@article{CharronCironeNegrettietal.2006, author = {Charron, Eric and Cirone, M. A. and Negretti, Antonio and Schmiedmayer, J{\"o}rg and Calarco, Tommaso}, title = {Theoretical analysis of a realistic atom-chip quantum gate}, issn = {1050-2947}, year = {2006}, abstract = {We present a detailed, realistic analysis of the implementation of a proposal for a quantum phase gate based on atomic vibrational states, specializing it to neutral rubidium atoms on atom chips. We show how to create a double-well potential with static currents on the atom chips, using for all relevant parameters values that are achieved with present technology. The potential barrier between the two wells can be modified by varying the currents in order to realize a quantum phase gate for qubit states encoded in the atomic external degree of freedom. The gate performance is analyzed through numerical simulations; the operation time is similar to 10 ms with a performance fidelity above 99.9\%. For storage of the state between the operations the qubit state can be transferred efficiently via Raman transitions to two hyperfine states, where its decoherence is strongly inhibited. In addition we discuss the limits imposed by the proximity of the surface to the gate fidelity.}, language = {en} } @article{WinterhalderSchelterKurthsetal.2006, author = {Winterhalder, Matthias and Schelter, B and Kurths, J{\"u}rgen and Schulze-Borthage, A and Timmer, Jens}, title = {Sensitivity and specificity of coherence and phase synchronization analysis}, doi = {10.1016/j.physleta.2006.03.018}, year = {2006}, abstract = {In this Letter, we show that coherence and phase synchronization analysis are sensitive but not specific in detecting the correct class of underlying dynamics. We propose procedures to increase specificity and demonstrate the power of the approach by application to paradigmatic dynamic model systems. (c) 2006 Elsevier B.V. All rights reserved}, language = {en} } @article{SchwabedalPikovskij2010, author = {Schwabedal, Justus T. C. and Pikovskij, Arkadij}, title = {Effective phase description of noise-perturbed and noise-induced oscillations}, issn = {1951-6355}, doi = {10.1140/epjst/e2010-01271-6}, year = {2010}, abstract = {An effective dynamical description of a general class of stochastic phase oscillators is presented. For this, the effective phase velocity is defined either by the stochastic phase oscillators invariant probability density or its first passage times. Using the first approach the effective phase exhibits the correct frequency and invariant distribution density, whereas the second approach models the proper phase resetting curve. The discrepancy of the effective models is most pronounced for noise-induced oscillations and is related to non-monotonicity of the stochastic phase variable due to fluctuations.}, language = {en} } @article{WegenerBergweilerZscherpeletal.2006, author = {Wegener, Michael and Bergweiler, Steffen and Zscherpel, Detlef and Wirges, Werner and Gerhard, Reimund}, title = {Detection of elliptical oscillations and monopole breathing of organ-pipe bodies with piezoelectric polymer sensors}, year = {2006}, abstract = {In this paper, a measuring technique is presented for the detection of radial oscillations of tube walls excited by changes in internal air pressure. On organ pipes, the oscillations were investigated by means of piezoelectric polymer films slightly tensioned around the pipe bodies. Employing sensors with patterned electrodes, the well-known elliptical oscillation of the cross section as well as an additional monopole breathing of the organ-pipe body were detected. For the monopole breathing, a close relationship between the pressure distribution of the air-column resonances inside the pipe and the circumference variations along the pipe was observed}, language = {en} } @article{WuZhouChenetal.2010, author = {Wu, Ye and Zhou, Changsong and Chen, Maoyin and Xiao, Jinghua and Kurths, J{\"u}rgen}, title = {Human comment dynamics in on-line social systems}, issn = {0378-4371}, doi = {10.1016/j.physa.2010.08.049}, year = {2010}, abstract = {Human comment is studied using data from 'tianya' which is one of the most popular on-line social systems in China. We found that the time interval between two consecutive comments on the same topic, called inter-event time, follows a power-law distribution. This result shows that there is no characteristic decay time on a topic. It allows for very long periods without comments that separate bursts of intensive comments. Furthermore, the frequency of a different ID commenting on a topic also follows a power-law distribution. It indicates that there are some "hubs" in the topic who lead the direction of the public opinion. Based on the personal comments habit, a model is introduced to explain these phenomena. The numerical simulations of the model fit well with the empirical results. Our findings are helpful for discovering regular patterns of human behavior in on-line society and the evolution of the public opinion on the virtual as well as real society.}, language = {en} } @article{HenkelJoulain2006, author = {Henkel, Carsten and Joulain, Karl}, title = {Electromagnetic field correlations near a surface with a nonlocal optical response}, issn = {0946-2171}, doi = {10.1007/s00340-006-2219-9}, year = {2006}, abstract = {The coherence length of the thermal electromagnetic field near a planar surface has a minimum value related to the nonlocal dielectric response of the material. We perform two model calculations of the electric energy density and the field's degree of spatial coherence. Above a polar crystal, the lattice constant gives the minimum coherence length. It also gives the upper limit to the near field energy density, cutting off its 1/z(3) divergence. Near an electron plasma described by the semiclassical Lindhard dielectric function, the corresponding length scale is fixed by plasma screening to the Thomas-Fermi length. The electron mean free path, however, sets a larger scale where significant deviations from the local description are visible}, language = {en} } @article{SchwabedalPikovskij2010, author = {Schwabedal, Justus T. C. and Pikovskij, Arkadij}, title = {Effective phase dynamics of noise-induced oscillations in excitable systems}, issn = {1539-3755}, doi = {10.1103/Physreve.81.046218}, year = {2010}, abstract = {We develop an effective description of noise-induced oscillations based on deterministic phase dynamics. The phase equation is constructed to exhibit correct frequency and distribution density of noise-induced oscillations. In the simplest one-dimensional case the effective phase equation is obtained analytically, whereas for more complex situations a simple method of data processing is suggested. As an application an effective coupling function is constructed that quantitatively describes periodically forced noise-induced oscillations.}, language = {en} } @article{AbelBergweilerGerhard2006, author = {Abel, Markus and Bergweiler, Steffen and Gerhard, Reimund}, title = {Synchronization of organ pipes : experimental observations and modeling}, issn = {0001-4966}, doi = {10.1121/1.217044}, year = {2006}, abstract = {We report measurements on the synchronization properties of organ pipes. First, we investigate influence of an external acoustical signal from a loudspeaker on the sound of an organ pipe. Second, the mutual influence of two pipes with different pitch is analyzed. In analogy to the externally driven, or mutually coupled self-sustained oscillators, one observes a frequency locking, which can be explained by synchronization theory. Further, we measure the dependence of the frequency of the signals emitted by two mutually detuned pipes with varying distance between the pipes. The spectrum shows a broad '' hump '' structure, not found for coupled oscillators. This indicates a complex coupling of the two organ pipes leading to nonlinear beat phenomena.}, language = {en} } @article{VarykhalovGudatAdamchuketal.2006, author = {Varykhalov, Andrei and Gudat, Wolfgang and Adamchuk, V. K. and Rader, Oliver}, title = {Magic numbers in two-dimensional self-organization of C-60 molecules}, doi = {10.1103/Physrevb.73.241404}, year = {2006}, abstract = {Employing the chemically passive carbon reconstruction W(110)/C-R(15x3) as substrate for deposition of C-60 molecules, we have discovered by scanning tunneling microscopy two-dimensional self-assembly of fullerenes into uniform molecular nanoclusters with "magic" numbers. Our photoemission measurements determine van der Waals forces as the dominating interaction in this self-organizing two-dimensional molecular gas. Based on this, a theoretical determination of the cluster structures in the framework of the Girifalco model gives perfect agreement with the experiment}, language = {en} } @book{FreudeKuznetsovPikovskij2006, author = {Freude, Ulrike and Kuznetsov, Sergey P. and Pikovskij, Arkadij}, title = {Strange nonchaotic attractors : dynamics between order and chaos in Quasiperiodically Forced Systems}, publisher = {World Scientific}, address = {Singapore}, isbn = {981-256633-3}, pages = {350 S.}, year = {2006}, language = {en} } @phdthesis{Reimann2006, author = {Reimann, Bernd}, title = {Gauge conditions in numerical relativity}, pages = {172 S. : graph. Darst.}, year = {2006}, language = {en} } @article{MellingerWegenerWirgesetal.2006, author = {Mellinger, Axel and Wegener, Michael and Wirges, Werner and Mallepally, Rajendar Reddy and Gerhard, Reimund}, title = {Thermal and temporal stability of ferroelectret films made from cellular polypropylene/air composites}, year = {2006}, abstract = {Ferroelectrets are thin films of polymer foams, exhibiting piezoelectric properties after electrical charging. Ferroelectret foams usually consist of a cellular polymer structure filled with air. Polymer-air composites are elastically soft due to their high air content as well as due to the size and shape of the polymer walls. Their elastically soft composite structure is one essential key for the working principle of ferroelectrets, besides the permanent trapping of electric charges inside the polymer voids. The elastic properties allow large deformations of the electrically charged voids. However, the composite structure can also possibly limit the stability and consequently the range of applications because of, e. g., penetration of gas and liquids accompanied by discharge phenomena or because of a mechanical pre-load which may be required during the application. Here, we discuss various stability aspects related to the piezoelectric properties of polypropylene ferroelectrets. Near and below room temperature, the piezoelectric effect and the stability of the trapped charges are practically independent from humidity during long-time storage in a humid atmosphere or water, or from operating conditions, such as continuous mechanical excitation. Thermal treatment of cellular polypropylene above -10 degrees C leads to a softening of the voided structure which is apparent from the decreasing values of the elastic modulus. This decrease results in an increase of the piezoelectric activity. Heating above 60 degrees C, however, leads to a decrease in piezoelectricity}, language = {en} } @article{Mikelskis2006, author = {Mikelskis, Helmut F.}, title = {Chaosphysik}, isbn = {3-589-22148-8}, year = {2006}, language = {de} } @article{Mikelskis2006, author = {Mikelskis, Helmut F.}, title = {Die Nanowelt}, isbn = {3-589-22148-8}, year = {2006}, language = {de} } @article{Mikelskis2006, author = {Mikelskis, Helmut F.}, title = {Offener Physikunterricht}, isbn = {3-589-22148-8}, year = {2006}, language = {de} } @article{Mikelskis2006, author = {Mikelskis, Helmut F.}, title = {Die Rolle des Physikbuches beim Unterrichten und Lernen von Physik}, isbn = {3-589-22148-8}, year = {2006}, language = {de} } @book{OPUS4-11736, title = {Physik-Didaktik : Praxishandbuch f{\"u}r die Sekundarstufe I und II}, editor = {Mikelskis, Helmut F.}, publisher = {Cornelsen Scriptor}, address = {Berlin}, isbn = {3-589-22148-8}, pages = {288 S.}, year = {2006}, language = {de} } @book{RahmstorfSchellnhuber2006, author = {Rahmstorf, Stefan and Schellnhuber, Hans Joachim}, title = {Der Klimawandel}, series = {Becksche Reihe}, volume = {2366}, journal = {Becksche Reihe}, publisher = {Beck}, address = {M{\"u}nchen}, isbn = {3-406-50866-9}, pages = {144 S.}, year = {2006}, language = {de} } @article{Mikelskis2006, author = {Mikelskis, Helmut F.}, title = {Physikunterricht als Beitrag zur Bew{\"a}ltigung gesellschaftlicher Schl{\"u}sselprobleme}, isbn = {3-589-22148-8}, year = {2006}, language = {de} } @article{ShklyaevStraube2010, author = {Shklyaev, Sergey and Straube, Arthur V.}, title = {Superexponential droplet fractalization as a hierarchical formation of dissipative compactons}, issn = {1539-3755}, doi = {10.1103/Physreve.82.020601}, year = {2010}, abstract = {We study the dynamics of a thin film over a substrate heated from below in a framework of a strongly nonlinear one-dimensional Cahn-Hilliard equation. The evolution leads to a fractalization into smaller and smaller scales. We demonstrate that a primitive element in the appearing hierarchical structure is a dissipative compacton. Both direct simulations and the analysis of a self-similar solution show that the compactons appear at superexponentially decreasing scales, which means vanishing dimension of the fractal.}, language = {en} } @article{Klamroth2006, author = {Klamroth, Tillmann}, title = {Optimal control of ultrafast laser driven many-electron dynamics in a polyatomic molecule: N-methyl-6-quinolone}, issn = {0021-9606}, doi = {10.1063/1.2185633}, year = {2006}, abstract = {We report time-dependent configuration interaction singles calculations for the ultrafast laser driven many- electron dynamics in a polyatomic molecule, N-methyl-6-quinolone. We employ optimal control theory to achieve a nearly state-selective excitation from the S-0 to the S-1 state, on a time scale of a few (approximate to 6) femtoseconds. The optimal control scheme is shown to correct for effects opposing a state-selective transition, such as multiphoton transitions and other, nonlinear phenomena, which are induced by the ultrashort and intense laser fields. In contrast, simple two-level pi pulses are not effective in state-selective excitations when very short pulses are used. Also, the dependence of multiphoton and nonlinear effects on the number of states included in the dynamical simulations is investigated.}, language = {en} } @article{MellingerFloresSuarezSinghetal.2006, author = {Mellinger, Axel and Flores Su{\´a}rez, Rosaura and Singh, Rajeev and Wegener, Michael and Wirges, Werner and Lang, Sidney B. and Gerhard, Reimund}, title = {High-resolution space-charge and polarization tomography with thermal pulses}, isbn = {3-8007-2939-3}, year = {2006}, abstract = {Die Arbeit wurde am 13.03.2006 mit dem "BEST PAPER AWARD" des deutschen IEEE Instrumentation and Measurement (I\&M) Chapter ausgezeichnet.}, language = {en} } @article{Rabe2006, author = {Rabe, Thorid}, title = {Motivation, Interesse und Selbstkonzept im Physikunterricht}, isbn = {3-589-22148-8}, year = {2006}, language = {de} } @article{Starauschek2006, author = {Starauschek, Erich}, title = {Zur Rolle der Sprache beim Lernen von Physik}, isbn = {3-589-22148-8}, year = {2006}, language = {de} } @phdthesis{Khalatyan2007, author = {Khalatyan, Arman}, title = {The influence of nuclear activity onto the morphology of galaxies}, address = {Potsdam}, pages = {XVII, 155 S. : Ill., graph. Darst.}, year = {2007}, language = {en} } @phdthesis{Ruffoni2007, author = {Ruffoni, Davide}, title = {Modeling of material and architectural quality of trabecular bone}, address = {Potsdam}, pages = {VI, 127 S. Ill., graph. Darst.}, year = {2007}, language = {en} } @phdthesis{Mueller2007, author = {M{\"u}ller, Renate}, title = {Einfluss der Temperatur auf die Nanomechanik von sph{\"a}rischen und zylindrischen Polyelektrolyt-Multischicht- Hohlk{\"o}rpern}, address = {Potsdam}, pages = {VI, 114 S. : Ill., graph. Darst.}, year = {2007}, language = {de} } @phdthesis{Raab2007, author = {Raab, Corinna}, title = {Entwicklung von Large-Scale-Dimensionsdichten und deren Anwendung auf biomedizinische Daten}, address = {Potsdam}, pages = {IX, 74 S. : graph. Darst.}, year = {2007}, language = {de} } @phdthesis{Grafmueller2007, author = {Grafm{\"u}ller, Andrea}, title = {The fusion of membranes and vesicles}, address = {Potsdam}, pages = {VII, 133 S. : Ill., graph. Darst.}, year = {2007}, language = {en} } @phdthesis{Voronina2007, author = {Voronina, Olena}, title = {Structure-property relations in polymer ferroelectrets}, address = {Potsdam}, pages = {IV, 145 S., IV : graph. Darst.}, year = {2007}, language = {en} } @phdthesis{Kremmer2007, author = {Kremmer, Alexander}, title = {Untersuchungen der Struktur von Polyamid 11 - Filmen und ihres Einflusses auf deren piezo- und ferroelektrische Eigenschaften}, address = {Potsdam}, pages = {100 Bl. : Ill., : graph. Darst.}, year = {2007}, language = {de} } @phdthesis{ColpanZenginoglu2007, author = {Colpan Zenginoglu, Anil}, title = {A conformal approach to numerical calculations of asymptotically flat spacetimes}, address = {Potsdam}, pages = {101 S. : graph. Darst.}, year = {2007}, language = {en} } @article{BeimGrabenAtmanspacher2006, author = {Beim Graben, Peter and Atmanspacher, Harald}, title = {Complementarity in classical dynamical systems}, issn = {0015-9018}, doi = {10.1007/s10701-005-9013-0}, year = {2006}, abstract = {The concept of complementarity, originally defined for non-commuting observables of quantum systems with states of non-vanishing dispersion, is extended to classical dynamical systems with a partitioned phase space. Interpreting partitions in terms of ensembles of epistemic states (symbols) with corresponding classical observables, it is shown that such observables are complementary to each other with respect to particular partitions unless those partitions are generating. This explains why symbolic descriptions based on an ad hoc partition of an underlying phase space description should generally be expected to be incompatible. Related approaches with different background and different objectives are discussed}, language = {en} } @article{WegenerWirgesTiersch2006, author = {Wegener, Michael and Wirges, Werner and Tiersch, Brigitte}, title = {Porous polytetrafluoroethylene (PTFE) electret films : porosity and time dependent charging behaviour of the free surface}, doi = {10.1007/s10934-006-9015-0}, year = {2006}, abstract = {Electrically charged porous polytetrafluoroethylene (PTFE) films are often discussed as active layers for electromechanical transducers. Here, the electric charging behavior of open-porous PTFE films with different porosities is investigated. Optimized electric charging of porous PTFE films is determined by variation of charging parameters such as electric fields and charging times. Maximum surface potentials are depending on the porosity of the PTFE films. Suitable charging leads to high surface potentials observed on non-stretched or slightly stretched porous PTFE films. Further increase of charging fields yields decreasing values of the surface potential accompanied with an increase of conductivity.}, language = {en} } @article{QiuMellingerWirgesetal.2007, author = {Qiu, Xunlin and Mellinger, Axel and Wirges, Werner and Gerhard, Reimund}, title = {Dielectric barrier discharges during the generation of ferroelectrets : optical spectroscopy for process monitoring}, isbn = {978-1-4244-1482-6}, year = {2007}, language = {en} } @article{BassoAltafimAltafimetal.2007, author = {Basso, Heitor Cury and Altafim, Ruy Alberto Pisani and Altafim, Ruy Alberto Pisani and Mellinger, Axel and Fang, Peng and Wirges, Werner and Gerhard, Reimund}, title = {Three-layer ferroelectrets from perforated Teflon-PTFE films fused between two homogeneous Teflon-FEP films}, isbn = {978-1-4244-1482-6}, year = {2007}, language = {en} } @article{WegenerWirgesPaajanenetal.2007, author = {Wegener, Michael and Wirges, Werner and Paajanen, Mika and Gerhard, Reimund}, title = {Charging behaviour and thermal stability of porous and non-porous polytetrafluoroethylene (PTFE) electrets}, isbn = {978-1-4244-1482-6}, year = {2007}, language = {en} } @article{QiuMellingerWegeneretal.2007, author = {Qiu, Xunlin and Mellinger, Axel and Wegener, Michael and Wirges, Werner and Gerhard, Reimund}, title = {Barrier discharges in cellular polypropylene ferroelectrets : how do they influence the electromechanical properties?}, year = {2007}, language = {en} } @article{ReddyPuranikGuptaetal.2007, author = {Reddy, Raghavendra V. and Puranik, Shikha and Gupta, Ajay and Leitenberger, Wolfram}, title = {Study of FePt films prepared by reactive sputtering}, year = {2007}, language = {en} } @phdthesis{Koseska2007, author = {Koseska, Aneta}, title = {Modeling and control of synthetic gene regulatory networks}, address = {Potsdam}, pages = {viii, 82 S.}, year = {2007}, language = {en} } @phdthesis{Wegener2007, author = {Wegener, Michael}, title = {Ferroelektrete und Polymersch{\"a}ume: Pr{\"a}paration, Eigenschaften und Anwendung als piezoelektrische Wandler}, address = {Potsdam}, pages = {129 S. : Ill., graph. Darst.}, year = {2007}, language = {de} } @phdthesis{Horn2007, author = {Horn, Martin Erik}, title = {Entwicklung und Evaluation eines Unterrichtskonzeptes zur Holographie mit Untersuchungen von Lernprozessen zur Interferenzoptik}, address = {Potsdam}, pages = {325 S. : graph. Darst.}, year = {2007}, language = {de} } @phdthesis{Beyer2007, author = {Beyer, Florian}, title = {Asymptotics and singularities in cosmological models with positive cosmological constant}, address = {Potsdam}, pages = {173 S. : graph. Darst.}, year = {2007}, language = {en} } @phdthesis{Liepelt2007, author = {Liepelt, Steffen}, title = {Energy transduction in network models of molecular motors}, address = {Potsdam}, pages = {102 S. : graph. Darst.}, year = {2007}, language = {en} } @article{SeehaferFuhrmannValorietal.2007, author = {Seehafer, Norbert and Fuhrmann, M. and Valori, Gherardo and Kliem, Bernhard}, title = {Force-free magnetic fields in the solar atmosphere}, year = {2007}, language = {en} } @phdthesis{Merlo2007, author = {Merlo, Claudia}, title = {A model of protein folding kinetics}, address = {Potsdam}, pages = {89 S. : graph. Darst.}, year = {2007}, language = {en} } @phdthesis{Silmy2007, author = {Silmy, Kamel}, title = {Micro-jet plasma chemical vapor deposition}, address = {Potsdam}, pages = {xviii, 96 S. : Ill., graph. Darst.}, year = {2007}, language = {en} } @article{MikelskisSeifertRabe2007, author = {Mikelskis-Seifert, Silke and Rabe, Thorid}, title = {Der darbietende Unterricht : Darstellung und Pr{\"a}sentation durch Lehrerinnen}, isbn = {978-3-589-22377-0}, year = {2007}, language = {de} } @article{Kasper2007, author = {Kasper, Lutz}, title = {Textarbeit und Narration : Naration}, isbn = {978-3-589-22377-0}, year = {2007}, language = {de} } @article{Rabe2007, author = {Rabe, Thorid}, title = {Textarbeit und Narration : Textarbeit}, isbn = {978-3-589-22377-0}, year = {2007}, language = {de} } @article{MikelskisSeifertLeisnerBodenthin2007, author = {Mikelskis-Seifert, Silke and Leisner-Bodenthin, Antje}, title = {Unterrichtsans{\"a}tze zu den Methoden physikalischer Erkenntnisgewinnung : die Modellmethode}, isbn = {978-3-589-22377-0}, year = {2007}, language = {de} } @book{OPUS4-11084, title = {Physik Methodik : Handbuch f{\"u}r die Sekundarstufe I und II}, editor = {Mikelskis-Seifert, Silke and Rabe, Thorid}, publisher = {Cornelsen}, address = {Berlin}, isbn = {978-3-589-22377-0}, pages = {240 S.}, year = {2007}, language = {de} } @article{Rabe2007, author = {Rabe, Thorid}, title = {Sch{\"u}lerzentierte Unterrichtsans{\"a}tze : Kooperatives Lernen in Gruppen}, isbn = {978-3-589-22377-0}, year = {2007}, language = {de} } @article{Menzel2007, author = {Menzel, Ralf}, title = {Photonics : linear and nonlinear interactions of laser light and matter}, publisher = {Springer}, address = {Berlin}, isbn = {978-540-67074-2}, pages = {1024 S.}, year = {2007}, language = {en} } @article{PalusKurthsSchwarzetal.2007, author = {Palus, Milan and Kurths, J{\"u}rgen and Schwarz, Udo and Seehafer, Norbert and Novotna, Dagmar and Charvatova, Ivanka}, title = {The solar activity cycle is weakly synchronized with the solar inertial motion}, doi = {10.1016/j.physleta.2007.01.039}, year = {2007}, abstract = {We study possible interrelations between the 300-year record of the yearly sunspot numbers and the solar inertial motion (SIM) using the recently developed technique of synchronization analysis. Phase synchronization of the sunspot cycle and the SIM is found and statistically confirmed in three epochs (1734-1790, 1855-1875 and 1907-1960) of the whole period 1700-2000. These results give quantitative support to the hypothesis that there is a weak interaction between the solar activity and the SIM.}, language = {en} } @article{Mikelskis2007, author = {Mikelskis, Helmut F.}, title = {Unterrichtsprinzipien : exemplarisch - genetisch - sokratisch}, isbn = {978-3-589-22377-0}, year = {2007}, language = {de} } @article{MikelskisSeifertRabe2007, author = {Mikelskis-Seifert, Silke and Rabe, Thorid}, title = {Der darbietende Unterricht : darbieten - was und wie?}, isbn = {978-3-589-22377-0}, year = {2007}, language = {de} } @article{KofodWirgesPaajanenetal.2007, author = {Kofod, Guggi and Wirges, Werner and Paajanen, Mika and Bauer, Siegfried}, title = {Energy minimization for self-organized structure formation and actuation}, issn = {0003-6951}, doi = {10.1063/1.2695785}, year = {2007}, abstract = {An approach for creating complex structures with embedded actuation in planar manufacturing steps is presented. Self-organization and energy minimization are central to this approach, illustrated with a model based on minimization of the hyperelastic free energy strain function of a stretched elastomer and the bending elastic energy of a plastic frame. A tulip-shaped gripper structure illustrates the technological potential of the approach. Advantages are simplicity of manufacture, complexity of final structures, and the ease with which any electroactive material can be exploited as means of actuation. (c) 2007 American Institute of Physics.}, language = {en} } @book{Barcelo2007, author = {Barcel{\´o}, Pedro}, title = {Alexander der Große}, publisher = {Primus-Verl.}, address = {Darmstadt}, isbn = {978-3-89678-610-4}, pages = {272 S.}, year = {2007}, language = {de} } @article{KowarikGerlachLeitenbergeretal.2007, author = {Kowarik, Stefan and Gerlach, Andreas and Leitenberger, Wolfram and Hu J, Witte and W{\"o}ll, Christoph and Schreiber, Frank}, title = {Energy-dispersive X-ray reflectivity and GID for real-time growth studies of pentacene thin films}, issn = {0040-6090}, doi = {10.1016/j.tsf.2006.12.020}, year = {2007}, abstract = {We use energy-dispersive X-ray reflectivity and grazing incidence diffraction (GID) to follow the growth of the crystalline organic semiconductor pentacene on silicon oxide in-situ and in real-time. The technique allows for monitoring Bragg reflections and measuring X-ray growth oscillations with a time resolution of 1 min in a wide q-range in reciprocal space extending over 0.25-0.80 angstrom(-1), i.e. sampling a large number of Fourier components simultaneously. A quantitative analysis of growth oscillations at several q-points yields the evolution of the surface roughness, showing a marked transition from layer-by-layer growth to strong roughening after four monolayers of pentacene have been deposited. (c) 2006 Elsevier B.V. All rights reserved.}, language = {en} } @phdthesis{Velagapudi2008, author = {Velagapudi, Rama Krishna}, title = {Preparation and characterization of thermally stable guest-host Polymer thin films for non-lunear optical applications}, address = {Potsdam}, pages = {111 S., i-viii, : graph. Darst.}, year = {2008}, language = {en} } @phdthesis{Velagapudi2008, author = {Velagapudi, Rama Krishna}, title = {Preparation and characterization of thermally stable guest-host polymer thin films for non-linear optical applications}, address = {Potsdam}, pages = {viii, 112 S.: Ill., graph. Darst.}, year = {2008}, language = {en} } @article{QiuMellingerWirgesetal.2007, author = {Qiu, Xunlin and Mellinger, Axel and Wirges, Werner and Gerhard, Reimund}, title = {Spectroscopic study of dielectric barrier discharges in cellular polypropylene ferroelectrets}, doi = {10.1063/1.2786597}, year = {2007}, abstract = {The transient light emission from the dielectric barrier discharges (DBDs) in cellular polypropylene ferroelectrets subjected to high electric poling fields was spectroscopically measured. The spectrum shows strong emission from the second positive system of molecular nitrogen, N-2(C (3)Pi(u))-> N-2(B (3)Pi(g)), and the first negative system of N-2(+), N-2(+)(B (2)Sigma(+)(u))-> N-2(+)(X (2)Sigma(+)(g)), consistent with a DBD in air. When a dc voltage is applied stepwise to the ferroelectret film, light emission starts above a threshold, coinciding with the threshold voltage in obtaining piezoelectricity. From selected vibronic band strength ratios, the electric field in the discharge was determined and found to agree with Townsend breakdown.}, language = {en} } @phdthesis{Kasper2008, author = {Kasper, Lutz}, title = {Diskursiv-narrative Elemente f{\"u}r den Physikunterricht. Entwicklung und Evaluation einer multimedialen Lernumgebung zum Erdmagnetismus}, address = {Potsdam}, pages = {253 S. : graph. Darst.}, year = {2008}, language = {de} } @phdthesis{Blecua2008, author = {Blecua, Pedro}, title = {Liquid morphologies on patterned surfaces}, address = {Potsdam}, pages = {104 S. : graph. Darst.}, year = {2008}, language = {en} } @phdthesis{Rausche2008, author = {Rausche, Germar}, title = {Ein Verfahren zur Bestimmung des Magnetfeldes in aktiven Strukturen der Sonnenkorona}, address = {Potsdam}, pages = {I, 109 S. : Ill., graph. Darst.}, year = {2008}, language = {de} } @article{FeudelTuckermanGellertetal.2015, author = {Feudel, Fred and Tuckerman, L. S. and Gellert, Marcus and Seehafer, Norbert}, title = {Bifurcations of rotating waves in rotating spherical shell convection}, series = {Physical Review E}, volume = {92}, journal = {Physical Review E}, number = {5}, publisher = {American Physical Society}, address = {Woodbury}, issn = {1539-3755}, doi = {10.1103/PhysRevE.92.053015}, year = {2015}, abstract = {The dynamics and bifurcations of convective waves in rotating and buoyancy-driven spherical Rayleigh-Benard convection are investigated numerically. The solution branches that arise as rotating waves (RWs) are traced by means of path-following methods, by varying the Rayleigh number as a control parameter for different rotation rates. The dependence of the azimuthal drift frequency of the RWs on the Ekman and Rayleigh numbers is determined and discussed. The influence of the rotation rate on the generation and stability of secondary branches is demonstrated. Multistability is typical in the parameter range considered.}, language = {en} } @phdthesis{Habicht2016, author = {Habicht, Klaus}, title = {Neutron-resonance spin-echo spectroscopy}, school = {Universit{\"a}t Potsdam}, pages = {276}, year = {2016}, language = {en} } @phdthesis{Kruesemann2016, author = {Kr{\"u}semann, Henning}, title = {First passage phenomena and single-file motion in ageing continuous time random walks and quenched energy landscapes}, school = {Universit{\"a}t Potsdam}, pages = {122}, year = {2016}, abstract = {In der Physik gibt es viele Prozesse, die auf Grund ihrer Komplexit{\"a}t nicht durch physikalische Gleichungen beschrieben werden k{\"o}nnen, beispielsweise die Bewegung eines Staubkorns in der Luft. Durch die vielen St{\"o}ße mit Luftmolek{\"u}len f{\"u}hrt es eine Zufallsbewegung aus, die so genannte Diffusion. Auch Molek{\"u}le in biologischen Zellen diffundieren, jedoch befinden sich in einer solchen Zelle im selben Volumen viel mehr oder viel gr{\"o}ßere Molek{\"u}le. Das beobachtete Teilchen st{\"o}ßt dementsprechend {\"o}fter mit anderen zusammen und die Diffusion wird langsamer, sie wird subdiffusiv. Mit der Zeit kann sich die Charakteristik der Subdiffusion {\"a}ndern; dies wird als (mikroskopisches) Altern bezeichnet. Ich untersuche in der vorliegenden Arbeit zwei mathematische Modelle f{\"u}r eindimensionale Subdiffusion, einmal den continuous time random walk (CTRW) und einmal die Zufallsbewegung in einer eingefrorenen Energielandschaft (QEL=quenched energy landscape). Beide sind Sprungprozesse, das heißt, sie sind Abfolgen von r{\"a}umlichen Spr{\"u}ngen, die durch zufallsverteilte Wartezeiten getrennt sind. Die Wartezeiten in der QEL sind r{\"a}umlich korrelliert, w{\"a}hrend sie im CTRW unkorrelliert sind. Ich untersuche in der vorliegenden Arbeit verschiedene statistische Gr{\"o}ßen in beiden Modellen. Zun{\"a}chst untersuche ich den Einfluss des Alters und den Einfluss der Korrellationen einer QEL auf die Verteilung der Zeiten, die das diffundierendes Teilchen ben{\"o}tigt, um eine (r{\"a}umliche) Schwelle zu {\"u}berqueren. Ausserdem bestimme ich den Effekt des Alters auf Str{\"o}me von (sub)diffundierenden Partikeln, die sich auf eine absorbierende Barriere zubewegen. Zuletzt besch{\"a}ftige ich mich mit der Diffusion einer eindimensionalen Anordnung von Teilchen in einer QEL, in der diese als harte Kugeln miteinander wechselwirken. Dabei vergleiche ich die gemeinsame Bewegung in einer QEL und als individuelle CTRWs miteinander {\"u}ber die Standartabweichung von der Startposition, f{\"u}r die ich das Mittel {\"u}ber mehrere QELs untersuche. Meine Arbeit setzt sich zusammen aus theoretischen {\"U}berlegungen und Berechnungen sowie der Simulation der Zufallsprozesse. Die Ergebnisse der Simulation und, soweit vorhanden, experimentelle Daten werden mit der Theorie verglichen.}, language = {en} } @phdthesis{Anielski2015, author = {Anielski, Alexander}, title = {Entwicklung einer mikrofluidischen, adaptiv geregelten Messapparatur zur quantitativen Untersuchung von Chemotaxis mit Hilfe der Flussfotolyse}, school = {Universit{\"a}t Potsdam}, pages = {iv, 130 Seiten : Illustrationen, Diagramme + 1 DVD}, year = {2015}, language = {de} } @phdthesis{Wenz2016, author = {Wenz, Leonie}, title = {Climate change impacts in an increasingly connected world}, school = {Universit{\"a}t Potsdam}, pages = {279}, year = {2016}, language = {en} } @article{FeldmannMaduarSanteretal.2016, author = {Feldmann, David and Maduar, Salim R. and Santer, Mark and Lomadze, Nino and Vinogradova, Olga I. and Santer, Svetlana}, title = {Manipulation of small particles at solid liquid interface}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep36443}, pages = {10}, year = {2016}, abstract = {The strong adhesion of sub-micron sized particles to surfaces is a nuisance, both for removing contaminating colloids from surfaces and for conscious manipulation of particles to create and test novel micro/nano-scale assemblies. The obvious idea of using detergents to ease these processes suffers from a lack of control: the action of any conventional surface-modifying agent is immediate and global. With photosensitive azobenzene containing surfactants we overcome these limitations. Such photo-soaps contain optical switches (azobenzene molecules), which upon illumination with light of appropriate wavelength undergo reversible trans-cis photo-isomerization resulting in a subsequent change of the physico-chemical molecular properties. In this work we show that when a spatial gradient in the composition of trans- and cis- isomers is created near a solid-liquid interface, a substantial hydrodynamic flow can be initiated, the spatial extent of which can be set, e.g., by the shape of a laser spot. We propose the concept of light induced diffusioosmosis driving the flow, which can remove, gather or pattern a particle assembly at a solid-liquid interface. In other words, in addition to providing a soap we implement selectivity: particles are mobilized and moved at the time of illumination, and only across the illuminated area.}, language = {en} } @article{deCarvalhoMetzlerCherstvy2016, author = {de Carvalho, Sidney J. and Metzler, Ralf and Cherstvy, Andrey G.}, title = {Critical adsorption of polyelectrolytes onto planar and convex highly charged surfaces}, series = {New journal of physics : the open-access journal for physics}, volume = {18}, journal = {New journal of physics : the open-access journal for physics}, publisher = {IOP Publ.}, address = {London}, issn = {1367-2630}, doi = {10.1088/1367-2630/18/8/083037}, year = {2016}, abstract = {We study the adsorption-desorption transition of polyelectrolyte chains onto planar, cylindrical and spherical surfaces with arbitrarily high surface charge densities by massive Monte Carlo computer simulations. We examine in detail how the well known scaling relations for the threshold transition—demarcating the adsorbed and desorbed domains of a polyelectrolyte near weakly charged surfaces—are altered for highly charged interfaces. In virtue of high surface potentials and large surface charge densities, the Debye-H{\"u}ckel approximation is often not feasible and the nonlinear Poisson-Boltzmann approach should be implemented. At low salt conditions, for instance, the electrostatic potential from the nonlinear Poisson-Boltzmann equation is smaller than the Debye-H{\"u}ckel result, such that the required critical surface charge density for polyelectrolyte adsorption σc increases. The nonlinear relation between the surface charge density and electrostatic potential leads to a sharply increasing critical surface charge density with growing ionic strength, imposing an additional limit to the critical salt concentration above which no polyelectrolyte adsorption occurs at all. We contrast our simulations findings with the known scaling results for weak critical polyelectrolyte adsorption onto oppositely charged surfaces for the three standard geometries. Finally, we discuss some applications of our results for some physical-chemical and biophysical systems.}, language = {en} } @phdthesis{Matuschek2015, author = {Matuschek, Hannes}, title = {Applications of reproducing Kernel Hilbert spaces and their approximations}, school = {Universit{\"a}t Potsdam}, pages = {83}, year = {2015}, language = {en} } @article{vonReppertPuddellKocetal.2016, author = {von Reppert, Alexander and Puddell, J. and Koc, A. and Reinhardt, M. and Leitenberger, Wolfram and Dumesnil, K. and Zamponi, Flavio and Bargheer, Matias}, title = {Persistent nonequilibrium dynamics of the thermal energies in the spin and phonon systems of an antiferromagnet}, series = {Structural dynamics}, volume = {3}, journal = {Structural dynamics}, publisher = {AIP Publishing LLC}, address = {Melville, NY}, issn = {2329-7778}, doi = {10.1063/1.4961253}, year = {2016}, abstract = {We present a temperature and fluence dependent Ultrafast X-Ray Diffraction study of a laser-heated antiferromagnetic dysprosium thin film. The loss of antiferromagnetic order is evidenced by a pronounced lattice contraction. We devise a method to determine the energy flow between the phonon and spin system from calibrated Bragg peak positions in thermal equilibrium. Reestablishing the magnetic order is much slower than the cooling of the lattice, especially around the N{\´e}el temperature. Despite the pronounced magnetostriction, the transfer of energy from the spin system to the phonons in Dy is slow after the spin-order is lost.}, language = {en} } @article{BodrovaChechkinCherstvyetal.2016, author = {Bodrova, Anna S. and Chechkin, Aleksei V. and Cherstvy, Andrey G. and Safdari, Hadiseh and Sokolov, Igor M. and Metzler, Ralf}, title = {Underdamped scaled Brownian motion}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep30520}, year = {2016}, abstract = {It is quite generally assumed that the overdamped Langevin equation provides a quantitative description of the dynamics of a classical Brownian particle in the long time limit. We establish and investigate a paradigm anomalous diffusion process governed by an underdamped Langevin equation with an explicit time dependence of the system temperature and thus the diffusion and damping coefficients. We show that for this underdamped scaled Brownian motion (UDSBM) the overdamped limit fails to describe the long time behaviour of the system and may practically even not exist at all for a certain range of the parameter values. Thus persistent inertial effects play a non-negligible role even at significantly long times. From this study a general questions on the applicability of the overdamped limit to describe the long time motion of an anomalously diffusing particle arises, with profound consequences for the relevance of overdamped anomalous diffusion models. We elucidate our results in view of analytical and simulations results for the anomalous diffusion of particles in free cooling granular gases.}, language = {en} } @phdthesis{Dionysopoulou2016, author = {Dionysopoulou, Kyriaki}, title = {General-relativistic magnetohydrodynamics in compact objects}, school = {Universit{\"a}t Potsdam}, pages = {144}, year = {2016}, language = {en} } @article{CherstvyMetzler2016, author = {Cherstvy, Andrey G. and Metzler, Ralf}, title = {Anomalous diffusion in time-fluctuating non-stationary diffusivity landscapes}, series = {Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies}, volume = {18}, journal = {Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies}, publisher = {RSC Publ.}, address = {Cambridge}, issn = {1463-9084}, doi = {10.1039/C6CP03101C}, pages = {23840 -- 23852}, year = {2016}, abstract = {We investigate the ensemble and time averaged mean squared displacements for particle diffusion in a simple model for disordered media by assuming that the local diffusivity is both fluctuating in time and has a deterministic average growth or decay in time. In this study we compare computer simulations of the stochastic Langevin equation for this random diffusion process with analytical results. We explore the regimes of normal Brownian motion as well as anomalous diffusion in the sub- and superdiffusive regimes. We also consider effects of the inertial term on the particle motion. The investigation of the resulting diffusion is performed for unconfined and confined motion.}, language = {en} } @article{GhoshCherstvyPetrovetal.2016, author = {Ghosh, Surya K. and Cherstvy, Andrey G. and Petrov, Eugene P. and Metzler, Ralf}, title = {Interactions of rod-like particles on responsive elastic sheets}, series = {Soft matter}, journal = {Soft matter}, publisher = {RSC}, address = {London}, issn = {1744-6848}, doi = {10.1039/C6SM01522K}, year = {2016}, abstract = {What are the physical laws of the mutual interactions of objects bound to cell membranes, such as various membrane proteins or elongated virus particles? To rationalise this, we here investigate by extensive computer simulations mutual interactions of rod-like particles adsorbed on the surface of responsive elastic two-dimensional sheets. Specifically, we quantify sheet deformations as a response to adhesion of such filamentous particles. We demonstrate that tip-to-tip contacts of rods are favoured for relatively soft sheets, while side-by-side contacts are preferred for stiffer elastic substrates. These attractive orientation-dependent substrate-mediated interactions between the rod-like particles on responsive sheets can drive their aggregation and self-assembly. The optimal orientation of the membrane-bound rods is established via responding to the elastic energy profiles created around the particles. We unveil the phase diagramme of attractive-repulsive rod-rod interactions in the plane of their separation and mutual orientation. Applications of our results to other systems featuring membrane-associated particles are also discussed.}, language = {en} } @phdthesis{Lehmann2016, author = {Lehmann, Jascha In-su}, title = {Changes in extratropical storm track activity and their implications for extreme weather events}, pages = {221}, year = {2016}, language = {en} } @phdthesis{Feldmann2015, author = {Feldmann, Johannes}, title = {Stability of the West Antarctic Ice Sheet}, pages = {v, 165}, year = {2015}, language = {en} } @article{KopyshevLomadzeFeldmanetal.2015, author = {Kopyshev, Alexey and Lomadze, Nino and Feldman, David and Genzer, Jan and Santer, Svetlana}, title = {Making polymer brush photosensitive with azobenzene containing surfactants}, series = {Polymer : the international journal for the science and technology of polymers}, volume = {79}, journal = {Polymer : the international journal for the science and technology of polymers}, publisher = {Elsevier Science}, address = {Oxford}, issn = {0032-3861}, doi = {10.1016/j.polymer.2015.09.023}, pages = {65 -- 72}, year = {2015}, abstract = {We report on rendering polyelectrolyte brushes photosensitive by loading them with azobenzene-containing cationic surfactants. Planar poly(methacrylic acid) (PMAA) brushes are synthesized using the "grafting from" free-radical polymerization scheme followed by exposure to a solution of photosensitive surfactants consisting of positively-charged head groups and hydrophobic tails into which azobenzene moieties are inserted. In this study the length of the hydrophobic methylene spacer connecting the azobenzene and the charged head group ranges from 4 to 10 CH2 groups. Under irradiation with UV light, the photo-isomerization of azobenzene integrated into a surfactant results in a change in size, geometry, dipole moment and free volume of the whole molecule. When the brush loaded with photosensitive surfactants is exposed to irradiation with UV interference patterns, the topography of the brush deforms following the distribution of the light intensity, exhibiting surface relief gratings (SRG). Since SRG formation is accompanied by a local rupturing of polymer chains in areas from which the polymer material is receding, most of the polymer material is removed from the surface during treatment with good solvent, leaving behind characteristic patterns of lines or dots. The azobenzene molecules still integrated within the polymer film can be removed by washing the brush with water. The remaining nano-structured brush can then be re-used for further functionalization. Although the opto-mechanically induced rupturing occurs for all surfactants, larger species do not penetrate deep enough into the brush such that after rupturing a leftover layer of polymer material remains on the substrate. This indicates that rupturing occurs predominantly in regions of high surfactant density.}, language = {en} } @phdthesis{Rettig2016, author = {Rettig, Robert}, title = {{\"U}ber die Anisotropie der Kosmischen Strahlung}, school = {Universit{\"a}t Potsdam}, pages = {90, XV}, year = {2016}, language = {de} } @phdthesis{Rezanezhad2016, author = {Rezanezhad, Vahid}, title = {Inversion of the 2004 M6.0 Parkfield Earthquake Coseismic Offsets by Partition Model}, school = {Universit{\"a}t Potsdam}, pages = {83}, year = {2016}, language = {en} } @article{KurpiersNeher2016, author = {Kurpiers, Jona and Neher, Dieter}, title = {Dispersive Non-Geminate Recombination in an Amorphous Polymer:Fullerene Blend}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep26832}, pages = {10}, year = {2016}, abstract = {Recombination of free charge is a key process limiting the performance of solar cells. For low mobility materials, such as organic semiconductors, the kinetics of non-geminate recombination (NGR) is strongly linked to the motion of charges. As these materials possess significant disorder, thermalization of photogenerated carriers in the inhomogeneously broadened density of state distribution is an unavoidable process. Despite its general importance, knowledge about the kinetics of NGR in complete organic solar cells is rather limited. We employ time delayed collection field (TDCF) experiments to study the recombination of photogenerated charge in the high-performance polymer:fullerene blend PCDTBT:PCBM. NGR in the bulk of this amorphous blend is shown to be highly dispersive, with a continuous reduction of the recombination coefficient throughout the entire time scale, until all charge carriers have either been extracted or recombined. Rapid, contact-mediated recombination is identified as an additional loss channel, which, if not properly taken into account, would erroneously suggest a pronounced field dependence of charge generation. These findings are in stark contrast to the results of TDCF experiments on photovoltaic devices made from ordered blends, such as P3HT:PCBM, where non-dispersive recombination was proven to dominate the charge carrier dynamics under application relevant conditions.}, language = {en} } @article{NeherKniepertElimelechetal.2016, author = {Neher, Dieter and Kniepert, Juliane and Elimelech, Arik and Koster, L. Jan Anton}, title = {A New Figure of Merit for Organic Solar Cells with Transport-limited Photocurrents}, series = {Scientific reports}, volume = {6}, journal = {Scientific reports}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep24861}, pages = {9}, year = {2016}, abstract = {Compared to their inorganic counterparts, organic semiconductors suffer from relatively low charge carrier mobilities. Therefore, expressions derived for inorganic solar cells to correlate characteristic performance parameters to material properties are prone to fail when applied to organic devices. This is especially true for the classical Shockley-equation commonly used to describe current-voltage (JV)-curves, as it assumes a high electrical conductivity of the charge transporting material. Here, an analytical expression for the JV-curves of organic solar cells is derived based on a previously published analytical model. This expression, bearing a similar functional dependence as the Shockley-equation, delivers a new figure of merit α to express the balance between free charge recombination and extraction in low mobility photoactive materials. This figure of merit is shown to determine critical device parameters such as the apparent series resistance and the fill factor.}, language = {en} } @article{RaetzelWilkensMenzel2016, author = {R{\"a}tzel, Dennis and Wilkens, Martin and Menzel, Ralf}, title = {Gravitational properties of light}, series = {New journal of physics : the open-access journal for physics}, volume = {18}, journal = {New journal of physics : the open-access journal for physics}, publisher = {IOP Science}, address = {London}, issn = {1367-2630}, doi = {10.1088/1367-2630/18/2/023009}, pages = {1 -- 16}, year = {2016}, abstract = {The gravitational field of a laser pulse of finite lifetime, is investigated in the framework of linearized gravity. Although the effects are very small, they may be of fundamental physical interest. It is shown that the gravitational field of a linearly polarized light pulse is modulated as the norm of the corresponding electric field strength, while no modulations arise for circular polarization. In general, the gravitational field is independent of the polarization direction. It is shown that all physical effects are confined to spherical shells expanding with the speed of light, and that these shells are imprints of the spacetime events representing emission and absorption of the pulse. Nearby test particles at rest are attracted towards the pulse trajectory by the gravitational field due to the emission of the pulse, and they are repelled from the pulse trajectory by the gravitational field due to its absorption. Examples are given for the size of the attractive effect. It is recovered that massless test particles do not experience any physical effect if they are co-propagating with the pulse, and that the acceleration of massless test particles counter-propagating with respect to the pulse is four times stronger than for massive particles at rest. The similarities between the gravitational effect of a laser pulse and Newtonian gravity in two dimensions are pointed out. The spacetime curvature close to the pulse is compared to that induced by gravitational waves from astronomical sources.}, language = {en} } @phdthesis{Kondic2015, author = {Kondic, Todor}, title = {Hall-MHD Instabilities of Shear Flows in Neutron Stars}, school = {Universit{\"a}t Potsdam}, pages = {80}, year = {2015}, language = {en} } @phdthesis{Sander2015, author = {Sander, Andreas Alexander Christoph}, title = {Radiatively driven winds of hot stars}, school = {Universit{\"a}t Potsdam}, pages = {153}, year = {2015}, language = {en} } @phdthesis{Deresch2015, author = {Deresch, Andreas}, title = {Modellierung von R{\"o}ntgenspektren f{\"u}r technische Anwendungen}, school = {Universit{\"a}t Potsdam}, pages = {104}, year = {2015}, language = {de} } @article{PulkkinenMetzler2015, author = {Pulkkinen, Otto and Metzler, Ralf}, title = {Variance-corrected Michaelis-Menten equation predicts transient rates of single-enzyme reactions and response times in bacterial gene-regulation}, series = {Scientific reports}, journal = {Scientific reports}, number = {5}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep17820}, year = {2015}, abstract = {Many chemical reactions in biological cells occur at very low concentrations of constituent molecules. Thus, transcriptional gene-regulation is often controlled by poorly expressed transcription-factors, such as E.coli lac repressor with few tens of copies. Here we study the effects of inherent concentration fluctuations of substrate-molecules on the seminal Michaelis-Menten scheme of biochemical reactions. We present a universal correction to the Michaelis-Menten equation for the reaction-rates. The relevance and validity of this correction for enzymatic reactions and intracellular gene-regulation is demonstrated. Our analytical theory and simulation results confirm that the proposed variance-corrected Michaelis-Menten equation predicts the rate of reactions with remarkable accuracy even in the presence of large non-equilibrium concentration fluctuations. The major advantage of our approach is that it involves only the mean and variance of the substrate-molecule concentration. Our theory is therefore accessible to experiments and not specific to the exact source of the concentration fluctuations.}, language = {en} } @phdthesis{Hollaender2015, author = {Holl{\"a}nder, Lars}, title = {Einfluss der remanenten Polarisation auf die optischen Transmissionseingenschaften eines ferroelektrischen Polymers mit nematischen Fl{\"u}ssigkristalleinschl{\"u}ssen}, school = {Universit{\"a}t Potsdam}, pages = {XXVII, 109}, year = {2015}, language = {de} } @phdthesis{Sborikas2015, author = {Sborikas, Martynas}, title = {Preparation and characterization of acoustic electret and electromechanical properties of polypropylene ferroelectrets}, pages = {129}, year = {2015}, language = {en} } @phdthesis{Siegel2015, author = {Siegel, Daniel}, title = {Binary neutron star mergers and short gamma-ray bursts}, school = {Universit{\"a}t Potsdam}, pages = {255}, year = {2015}, language = {en} } @phdthesis{Hainich2015, author = {Hainich, Rainer}, title = {The Wolf-Rayet stars of the nitrogen sequence in environments of different metallicities}, school = {Universit{\"a}t Potsdam}, pages = {161}, year = {2015}, language = {en} } @phdthesis{Ermilova2015, author = {Ermilova, Elena}, title = {Breitbandige dielektrische Charakterisierung biologisch relevanter Polymere}, school = {Universit{\"a}t Potsdam}, pages = {142}, year = {2015}, language = {de} } @phdthesis{Sauter2015, author = {Sauter, Tilman}, title = {Function by structure}, school = {Universit{\"a}t Potsdam}, pages = {166}, year = {2015}, language = {en} } @phdthesis{Mengel2015, author = {Mengel, Matthias}, title = {Forcing Earth's sea level}, school = {Universit{\"a}t Potsdam}, pages = {173}, year = {2015}, language = {en} } @phdthesis{Brem2014, author = {Brem, Patrick}, title = {Compact objects in dense astrophysical environments}, school = {Universit{\"a}t Potsdam}, pages = {173}, year = {2014}, language = {en} } @article{MetzlerBauerRasmussenetal.2015, author = {Metzler, Ralf and Bauer, Maximilian and Rasmussen, Emil S. and Lomholt, Michael A.}, title = {Real sequence effects on the search dynamics of transcription factors on DNA}, series = {Scientific Reports}, volume = {5}, journal = {Scientific Reports}, number = {10072}, publisher = {Nature Publishing Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/srep10072}, year = {2015}, abstract = {Recent experiments show that transcription factors (TFs) indeed use the facilitated diffusion mechanism to locate their target sequences on DNA in living bacteria cells: TFs alternate between sliding motion along DNA and relocation events through the cytoplasm. From simulations and theoretical analysis we study the TF-sliding motion for a large section of the DNA-sequence of a common E. coli strain, based on the two-state TF-model with a fast-sliding search state and a recognition state enabling target detection. For the probability to detect the target before dissociating from DNA the TF-search times self-consistently depend heavily on whether or not an auxiliary operator (an accessible sequence similar to the main operator) is present in the genome section. Importantly, within our model the extent to which the interconversion rates between search and recognition states depend on the underlying nucleotide sequence is varied. A moderate dependence maximises the capability to distinguish between the main operator and similar sequences. Moreover, these auxiliary operators serve as starting points for DNA looping with the main operator, yielding a spectrum of target detection times spanning several orders of magnitude. Auxiliary operators are shown to act as funnels facilitating target detection by TFs.}, language = {en} }