@book{Rabe2011,
  author    = {Rabe, Thorid},
  title     = {Physikdidaktische Lehrerprofessionalisierung zwischen Anspruch und Wirklichkeit : Antrittsvorlesung 2011-06-08},
  publisher = {Univ.-Bibl.},
  address   = {Potsdam},
  year      = {2011},
  abstract  = {Physiklehrer bestimmen durch die Gestaltung des Unterrichts und damit durch ihr professionelles Handeln maßgeblich mit, wie die individuellen Lernprozesse der Sch{\"u}ler zu Inhalten der Physik ablaufen. F{\"u}r die Entwicklung ihrer professionellen Handlungskompetenz m{\"u}ssen zuk{\"u}nftige Physiklehrer einerseits physikalisches, physikdidaktisches und p{\"a}dagogisches Wissen erwerben und andererseits motiviert sein, dieses Wissen auch anzuwenden. In ihrer Vorlesung geht Thorid Rabe der Frage nach, welche physikdidaktischen Kompetenzen Studierende im Rahmen der universit{\"a}ren Ausbildung erwerben sollten. Am Beispiel der Lehrveranstaltung "Physikalische Schulexperimente" zeigt sie, wie physikdidaktische Theorie und praktisches Lehrerhandeln aufeinander bezogen werden k{\"o}nnen. Zudem wird sie ein Forschungsprojekt vorstellen, das einem bisher vernachl{\"a}ssigten Aspekt professioneller Handlungskompetenz nachgeht, n{\"a}mlich den dom{\"a}nenspezifischen Selbstwirksamkeitserwartungen - dem Zutrauen in sich selbst, als Physiklehrer angemessen und erfolgreich handeln zu k{\"o}nnen.},
  language  = {de}
}
@article{QiuWirgesGerhard2011,
  author    = {Qiu, Xunlin and Wirges, Werner and Gerhard, Reimund},
  title     = {Beneficial and detrimental fatigue effects of dielectric barrier discharges on the piezoelectricity of polypropylene ferroelectrets},
  series = {Journal of applied physics},
  volume    = {110},
  journal   = {Journal of applied physics},
  number    = {2},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-8979},
  doi       = {10.1063/1.3610507},
  pages     = {8},
  year      = {2011},
  abstract  = {Cellular polypropylene (PP) ferroelectrets combine a large piezoelectricity with mechanical flexibility and elastic compliance. Their charging process represents a series of dielectric barrier discharges (DBDs) that generate a cold plasma with numerous active species and thus modify the inner polymer surfaces of the foam cells. Both the threshold for the onset of DBDs and the piezoelectricity of ferroelectrets are sensitive to repeated DBDs in the voids. It is found that the threshold voltage is approximately halved and the charging efficiency is clearly improved after only 10(3) DBD cycles. However, plasma modification of the inner surfaces from repeated DBDs deteriorates the chargeability of the voids, leading to a significant reduction of the piezoelectricity in ferroelectrets. After a significant waiting period, the chargeability of previously fatigued voids shows a partial recovery. The plasma modification is, however, detrimental to the stability of the deposited charges and thus also of the macroscopic dipoles and of the piezoelectricity. Fatigue from only 10(3) DBD cycles already results in significantly less stable piezoelectricity in cellular PP ferroelectrets. The fatigue rate as a function of the number of voltage cycles follows a stretched exponential. Fatigue from repeated DBDs can be avoided if most of the gas molecules inside the voids are removed via a suitable evacuation process.},
  language  = {en}
}
@article{QiuGerhardMellinger2011,
  author    = {Qiu, Xunlin and Gerhard, Reimund and Mellinger, Axel},
  title     = {Turning polymer foams or polymer-film systems into ferroelectrets dielectric barrier discharges in voids},
  series = {IEEE transactions on dielectrics and electrical insulation},
  volume    = {18},
  journal   = {IEEE transactions on dielectrics and electrical insulation},
  number    = {1},
  publisher = {Inst. of Electr. and Electronics Engineers},
  address   = {Piscataway},
  issn      = {1070-9878},
  doi       = {10.1109/TDEI.2011.5704490},
  pages     = {34 -- 42},
  year      = {2011},
  abstract  = {Polymer foams and void-containing polymer-film systems with internally charged voids combine large piezoelectricity with mechanical flexibility and elastic compliance. This new class of soft materials (often called ferro-or piezoelectrets) has attracted considerable attention from science and industry. It has been found that the voids can be internally charged by means of dielectric barrier discharges (DBDs) under high electric fields. The charged voids can be considered as man-made macroscopic dipoles. Depending on the ferroelectret structure and the pressure of the internal gas, the voids may be highly compressible. Consequently, very large dipole-moment changes can be induced by mechanical or electrical stresses, leading to large piezoelectricity. DBD charging of the voids is a critical process for rendering polymer foams piezoelectric. Thus a comprehensive exploration of DBD charging is essential for the understanding and the optimization of piezoelectricity in ferroelectrets. Recent studies show that DBDs in the voids are triggered when the internal electric field reaches a threshold value according to Townsend's model of Paschen breakdown. During the DBDs, charges of opposite polarity are generated and trapped at the top and bottom internal surfaces of the gas-filled voids, respectively. The deposited charges induce an electric field opposite to the externally applied one and thus extinguish the DBDs. Back discharges may eventually be triggered when the external voltage is reduced or turned off. In order to optimize the efficiency of DBD charging, the geometry (in particular the height) of the voids, the type of gas and its pressure inside the voids are essential factors to be considered and to be optimized. In addition, the influence of the plasma treatment on the internal void surfaces during the DBDs should be taken into consideration.},
  language  = {en}
}
@misc{Qiu2011,
  author    = {Qiu, Xunlin},
  title     = {Patterned piezo-, pyro-, and ferroelectricity of poled polymer electrets},
  series = {Journal of applied physics},
  volume    = {110},
  journal   = {Journal of applied physics},
  number    = {5},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-8979},
  doi       = {10.1063/1.3638069},
  pages     = {1},
  year      = {2011},
  language  = {en}
}
@article{ProsenIlievski2011,
  author    = {Prosen, Tomaz and Ilievski, Enej},
  title     = {Nonequilibrium phase transition in a periodically driven XY spin chain},
  series = {Physical review letters},
  volume    = {107},
  journal   = {Physical review letters},
  number    = {6},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.107.060403},
  pages     = {4},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{Prosen2011,
  author    = {Prosen, Tomaz},
  title     = {Complexity and nonseparability of classical Liouvillian dynamics},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {83},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  number    = {3},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {1539-3755},
  doi       = {10.1103/PhysRevE.83.031124},
  pages     = {5},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{PostbergSchmidtHillieretal.2011,
  author    = {Postberg, Frank and Schmidt, J. and Hillier, J. and Kempf, Sascha and Srama, Ralf},
  title     = {A salt-water reservoir as the source of a compositionally stratified plume on Enceladus},
  series = {Nature : the international weekly journal of science},
  volume    = {474},
  journal   = {Nature : the international weekly journal of science},
  number    = {7353},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {0028-0836},
  doi       = {10.1038/nature10175},
  pages     = {620 -- 622},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{PontiusKachelSchuesslerLangeheineetal.2011,
  author    = {Pontius, N. and Kachel, T. and Sch{\"u}ssler-Langeheine, C. and Schlotter, W. F. and Beye, Martin and Sorgenfrei, Nomi and Chang, C. F. and F{\"o}hlisch, Alexander and Wurth, W. and Metcalf, P. and Leonov, I. and Yaresko, A. and Stojanovic, N. and Berglund, Martin and Guerassimova, N. and Duesterer, S. and Redlin, H. and Duerr, H. A.},
  title     = {Time-resolved resonant soft x-ray diffraction with free-electron lasers femtosecond dynamics across the Verwey transition in magnetite},
  series = {Applied physics letters},
  volume    = {98},
  journal   = {Applied physics letters},
  number    = {18},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0003-6951},
  doi       = {10.1063/1.3584855},
  pages     = {3},
  year      = {2011},
  abstract  = {Resonant soft x-ray diffraction (RSXD) with femtosecond (fs) time resolution is a powerful tool for disentangling the interplay between different degrees of freedom in strongly correlated electron materials. It allows addressing the coupling of particular degrees of freedom upon an external selective perturbation, e. g., by an optical or infrared laser pulse. Here, we report a time-resolved RSXD experiment from the prototypical correlated electron material magnetite using soft x-ray pulses from the free-electron laser FLASH in Hamburg. We observe ultrafast melting of the charge-orbital order leading to the formation of a transient phase, which has not been observed in equilibrium.},
  language  = {en}
}
@article{PohlEichler2011,
  author    = {Pohl, Martin and Eichler, David},
  title     = {Origin of ultra-high-energy galactic cosmic rays the isotropy problem},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {742},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  number    = {2},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.1088/0004-637X/742/2/114},
  pages     = {11},
  year      = {2011},
  abstract  = {We study the propagation of ultra-high-energy cosmic rays (UHECRs) in the Galaxy, concentrating on the energy range below the ankle in the spectrum at 4 EeV. A Monte Carlo method, based on analytical solutions to the time-dependent diffusion problem, is used to account for intermittency by placing sources at random locations. Assuming a source population that scales with baryon mass density or star formation (e.g., long GRB), we derive constraints arising from intermittency and the observational limits on the composition and anisotropy. It is shown that the composition and anisotropy at 10(18) eV are difficult to reproduce and require that either (1) the particle mean free path is much smaller than a gyroradius, implying the escape time is very long, (2) the composition is heavier than suggested by recent Auger data, (3) the ultra-high-energy sub-ankle component is mostly extragalactic, or (4) we are living in a rare lull in the UHECR production, and the current UHECR intensity is far below the Galactic time average. We therefore recommend a strong observational focus on determining the UHECR composition around 10(18) eV.},
  language  = {en}
}
@article{PikovskijRosenblum2011,
  author    = {Pikovskij, Arkadij and Rosenblum, Michael},
  title     = {Dynamics of heterogeneous oscillator ensembles in terms of collective variables},
  series = {Physica :D, Nonlinear phenomena},
  volume    = {240},
  journal   = {Physica :D, Nonlinear phenomena},
  number    = {9-10},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0167-2789},
  doi       = {10.1016/j.physd.2011.01.002},
  pages     = {872 -- 881},
  year      = {2011},
  abstract  = {We consider general heterogeneous ensembles of phase oscillators, sine coupled to arbitrary external fields. Starting with the infinitely large ensembles, we extend the Watanabe-Strogatz theory, valid for identical oscillators, to cover the case of an arbitrary parameter distribution. The obtained equations yield the description of the ensemble dynamics in terms of collective variables and constants of motion. As a particular case of the general setup we consider hierarchically organized ensembles, consisting of a finite number of subpopulations, whereas the number of elements in a subpopulation can be both finite or infinite. Next, we link the Watanabe-Strogatz and Ott-Antonsen theories and demonstrate that the latter one corresponds to a particular choice of constants of motion. The approach is applied to the standard Kuramoto-Sakaguchi model, to its extension for the case of nonlinear coupling, and to the description of two interacting subpopulations, exhibiting a chimera state. With these examples we illustrate that, although the asymptotic dynamics can be found within the framework of the Ott-Antonsen theory, the transients depend on the constants of motion. The most dramatic effect is the dependence of the basins of attraction of different synchronous regimes on the initial configuration of phases.},
  language  = {en}
}
@article{PikovskijFishman2011,
  author    = {Pikovskij, Arkadij and Fishman, Shmuel},
  title     = {Scaling properties of weak chaos in nonlinear disordered lattices},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {83},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  number    = {2},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {1539-3755},
  doi       = {10.1103/PhysRevE.83.025201},
  pages     = {4},
  year      = {2011},
  abstract  = {We study the discrete nonlinear Schrodinger equation with a random potential in one dimension. It is characterized by the length, the strength of the random potential, and the field density that determines the effect of nonlinearity. Following the time evolution of the field and calculating the largest Lyapunov exponent, the probability of the system to be regular is established numerically and found to be a scaling function of the parameters. This property is used to calculate the asymptotic properties of the system in regimes beyond our computational power.},
  language  = {en}
}
@article{PietzschSunHenniesetal.2011,
  author    = {Pietzsch, Annette and Sun, Y. -P. and Hennies, Franz and Rinkevicius, Z. and Karlsson, Hans O. and Schmitt, Thorsten and Strocov, Vladimir N. and Andersson, Joakim and Kennedy, B. and Schlappa, J. and F{\"o}hlisch, Alexander and Rubensson, Jan-Erik and Gel'mukhanov, F.},
  title     = {Spatial quantum beats in vibrational resonant inelastic soft X-ray scattering at dissociating states in oxygen},
  series = {Physical review letters},
  volume    = {106},
  journal   = {Physical review letters},
  number    = {15},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.106.153004},
  pages     = {4},
  year      = {2011},
  abstract  = {Resonant inelastic soft x-ray scattering (RIXS) spectra excited at the 1 sigma(g) -> 3 sigma(u) resonance in gas-phase O-2 show excitations due to the nuclear degrees of freedom with up to 35 well-resolved discrete vibronic states and a continuum due to the kinetic energy distribution of the separated atoms. The RIXS profile demonstrates spatial quantum beats caused by two interfering wave packets with different momenta as the atoms separate. Thomson scattering strongly affects both the spectral profile and the scattering anisotropy.},
  language  = {en}
}
@phdthesis{Partl2011,
  author    = {Partl, Adrian M.},
  title     = {Cosmological radiative transfer and the lonisation of the integalactic medium},
  address   = {Potsdam},
  pages     = {205 S.},
  year      = {2011},
  language  = {en}
}
@phdthesis{Osterloh2011,
  author    = {Osterloh, Lukas},
  title     = {Retrieving aerosol microphysical properties from multiwavelength Lidar Data},
  address   = {Potsdam},
  pages     = {125 S.},
  year      = {2011},
  language  = {en}
}
@article{OskinovaTodtIgnaceetal.2011,
  author    = {Oskinova, Lida and Todt, Helge Tobias and Ignace, Richard and Brown, John C. and Cassinelli, Joseph P. and Hamann, Wolf-Rainer},
  title     = {Early magnetic B-type stars X-ray emission and wind properties},
  series = {Monthly notices of the Royal Astronomical Society},
  volume    = {416},
  journal   = {Monthly notices of the Royal Astronomical Society},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0035-8711},
  doi       = {10.1111/j.1365-2966.2011.19143.x},
  pages     = {1456 -- 1474},
  year      = {2011},
  abstract  = {We present a comprehensive study of X-ray emission by, and wind properties of, massive magnetic early B-type stars. Dedicated XMM-Newton observations were obtained for three early-type B-type stars, xi(1) CMa, V2052 Oph and zeta Cas, with recently discovered magnetic fields. We report the first detection of X-ray emission from V2052 Oph and zeta Cas. The latter is one the softest X-ray sources among the early-type stars, while the former is one of the X-ray faintest. The observations show that the X-ray spectra of our programme stars are quite soft with the bulk of X-ray emitting material having a temperature of about 1 MK. We compile the complete sample of early B-type stars with detected magnetic fields to date and existing X-ray measurements, in order to study whether the X-ray emission can be used as a general proxy for stellar magnetism. We find that the X-ray properties of early massive B-type magnetic stars are diverse, and that hard and strong X-ray emission does not necessarily correlate with the presence of a magnetic field, corroborating similar conclusions reached earlier for the classical chemically peculiar magnetic Bp-Ap stars. We analyse the ultraviolet (UV) spectra of five non-supergiant B stars with magnetic fields (tau Sco, beta Cep, xi(1) CMa, V2052 Oph and zeta Cas) by means of non-local thermodynamic equilibrium (non-LTE) iron-blanketed model atmospheres. The latter are calculated with the Potsdam Wolf-Rayet (PoWR) code, which treats the photosphere as well as the wind, and also accounts for X-rays. With the exception of t Sco, this is the first analysis of these stars by means of stellar wind models. Our models accurately fit the stellar photospheric spectra in the optical and the UV. The parameters of X-ray emission, temperature and flux are included in the model in accordance with observations. We confirm the earlier findings that the filling factors of X-ray emitting material are very high. Our analysis reveals that the magnetic early-type B stars studied here have weak winds with velocities not significantly exceeding upsilon(esc). The mass-loss rates inferred from the analysis of UV lines are significantly lower than predicted by hydrodynamically consistent models. We find that, although the X-rays strongly affect the ionization structure of the wind, this effect is not sufficient in reducing the total radiative acceleration. When the X-rays are accounted for at the intensity and temperatures observed, there is still sufficient radiative acceleration to drive a stronger mass-loss than we empirically infer from the UV spectral lines.},
  language  = {en}
}
@article{OskinovaHamannCassinellietal.2011,
  author    = {Oskinova, Lida and Hamann, Wolf-Rainer and Cassinelli, Joseph P. and Brown, John C. and Todt, Helge Tobias},
  title     = {X-ray emission from massive stars with magnetic fields},
  series = {Astronomische Nachrichten = Astronomical notes},
  volume    = {332},
  journal   = {Astronomische Nachrichten = Astronomical notes},
  number    = {9-10},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {0004-6337},
  doi       = {10.1002/asna.201111602},
  pages     = {988 -- 993},
  year      = {2011},
  abstract  = {We investigate the connections between the magnetic fields and the X-ray emission from massive stars. Our study shows that the X-ray properties of known strongly magnetic stars are diverse: while some comply to the predictions of the magnetically confined wind model, others do not. We conclude that strong, hard, and variable X-ray emission may be a sufficient attribute of magnetic massive stars, but it is not a necessary one. We address the general properties of X-ray emission from "normal" massive stars, especially the long standing mystery about the correlations between the parameters of X-ray emission and fundamental stellar properties. The recent development in stellar structure modeling shows that small-scale surface magnetic fields may be common. We suggest a "hybrid" scenario which could explain the X-ray emission from massive stars by a combination of magnetic mechanisms on the surface and shocks in the stellar wind. The magnetic mechanisms and the wind shocks are triggered by convective motions in sub-photospheric layers. This scenario opens the door for a natural explanation of the well established correlation between bolometric and X-ray luminosities.},
  language  = {en}
}
@article{NavirianHerzogGoldshteynetal.2011,
  author    = {Navirian, Hengameh A. and Herzog, Marc and Goldshteyn, J. and Leitenberger, Wolfram and Vrejoiu, Ionella and Khakhulin, D. and Wulff, M. and Shayduk, Roman and Gaal, P. and Bargheer, Matias},
  title     = {Shortening x-ray pulses for pump-probe experiments at synchrotrons},
  series = {Journal of applied physics},
  volume    = {109},
  journal   = {Journal of applied physics},
  number    = {12},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-8979},
  doi       = {10.1063/1.3601057},
  pages     = {3},
  year      = {2011},
  abstract  = {We implemented an experimental scheme for ultrafast x-ray diffraction at storage rings based on a laser-driven Bragg-switch that shortens the x-ray pulses emitted from an undulator. The increased time-resolution is demonstrated by observing changes of intensity, position and width of the diffraction peaks of a La(0.7)Sr(0.3)MnO(3)/SrTiO(3) superlattice sample after optical excitation, i.e., by quantitatively measuring the propagation of an expansion wave through the sample. These experimental transients with timescales of 35 to 60 ps evidence a reduction of the x-ray pulse duration by a factor of two.},
  language  = {en}
}
@article{MuellerHaakhCalarcoetal.2011,
  author    = {M{\"u}ller, Matthias M. and Haakh, Harald R. and Calarco, Tommaso and Koch, Christiane P. and Henkel, Carsten},
  title     = {Prospects for fast Rydberg gates on an atom chip},
  series = {Quantum information processing},
  volume    = {10},
  journal   = {Quantum information processing},
  number    = {6},
  publisher = {Springer},
  address   = {New York},
  issn      = {1570-0755},
  doi       = {10.1007/s11128-011-0296-0},
  pages     = {771 -- 792},
  year      = {2011},
  abstract  = {Atom chips are a promising candidate for a scalable architecture for quantum information processing provided a universal set of gates can be implemented with high fidelity. The difficult part in achieving universality is the entangling two-qubit gate. We consider a Rydberg phase gate for two atoms trapped on a chip and employ optimal control theory to find the shortest gate that still yields a reasonable gate error. Our parameters correspond to a situation where the Rydberg blockade regime is not yet reached. We discuss the role of spontaneous emission and the effect of noise from the chip surface on the atoms in the Rydberg state.},
  language  = {en}
}
@article{MuellerGrossEisert2011,
  author    = {M{\"u}ller, Markus P. and Gross, David and Eisert, Jens},
  title     = {Concentration of Measure for Quantum States with a Fixed Expectation Value},
  series = {Communications in mathematical physics},
  volume    = {303},
  journal   = {Communications in mathematical physics},
  number    = {3},
  publisher = {Springer},
  address   = {New York},
  issn      = {0010-3616},
  doi       = {10.1007/s00220-011-1205-1},
  pages     = {785 -- 824},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@phdthesis{Moesta2011,
  author    = {M{\"o}sta, Philipp},
  title     = {Novel aspects of the dynamics of binary black-hole mergers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59820},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {The inspiral and merger of two black holes is among the most exciting and extreme events in our universe. Being one of the loudest sources of gravitational waves, they provide a unique dynamical probe of strong-field general relativity and a fertile ground for the observation of fundamental physics. While the detection of gravitational waves alone will allow us to observe our universe through an entirely new window, combining the information obtained from both gravitational wave and electro-magnetic observations will allow us to gain even greater insight in some of the most exciting astrophysical phenomena. In addition, binary black-hole mergers serve as an intriguing tool to study the geometry of space-time itself. In this dissertation we study the merger process of binary black-holes in a variety of conditions. Our results show that asymmetries in the curvature distribution on the common apparent horizon are correlated to the linear momentum acquired by the merger remnant. We propose useful tools for the analysis of black holes in the dynamical and isolated horizon frameworks and shed light on how the final merger of apparent horizons proceeds after a common horizon has already formed. We connect mathematical theorems with data obtained from numerical simulations and provide a first glimpse on the behavior of these surfaces in situations not accessible to analytical tools. We study electro-magnetic counterparts of super-massive binary black-hole mergers with fully 3D general relativistic simulations of binary black-holes immersed both in a uniform magnetic field in vacuum and in a tenuous plasma. We find that while a direct detection of merger signatures with current electro-magnetic telescopes is unlikely, secondary emission, either by altering the accretion rate of the circumbinary disk or by synchrotron radiation from accelerated charges, may be detectable. We propose a novel approach to measure the electro-magnetic radiation in these simulations and find a non-collimated emission that dominates over the collimated one appearing in the form of dual jets associated with each of the black holes. Finally, we provide an optimized gravitational wave detection pipeline using phenomenological waveforms for signals from compact binary coalescence and show that by including spin effects in the waveform templates, the detection efficiency is drastically improved as well as the bias on recovered source parameters reduced. On the whole, this disseration provides evidence that a multi-messenger approach to binary black-hole merger observations provides an exciting prospect to understand these sources and, ultimately, our universe.},
  language  = {en}
}
@article{MulanskyAhnertPikovskijetal.2011,
  author    = {Mulansky, Mario and Ahnert, Karsten and Pikovskij, Arkadij and Shepelyansky, Dima L.},
  title     = {Strong and weak chaos in weakly nonintegrable many-body hamiltonian systems},
  series = {Journal of statistical physics},
  volume    = {145},
  journal   = {Journal of statistical physics},
  number    = {5},
  publisher = {Springer},
  address   = {New York},
  issn      = {0022-4715},
  doi       = {10.1007/s10955-011-0335-3},
  pages     = {1256 -- 1274},
  year      = {2011},
  abstract  = {We study properties of chaos in generic one-dimensional nonlinear Hamiltonian lattices comprised of weakly coupled nonlinear oscillators by numerical simulations of continuous-time systems and symplectic maps. For small coupling, the measure of chaos is found to be proportional to the coupling strength and lattice length, with the typical maximal Lyapunov exponent being proportional to the square root of coupling. This strong chaos appears as a result of triplet resonances between nearby modes. In addition to strong chaos we observe a weakly chaotic component having much smaller Lyapunov exponent, the measure of which drops approximately as a square of the coupling strength down to smallest couplings we were able to reach. We argue that this weak chaos is linked to the regime of fast Arnold diffusion discussed by Chirikov and Vecheslavov. In disordered lattices of large size we find a subdiffusive spreading of initially localized wave packets over larger and larger number of modes. The relations between the exponent of this spreading and the exponent in the dependence of the fast Arnold diffusion on coupling strength are analyzed. We also trace parallels between the slow spreading of chaos and deterministic rheology.},
  language  = {en}
}
@article{MulanskyAhnertPikovskij2011,
  author    = {Mulansky, Mario and Ahnert, Karsten and Pikovskij, Arkadij},
  title     = {Scaling of energy spreading in strongly nonlinear disordered lattices},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {83},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  number    = {2},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {1539-3755},
  doi       = {10.1103/PhysRevE.83.026205},
  pages     = {4},
  year      = {2011},
  abstract  = {To characterize a destruction of Anderson localization by nonlinearity, we study the spreading behavior of initially localized states in disordered, strongly nonlinear lattices. Due to chaotic nonlinear interaction of localized linear or nonlinear modes, energy spreads nearly subdiffusively. Based on a phenomenological description by virtue of a nonlinear diffusion equation, we establish a one-parameter scaling relation between the velocity of spreading and the density, which is confirmed numerically. From this scaling it follows that for very low densities the spreading slows down compared to the pure power law.},
  language  = {en}
}
@article{MontoyaBornLevermann2011,
  author    = {Montoya, Marisa and Born, Andreas and Levermann, Anders},
  title     = {Reversed North Atlantic gyre dynamics in present and glacial climates},
  series = {Climate dynamics : observational, theoretical and computational research on the climate system},
  volume    = {36},
  journal   = {Climate dynamics : observational, theoretical and computational research on the climate system},
  number    = {5-6},
  publisher = {Springer},
  address   = {New York},
  issn      = {0930-7575},
  doi       = {10.1007/s00382-009-0729-y},
  pages     = {1107 -- 1118},
  year      = {2011},
  abstract  = {The dynamics of the North Atlantic subpolar gyre (SPG) are assessed under present and glacial boundary conditions by investigating the SPG sensitivity to surface wind-stress changes in a coupled climate model. To this end, the gyre transport is decomposed in Ekman, thermohaline, and bottom transports. Surface wind-stress variations are found to play an important indirect role in SPG dynamics through their effect on water-mass densities. Our results suggest the existence of two dynamically distinct regimes of the SPG, depending on the absence or presence of deep water formation (DWF) in the Nordic Seas and a vigorous Greenland-Scotland ridge (GSR) overflow. In the first regime, the GSR overflow is weak and the SPG strength increases with wind-stress as a result of enhanced outcropping of isopycnals in the centre of the SPG. As soon as a vigorous GSR overflow is established, its associated positive density anomalies on the southern GSR slope reduce the SPG strength. This has implications for past glacial abrupt climate changes, insofar as these can be explained through latitudinal shifts in North Atlantic DWF sites and strengthening of the North Atlantic current. Regardless of the ultimate trigger, an abrupt shift of DWF into the Nordic Seas could result both in a drastic reduction of the SPG strength and a sudden reversal in its sensitivity to wind-stress variations. Our results could provide insight into changes in the horizontal ocean circulation during abrupt glacial climate changes, which have been largely neglected up to now in model studies.},
  language  = {en}
}
@article{MizunoPohlNiemiecetal.2011,
  author    = {Mizuno, Yosuke and Pohl, Martin and Niemiec, Jacek and Zhang, Bing and Nishikawa, Ken-Ichi and Hardee, Philip E.},
  title     = {Magnetic-field amplification by turbulence in a relativistic shockpropagating through an inhomogeneous medium},
  series = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  volume    = {726},
  journal   = {The astrophysical journal : an international review of spectroscopy and astronomical physics},
  number    = {2},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0004-637X},
  doi       = {10.1088/0004-637X/726/2/62},
  pages     = {11},
  year      = {2011},
  abstract  = {We perform two-dimensional relativistic magnetohydrodynamic simulations of a mildly relativistic shock propagating through an inhomogeneous medium. We show that the postshock region becomes turbulent owing to preshock density inhomogeneity, and the magnetic field is strongly amplified due to the stretching and folding of field lines in the turbulent velocity field. The amplified magnetic field evolves into a filamentary structure in two-dimensional simulations. The magnetic energy spectrum is flatter than the Kolmogorov spectrum and indicates that a so-called small-scale dynamo is occurring in the postshock region. We also find that the amount of magnetic-field amplification depends on the direction of the mean preshock magnetic field, and the timescale of magnetic-field growth depends on the shock strength.},
  language  = {en}
}
@phdthesis{Mielke2011,
  author    = {Mielke, Moritz},
  title     = {Atmosph{\"a}rische Prozesstudien auf der Basis von Beobachtungen und regionalen Klimamodellsimulationen in der Arktis},
  address   = {Potsdam},
  pages     = {130 S.},
  year      = {2011},
  language  = {de}
}
@article{MellingerMellinger2011,
  author    = {Mellinger, Axel and Mellinger, Olena},
  title     = {Breakdown threshold of dielectric barrier discharges in ferroelectrets where Paschen's law fails},
  series = {IEEE transactions on dielectrics and electrical insulation},
  volume    = {18},
  journal   = {IEEE transactions on dielectrics and electrical insulation},
  number    = {1},
  publisher = {Inst. of Electr. and Electronics Engineers},
  address   = {Piscataway},
  issn      = {1070-9878},
  doi       = {10.1109/TDEI.2011.5704491},
  pages     = {43 -- 48},
  year      = {2011},
  abstract  = {The piezoelectric activity of charged cellular foams (so-called ferroelectrets) is compared against simulations based on a multi-layer electromechanical model and Townsend's model of Paschen breakdown, with the distribution of void heights determined from scanning electron micrographs. While the calculated space charge hysteresis curves are in good agreement with experimental data, the onset of piezoelectric activity is observed at significantly higher electric fields than predicted by Paschen's law. One likely explanation is that the commonly accepted Paschen curve for electric breakdown in air poorly describes the critical electric field for dielectric barrier discharges in micrometer-size cavities.},
  language  = {en}
}
@phdthesis{Matthes2011,
  author    = {Matthes, Heidrun},
  title     = {Interaction of land surface processes and the atmophere in the Arctic - senitivities and extremes},
  address   = {Potsdam},
  pages     = {123 S.},
  year      = {2011},
  language  = {en}
}
@article{MasanesMueller2011,
  author    = {Masanes, Lluis and M{\"u}ller, Markus P.},
  title     = {A derivation of quantum theory from physical requirements},
  series = {New journal of physics : the open-access journal for physics},
  volume    = {13},
  journal   = {New journal of physics : the open-access journal for physics},
  number    = {1},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/13/6/063001},
  pages     = {29},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{MartinWinkelmannHaseloffetal.2011,
  author    = {Martin, Maria A. and Winkelmann, Ricarda and Haseloff, M. and Albrecht, Tanja and Bueler, Ed and Khroulev, C. and Levermann, Anders},
  title     = {The Potsdam parallel ice sheet model (PISM-PIK) - Part 2: Dynamic equilibrium simulation of the Antarctic ice sheet},
  series = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  volume    = {5},
  journal   = {The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union},
  number    = {3},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1994-0416},
  doi       = {10.5194/tc-5-727-2011},
  pages     = {727 -- 740},
  year      = {2011},
  abstract  = {We present a dynamic equilibrium simulation of the ice sheet-shelf system on Antarctica with the Potsdam Parallel Ice Sheet Model (PISM-PIK). The simulation is initialized with present-day conditions for bed topography and ice thickness and then run to steady state with constant present-day surface mass balance. Surface temperature and sub-shelf basal melt distribution are parameterized. Grounding lines and calving fronts are free to evolve, and their modeled equilibrium state is compared to observational data. A physically-motivated calving law based on horizontal spreading rates allows for realistic calving fronts for various types of shelves. Steady-state dynamics including surface velocity and ice flux are analyzed for whole Antarctica and the Ronne-Filchner and Ross ice shelf areas in particular. The results show that the different flow regimes in sheet and shelves, and the transition zone between them, are captured reasonably well, supporting the approach of superposition of SIA and SSA for the representation of fast motion of grounded ice. This approach also leads to a natural emergence of sliding-dominated flow in stream-like features in this new 3-D marine ice sheet model.},
  language  = {en}
}
@article{MariKielingNielsenetal.2011,
  author    = {Mari, Andrea and Kieling, Konrad and Nielsen, B. Melholt and Polzik, E. S. and Eisert, Jens},
  title     = {Directly estimating nonclassicality},
  series = {Physical review letters},
  volume    = {106},
  journal   = {Physical review letters},
  number    = {1},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.106.010403},
  pages     = {4},
  year      = {2011},
  abstract  = {We establish a method of directly measuring and estimating nonclassicality-operationally defined in terms of the distinguishability of a given state from one with a positive Wigner function. It allows us to certify nonclassicality, based on possibly much fewer measurement settings than necessary for obtaining complete tomographic knowledge, and is at the same time equipped with a full certificate. We find that even from measuring two conjugate variables alone, one may infer the nonclassicality of quantum mechanical modes. This method also provides a practical tool to eventually certify such features in mechanical degrees of freedom in opto-mechanics. The proof of the result is based on Bochner's theorem characterizing classical and quantum characteristic functions and on semidefinite programming. In this joint theoretical-experimental work we present data from experimental optical Fock state preparation.},
  language  = {en}
}
@article{MannYoungFuuentesSchuller2011,
  author    = {Mann, R. B. and Young, M. B. and Fu{\"u}ntes-Schuller, I.},
  title     = {A perturbative approach to inelastic collisions in a Bose-Einstein condensate},
  series = {Journal of physics : B, Atomic, molecular and optical physics},
  volume    = {44},
  journal   = {Journal of physics : B, Atomic, molecular and optical physics},
  number    = {8},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0953-4075},
  doi       = {10.1088/0953-4075/44/8/085301},
  pages     = {17},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@phdthesis{Malik2011,
  author    = {Malik, Nishant},
  title     = {Extremes in events and dynamics : a nonlinear data analysis perspective on the past and present dynamics of the Indian summer monsoon},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-58016},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {To identify extreme changes in the dynamics of the Indian Summer Monsoon (ISM) in the past, I propose a new approach based on the quantification of fluctuations of a nonlinear similarity measure, to identify regimes of distinct dynamical complexity in short time series. I provide an analytical derivation for the relationship of the new measure with the dynamical invariants such as dimension and Lyapunov exponents of the underlying system. A statistical test is also developed to estimate the significance of the identified transitions. Our method is justified by uncovering bifurcation structures in several paradigmatic models, providing more complex transitions compared with traditional Lyapunov exponents. In a real world situation, we apply the method to identify millennial-scale dynamical transitions in Pleistocene proxy records of the south Asian summer monsoon system. We infer that many of these transitions are induced by the external forcing of solar insolation and are also affected by internal forcing on Monsoonal dynamics, i.e., the glaciation cycles of the Northern Hemisphere and the onset of the tropical Walker circulation. Although this new method has general applicability, it is particularly useful in analysing short palaeo-climate records. Rainfall during the ISM over the Indian subcontinent occurs in form of enormously complex spatiotemporal patterns due to the underlying dynamics of atmospheric circulation and varying topography. I present a detailed analysis of summer monsoon rainfall over the Indian peninsular using Event Synchronization (ES), a measure of nonlinear correlation for point processes such as rainfall. First, using hierarchical clustering I identify principle regions where the dynamics of monsoonal rainfall is more coherent or homogenous. I also provide a method to reconstruct the time delay patterns of rain events. Moreover, further analysis is carried out employing the tools of complex network theory. This study provides valuable insights into the spatial organization, scales, and structure of the 90th and 94th percentile rainfall events during the ISM (June to September). I furthermore analyse the influence of different critical synoptic atmospheric systems and the impact of the steep Himalayan topography on rainfall patterns. The presented method not only helps in visualising the structure of the extremeevent rainfall fields, but also identifies the water vapor pathways and decadal-scale moisture sinks over the region. Furthermore a simple scheme based on complex networks is presented to decipher the spatial intricacies and temporal evolution of monsoonal rainfall patterns over the last six decades. Some supplementary results on the evolution of monsoonal rainfall extremes over the last sixty years are also presented.},
  language  = {de}
}
@article{MalicWeberRichteretal.2011,
  author    = {Malic, E. and Weber, C. and Richter, M. and Atalla, V. and Klamroth, Tillmann and Saalfrank, Peter and Reich, Sebastian and Knorr, A.},
  title     = {Microscopic model of the optical absorption of carbon nanotubes functionalized with molecular spiropyran photoswitches},
  series = {Physical review letters},
  volume    = {106},
  journal   = {Physical review letters},
  number    = {9},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.106.097401},
  pages     = {4},
  year      = {2011},
  abstract  = {The adsorption of molecules to the surface of carbon nanostructures opens a new field of hybrid systems with distinct and controllable properties. We present a microscopic study of the optical absorption in carbon nanotubes functionalized with molecular spiropyran photoswitches. The switching process induces a change in the dipole moment leading to a significant coupling to the charge carriers in the nanotube. As a result, the absorption spectra of functionalized tubes reveal a considerable redshift of transition energies depending on the switching state of the spiropyran molecule. Our results suggest that carbon nanotubes are excellent substrates for the optical readout of spiropyran-based molecular switches. The gained insights can be applied to other noncovalently functionalized one-dimensional nanostructures in an externally induced dipole field.},
  language  = {en}
}
@article{MakhmudoMakhmudovTarkhanov2011,
  author    = {Makhmudo, K. O. and Makhmudov, O. I. and Tarkhanov, Nikolai Nikolaevich},
  title     = {Equations of Maxwell type},
  series = {Journal of mathematical analysis and applications},
  volume    = {378},
  journal   = {Journal of mathematical analysis and applications},
  number    = {1},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {0022-247X},
  doi       = {10.1016/j.jmaa.2011.01.012},
  pages     = {64 -- 75},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{LueckPikovskij2011,
  author    = {Lueck, S. and Pikovskij, Arkadij},
  title     = {Dynamics of multi-frequency oscillator ensembles with resonant coupling},
  series = {Modern physics letters : A, Particles and fields, gravitation, cosmology, nuclear physics},
  volume    = {375},
  journal   = {Modern physics letters : A, Particles and fields, gravitation, cosmology, nuclear physics},
  number    = {28-29},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0375-9601},
  doi       = {10.1016/j.physleta.2011.06.016},
  pages     = {2714 -- 2719},
  year      = {2011},
  abstract  = {We study dynamics of populations of resonantly coupled oscillators having different frequencies. Starting from the coupled van der Pol equations we derive the Kuramoto-type phase model for the situation, where the natural frequencies of two interacting subpopulations are in relation 2 : 1. Depending on the parameter of coupling, ensembles can demonstrate fully synchronous clusters, partial synchrony (only one subpopulation synchronizes), or asynchrony in both subpopulations. Theoretical description of the dynamics based on the Watanabe-Strogatz approach is developed.},
  language  = {en}
}
@article{LomadzeKopyshevRueheetal.2011,
  author    = {Lomadze, Nino and Kopyshev, Alexey and R{\"u}he, J{\"u}rgen and Santer, Svetlana},
  title     = {Light-Induced chain scission in photosensitive polymer brushes},
  series = {Macromolecules : a publication of the American Chemical Society},
  volume    = {44},
  journal   = {Macromolecules : a publication of the American Chemical Society},
  number    = {18},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0024-9297},
  doi       = {10.1021/ma201016q},
  pages     = {7372 -- 7377},
  year      = {2011},
  abstract  = {We report on a process inducing photomechanical fracture of chemical bonds in photosensitive PMAA polymer brushes. The photosensitive PMAA polymer brushes were prepared by covalent attachment of azobenzene groups to poly(methylacrylic acid) (PMAA) chains generated by surface-initiated polymerization. While homogeneous irradiation leaves the polymer topography unchanged, the azo-PMAA brushes show a strong response upon irradiation with UV interference patterns. The photoisomerization process in the surface-attached polymer films results in the irreversible formation of surface relief gratings (SRG), which are strongly enhanced upon washing with a good solvent for the polymer. The photomechanical forces during mass transport induced by the irradiation lead to the scission of covalent bounds and accordingly to a degrafting of the polymer chains in areas where the polymer is receding from. It is observed that the number of ruptured chains depends strongly on the amount of azo side chains in the polymer.},
  language  = {en}
}
@misc{LoksteinKrikunovaTeuchneretal.2011,
  author    = {Lokstein, Heiko and Krikunova, Maria and Teuchner, Klaus and Voigt, Bernd},
  title     = {Elucidation of structure-function relationships in photosynthetic light-harvesting antenna complexes by non-linear polarization spectroscopy in the frequency domain (NLPF)},
  series = {Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants},
  volume    = {168},
  journal   = {Journal of plant physiology : biochemistry, physiology, molecular biology and biotechnology of plants},
  number    = {12},
  publisher = {Elsevier},
  address   = {Jena},
  issn      = {0176-1617},
  doi       = {10.1016/j.jplph.2010.12.012},
  pages     = {1488 -- 1496},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{LissoSchroederFisahnetal.2011,
  author    = {Lisso, Janina and Schr{\"o}der, Florian and Fisahn, Joachim and Muessig, Carsten},
  title     = {NFX1-LIKE2 (NFXL2) Suppresses Abscisic Acid Accumulation and Stomatal Closure in Arabidopsis thaliana},
  series = {PLoS one},
  volume    = {6},
  journal   = {PLoS one},
  number    = {11},
  publisher = {PLoS},
  address   = {San Fransisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0026982},
  pages     = {12},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{LevnajicPikovskij2011,
  author    = {Levnajic, Zoran and Pikovskij, Arkadij},
  title     = {Network reconstruction from random phase resetting},
  series = {Physical review letters},
  volume    = {107},
  journal   = {Physical review letters},
  number    = {3},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.107.034101},
  pages     = {4},
  year      = {2011},
  abstract  = {We propose a novel method of reconstructing the topology and interaction functions for a general oscillator network. An ensemble of initial phases and the corresponding instantaneous frequencies is constructed by repeating random phase resets of the system dynamics. The desired details of network structure are then revealed by appropriately averaging over the ensemble. The method is applicable for a wide class of networks with arbitrary emergent dynamics, including full synchrony.},
  language  = {en}
}
@article{Levnajic2011,
  author    = {Levnajic, Zoran},
  title     = {Emergent multistability and frustration in phase-repulsive networks of oscillators},
  series = {Physical review : E, Statistical, nonlinear and soft matter physics},
  volume    = {84},
  journal   = {Physical review : E, Statistical, nonlinear and soft matter physics},
  number    = {1},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {1539-3755},
  doi       = {10.1103/PhysRevE.84.016231},
  pages     = {10},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{LemrCernochSoubustaetal.2011,
  author    = {Lemr, Karel and Cernoch, A. and Soubusta, Jan and Kieling, Konrad and Eisert, Jens and Dusek, M.},
  title     = {Experimental implementation of the optimal linear-optical controlled phase gate},
  series = {Physical review letters},
  volume    = {106},
  journal   = {Physical review letters},
  number    = {1},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.106.013602},
  pages     = {4},
  year      = {2011},
  abstract  = {We report on the first experimental realization of optimal linear-optical controlled phase gates for arbitrary phases. The realized scheme is entirely flexible in that the phase shift can be tuned to any given value. All such controlled phase gates are optimal in the sense that they operate at the maximum possible success probabilities that are achievable within the framework of postselected linear-optical implementations with vacuum ancillas. The quantum gate is implemented by using bulk optical elements and polarization encoding of qubit states. We have experimentally explored the remarkable observation that the optimum success probability is not monotone in the phase.},
  language  = {en}
}
@article{LangeBlakesleyFrischetal.2011,
  author    = {Lange, Ilja and Blakesley, James C. and Frisch, Johannes and Vollmer, Antje and Koch, Norbert and Neher, Dieter},
  title     = {Band bending in conjugated polymer layers},
  series = {Physical review letters},
  volume    = {106},
  journal   = {Physical review letters},
  number    = {21},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {0031-9007},
  doi       = {10.1103/PhysRevLett.106.216402},
  pages     = {4},
  year      = {2011},
  abstract  = {We use the Kelvin probe method to study the energy-level alignment of four conjugated polymers deposited on various electrodes. Band bending is observed in all polymers when the substrate work function exceeds critical values. Through modeling, we show that the band bending is explained by charge transfer from the electrodes into a small density of states that extends several hundred meV into the band gap. The energetic spread of these states is correlated with charge-carrier mobilities, suggesting that the same states also govern charge transport in the bulk of these polymers.},
  language  = {en}
}
@article{LachmuthDurkaSchurr2011,
  author    = {Lachmuth, Susanne and Durka, Walter and Schurr, Frank Martin},
  title     = {Differentiation of reproductive and competitive ability in the invaded range of Senecio inaequidens the role of genetic Allee effects, adaptive and nonadaptive evolution},
  series = {New phytologist : international journal of plant science},
  volume    = {192},
  journal   = {New phytologist : international journal of plant science},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {0028-646X},
  doi       = {10.1111/j.1469-8137.2011.03808.x},
  pages     = {529 -- 541},
  year      = {2011},
  abstract  = {Genetic differentiation in the competitive and reproductive ability of invading populations can result from genetic Allee effects or r/K selection at the local or range-wide scale. However, the neutral relatedness of populations may either mask or falsely suggest adaptation and genetic Allee effects. In a common-garden experiment, we investigated the competitive and reproductive ability of invasive Senecio inaequidens populations that vary in neutral genetic diversity, population age and field vegetation cover. To account for population relatedness, we analysed the experimental results with 'animal models' adopted from quantitative genetics. Consistent with adaptive r/K differentiation at local scales, we found that genotypes from low-competition environments invest more in reproduction and are more sensitive to competition. By contrast, apparent effects of large-scale r/K differentiation and apparent genetic Allee effects can largely be explained by neutral population relatedness. Invading populations should not be treated as homogeneous groups, as they may adapt quickly to small-scale environmental variation in the invaded range. Furthermore, neutral population differentiation may strongly influence invasion dynamics and should be accounted for in analyses of common-garden experiments.},
  language  = {en}
}
@article{Kuznetsov2011,
  author    = {Kuznetsov, Sergey P.},
  title     = {Plykin type attractor in electronic device simulated in MULTISIM},
  series = {Chaos : an interdisciplinary journal of nonlinear science},
  volume    = {21},
  journal   = {Chaos : an interdisciplinary journal of nonlinear science},
  number    = {4},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {1054-1500},
  doi       = {10.1063/1.3646903},
  pages     = {8},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{KussmaulRisseKofodetal.2011,
  author    = {Kussmaul, Bjoern and Risse, Sebastian and Kofod, Guggi and Wache, Remi and Wegener, Michael and McCarthy, Denis N. and Kr{\"u}ger, Hartmut and Gerhard, Reimund},
  title     = {Enhancement of dielectric permittivity and electromechanical response in silicone elastomers molecular grafting of organic dipoles to the macromolecular Network},
  series = {Advanced functional materials},
  volume    = {21},
  journal   = {Advanced functional materials},
  number    = {23},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1616-301X},
  doi       = {10.1002/adfm.201100884},
  pages     = {4589 -- 4594},
  year      = {2011},
  abstract  = {A novel method is established for permittivity enhancement of a silicone matrix for dielectric elastomer actuators (DEAs) by molecular level modifications of the elastomer matrix. A push-pull dipole is synthesized to be compatible with the silicone crosslinking chemistry, allowing for direct grafting to the crosslinker molecules in a one-step film formation process. This method prevents agglomeration and yields elastomer films that are homogeneous down to the molecular level. The dipole-to-silicone network grafting reaction is studied by FTIR. The chemical, thermal, mechanical and electrical properties of films with dipole contents ranging from 0 wt\% to 13.4 wt\% were thoroughly characterized. The grafting of dipoles modifies the relative permittivity and the stiffness, resulting in the actuation strain at a given electrical field being improved by a factor of six.},
  language  = {en}
}
@article{KuehnPingelBreusingetal.2011,
  author    = {Kuehn, Sergei and Pingel, Patrick and Breusing, Markus and Fischer, Thomas and Stumpe, Joachim and Neher, Dieter and Elsaesser, Thomas},
  title     = {High-Resolution Near-Field Optical Investigation of Crystalline Domains in Oligomeric PQT-12 Thin Films},
  series = {Advanced functional materials},
  volume    = {21},
  journal   = {Advanced functional materials},
  number    = {5},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {1616-301X},
  doi       = {10.1002/adfm.201001978},
  pages     = {860 -- 868},
  year      = {2011},
  abstract  = {The structure and morphology on different length scales dictate both the electrical and optical properties of organic semiconductor thin films. Using a combination of spectroscopic methods, including scanning near-field optical microscopy, we study the domain structure and packing quality of highly crystalline thin films of oligomeric PQT-12 with 100 nanometer spatial resolution. The pronounced optical anisotropy of these layers measured by polarized light microscopy facilitates the identification of regions with uniform molecular orientation. We find that a hierarchical order on three different length scales exists in these layers, made up of distinct well-ordered dichroic areas at the ten-micrometer-scale, which are sub-divided into domains with different molecular in-plane orientation. These serve as a template for the formation of smaller needle-like crystallites at the layer surface. A high degree of crystalline order is believed to be the cause of the rather high field-effect mobility of these layers of 10(-3) cm 2 V(-1) s(-1), whereas it is limited by the presence of domain boundaries at macroscopic distances.},
  language  = {en}
}
@phdthesis{Krey2011,
  author    = {Krey, Olaf},
  title     = {Zur Rolle der Mathematik in der Physik : Wissenschaftstheoretische Aspekte und Vorstellungen Physiklernender},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59412},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {Mathematik spielt im Physikunterricht eine nicht unerhebliche Rolle - wenn auch eine zwiesp{\"a}ltige. Oft wird sie sogar zum Hindernis beim Lernen von Physik und kann ihr emanzipatorisches Potenzial nicht entfalten. Die vorliegende Arbeit stellt zwei Bausteine f{\"u}r eine begr{\"u}ndete Konzeption zum Umgang mit Mathematik beim Lernen von Physik zur Verf{\"u}gung. Im Theorieteil der Arbeit werden zum Einen wissenschaftstheoretische Aspekte der Rolle der Mathematik in der Physik aufgearbeitet und der physikdidaktischen Forschungsgemeinschaft im Zusammenhang zug{\"a}nglich gemacht. Zum anderen werden Forschungsergebnisse zu Vorstellungen Lernender {\"u}ber Physik und Mathematik sowie im Bereich der Epistemologie zusammengestellt. Im empirischen Teil der Arbeit werden Vorstellungen zur Rolle der Mathematik in der Physik von Sch{\"u}lerinnen und Sch{\"u}lern der Klassenstufen 10 und 12 sowie Physik-Lehramtstudierenden im Grundstudium mit Hilfe eines Fragebogens erhoben und unter Verwendung inhaltsanalytischer bzw. statistischer Methoden ausgewertet. Die Ergebnisse zeigen unter Anderem, dass Mathematik im Physikunterricht entgegen g{\"a}ngiger Meinungen bei den Lernenden nicht negativ, aber zumindest bei j{\"u}ngeren Lernenden formal und algorithmisch konnotiert ist.},
  language  = {de}
}
@article{KralemannPikovskijRosenblum2011,
  author    = {Kralemann, Bj{\"o}rn and Pikovskij, Arkadij and Rosenblum, Michael},
  title     = {Reconstructing phase dynamics of oscillator networks},
  series = {Chaos : an interdisciplinary journal of nonlinear science},
  volume    = {21},
  journal   = {Chaos : an interdisciplinary journal of nonlinear science},
  number    = {2},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {1054-1500},
  doi       = {10.1063/1.3597647},
  pages     = {10},
  year      = {2011},
  abstract  = {We generalize our recent approach to the reconstruction of phase dynamics of coupled oscillators from data [B. Kralemann et al., Phys. Rev. E 77, 066205 (2008)] to cover the case of small networks of coupled periodic units. Starting from a multivariate time series, we first reconstruct genuine phases and then obtain the coupling functions in terms of these phases. Partial norms of these coupling functions quantify directed coupling between oscillators. We illustrate the method by different network motifs for three coupled oscillators and for random networks of five and nine units. We also discuss nonlinear effects in coupling.},
  language  = {en}
}
@article{KoseskaVolkovKurths2011,
  author    = {Koseska, Aneta and Volkov, Evgenii and Kurths, J{\"u}rgen},
  title     = {Synthetic multicellular oscillatory systems controlling protein dynamics with genetic circuits},
  series = {Physica scripta : an international journal for experimental and theoretical physics},
  volume    = {84},
  journal   = {Physica scripta : an international journal for experimental and theoretical physics},
  number    = {4},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0031-8949},
  doi       = {10.1088/0031-8949/84/04/045007},
  pages     = {10},
  year      = {2011},
  abstract  = {Synthetic biology is a relatively new research discipline that combines standard biology approaches with the constructive nature of engineering. Thus, recent efforts in the field of synthetic biology have given a perspective to consider cells as 'programmable matter'. Here, we address the possibility of using synthetic circuits to control protein dynamics. In particular, we show how intercellular communication and stochasticity can be used to manipulate the dynamical behavior of a population of coupled synthetic units and, in this manner, finely tune the expression of specific proteins of interest, e.g. in large bioreactors.},
  language  = {en}
}
@phdthesis{Koseska2011,
  author    = {Koseska, Aneta},
  title     = {Dynamics of biological networks : data analysis, modeling and bifurcations},
  address   = {Potsdam},
  year      = {2011},
  language  = {en}
}