Saniya A1 - Luri, Xavier A1 - Miglio, Andrea A1 - Minchev, Ivan A1 - Ramos, Pau A1 - Santiago, Basillio Xavier A1 - Steinmetz, Matthias T1 - Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5 JF - Astronomy and astrophysics N2 - We present a catalogue of 362 million stellar parameters, distances, and extinctions derived from Gaia's Early Data Release (EDR3) cross-matched with the photometric catalogues of Pan-STARRS1, SkyMapper, 2MASS, and All WISE. The higher precision of the Gaia EDR3 data, combined with the broad wavelength coverage of the additional photometric surveys and the new stellar-density priors of the StarHorse code, allows us to substantially improve the accuracy and precision over previous photo-astrometric stellar-parameter estimates. At magnitude G = 14 (17), our typical precisions amount to 3% (15%) in distance, 0.13 mag (0.15 mag) in V-band extinction, and 140 K (180 K) in effective temperature. Our results are validated by comparisons with open clusters, as well as with asteroseismic and spectroscopic measurements, indicating systematic errors smaller than the nominal uncertainties for the vast majority of objects. We also provide distance- and extinction-corrected colour-magnitude diagrams, extinction maps, and extensive stellar density maps that reveal detailed substructures in the Milky Way and beyond. The new density maps now probe a much greater volume, extending to regions beyond the Galactic bar and to Local Group galaxies, with a larger total number density. We publish our results through an ADQL query interface (gaia . aip . de) as well as via tables containing approximations of the full posterior distributions. Our multi-wavelength approach and the deep magnitude limit render our results useful also beyond the next Gaia release, DR3. KW - stars: distances KW - stars: fundamental parameters KW - Galaxy: general KW - Galaxy: stellar content KW - Galaxy: structure Y1 - 2022 U6 - https://doi.org/10.1051/0004-6361/202142369 SN - 0004-6361 SN - 1432-0746 VL - 658 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Keles, Engin A1 - Mallonn, Matthias A1 - Kitzmann, Daniel A1 - Poppenhäger, Katja A1 - Hoeijmakers, H. Jens A1 - Ilyin, Ilya A1 - Alexoudi, Xanthippi A1 - Carroll, Thorsten A. A1 - Alvarado-Gomez, Julian A1 - Ketzer, Laura A1 - Bonomo, Aldo S. A1 - Borsa, Francesco A1 - Gaudi, B. Scott A1 - Henning, Thomas A1 - Malavolta, Luca A1 - Molaverdikhani, Karan A1 - Nascimbeni, Valerio A1 - Patience, Jennifer A1 - Pino, Lorenzo A1 - Scandariato, Gaetano A1 - Schlawin, Everett A1 - Shkolnik, Evgenya A1 - Sicilia, Daniela A1 - Sozzetti, Alessandro A1 - Foster, Mary G. A1 - Veillet, Christian A1 - Wang, Ji A1 - Yan, Fei A1 - Strassmeier, Klaus G. T1 - The PEPSI exoplanet transit survey (PETS) I: Investigating the presence of a silicate atmosphere on the super-earth 55 Cnc e JF - Monthly notices of the Royal Astronomical Society N2 - The study of exoplanets and especially their atmospheres can reveal key insights on their evolution by identifying specific atmospheric species. For such atmospheric investigations, high-resolution transmission spectroscopy has shown great success, especially for Jupiter-type planets. Towards the atmospheric characterization of smaller planets, the super-Earth exoplanet 55 Cnc e is one of the most promising terrestrial exoplanets studied to date. Here, we present a high-resolution spectroscopic transit observation of this planet, acquired with the PEPSI instrument at the Large Binocular Telescope. Assuming the presence of Earth-like crust species on the surface of 55 Cnc e, from which a possible silicate-vapor atmosphere could have originated, we search in its transmission spectrum for absorption of various atomic and ionized species such as Fe , Fe (+), Ca , Ca (+), Mg, and K , among others. Not finding absorption for any of the investigated species, we are able to set absorption limits with a median value of 1.9 x R-P. In conclusion, we do not find evidence of a widely extended silicate envelope on this super-Earth reaching several planetary radii. KW - planets and satellites: atmospheres KW - planets and satellites: composition Y1 - 2022 U6 - https://doi.org/10.1093/mnras/stac810 SN - 0035-8711 SN - 1365-2966 VL - 513 IS - 1 SP - 1544 EP - 1556 PB - Oxford University Press CY - Oxford ER - TY - JOUR A1 - Kramer, Koen A1 - Bouriaud, Laura A1 - Feindt, Peter H. A1 - van Wassenaer, Lan A1 - Glanemann, Nicole A1 - Hanewinkel, Marc A1 - van der Heide, Martijn A1 - Hengeveld, Geerten M. A1 - Hoogstra, Marjanke A1 - Ingram, Verina A1 - Levermann, Anders A1 - Lindner, Marcus A1 - Mátyás, Csaba A1 - Mohren, Frits A1 - Muys, Bart A1 - Nabuurs, Gert-Jan A1 - Palahi, Marc A1 - Polman, Nico A1 - Reyer, Christopher P. O. A1 - Schulze, Ernst-Detlef A1 - Seidl, Rupert A1 - de Vries, Wim A1 - Werners, Saskia E. A1 - Winkel, Georg A1 - Yousefpour, Rasoul T1 - Perspective Roadmap to develop a stress test for forest ecosystem services supply JF - One Earth N2 - Forests play a key role in a bio-based economy by providing renewable materials, mitigating climate change, and accommodating biodiversity. However, forests experience massive increases in stresses in their ecological and socioeconomic environments, threatening forest ecosystem services supply. Alleviating those stresses is hampered by conflicting and disconnected governance arrangements, competing interests and claims, and rapid changes in technology and social demands. Identifying which stresses threaten forest ecosystem services supply and which factors hamper their alleviation requires stakeholders' perceptions. Stakeholder-oriented stress tests for the supply of forest ecosystem services are therefore necessary but are not yet available. This perspective presents a roadmap to develop a stress test tailored to multiple stakeholders' needs and demands across spatial scales. We provide the Cascade and Resilience Rosetta, with accompanying performance- and resilience indicators, as tools to facilitate development of the stress test. The application of the stress test will facilitate the transition toward a bio-based economy in which healthy and diverse forests provide sustainable and resilient ecosystem services. Y1 - 2022 U6 - https://doi.org/10.1016/j.oneear.2021.12.009 SN - 2590-3330 SN - 2590-3322 VL - 5 IS - 1 SP - 25 EP - 34 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Hempel, Hannes A1 - Savenjie, Tom J. A1 - Stolterfoht, Martin A1 - Neu, Jens A1 - Failla, Michele A1 - Paingad, Vaisakh C. A1 - Kužel, Petr A1 - Heilweil, Edwin J. A1 - Spies, Jacob A. A1 - Schleuning, Markus A1 - Zhao, Jiashang A1 - Friedrich, Dennis A1 - Schwarzburg, Klaus A1 - Siebbeles, Laurens D. A. A1 - Dörflinger, Patrick A1 - Dyakonov, Vladimir A1 - Katoh, Ryuzi A1 - Hong, Min Ji A1 - Labram, John G. A1 - Monti, Maurizio A1 - Butler-Caddle, Edward A1 - Lloyd-Hughes, James A1 - Taheri, Mohammad M. A1 - Baxter, Jason B. A1 - Magnanelli, Timothy J. A1 - Luo, Simon A1 - Cardon, Joseph M. A1 - Ardo, Shane A1 - Unold, Thomas T1 - Predicting solar cell performance from terahertz and microwave spectroscopy JF - Advanced energy materials N2 - Mobilities and lifetimes of photogenerated charge carriers are core properties of photovoltaic materials and can both be characterized by contactless terahertz or microwave measurements. Here, the expertise from fifteen laboratories is combined to quantitatively model the current-voltage characteristics of a solar cell from such measurements. To this end, the impact of measurement conditions, alternate interpretations, and experimental inter-laboratory variations are discussed using a (Cs,FA,MA)Pb(I,Br)(3) halide perovskite thin-film as a case study. At 1 sun equivalent excitation, neither transport nor recombination is significantly affected by exciton formation or trapping. Terahertz, microwave, and photoluminescence transients for the neat material yield consistent effective lifetimes implying a resistance-free JV-curve with a potential power conversion efficiency of 24.6 %. For grainsizes above approximate to 20 nm, intra-grain charge transport is characterized by terahertz sum mobilities of approximate to 32 cm(2) V-1 s(-1). Drift-diffusion simulations indicate that these intra-grain mobilities can slightly reduce the fill factor of perovskite solar cells to 0.82, in accordance with the best-realized devices in the literature. Beyond perovskites, this work can guide a highly predictive characterization of any emerging semiconductor for photovoltaic or photoelectrochemical energy conversion. A best practice for the interpretation of terahertz and microwave measurements on photovoltaic materials is presented. KW - lifetime KW - microwaves KW - mobility KW - solar cells KW - terahertz Y1 - 2022 U6 - https://doi.org/10.1002/aenm.202102776 SN - 1614-6832 SN - 1614-6840 VL - 12 IS - 13 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Huth, Sabrina A1 - Pang, Peter Tsun Ho A1 - Tews, Ingo A1 - Dietrich, Tim A1 - Le Fèvre, Arnaud A1 - Schwenk, Achim A1 - Trautmann, Wolfgang A1 - Agarwal, Kshitij A1 - Bulla, Mattia A1 - Coughlin, Michael W. A1 - Van den Broeck, Chris T1 - Constraining neutron-star matter with microscopic and macroscopic collisions JF - Nature : the international weekly journal of science N2 - Interpreting high-energy, astrophysical phenomena, such as supernova explosions or neutron-star collisions, requires a robust understanding of matter at supranuclear densities. However, our knowledge about dense matter explored in the cores of neutron stars remains limited. Fortunately, dense matter is not probed only in astrophysical observations, but also in terrestrial heavy-ion collision experiments. Here we use Bayesian inference to combine data from astrophysical multi-messenger observations of neutron stars(1-9) and from heavy-ion collisions of gold nuclei at relativistic energies(10,11) with microscopic nuclear theory calculations(12-17) to improve our understanding of dense matter. We find that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent observations by the Neutron Star Interior Composition Explorer mission(5-8,18). Our findings show that constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. This work combines nuclear theory, nuclear experiment and astrophysical observations, and shows how joint analyses can shed light on the properties of neutron-rich supranuclear matter over the density range probed in neutron stars. Y1 - 2022 U6 - https://doi.org/10.1038/s41586-022-04750-w SN - 0028-0836 SN - 1476-4687 VL - 606 IS - 7913 SP - 276 EP - 295 PB - Nature Publ. Group CY - London [u.a.] ER - TY - JOUR A1 - Kluge, Lucas A1 - Socolar, Joshua E. S. A1 - Schöll, Eckehard T1 - Random logic networks BT - from classical Boolean to quantum dynamics JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - We investigate dynamical properties of a quantum generalization of classical reversible Boolean networks. The state of each node is encoded as a single qubit, and classical Boolean logic operations are supplemented by controlled bit-flip and Hadamard operations. We consider synchronous updating schemes in which each qubit is updated at each step based on stored values of the qubits from the previous step. We investigate the periodic or quasiperiodic behavior of quantum networks, and we analyze the propagation of single site perturbations through the quantum networks with input degree one. A nonclassical mechanism for perturbation propagation leads to substantially different evolution of the Hamming distance between the original and perturbed states. Y1 - 2021 U6 - https://doi.org/10.1103/PhysRevE.104.064308 SN - 2470-0045 SN - 2470-0053 VL - 104 IS - 6 PB - American Physical Society CY - Woodbury, NY ER - TY - JOUR A1 - Chigarev, Vladimir A1 - Kazakov, Alexey A1 - Pikovskij, Arkadij T1 - Mutual singularities of overlapping attractor and repeller JF - Chaos : an interdisciplinary journal of nonlinear science N2 - We apply the concepts of relative dimensions and mutual singularities to characterize the fractal properties of overlapping attractor and repeller in chaotic dynamical systems. We consider one analytically solvable example (a generalized baker's map); two other examples, the Anosov-Mobius and the Chirikov-Mobius maps, which possess fractal attractor and repeller on a two-dimensional torus, are explored numerically. We demonstrate that although for these maps the stable and unstable directions are not orthogonal to each other, the relative Renyi and Kullback-Leibler dimensions as well as the mutual singularity spectra for the attractor and repeller can be well approximated under orthogonality assumption of two fractals. Y1 - 2021 U6 - https://doi.org/10.1063/5.0056891 SN - 1054-1500 SN - 1089-7682 VL - 31 IS - 8 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Milde, Peter A1 - Langenhorst, Malte A1 - Hölscher, Hendrik A1 - Rottmann-Matthes, Jens A1 - Hundertmark, Dirk A1 - Eng, Lukas A1 - Hoffmann-Vogel, Regina T1 - Out-of-equilibrium optomechanical resonance self-excitation JF - Journal of applied physics N2 - The fundamental sensitivity limit of atomic force microscopy is strongly correlated to the thermal noise of cantilever oscillation. A method to suppress this unwanted noise is to reduce the bandwidth of the measurement, but this approach is limited by the speed of the measurement and the width of the cantilever resonance, commonly defined through the quality factor Q. However, it has been shown that optomechanical resonances in interferometers might affect cantilever oscillations resulting in an effective quality factor Q(eff). When the laser power is sufficiently increased cantilever oscillations might even reach the regime of self-oscillation. In this self-oscillation state, the noise of the system is partially determined by the interaction with laser light far from equilibrium. Here, we show and discuss how tuning of laser power leads to nonlinear optomechanical effects that can dramatically increase the effective quality factor of the cantilever leading to out-of-equilibrium noise. We model the effects using a fourth order nonlinearity of the damping coefficient. Published under an exclusive license by AIP Publishing. KW - Electrical properties and parameters KW - Ultra-high vacuum KW - Electronic noise KW - Signal processing KW - Noise floor KW - Atomic force microscopy KW - Hooke's law KW - Interferometry KW - Optical resonators KW - Thermo optic effects Y1 - 2021 U6 - https://doi.org/10.1063/5.0054509 SN - 0021-8979 SN - 1089-7550 VL - 130 IS - 3 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Petrov, Polina A1 - Singer, Leo P. A1 - Coughlin, Michael W. A1 - Kumar, Vishwesh A1 - Almualla, Mouza A1 - Anand, Shreya A1 - Bulla, Mattia A1 - Dietrich, Tim A1 - Foucart, Francois A1 - Guessoum, Nidhal T1 - Data-driven expectations for electromagnetic counterpart searches based on LIGO/Virgo public alerts JF - The astrophysical journal : an international review of spectroscopy and astronomical physics; part 1 N2 - Searches for electromagnetic counterparts of gravitational-wave signals have redoubled since the first detection in 2017 of a binary neutron star merger with a gamma-ray burst, optical/infrared kilonova, and panchromatic afterglow. Yet, one LIGO/Virgo observing run later, there has not yet been a second, secure identification of an electromagnetic counterpart. This is not surprising given that the localization uncertainties of events in LIGO and Virgo's third observing run, O3, were much larger than predicted. We explain this by showing that improvements in data analysis that now allow LIGO/Virgo to detect weaker and hence more poorly localized events have increased the overall number of detections, of which well-localized, gold-plated events make up a smaller proportion overall. We present simulations of the next two LIGO/Virgo/KAGRA observing runs, O4 and O5, that are grounded in the statistics of O3 public alerts. To illustrate the significant impact that the updated predictions can have, we study the follow-up strategy for the Zwicky Transient Facility. Realistic and timely forecasting of gravitational-wave localization accuracy is paramount given the large commitments of telescope time and the need to prioritize which events are followed up. We include a data release of our simulated localizations as a public proposal planning resource for astronomers. Y1 - 2022 U6 - https://doi.org/10.3847/1538-4357/ac366d SN - 1538-4357 VL - 924 IS - 2 PB - Institute of Physics Publ. CY - London ER - TY - JOUR A1 - Kollmann, Peter A1 - Roussos, Elias A1 - Clark, George A1 - Cooper, John F. A1 - Sturner, Steven J. A1 - Kotova, Anna A1 - Regoli, Leonardo A1 - Shprits, Yuri A1 - Aseev, Nikita A1 - Krupp, Norbert T1 - Spectra of Saturn's proton belts revealed JF - Icarus N2 - Saturn is permanently surrounded by 6 discrete proton radiation belts that are rigidly separated by the orbits of its inner moons and dense rings. These radiation belts are ideal environments to study the details of radial diffusion and the CRAND source process, yet progress has been hindered by the fact that the energy spectra are not known with certainty: Reanalysis of the response functions of the LEMMS instrument on-board the Cassini orbiter has shown that measurements of less than or similar to 10 MeV protons may be easily contaminated by greater than or similar to 10 MeV protons and that many available measurements characterize a very broad energy range, so that the calculation of an energy-resolved spectrum is not as straightforward as previously assumed. Here we use forward modeling of the measurements based on the instrument response and combine this technique where useful with numerical modeling of the proton belt physics in order to determine Saturn's spectra with higher certainty. We find significant proton intensities up to approximate to 1 GeV. While earlier studies reported on proton spectra roughly following a power law with exponent approximate to -2, our more advanced analysis shows harder spectra with exponent approximate to -1. The observed spectra provide independent confirmation that Saturn's proton belts are sourced by CRAND and are consistent with the provided protons being subsequently cooled in the tenuous gas originating from Saturn or Enceladus. The intensities at Saturn are found to be lower than at Jupiter and Earth, which is also consistent with the source of Saturn being exclusively CRAND, while the other planets can draw from additional processes. Our new spectra can be used in the future to further our understanding of Saturn's proton belts and the respective physical processes that occur at other magnetized planets in general. Also, the spectra have applications for several topics of planetary science, such as space weathering of Saturn's moons and rings, and can be useful to constrain properties of the main rings through their production of secondary particles. KW - Radiation belts KW - Saturn KW - CRAND KW - Proton Y1 - 2022 U6 - https://doi.org/10.1016/j.icarus.2021.114795 SN - 0019-1035 SN - 1090-2643 VL - 376 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Schaerer, Daniel A1 - Izotov, Yuri I. A1 - Worseck, Gábor A1 - Berg, Danielle A1 - Chisholm, John A1 - Jaskot, Anne A1 - Nakajima, Kimihiko A1 - Ravindranath, Swara A1 - Thuan, Trinh X. A1 - Verhamme, Anne T1 - Strong Lyman continuum emitting galaxies show intense C IV λ 1550 emission JF - Astronomy and astrophysics N2 - Using the Space Telescope Imaging Spectrograph, we have obtained ultraviolet spectra from similar to 1200 to 2000 angstrom of known Lyman continuum (LyC) emitting galaxies at low redshift (z similar to 0.3-0.4) with varying absolute LyC escape fractions ( f(esc) similar to 0.01-0.72). Our observations include in particular the galaxy J1243+4646, which has the highest known LyC escape fraction at low redshift. While all galaxies are known Lyman alpha emitters, we consistently detect an inventory of additional emission lines, including C IV lambda 1550, He II lambda 1640, O III] lambda 1666, and C III] lambda 1909, whose origin is presumably essentially nebular. C IV lambda 1550 emission is detected above 4 sigma in six out of eight galaxies, with equivalent widths of EW(C IV) = 12-15 angstrom for two galaxies, which exceeds the previously reported maximum emission in low-z star-forming galaxies. We detect C IV lambda 1550 emission in all LyC emitters with escape fractions f(esc) > 0.1 and find a tentative increase in the flux ratio C IV lambda 1550 /C III] lambda 1909 with f(esc). Based on the data, we propose a new criterion to select and classify strong leakers (galaxies with f(esc) > 0.1): C IV lambda 1550 /C III] lambda 1909 greater than or similar to 0.75. Finally, we also find He II lambda 1640 emission in all the strong leakers with equivalent widths from 3 to 8 angstrom rest frame. These are among the highest values observed in star-forming galaxies and are primarily due to a high rate of ionizing photon production. The nebular He II lambda 1640 emission of the strong LyC emitters does not require harder ionizing spectra at >54 eV compared to those of typical star-forming galaxies at similarly low metallicity. KW - galaxies: starburst KW - galaxies: high-redshift KW - dark ages, reionization KW - first stars KW - ultraviolet: galaxies Y1 - 2022 U6 - https://doi.org/10.1051/0004-6361/202243149 SN - 0004-6361 SN - 1432-0746 VL - 658 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Ciarniello, Mauro A1 - Fulle, Marco A1 - Raponi, Andrea A1 - Filacchione, Gianrico A1 - Capaccioni, Fabrizio A1 - Rotundi, Alessandra A1 - Rinaldi, Giovanna A1 - Formisano, Michelangelo A1 - Magni, Gianfranco A1 - Tosi, Federico A1 - De Sanctis, Maria Cristina A1 - Capria, Maria Teresa A1 - Longobardo, Andrea A1 - Beck, Pierre A1 - Fornasier, Sonia A1 - Kappel, David A1 - Mennella, Vito A1 - Mottola, Stefano A1 - Rousseau, Batiste A1 - Arnold, Gabriele T1 - Macro and micro structures of pebble-made cometary nuclei reconciled by seasonal evolution JF - Nature astronomy N2 - Comets evolve due to sublimation of ices embedded inside porous dust, triggering dust emission (that is, erosion) followed by mass loss, mass redistribution and surface modifications. Surface changes were revealed by the Deep Impact and Stardust NExT missions for comet 9P/Tempel 1 (ref.(1)), and a full inventory of the processes modifying cometary nuclei was provided by Rosetta while it escorted comet 67P/Churyumov-Gerasimenko for approximately two years(2-4). Such observations also showed puzzling water-ice-rich spots that stood out as patches optically brighter and spectrally bluer than the average cometary surfaces(5-9). These are up to tens of metres large and indicate macroscopic compositional dishomogeneities apparently in contrast with the structural homogeneity above centimetre scales of pebble-made nuclei(10). Here we show that the occurrence of blue patches determines the seasonal variability of the nucleus colour(4,11,12) and gives insight into the internal structure of comets. We define a new model that links the centimetre-sized pebbles composing the nucleus(10) and driving cometary activity(13,14) to metre-sized water-ice-enriched blocks embedded in a drier matrix. The emergence of blue patches is due to the matrix erosion driven by CO2-ice sublimation that exposes the water-ice-enriched blocks, which in turn are eroded by water-ice sublimation when exposed to sunlight. Our model explains the observed seasonal evolution of the nucleus and reconciles the available data at micro (sub-centimetre) and macro (metre) scales. KW - Asteroids, comets and Kuiper belt KW - Planetary science Y1 - 2022 U6 - https://doi.org/10.1038/s41550-022-01625-y SN - 2397-3366 VL - 6 IS - 5 SP - 546 EP - 553 PB - Nature Research CY - Berlin ER - TY - JOUR A1 - Dahlenburg, Marcus A1 - Chechkin, Aleksei A1 - Schumer, Rina A1 - Metzler, Ralf T1 - Stochastic resetting by a random amplitude JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - Stochastic resetting, a diffusive process whose amplitude is reset to the origin at random times, is a vividly studied strategy to optimize encounter dynamics, e.g., in chemical reactions. Here we generalize the resetting step by introducing a random resetting amplitude such that the diffusing particle may be only partially reset towards the trajectory origin or even overshoot the origin in a resetting step. We introduce different scenarios for the random-amplitude stochastic resetting process and discuss the resulting dynamics. Direct applications are geophysical layering (stratigraphy) and population dynamics or financial markets, as well as generic search processes. Y1 - 2021 U6 - https://doi.org/10.1103/PhysRevE.103.052123 SN - 2470-0045 SN - 2470-0053 VL - 103 IS - 5 PB - American Physical Society CY - Woodbury, NY ER - TY - JOUR A1 - Petreska, Irina A1 - Sandev, Trifce A1 - Lenzi, Ervin Kaminski T1 - Comb-like geometric constraints leading to emergence of the time-fractional Schrödinger equation JF - Modern physics letters : A, Particles and fields, gravitation, cosmology, nuclear physics N2 - This paper presents an overview over several examples, where the comb-like geometric constraints lead to emergence of the time-fractional Schrodinger equation. Motion of a quantum object on a comb structure is modeled by a suitable modification of the kinetic energy operator, obtained by insertion of the Dirac delta function in the Laplacian. First, we consider motion of a free particle on two- and three-dimensional comb structures, and then we extend the study to the interacting cases. A general form of a nonlocal term, which describes the interactions of the particle with the medium, is included in the Hamiltonian, and later on, the cases of constant and Dirac delta potentials are analyzed. At the end, we discuss the case of non-integer dimensions, considering separately the case of fractal dimension between one and two, and the case of fractal dimension between two and three. All these examples show that even though we are starting with the standard time-dependent Schrodinger equation on a comb, the time-fractional equation for the Green's functions appears, due to these specific geometric constraints. KW - Comb model KW - time-fractional Schrödinger equation KW - Green’ s functions Y1 - 2021 U6 - https://doi.org/10.1142/S0217732321300056 SN - 0217-7323 SN - 1793-6632 VL - 36 IS - 14 PB - World Scientific CY - Singapore ER -