TY - THES A1 - Partl, Adrian M. T1 - Cosmological radiative transfer and the lonisation of the integalactic medium Y1 - 2011 CY - Potsdam ER - TY - THES A1 - Osterloh, Lukas T1 - Retrieving aerosol microphysical properties from multiwavelength Lidar Data Y1 - 2011 CY - Potsdam ER - TY - THES A1 - Matthes, Heidrun T1 - Interaction of land surface processes and the atmophere in the Arctic - senitivities and extremes Y1 - 2011 CY - Potsdam ER - TY - THES A1 - Dosche, Carsten T1 - Funktionale Farbstoffe und ihre Photophysik und Anwendung in komplexen Matrizes Y1 - 2011 CY - Potsdam ER - TY - BOOK A1 - Brehmer, Ludwig T1 - Die Brandeburgische Landeshochschule zu Potsdam im Jahre eins : die Hochschule in Potsdamer Schulen ; Daten und Fakten ; Kommentare und Dokumente Y1 - 2011 SN - 978-3-00-034135-9 VL - 4 PB - Eigenverl. des Verf CY - Potsdam ER - TY - THES A1 - Schewe, Jacob T1 - Basic physical mechanisms for monsoon failure in past and future climate Y1 - 2011 CY - Potsdam ER - TY - THES A1 - Mielke, Moritz T1 - Atmosphärische Prozesstudien auf der Basis von Beobachtungen und regionalen Klimamodellsimulationen in der Arktis Y1 - 2011 CY - Potsdam ER - TY - THES A1 - Koseska, Aneta T1 - Dynamics of biological networks : data analysis, modeling and bifurcations Y1 - 2011 CY - Potsdam ER - TY - JOUR A1 - Janotta, Peter A1 - Gogolin, Christian A1 - Barrett, Jonathan A1 - Brunner, Nicolas T1 - Limits on nonlocal correlations from the structure of the local state space JF - New journal of physics : the open-access journal for physics N2 - The outcomes of measurements on entangled quantum systems can be nonlocally correlated. However, while it is easy to write down toy theories allowing arbitrary nonlocal correlations, those allowed in quantum mechanics are limited. Quantum correlations cannot, for example, violate a principle known as macroscopic locality, which implies that they cannot violate Tsirelson's bound. This paper shows that there is a connection between the strength of nonlocal correlations in a physical theory and the structure of the state spaces of individual systems. This is illustrated by a family of models in which local state spaces are regular polygons, where a natural analogue of a maximally entangled state of two systems exists. We characterize the nonlocal correlations obtainable from such states. The family allows us to study the transition between classical, quantum and super-quantum correlations by varying only the local state space. We show that the strength of nonlocal correlations-in particular whether the maximally entangled state violates Tsirelson's bound or not-depends crucially on a simple geometric property of the local state space, known as strong self-duality. This result is seen to be a special case of a general theorem, which states that a broad class of entangled states in probabilistic theories-including, by extension, all bipartite classical and quantum states-cannot violate macroscopic locality. Finally, our results show that models exist that are locally almost indistinguishable from quantum mechanics, but can nevertheless generate maximally nonlocal correlations. Y1 - 2011 U6 - https://doi.org/10.1088/1367-2630/13/6/063024 SN - 1367-2630 VL - 13 IS - 23 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Brandao, F. G. S. L. A1 - Eisert, Jens A1 - Horodecki, M. A1 - Yang, Dong T1 - Entangled inputs cannot make imperfect quantum channels perfect JF - Physical review letters N2 - Entangled inputs can enhance the capacity of quantum channels, this being one of the consequences of the celebrated result showing the nonadditivity of several quantities relevant for quantum information science. In this work, we answer the converse question (whether entangled inputs can ever render noisy quantum channels to have maximum capacity) to the negative: No sophisticated entangled input of any quantum channel can ever enhance the capacity to the maximum possible value, a result that holds true for all channels both for the classical as well as the quantum capacity. This result can hence be seen as a bound as to how "nonadditive quantum information can be.'' As a main result, we find first practical and remarkably simple computable single-shot bounds to capacities, related to entanglement measures. As examples, we discuss the qubit amplitude damping and identify the first meaningful bound for its classical capacity. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.106.230502 SN - 0031-9007 VL - 106 IS - 23 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Schmidt, Hans-Jürgen T1 - Perihelion advance for orbits with large eccentricities in the Schwarzschild black hole JF - Physical review : D, Particles, fields, gravitation, and cosmology N2 - We deduce a new formula for the perihelion advance Theta of a test particle in the Schwarzschild black hole by applying a newly developed nonlinear transformation within the Schwarzschild space-time. By this transformation we are able to apply the well-known formula valid in the weak-field approximation near infinity also to trajectories in the strong-field regime near the horizon of the black hole. The resulting formula has the structure Theta = c(1) - c(2) ln(c(3)(2) - e(2)) with positive constants c(1,2,3) depending on the angular momentum of the test particle. It is especially useful for orbits with large eccentricities e < c(3) < 1 showing that Theta -> infinity as e -> c(3). Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevD.83.124010 SN - 1550-7998 VL - 83 IS - 12 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Worseck, Gabor A1 - Prochaska, J. Xavier A1 - McQuinn, Matthew A1 - Dall'Aglio, Aldo A1 - Fechner, Cora A1 - Hennawi, Joseph F. A1 - Reimers, Dieter A1 - Richter, Philipp A1 - Wisotzki, Lutz T1 - The end of Helium Reionization at z similar or equal to 2.7 Inferred from cosmic variance in HST/COS He II Ly alpha Absorption spectra JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters N2 - We report on the detection of strongly varying intergalactic He II absorption in HST/COS spectra of two z(em) similar or equal to 3 quasars. From our homogeneous analysis of the He II absorption in these and three archival sightlines, we find a marked increase in the mean He II effective optical depth from similar or equal to 1 at z similar or equal to 2.3 to greater than or similar to 5 at z similar or equal to 3.2, but with a large scatter of 2 less than or similar to tau(eff, He II) less than or similar to 5 at 2.7 < z < 3 on scales of similar to 10 proper Mpc. This scatter is primarily due to fluctuations in the He II fraction and the He II-ionizing background, rather than density variations that are probed by the coeval Hi forest. Semianalytic models of He II absorption require a strong decrease in the He II-ionizing background to explain the strong increase of the absorption at z greater than or similar to 2.7, probably indicating He II reionization was incomplete at z(reion) greater than or similar to 2.7. Likewise, recent three-dimensional numerical simulations of He II reionization qualitatively agree with the observed trend only if He II reionization completes at z(reion) similar or equal to 2.7 or even below, as suggested by a large tau(eff, He II) greater than or similar to 3 in two of our five sightlines at z < 2.8. By doubling the sample size at 2.7 less than or similar to z less than or similar to 3, our newly discovered He II sightlines for the first time probe the diversity of the second epoch of reionization when helium became fully ionized. KW - dark ages, reionization, first stars KW - diffuse radiation KW - intergalactic medium KW - quasars: absorption lines KW - quasars: individual (SDSS J092447.36+485242.8, SDSS J110155.74+105302.3) Y1 - 2011 U6 - https://doi.org/10.1088/2041-8205/733/2/L24 SN - 2041-8205 VL - 733 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Zakharova, Anna A1 - Kurths, Jürgen A1 - Vadivasova, Tatyana A1 - Koseska, Aneta T1 - Analysing dynamical behavior of cellular networks via stochastic bifurcations JF - PLoS one N2 - The dynamical structure of genetic networks determines the occurrence of various biological mechanisms, such as cellular differentiation. However, the question of how cellular diversity evolves in relation to the inherent stochasticity and intercellular communication remains still to be understood. Here, we define a concept of stochastic bifurcations suitable to investigate the dynamical structure of genetic networks, and show that under stochastic influence, the expression of given proteins of interest is defined via the probability distribution of the phase variable, representing one of the genes constituting the system. Moreover, we show that under changing stochastic conditions, the probabilities of expressing certain concentration values are different, leading to different functionality of the cells, and thus to differentiation of the cells in the various types. Y1 - 2011 U6 - https://doi.org/10.1371/journal.pone.0019696 SN - 1932-6203 VL - 6 IS - 5 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Jewitt, David A1 - Weaver, Harold A1 - Mutchler, Max A1 - Larson, Stephen A1 - Agarwal, Jessica T1 - Hubble space telescope observations of main-belt comet (596) scheila JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters N2 - We present Hubble Space Telescope Observations of (596) Scheila during its recent dust outburst. The nucleus remained point-like with absolute magnitude H(V) = 8.85 +/- 0.02 in our data, equal to the pre-outburst value, with no secondary fragments of diameter >= 100m (for assumed albedos 0.04). We find a coma having a peak scattering cross section similar to 2.2x10(4) km(2), corresponding to a mass in micron-sized particles of similar to 4x10(7) kg. The particles are deflected by solar radiation pressure on projected spatial scales similar to 2x10(4) km, in the sunward direction, and swept from the vicinity of the nucleus on timescales of weeks. The coma fades by similar to 30% between observations on UT 2010 December 27 and 2011 January 4. The observed mass loss is inconsistent with an origin either by rotational instability of the nucleus or by electrostatic ejection of regolith charged by sunlight. Dust ejection could be caused by the sudden but unexplained exposure of buried ice. However, the data are most simply explained by the impact, at similar to 5 km s(-1), of a previously unknown asteroid similar to 35m in diameter. KW - comets: general KW - comets: individual ((596) Scheila) KW - minor planets, asteroids: general Y1 - 2011 U6 - https://doi.org/10.1088/2041-8205/733/1/L4 SN - 2041-8205 VL - 733 IS - 1 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Postberg, Frank A1 - Schmidt, J. A1 - Hillier, J. A1 - Kempf, Sascha A1 - Srama, Ralf T1 - A salt-water reservoir as the source of a compositionally stratified plume on Enceladus JF - Nature : the international weekly journal of science N2 - The discovery of a plume of water vapour and ice particles emerging from warm fractures ('tiger stripes') in Saturn's small, icy moon Enceladus(1-6) raised the question of whether the plume emerges from a subsurface liquid source(6-8) or from the decomposition of ice(9-12). Previous compositional analyses of particles injected by the plume into Saturn's diffuse E ring have already indicated the presence of liquid water(8), but the mechanisms driving the plume emission are still debated(13). Here we report an analysis of the composition of freshly ejected particles close to the sources. Salt-rich ice particles are found to dominate the total mass flux of ejected solids (more than 99 per cent) but they are depleted in the population escaping into Saturn's E ring. Ice grains containing organic compounds are found to be more abundant in dense parts of the plume. Whereas previous Cassini observations were compatible with a variety of plume formation mechanisms, these data eliminate or severely constrain non-liquid models and strongly imply that a salt-water reservoir with a large evaporating surface(7,8) provides nearly all of the matter in the plume. Y1 - 2011 U6 - https://doi.org/10.1038/nature10175 SN - 0028-0836 VL - 474 IS - 7353 SP - 620 EP - 622 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Kar, Parimal A1 - Lipowsky, Reinhard A1 - Knecht, Volker T1 - Importance of polar solvation for cross-reactivity of antibody and its variants with steroids JF - The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces & biophysical chemistry N2 - Understanding the factors determining the binding of ligands to receptors in detail is essential for rational drug design. Here, the free energies of binding of the steroids progesterone (PRG) and 5 beta-androstane-3,17-dione (SAD) to the Diels-Alderase antibody 1E9, as well as the Leu(H47)Trp/Arg(H100)Trp 1E9 double mutant (1E9dm) and the corresponding single mutants, have been estimated and decomposed using the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method. Also the difference in binding free energies between the PRG-1E9dm complex and the complex of PRG with the antiprogesterone antibody DB3 have been evaluated and decomposed. The steroids bind less strongly to 1E9 than to DB3, but the mutations tend to improve the steroid affinity, in quantitative agreement with experimental data. Although the complexes formed by PRG or SAD with 1E9dm and by PRG with DB3 have similar affinity, the binding mechanisms are different. Reduced Waals for SAD-1E9dm versus PRG-1E9dm or for PRG-1E9dm versus PRG-DB3 are energetically compensated by an increased solvation of polar groups, partly contrasting previous conclusions based on structural inspection. Our study illustrates that deducing binding mechanisms from structural models alone can be misleading. Therefore, taking into account solvation effects as in MM-PBSA calculations is essential to elucidate molecular recognition. Y1 - 2011 U6 - https://doi.org/10.1021/jp201538t SN - 1520-6106 VL - 115 IS - 23 SP - 7661 EP - 7669 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Masanes, Lluis A1 - Müller, Markus P. T1 - A derivation of quantum theory from physical requirements JF - New journal of physics : the open-access journal for physics N2 - Quantum theory (QT) is usually formulated in terms of abstract mathematical postulates involving Hilbert spaces, state vectors and unitary operators. In this paper, we show that the full formalism of QT can instead be derived from five simple physical requirements, based on elementary assumptions regarding preparations, transformations and measurements. This is very similar to the usual formulation of special relativity, where two simple physical requirements-the principles of relativity and light speed invariance-are used to derive the mathematical structure of Minkowski space-time. Our derivation provides insights into the physical origin of the structure of quantum state spaces (including a group-theoretic explanation of the Bloch ball and its three dimensionality) and suggests several natural possibilities to construct consistent modifications of QT. Y1 - 2011 U6 - https://doi.org/10.1088/1367-2630/13/6/063001 SN - 1367-2630 VL - 13 IS - 1 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Makhmudo, K. O. A1 - Makhmudov, O. I. A1 - Tarkhanov, Nikolai Nikolaevich T1 - Equations of Maxwell type JF - Journal of mathematical analysis and applications N2 - For an elliptic complex of first order differential operators on a smooth manifold X, we define a system of two equations which can be thought of as abstract Maxwell equations. The formal theory of this system proves to be very similar to that of classical Maxwell's equations. The paper focuses on boundary value problems for the abstract Maxwell equations, especially on the Cauchy problem. KW - Electromagnetic waves KW - Scattering KW - Elliptic complex KW - Green formulas KW - Stratton-Chu formulas KW - Cauchy problem Y1 - 2011 U6 - https://doi.org/10.1016/j.jmaa.2011.01.012 SN - 0022-247X VL - 378 IS - 1 SP - 64 EP - 75 PB - Elsevier CY - San Diego ER - TY - JOUR A1 - Baumgärtel, Hellmut T1 - A Characteristic decay semigroup for the resonances of trace class perturbations with analyticity conditions of semibounded hamiltonians JF - International journal of theoretical physic N2 - To asymptotic complete scattering systems {M(+) + V, M(+)} on H(+) := L(2)(R(+), K, d lambda), where M(+) is the multiplication operator on H(+) and V is a trace class operator with analyticity conditions, a decay semigroup is associated such that the spectrum of the generator of this semigroup coincides with the set of all resonances (poles of the analytic continuation of the scattering matrix into the lower half plane across the positive half line), i.e. the decay semigroup yields a "time-dependent" characterization of the resonances. As a counterpart a "spectral characterization" is mentioned which is due to the "eigenvalue-like" properties of resonances. KW - Resonances KW - Scattering theory KW - Lax-Phillips theory KW - Decay semigroups Y1 - 2011 U6 - https://doi.org/10.1007/s10773-010-0533-9 SN - 0020-7748 VL - 50 IS - 7 SP - 2002 EP - 2008 PB - Springer CY - New York ER - TY - JOUR A1 - Grass, T. D. A1 - dos Santos, Francisca E. A. A1 - Pelster, Axel T1 - Real-time Ginzburg-Landau theory for bosons in optical lattices JF - Laser physics N2 - Within the Schwinger-Keldysh formalism we derive a Ginzburg-Landau theory for the Bose-Hubbard model which describes the real-time dynamics of the complex order parameter field. Analyzing the excitations in the vicinity of the quantum phase transitions it turns out that particle/hole dispersions in the Mott phase map continuously onto corresponding amplitude/phase excitations in the superfluid phase. Furthermore, in the superfluid phase we find a sound mode, which is in accordance with recent Bragg spectroscopy measurements in the Bogoliubov regime, as well as an additional gapped mode, which seems to have been detected via lattice modulation. Y1 - 2011 U6 - https://doi.org/10.1134/S1054660X11150096 SN - 1054-660X SN - 1555-6611 VL - 21 IS - 8 SP - 1459 EP - 1463 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Levnajic, Zoran T1 - Emergent multistability and frustration in phase-repulsive networks of oscillators JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - The collective dynamics of oscillator networks with phase-repulsive coupling is studied, considering various network sizes and topologies. The notion of link frustration is introduced to characterize and quantify the network dynamical states. In opposition to widely studied phase-attractive case, the properties of final dynamical states in our model critically depend on the network topology. In particular, each network's total frustration value is intimately related to its topology. Moreover, phase-repulsive networks in general display multiple final frustration states, whose statistical and stability properties are uniquely identifying them. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.84.016231 SN - 1539-3755 VL - 84 IS - 1 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Fechner, Cora T1 - Reconstructing the intergalactic UV background with QSO absorption lines JF - Astronomy and astrophysics : an international weekly journal N2 - We present a new approach to observationally constraining the spectral energy distribution of the intergalactic UV background by studying metal absorption systems. We study single-component metal line systems that exhibit various well-measured species. Among the observed transitions, at least two ratios of ionization stages from the same element are required, e. g. C III/C IV and Si III/Si IV. For each system photoionization models are constructed by varying the spectrum of the ionizing radiation. The spectral energy distribution can then be constrained by comparing the models with the observed column density ratios. Extensive tests with artificial absorbers show that the spectrum of the ionizing radiation cannot be reconstructed unambiguously, but it is possible to constrain the main characteristics of the spectrum. Furthermore, the resulting physical parameters of the absorber, such as ionization parameter, metallicity, and relative abundances, may depend strongly on the adopted ionizing spectrum. Even in case of well-fitting models, the uncertainties can be as high as similar to 0.5 dex for the ionization parameter and up to similar to 1.5 dex for the metallicity. Therefore, it is essential to know the hardness of the UV background when estimating the metallicity of the intergalactic medium. Applying the procedure to a small sample of 3 observed single-component metal line systems yields a soft ionizing radiation at z > 2 and a slightly harder spectrum at z < 2. The resulting energy distributions exhibit strong He II Lya re-emission features, suggesting that reprocessing by intergalactic He II is important. Comparing the observed systems to UV background spectra from the literature indicates that a recent model that includes sawtooth modulation due to reprocessing by intergalactic He II with delayed helium reionization fits the investigated systems very well. KW - intergalactic medium KW - quasars: absorption lines KW - diffuse radiation Y1 - 2011 U6 - https://doi.org/10.1051/0004-6361/201117080 SN - 0004-6361 VL - 532 IS - 2 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Gerhardt, Matthias A1 - Groeger, Gillian A1 - MacCarthy, Niall T1 - Monopolar vs. bipolar subretinal stimulation-An in vitro study JF - Journal of neuroscience methods N2 - This study uses an in vitro rd10 mouse model to quantify and compare the ability of the monopolar and the (concentric) bipolar electrode configurations for subretinal stimulation. To allow for results which can be directly compared an identical region of the retina was stimulated due to the circumstance that the bipolar electrode configuration allows also for monopolar stimulation, if the concentric counter-electrode is set potential-free (floating). A ganglion cell, located centrally over the bipolar electrode configuration was selected to extracellularly record action potentials during stimulation. To analyse the recorded action potentials, we introduce a new method which combines the advantages of (a) singular value decomposition (SVD) for weighting similar modulation patterns with which the recorded action potentials are characterized and (b) multi curve fitting to identify a common threshold level, required to finally assemble a strength-duration relationship (SDR). By directly comparing the obtained SDR curves, we found that the efficiency of stimulation with the monopolar electrode configuration is significantly higher than with the bipolar electrode configuration. All obtained SDR curves were fitted using the Lapicque model to estimate the chronaxie times and the rheobase currents. Liquid inclusions, eventually separating the retina from the electrodes are discussed to be a major cause for low ganglion cell responses during stimulation with the bipolar electrode configuration. KW - SVD KW - Subretinal KW - Electrodes KW - Monopolar KW - Bipolar KW - Retina KW - Ganglion KW - Cells Y1 - 2011 U6 - https://doi.org/10.1016/j.jneumeth.2011.04.017 SN - 0165-0270 VL - 199 IS - 1 SP - 26 EP - 34 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Prosen, Tomaz A1 - Ilievski, Enej T1 - Nonequilibrium phase transition in a periodically driven XY spin chain JF - Physical review letters N2 - We present a general formulation of Floquet states of periodically time-dependent open Markovian quasifree fermionic many-body systems in terms of a discrete Lyapunov equation. Illustrating the technique, we analyze periodically kicked XY spin-1/2 chain which is coupled to a pair of Lindblad reservoirs at its ends. A complex phase diagram is reported with reentrant phases of long range and exponentially decaying spin-spin correlations as some of the system's parameters are varied. The structure of phase diagram is reproduced in terms of counting nontrivial stationary points of Floquet quasiparticle dispersion relation. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.060403 SN - 0031-9007 VL - 107 IS - 6 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - DiGuglielmo, J. A1 - Samblowski, A. A1 - Hage, B. A1 - Pineda, Carlos A1 - Eisert, Jens A1 - Schnabel, R. T1 - Experimental Unconditional Preparation and Detection of a Continuous Bound Entangled State of Light JF - Physical review letters N2 - Among the possibly most intriguing aspects of quantum entanglement is that it comes in free and bound instances. The existence of bound entangled states certifies an intrinsic irreversibility of entanglement in nature and suggests a connection with thermodynamics. In this Letter, we present a first unconditional, continuous-variable preparation and detection of a bound entangled state of light. We use convex optimization to identify regimes rendering its bound character well certifiable, and continuously produce a distributed bound entangled state with an extraordinary and unprecedented significance of more than 10 standard deviations away from both separability and distillability. Our results show that the approach chosen allows for the efficient and precise preparation of multimode entangled states of light with various applications in quantum information, quantum state engineering, and high precision metrology. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.240503 SN - 0031-9007 VL - 107 IS - 24 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Lisso, Janina A1 - Schröder, Florian A1 - Fisahn, Joachim A1 - Muessig, Carsten T1 - NFX1-LIKE2 (NFXL2) Suppresses Abscisic Acid Accumulation and Stomatal Closure in Arabidopsis thaliana JF - PLoS one N2 - The NFX1-LIKE1 (NFXL1) and NFXL2 genes were identified as regulators of salt stress responses. The NFXL1 protein is a nuclear factor that positively affects adaptation to salt stress. The nfxl1-1 loss-of-function mutant displayed reduced survival rates under salt and high light stress. In contrast, the nfxl2-1 mutant, defective in the NFXL2 gene, and NFXL2-antisense plants exhibited enhanced survival under these conditions. We show here that the loss of NFXL2 function results in abscisic acid (ABA) overaccumulation, reduced stomatal conductance, and enhanced survival under drought stress. The nfxl2-1 mutant displayed reduced stomatal aperture under all conditions tested. Fusicoccin treatment, exposition to increasing light intensities, and supply of decreasing CO2 concentrations demonstrated full opening capacity of nfxl2-1 stomata. Reduced stomatal opening presumably is a consequence of elevated ABA levels. Furthermore, seedling growth, root growth, and stomatal closure were hypersensitive to exogenous ABA. The enhanced ABA responses may contribute to the improved drought stress resistance of the mutant. Three NFXL2 splice variants were cloned and named NFXL2-78, NFXL2-97, and NFXL2-100 according to the molecular weight of the putative proteins. Translational fusions to the green fluorescent protein suggest nuclear localisation of the NFXL2 proteins. Stable expression of the NFXL2-78 splice variant in nfxl2-1 plants largely complemented the mutant phenotype. Our data show that NFXL2 controls ABA levels and suppresses ABA responses. NFXL2 may prevent unnecessary and costly stress adaptation under favourable conditions. Y1 - 2011 U6 - https://doi.org/10.1371/journal.pone.0026982 SN - 1932-6203 VL - 6 IS - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Abel, M. W. A1 - Shepelyansky, Dima L. T1 - Google matrix of business process management JF - The European physical journal : B, Condensed matter and complex systems N2 - Development of efficient business process models and determination of their characteristic properties are subject of intense interdisciplinary research. Here, we consider a business process model as a directed graph. Its nodes correspond to the units identified by the modeler and the link direction indicates the causal dependencies between units. It is of primary interest to obtain the stationary flow on such a directed graph, which corresponds to the steady-state of a firm during the business process. Following the ideas developed recently for the World Wide Web, we construct the Google matrix for our business process model and analyze its spectral properties. The importance of nodes is characterized by PageRank and recently proposed CheiRank and 2DRank, respectively. The results show that this two-dimensional ranking gives a significant information about the influence and communication properties of business model units. We argue that the Google matrix method, described here, provides a new efficient tool helping companies to make their decisions on how to evolve in the exceedingly dynamic global market. Y1 - 2011 U6 - https://doi.org/10.1140/epjb/e2010-10710-y SN - 1434-6028 VL - 84 IS - 4 SP - 493 EP - 500 PB - Springer CY - New York ER - TY - JOUR A1 - Abdolvahab, Rouhollah Haji A1 - Metzler, Ralf A1 - Ejtehadi, Mohammad Reza T1 - First passage time distribution of chaperone driven polymer translocation through a nanopore homopolymer and heteropolymer cases JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr N2 - Combining the advection-diffusion equation approach with Monte Carlo simulations we study chaperone driven polymer translocation of a stiff polymer through a nanopore. We demonstrate that the probability density function of first passage times across the pore depends solely on the Peclet number, a dimensionless parameter comparing drift strength and diffusivity. Moreover it is shown that the characteristic exponent in the power-law dependence of the translocation time on the chain length, a function of the chaperone-polymer binding energy, the chaperone concentration, and the chain length, is also effectively determined by the Peclet number. We investigate the effect of the chaperone size on the translocation process. In particular, for large chaperone size, the translocation progress and the mean waiting time as function of the reaction coordinate exhibit pronounced sawtooth-shapes. The effects of a heterogeneous polymer sequence on the translocation dynamics is studied in terms of the translocation velocity, the probability distribution for the translocation progress, and the monomer waiting times. (C) 2011 American Institute of Physics. Y1 - 2011 U6 - https://doi.org/10.1063/1.3669427 SN - 0021-9606 VL - 135 IS - 24 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Gruber, W. A1 - Chakravarty, S. A1 - Baehtz, C. A1 - Leitenberger, Wolfram A1 - Bruns, M. A1 - Kobler, A. A1 - Kübel, Christian A1 - Schmidt, H. T1 - Strain relaxation and vacancy creation in thin platinum films JF - Physical review letters N2 - Synchrotron based combined in situ x-ray diffractometry and reflectometry is used to investigate the role of vacancies for the relaxation of residual stress in thin metallic Pt films. From the experimentally determined relative changes of the lattice parameter a and of the film thickness L the modification of vacancy concentration and residual strain was derived as a function of annealing time at 130 degrees C. The results indicate that relaxation of strain resulting from compressive stress is accompanied by the creation of vacancies at the free film surface. This proves experimentally the postulated dominant role of vacancies for stress relaxation in thin metal films close to room temperature. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.265501 SN - 0031-9007 VL - 107 IS - 26 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Kuznetsov, Sergey P. T1 - Plykin type attractor in electronic device simulated in MULTISIM JF - Chaos : an interdisciplinary journal of nonlinear science N2 - An electronic device is suggested representing a non-autonomous dynamical system with hyperbolic chaotic attractor of Plykin type in the stroboscopic map, and the results of its simulation with software package NI MULTISIM are considered in comparison with numerical integration of the underlying differential equations. A main practical advantage of electronic devices of this kind is their structural stability that means insensitivity of the chaotic dynamics in respect to variations of functions and parameters of elements constituting the system as well as to interferences and noises. Y1 - 2011 U6 - https://doi.org/10.1063/1.3646903 SN - 1054-1500 VL - 21 IS - 4 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Feudel, Fred A1 - Bergemann, Kay A1 - Tuckerman, Laurette S. A1 - Egbers, C. A1 - Futterer, B. A1 - Gellert, Marcus A1 - Hollerbach, Rainer T1 - Convection patterns in a spherical fluid shell JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - Symmetry-breaking bifurcations have been studied for convection in a nonrotating spherical shell whose outer radius is twice the inner radius, under the influence of an externally applied central force field with a radial dependence proportional to 1/r(5). This work is motivated by the GeoFlow experiment, which is performed under microgravity condition at the International Space Station where this particular central force can be generated. In order to predict the observable patterns, simulations together with path-following techniques and stability computations have been applied. Branches of axisymmetric, octahedral, and seven-cell solutions have been traced. The bifurcations producing them have been identified and their stability ranges determined. At higher Rayleigh numbers, time-periodic states with a complex spatiotemporal symmetry are found, which we call breathing patterns. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.83.046304 SN - 1539-3755 VL - 83 IS - 4 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Richter, Philipp A1 - Krause, F. A1 - Fechner, Cora A1 - Charlton, Jane C. A1 - Murphy, M. T. T1 - The neutral gas extent of galaxies as derived from weak intervening Ca II absorbers JF - Astronomy and astrophysics : an international weekly journal N2 - We present a systematic study of weak intervening CaII absorbers at low redshift (z < 0.5), based on the analysis of archival high-resolution (R >= 45 000) optical spectra of 304 quasars and active galactic nuclei observed with VLT/UVES. Along a total redshift path of Delta z approximate to 100 we detected 23 intervening CaII absorbers in both the CaII H & K lines, with rest frame equivalent widths W-r,W-3934 = 15-799 m angstrom and column densities log N(CaII) = 11.25-13.04 (obtained by fitting Voigt-profile components). We obtain a bias-corrected number density of weak intervening CaII absorbers of dN/dz = 0.117 +/- 0.044 at < z(abs)> = 0.35 for absorbers with log N(CaII) >= 11.65 (W-r,W-3934 >= 32 m angstrom). This is similar to 2.6 times the value obtained for damped Lyman alpha absorbers (DLAs) at low redshift. All CaII absorbers in our sample show associated absorption by other low ions such as MgII and FeII; 45 percent of them have associated NaI absorption. From ionization modelling we conclude that intervening CaII absorption with log N(CaII) >= 11.5 arises in DLAs, sub-DLAs and Lyman-limit systems (LLS) at HI column densities of log N(HI) >= 17.4. Using supplementary HI information for nine of the absorbers we find that the CaII/HI ratio decreases strongly with increasing HI column density, indicating a column-density-dependent dust depletion of Ca. The observed column density distribution function of CaII absorption components follows a relatively steep power law, f(N) proportional to N-beta, with a slope of -beta = -1.68, which again points towards an enhanced dust depletion in high column density systems. The relatively large cross section of these absorbers together with the frequent detection of CaII absorption in high-velocity clouds (HVCs) in the halo of the Milky Way suggests that a considerable fraction of the intervening CaII systems trace (partly) neutral gas structures in the halos and circumgalactic environment of galaxies (i.e., they are HVC analogs). Based on the recently measured detection rate of CaII absorption in the Milky Way HVCs we estimate that the mean (projected) CaII covering fraction of galaxies and their gaseous halos is < f(c,CaII)> = 0.33. Using this value and considering all galaxies with luminosities L >= 0.05 L-star we calculate that the characteristic radial extent of (partly) neutral gas clouds with log N(HI) >= 17.4 around low-redshift galaxies is R-HVC approximate to 55 kpc. KW - galaxies: halos KW - galaxies: formation KW - galaxies: ISM KW - intergalactic medium KW - quasars: absorption lines Y1 - 2011 U6 - https://doi.org/10.1051/0004-6361/201015566 SN - 0004-6361 VL - 528 IS - 4 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Müller, Markus P. A1 - Gross, David A1 - Eisert, Jens T1 - Concentration of Measure for Quantum States with a Fixed Expectation Value JF - Communications in mathematical physics N2 - Given some observable H on a finite-dimensional quantum system, we investigate the typical properties of random state vectors vertical bar psi >> that have a fixed expectation value < psi vertical bar H vertical bar psi > = E with respect to H. Under some conditions on the spectrum, we prove that this manifold of quantum states shows a concentration of measure phenomenon: any continuous function on this set is almost everywhere close to its mean. We also give a method to estimate the corresponding expectation values analytically, and we prove a formula for the typical reduced density matrix in the case that H is a sum of local observables. We discuss the implications of our results as new proof tools in quantum information theory and to study phenomena in quantum statistical mechanics. As a by-product, we derive a method to sample the resulting distribution numerically, which generalizes the well-known Gaussian method to draw random states from the sphere. Y1 - 2011 U6 - https://doi.org/10.1007/s00220-011-1205-1 SN - 0010-3616 VL - 303 IS - 3 SP - 785 EP - 824 PB - Springer CY - New York ER - TY - JOUR A1 - Mann, R. B. A1 - Young, M. B. A1 - Fuüntes-Schuller, I. T1 - A perturbative approach to inelastic collisions in a Bose-Einstein condensate JF - Journal of physics : B, Atomic, molecular and optical physics N2 - It has recently been discovered that for certain rates of mode-exchange collisions analytic solutions can be found for a Hamiltonian describing the two-mode Bose-Einstein condensate. We proceed to study the behaviour of the system using perturbation theory if the coupling constants only approximately match these parameter constraints. We find that the model is robust to such perturbations. We study the effects of degeneracy on the perturbations and find that the induced changes differ greatly from the non-degenerate case. We also model inelastic collisions that result in particle loss or condensate decay as external perturbations and use this formalism to examine the effects of three-body recombination and background collisions. Y1 - 2011 U6 - https://doi.org/10.1088/0953-4075/44/8/085301 SN - 0953-4075 VL - 44 IS - 8 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Valleriani, Angelo A1 - Zhang, Gong A1 - Nagar, Apoorva A1 - Ignatova, Zoya A1 - Lipowsky, Reinhard T1 - Length-dependent translation of messenger RNA by ribosomes JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - A simple measure for the efficiency of protein synthesis by ribosomes is provided by the steady state amount of protein per messenger RNA (mRNA), the so-called translational ratio, which is proportional to the translation rate. Taking the degradation of mRNA into account, we show theoretically that both the translation rate and the translational ratio decrease with increasing mRNA length, in agreement with available experimental data for the prokaryote Escherichia coli. We also show that, compared to prokaryotes, mRNA degradation in eukaryotes leads to a less rapid decrease of the translational ratio. This finding is consistent with the fact that, compared to prokaryotes, eukaryotes tend to have longer proteins. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.83.042903 SN - 1539-3755 VL - 83 IS - 4 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Tepper-Garcia, Thorsten A1 - Richter, Philipp A1 - Schaye, Joop A1 - Booth, C. M. A1 - Vecchia, Claudio Dalla A1 - Theuns, Tom A1 - Wiersma, Robert P. C. T1 - Absorption signatures of warm-hot gas at low redshift o vi JF - Monthly notices of the Royal Astronomical Society N2 - We investigate the origin and physical properties of O vi absorbers at low redshift (z = 0.25) using a subset of cosmological, hydrodynamical simulations from the OverWhelmingly Large Simulations (OWLS) project. Intervening O vi absorbers are believed to trace shock-heated gas in the warm-hot intergalactic medium (WHIM) and may thus play a key role in the search for the missing baryons in the present-day Universe. When compared to observations, the predicted distributions of the different O vi line parameters (column density, Doppler parameter, rest equivalent width W-r) from our simulations exhibit a lack of strong O vi absorbers, a discrepancy that has also been found by Oppenheimer & Dave. This suggests that physical processes on subgrid scales (e.g. turbulence) may strongly influence the observed properties of O vi systems. We find that the intervening O vi absorption arises mainly in highly metal enriched (10-1 < Z/Z(circle dot) less than or similar to 1) gas at typical overdensities of 1 < /<<>> less than or similar to 102. One-third of the O vi absorbers in our simulation are found to trace gas at temperatures T < 105 K, while the rest arises in gas at higher temperatures, most of them around T = 105.3 +/- 0.5 K. These temperatures are much higher than inferred by Oppenheimer & Dave, probably because that work did not take the suppression of metal-line cooling by the photoionizing background radiation into account. While the O vi resides in a similar region of (, T)-space as much of the shock-heated baryonic matter, the vast majority of this gas has a lower metal content and does not give rise to detectable O vi absorption. As a consequence of the patchy metal distribution, O vi absorbers in our simulations trace only a very small fraction of the cosmic baryons (< 2 per cent) and the cosmic metals. Instead, these systems presumably trace previously shock-heated, metal-rich material from galactic winds that is now mixing with the ambient gas and cooling. The common approach of comparing O vi and H i column densities to estimate the physical conditions in intervening absorbers from QSO observations may be misleading, as most of the H i (and most of the gas mass) is not physically connected with the high-metallicity patches that give rise to the O vi absorption. KW - methods: numerical KW - galaxies: formation KW - intergalactic medium KW - quasars: absorption lines KW - cosmology: theory Y1 - 2011 U6 - https://doi.org/10.1111/j.1365-2966.2010.18123.x SN - 0035-8711 VL - 413 IS - 1 SP - 190 EP - 212 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Schmidt, Hans-Jürgen T1 - Gauss-Bonnet lagrangian G lnG and cosmological exact solutions JF - Physical review : D, Particles, fields, gravitation, and cosmology N2 - For the Lagrangian L = G lnG where G is the Gauss-Bonnet curvature scalar we deduce the field equation and solve it in closed form for 3-flat Friedmann models using a state-finder parametrization. Further we show that among all Lagrangians F(G) this L is the only one not having the form G(r) with a real constant r but possessing a scale-invariant field equation. This turns out to be one of its analogies to f(R) theories in two-dimensional space-time. In the appendix, we systematically list several formulas for the decomposition of the Riemann tensor in arbitrary dimensions n, which are applied in the main deduction for n = 4. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevD.83.083513 SN - 1550-7998 VL - 83 IS - 8 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Beye, Martin A1 - Föhlisch, Alexander T1 - A soft X-ray approach to electron-phonon interactions beyond the Born-Oppenheimer approximation JF - Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy N2 - With modern soft X-ray methods, the whole field of electron-phonon interactions becomes accessible directly in the ultrafast time domain with ultrashort pulsed X-ray sources, as well as in the energy domain through modern highly resolving spectrometers. The well-known core-hole clock approach plays an intermediate role, resolving energetic and temporal features at the same time. In this perspective paper, we review several experiments to illustrate the modern advances in the selective study of electron-phonon interactions as fundamentally determining ingredients for materials properties. We present the different complementary approaches that can be taken with soft X-ray methods to conquer this field beyond the Born-Oppenheimer approximation. KW - Electron-phonon coupling KW - Resonant inelastic X-ray scattering KW - X-ray emission spectroscopy KW - Near edge X-ray absorption fine structure Y1 - 2011 U6 - https://doi.org/10.1016/j.elspec.2010.12.032 SN - 0368-2048 VL - 184 IS - 3-6 SP - 313 EP - 317 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Campbell, Earl T. T1 - Catalysis and activation of magic states in fault-tolerant architectures JF - Physical review : A, Atomic, molecular, and optical physics N2 - In many architectures for fault-tolerant quantum computing universality is achieved by a combination of Clifford group unitary operators and preparation of suitable nonstabilizer states, the so-called magic states. Universality is possible even for some fairly noisy nonstabilizer states, as distillation can convert many noisy copies into fewer purer magic states. Here we propose protocols that exploit multiple species of magic states in surprising ways. These protocols provide examples of previously unobserved phenomena that are analogous to catalysis and activation well known in entanglement theory. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevA.83.032317 SN - 1050-2947 VL - 83 IS - 3 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Schaefer, Edith A1 - Westendorf, Christian A1 - Bodenschatz, Eberhard A1 - Beta, Carsten A1 - Geil, Burkhard A1 - Janshoff, Andreas T1 - Shape oscillations of dictyostelium discoideum cells on ultramicroelectrodes monitored by impedance analysis JF - Small Y1 - 2011 U6 - https://doi.org/10.1002/smll.201001955 SN - 1613-6810 VL - 7 IS - 6 SP - 723 EP - 726 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Prosen, Tomaz T1 - Complexity and nonseparability of classical Liouvillian dynamics JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - We propose a simple complexity indicator of classical Liouvillian dynamics, namely the separability entropy, which determines the logarithm of an effective number of terms in a Schmidt decomposition of phase space density with respect to an arbitrary fixed product basis. We show that linear growth of separability entropy provides a stricter criterion of complexity than Kolmogorov-Sinai entropy, namely it requires that the dynamics be exponentially unstable, nonlinear, and non-Markovian. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.83.031124 SN - 1539-3755 VL - 83 IS - 3 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Stich, Michael A1 - Beta, Carsten T1 - Standing waves in a complex Ginzburg-Landau equation with time-delay feedback JF - Discrete and continuous dynamical systems : a journal bridging mathematics and sciences N2 - Standing waves are studied as solutions of a complex Ginsburg-Landau equation subjected to local and global time-delay feedback terms. The onset of standing waves is studied at the instability of the homogeneous periodic solution with respect to spatially periodic perturbations. The solution of this spatiotemporal wave pattern is given and is compared to the homogeneous periodic solution. KW - pattern formation KW - reaction-diffusion system KW - control Y1 - 2011 SN - 1078-0947 SN - 1553-5231 IS - 1 SP - 1329 EP - 1334 PB - American Institute of Mathematical Sciences CY - Springfield ER - TY - JOUR A1 - Kliesch, Martin A1 - Barthel, Thomas A1 - Gogolin, C. A1 - Kastoryano, M. A1 - Eisert, J. T1 - Dissipative quantum church-turing theorem JF - Physical review letters N2 - We show that the time evolution of an open quantum system, described by a possibly time dependent Liouvillian, can be simulated by a unitary quantum circuit of a size scaling polynomially in the simulation time and the size of the system. An immediate consequence is that dissipative quantum computing is no more powerful than the unitary circuit model. Our result can be seen as a dissipative Church-Turing theorem, since it implies that under natural assumptions, such as weak coupling to an environment, the dynamics of an open quantum system can be simulated efficiently on a quantum computer. Formally, we introduce a Trotter decomposition for Liouvillian dynamics and give explicit error bounds. This constitutes a practical tool for numerical simulations, e.g., using matrix-product operators. We also demonstrate that most quantum states cannot be prepared efficiently. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.120501 SN - 0031-9007 VL - 107 IS - 12 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Schuch, Norbert A1 - Harrison, Sarah K. A1 - Osborne, Tobias J. A1 - Eisert, Jens T1 - Information propagation for interacting-particle systems JF - Physical review : A, Atomic, molecular, and optical physics N2 - We study the speed at which information propagates through systems of interacting quantum particles moving on a regular lattice and show that for a certain class of initial conditions there exists a maximum speed of sound at which information can propagate. Our argument applies equally to quantum spins, bosons such as in the Bose-Hubbard model, fermions, anyons, and general mixtures thereof, on arbitrary lattices of any dimension. It also pertains to dissipative dynamics on the lattice, and generalizes to the continuum for quantum fields. Our result can be seen as an analog of the Lieb-Robinson bound for strongly correlated models. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevA.84.032309 SN - 1050-2947 VL - 84 IS - 3 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Hübener, Robert A1 - Kruszynska, Caroline A1 - Hartmann, Lorenz A1 - Duer, Wolfgang A1 - Plenio, Martin B. A1 - Eisert, Jens T1 - Tensor network methods with graph enhancement JF - Physical review : B, Condensed matter and materials physics N2 - We present applications of the renormalization algorithm with graph enhancement (RAGE). This analysis extends the algorithms and applications given for approaches based on matrix product states introduced in [Phys. Rev. A 79, 022317 (2009)] to other tensor-network states such as the tensor tree states (TTS) and projected entangled pair states. We investigate the suitability of the bare TTS to describe ground states, showing that the description of certain graph states and condensed-matter models improves. We investigate graph-enhanced tensor-network states, demonstrating that in some cases (disturbed graph states and for certain quantum circuits) the combination of weighted graph states with TTS can greatly improve the accuracy of the description of ground states and time-evolved states. We comment on delineating the boundary of the classically efficiently simulatable states of quantum many-body systems. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevB.84.125103 SN - 1098-0121 VL - 84 IS - 12 PB - American Physical Society CY - College Park ER - TY - GEN A1 - Qiu, Xunlin T1 - Patterned piezo-, pyro-, and ferroelectricity of poled polymer electrets T2 - Journal of applied physics Y1 - 2011 U6 - https://doi.org/10.1063/1.3638069 SN - 0021-8979 VL - 110 IS - 5 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Lokstein, Heiko A1 - Krikunova, Maria A1 - Teuchner, Klaus A1 - Voigt, Bernd T1 - Elucidation of structure-function relationships in photosynthetic light-harvesting antenna complexes by non-linear polarization spectroscopy in the frequency domain (NLPF) JF - Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants N2 - Photosynthetically active pigments are usually organized into pigment-protein complexes. These include light-harvesting antenna complexes (LHCs) and reaction centers. Site energies of the bound pigments are determined by interactions with their environment, i.e., by pigment-protein as well as pigment-pigment interactions. Thus, resolution of spectral substructures of the pigment-protein complexes may provide valuable insight into structure-function relationships. By means of conventional (linear) and time-resolved spectroscopic techniques, however, it is often difficult to resolve the spectral substructures of complex pigment-protein assemblies. Nonlinear polarization spectroscopy in the frequency domain (NLPF) is shown to be a valuable technique in this regard. Based on initial experimental work with purple bacterial antenna complexes as well as model systems NLPF has been extended to analyse the substructure(s) of very complex spectra, including analyses of interactions between chlorophylls and "optically dark" states of carotenoids in LHCs. The paper reviews previous work and outlines perspectives regarding the application of NLPF spectroscopy to disentangle structure-function relationships in pigment-protein complexes. KW - Excitonic interactions KW - Laser spectroscopy KW - Light-harvesting complex KW - Nonlinear polarization spectroscopy in the frequency domain KW - Pigment-pigment interactions Y1 - 2011 U6 - https://doi.org/10.1016/j.jplph.2010.12.012 SN - 0176-1617 VL - 168 IS - 12 SP - 1488 EP - 1496 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Schütz, Nadine A1 - Holschneider, Matthias T1 - Detection of trend changes in time series using Bayesian inference JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - Change points in time series are perceived as isolated singularities where two regular trends of a given signal do not match. The detection of such transitions is of fundamental interest for the understanding of the system's internal dynamics or external forcings. In practice observational noise makes it difficult to detect such change points in time series. In this work we elaborate on a Bayesian algorithm to estimate the location of the singularities and to quantify their credibility. We validate the performance and sensitivity of our inference method by estimating change points of synthetic data sets. As an application we use our algorithm to analyze the annual flow volume of the Nile River at Aswan from 1871 to 1970, where we confirm a well-established significant transition point within the time series. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.84.021120 SN - 1539-3755 SN - 1550-2376 VL - 84 IS - 2 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Sun, Zhongkui A1 - Yang, Xiaoli T1 - Generating and enhancing lag synchronization of chaotic systems by white noise JF - Chaos : an interdisciplinary journal of nonlinear science N2 - In this paper, we study the crucial impact of white noise on lag synchronous regime in a pair of time-delay unidirectionally coupled systems. Our result demonstrates that merely via white-noise-based coupling lag synchronization could be achieved between the coupled systems (chaotic or not). And it is also demonstrated that a conventional lag synchronous regime can be enhanced by white noise. Sufficient conditions are further proved mathematically for noise-inducing and noise-enhancing lag synchronization, respectively. Additionally, the influence of parameter mismatch on the proposed lag synchronous regime is studied, by which we announce the robustness and validity of the new strategy. Two numerical examples are provided to illustrate the validity and some possible applications of the theoretical result. Y1 - 2011 U6 - https://doi.org/10.1063/1.3623440 SN - 1054-1500 SN - 1089-7682 VL - 21 IS - 3 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Winkel, B. A1 - Ben Bekhti, Nadya A1 - Darmstaedter, V. A1 - Floeer, L. A1 - Kerp, J. A1 - Richter, Philipp T1 - The high-velocity cloud complex Galactic center negative as seen by EBHIS and GASS I. Cloud catalog and global properties JF - Astronomy and astrophysics : an international weekly journal N2 - Using Milky Way data of the new Effelsberg-Bonn HI Survey (EBHIS) and the Galactic All-Sky Survey (GASS), we present a revised picture of the high-velocity cloud (HVC) complex Galactic center negative (GCN). Owing to the higher angular resolution of these surveys compared to previous studies (e.g., the Leiden Dwingeloo Survey), we resolve complex GCN into lots of individual tiny clumps, that mostly have relatively broad line widths of more than 15 km s(-1). We do not detect a diffuse extended counterpart, which is unusual for an HVC complex. In total 243 clumps were identified and parameterized which allows us to statistically analyze the data. Cold-line components (i.e.,Delta upsilon(fwhm) < 7.5 km s(-1)) are found in about 5% only of the identified cloudlets. Our analysis reveals that complex GCN is likely built up of several subpopulations that do not share a common origin. Furthermore, complex GCN might be a prime example for warm-gas accretion onto the Milky Way, where neutral HI clouds are not stable against interaction with the Milky Way gas halo and become ionized prior to accretion. KW - ISM: clouds KW - Galaxy: halo Y1 - 2011 U6 - https://doi.org/10.1051/0004-6361/201117357 SN - 0004-6361 VL - 533 IS - 18 PB - EDP Sciences CY - Les Ulis ER -