TY - JOUR A1 - Levnajic, Zoran T1 - Emergent multistability and frustration in phase-repulsive networks of oscillators JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - The collective dynamics of oscillator networks with phase-repulsive coupling is studied, considering various network sizes and topologies. The notion of link frustration is introduced to characterize and quantify the network dynamical states. In opposition to widely studied phase-attractive case, the properties of final dynamical states in our model critically depend on the network topology. In particular, each network's total frustration value is intimately related to its topology. Moreover, phase-repulsive networks in general display multiple final frustration states, whose statistical and stability properties are uniquely identifying them. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.84.016231 SN - 1539-3755 VL - 84 IS - 1 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Fechner, Cora T1 - Reconstructing the intergalactic UV background with QSO absorption lines JF - Astronomy and astrophysics : an international weekly journal N2 - We present a new approach to observationally constraining the spectral energy distribution of the intergalactic UV background by studying metal absorption systems. We study single-component metal line systems that exhibit various well-measured species. Among the observed transitions, at least two ratios of ionization stages from the same element are required, e. g. C III/C IV and Si III/Si IV. For each system photoionization models are constructed by varying the spectrum of the ionizing radiation. The spectral energy distribution can then be constrained by comparing the models with the observed column density ratios. Extensive tests with artificial absorbers show that the spectrum of the ionizing radiation cannot be reconstructed unambiguously, but it is possible to constrain the main characteristics of the spectrum. Furthermore, the resulting physical parameters of the absorber, such as ionization parameter, metallicity, and relative abundances, may depend strongly on the adopted ionizing spectrum. Even in case of well-fitting models, the uncertainties can be as high as similar to 0.5 dex for the ionization parameter and up to similar to 1.5 dex for the metallicity. Therefore, it is essential to know the hardness of the UV background when estimating the metallicity of the intergalactic medium. Applying the procedure to a small sample of 3 observed single-component metal line systems yields a soft ionizing radiation at z > 2 and a slightly harder spectrum at z < 2. The resulting energy distributions exhibit strong He II Lya re-emission features, suggesting that reprocessing by intergalactic He II is important. Comparing the observed systems to UV background spectra from the literature indicates that a recent model that includes sawtooth modulation due to reprocessing by intergalactic He II with delayed helium reionization fits the investigated systems very well. KW - intergalactic medium KW - quasars: absorption lines KW - diffuse radiation Y1 - 2011 U6 - https://doi.org/10.1051/0004-6361/201117080 SN - 0004-6361 VL - 532 IS - 2 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Gerhardt, Matthias A1 - Groeger, Gillian A1 - MacCarthy, Niall T1 - Monopolar vs. bipolar subretinal stimulation-An in vitro study JF - Journal of neuroscience methods N2 - This study uses an in vitro rd10 mouse model to quantify and compare the ability of the monopolar and the (concentric) bipolar electrode configurations for subretinal stimulation. To allow for results which can be directly compared an identical region of the retina was stimulated due to the circumstance that the bipolar electrode configuration allows also for monopolar stimulation, if the concentric counter-electrode is set potential-free (floating). A ganglion cell, located centrally over the bipolar electrode configuration was selected to extracellularly record action potentials during stimulation. To analyse the recorded action potentials, we introduce a new method which combines the advantages of (a) singular value decomposition (SVD) for weighting similar modulation patterns with which the recorded action potentials are characterized and (b) multi curve fitting to identify a common threshold level, required to finally assemble a strength-duration relationship (SDR). By directly comparing the obtained SDR curves, we found that the efficiency of stimulation with the monopolar electrode configuration is significantly higher than with the bipolar electrode configuration. All obtained SDR curves were fitted using the Lapicque model to estimate the chronaxie times and the rheobase currents. Liquid inclusions, eventually separating the retina from the electrodes are discussed to be a major cause for low ganglion cell responses during stimulation with the bipolar electrode configuration. KW - SVD KW - Subretinal KW - Electrodes KW - Monopolar KW - Bipolar KW - Retina KW - Ganglion KW - Cells Y1 - 2011 U6 - https://doi.org/10.1016/j.jneumeth.2011.04.017 SN - 0165-0270 VL - 199 IS - 1 SP - 26 EP - 34 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Prosen, Tomaz A1 - Ilievski, Enej T1 - Nonequilibrium phase transition in a periodically driven XY spin chain JF - Physical review letters N2 - We present a general formulation of Floquet states of periodically time-dependent open Markovian quasifree fermionic many-body systems in terms of a discrete Lyapunov equation. Illustrating the technique, we analyze periodically kicked XY spin-1/2 chain which is coupled to a pair of Lindblad reservoirs at its ends. A complex phase diagram is reported with reentrant phases of long range and exponentially decaying spin-spin correlations as some of the system's parameters are varied. The structure of phase diagram is reproduced in terms of counting nontrivial stationary points of Floquet quasiparticle dispersion relation. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.060403 SN - 0031-9007 VL - 107 IS - 6 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - DiGuglielmo, J. A1 - Samblowski, A. A1 - Hage, B. A1 - Pineda, Carlos A1 - Eisert, Jens A1 - Schnabel, R. T1 - Experimental Unconditional Preparation and Detection of a Continuous Bound Entangled State of Light JF - Physical review letters N2 - Among the possibly most intriguing aspects of quantum entanglement is that it comes in free and bound instances. The existence of bound entangled states certifies an intrinsic irreversibility of entanglement in nature and suggests a connection with thermodynamics. In this Letter, we present a first unconditional, continuous-variable preparation and detection of a bound entangled state of light. We use convex optimization to identify regimes rendering its bound character well certifiable, and continuously produce a distributed bound entangled state with an extraordinary and unprecedented significance of more than 10 standard deviations away from both separability and distillability. Our results show that the approach chosen allows for the efficient and precise preparation of multimode entangled states of light with various applications in quantum information, quantum state engineering, and high precision metrology. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.240503 SN - 0031-9007 VL - 107 IS - 24 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Lisso, Janina A1 - Schröder, Florian A1 - Fisahn, Joachim A1 - Muessig, Carsten T1 - NFX1-LIKE2 (NFXL2) Suppresses Abscisic Acid Accumulation and Stomatal Closure in Arabidopsis thaliana JF - PLoS one N2 - The NFX1-LIKE1 (NFXL1) and NFXL2 genes were identified as regulators of salt stress responses. The NFXL1 protein is a nuclear factor that positively affects adaptation to salt stress. The nfxl1-1 loss-of-function mutant displayed reduced survival rates under salt and high light stress. In contrast, the nfxl2-1 mutant, defective in the NFXL2 gene, and NFXL2-antisense plants exhibited enhanced survival under these conditions. We show here that the loss of NFXL2 function results in abscisic acid (ABA) overaccumulation, reduced stomatal conductance, and enhanced survival under drought stress. The nfxl2-1 mutant displayed reduced stomatal aperture under all conditions tested. Fusicoccin treatment, exposition to increasing light intensities, and supply of decreasing CO2 concentrations demonstrated full opening capacity of nfxl2-1 stomata. Reduced stomatal opening presumably is a consequence of elevated ABA levels. Furthermore, seedling growth, root growth, and stomatal closure were hypersensitive to exogenous ABA. The enhanced ABA responses may contribute to the improved drought stress resistance of the mutant. Three NFXL2 splice variants were cloned and named NFXL2-78, NFXL2-97, and NFXL2-100 according to the molecular weight of the putative proteins. Translational fusions to the green fluorescent protein suggest nuclear localisation of the NFXL2 proteins. Stable expression of the NFXL2-78 splice variant in nfxl2-1 plants largely complemented the mutant phenotype. Our data show that NFXL2 controls ABA levels and suppresses ABA responses. NFXL2 may prevent unnecessary and costly stress adaptation under favourable conditions. Y1 - 2011 U6 - https://doi.org/10.1371/journal.pone.0026982 SN - 1932-6203 VL - 6 IS - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Abel, M. W. A1 - Shepelyansky, Dima L. T1 - Google matrix of business process management JF - The European physical journal : B, Condensed matter and complex systems N2 - Development of efficient business process models and determination of their characteristic properties are subject of intense interdisciplinary research. Here, we consider a business process model as a directed graph. Its nodes correspond to the units identified by the modeler and the link direction indicates the causal dependencies between units. It is of primary interest to obtain the stationary flow on such a directed graph, which corresponds to the steady-state of a firm during the business process. Following the ideas developed recently for the World Wide Web, we construct the Google matrix for our business process model and analyze its spectral properties. The importance of nodes is characterized by PageRank and recently proposed CheiRank and 2DRank, respectively. The results show that this two-dimensional ranking gives a significant information about the influence and communication properties of business model units. We argue that the Google matrix method, described here, provides a new efficient tool helping companies to make their decisions on how to evolve in the exceedingly dynamic global market. Y1 - 2011 U6 - https://doi.org/10.1140/epjb/e2010-10710-y SN - 1434-6028 VL - 84 IS - 4 SP - 493 EP - 500 PB - Springer CY - New York ER - TY - JOUR A1 - Abdolvahab, Rouhollah Haji A1 - Metzler, Ralf A1 - Ejtehadi, Mohammad Reza T1 - First passage time distribution of chaperone driven polymer translocation through a nanopore homopolymer and heteropolymer cases JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr N2 - Combining the advection-diffusion equation approach with Monte Carlo simulations we study chaperone driven polymer translocation of a stiff polymer through a nanopore. We demonstrate that the probability density function of first passage times across the pore depends solely on the Peclet number, a dimensionless parameter comparing drift strength and diffusivity. Moreover it is shown that the characteristic exponent in the power-law dependence of the translocation time on the chain length, a function of the chaperone-polymer binding energy, the chaperone concentration, and the chain length, is also effectively determined by the Peclet number. We investigate the effect of the chaperone size on the translocation process. In particular, for large chaperone size, the translocation progress and the mean waiting time as function of the reaction coordinate exhibit pronounced sawtooth-shapes. The effects of a heterogeneous polymer sequence on the translocation dynamics is studied in terms of the translocation velocity, the probability distribution for the translocation progress, and the monomer waiting times. (C) 2011 American Institute of Physics. Y1 - 2011 U6 - https://doi.org/10.1063/1.3669427 SN - 0021-9606 VL - 135 IS - 24 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Gruber, W. A1 - Chakravarty, S. A1 - Baehtz, C. A1 - Leitenberger, Wolfram A1 - Bruns, M. A1 - Kobler, A. A1 - Kübel, Christian A1 - Schmidt, H. T1 - Strain relaxation and vacancy creation in thin platinum films JF - Physical review letters N2 - Synchrotron based combined in situ x-ray diffractometry and reflectometry is used to investigate the role of vacancies for the relaxation of residual stress in thin metallic Pt films. From the experimentally determined relative changes of the lattice parameter a and of the film thickness L the modification of vacancy concentration and residual strain was derived as a function of annealing time at 130 degrees C. The results indicate that relaxation of strain resulting from compressive stress is accompanied by the creation of vacancies at the free film surface. This proves experimentally the postulated dominant role of vacancies for stress relaxation in thin metal films close to room temperature. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.107.265501 SN - 0031-9007 VL - 107 IS - 26 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Kuznetsov, Sergey P. T1 - Plykin type attractor in electronic device simulated in MULTISIM JF - Chaos : an interdisciplinary journal of nonlinear science N2 - An electronic device is suggested representing a non-autonomous dynamical system with hyperbolic chaotic attractor of Plykin type in the stroboscopic map, and the results of its simulation with software package NI MULTISIM are considered in comparison with numerical integration of the underlying differential equations. A main practical advantage of electronic devices of this kind is their structural stability that means insensitivity of the chaotic dynamics in respect to variations of functions and parameters of elements constituting the system as well as to interferences and noises. Y1 - 2011 U6 - https://doi.org/10.1063/1.3646903 SN - 1054-1500 VL - 21 IS - 4 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Feudel, Fred A1 - Bergemann, Kay A1 - Tuckerman, Laurette S. A1 - Egbers, C. A1 - Futterer, B. A1 - Gellert, Marcus A1 - Hollerbach, Rainer T1 - Convection patterns in a spherical fluid shell JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - Symmetry-breaking bifurcations have been studied for convection in a nonrotating spherical shell whose outer radius is twice the inner radius, under the influence of an externally applied central force field with a radial dependence proportional to 1/r(5). This work is motivated by the GeoFlow experiment, which is performed under microgravity condition at the International Space Station where this particular central force can be generated. In order to predict the observable patterns, simulations together with path-following techniques and stability computations have been applied. Branches of axisymmetric, octahedral, and seven-cell solutions have been traced. The bifurcations producing them have been identified and their stability ranges determined. At higher Rayleigh numbers, time-periodic states with a complex spatiotemporal symmetry are found, which we call breathing patterns. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.83.046304 SN - 1539-3755 VL - 83 IS - 4 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Richter, Philipp A1 - Krause, F. A1 - Fechner, Cora A1 - Charlton, Jane C. A1 - Murphy, M. T. T1 - The neutral gas extent of galaxies as derived from weak intervening Ca II absorbers JF - Astronomy and astrophysics : an international weekly journal N2 - We present a systematic study of weak intervening CaII absorbers at low redshift (z < 0.5), based on the analysis of archival high-resolution (R >= 45 000) optical spectra of 304 quasars and active galactic nuclei observed with VLT/UVES. Along a total redshift path of Delta z approximate to 100 we detected 23 intervening CaII absorbers in both the CaII H & K lines, with rest frame equivalent widths W-r,W-3934 = 15-799 m angstrom and column densities log N(CaII) = 11.25-13.04 (obtained by fitting Voigt-profile components). We obtain a bias-corrected number density of weak intervening CaII absorbers of dN/dz = 0.117 +/- 0.044 at < z(abs)> = 0.35 for absorbers with log N(CaII) >= 11.65 (W-r,W-3934 >= 32 m angstrom). This is similar to 2.6 times the value obtained for damped Lyman alpha absorbers (DLAs) at low redshift. All CaII absorbers in our sample show associated absorption by other low ions such as MgII and FeII; 45 percent of them have associated NaI absorption. From ionization modelling we conclude that intervening CaII absorption with log N(CaII) >= 11.5 arises in DLAs, sub-DLAs and Lyman-limit systems (LLS) at HI column densities of log N(HI) >= 17.4. Using supplementary HI information for nine of the absorbers we find that the CaII/HI ratio decreases strongly with increasing HI column density, indicating a column-density-dependent dust depletion of Ca. The observed column density distribution function of CaII absorption components follows a relatively steep power law, f(N) proportional to N-beta, with a slope of -beta = -1.68, which again points towards an enhanced dust depletion in high column density systems. The relatively large cross section of these absorbers together with the frequent detection of CaII absorption in high-velocity clouds (HVCs) in the halo of the Milky Way suggests that a considerable fraction of the intervening CaII systems trace (partly) neutral gas structures in the halos and circumgalactic environment of galaxies (i.e., they are HVC analogs). Based on the recently measured detection rate of CaII absorption in the Milky Way HVCs we estimate that the mean (projected) CaII covering fraction of galaxies and their gaseous halos is < f(c,CaII)> = 0.33. Using this value and considering all galaxies with luminosities L >= 0.05 L-star we calculate that the characteristic radial extent of (partly) neutral gas clouds with log N(HI) >= 17.4 around low-redshift galaxies is R-HVC approximate to 55 kpc. KW - galaxies: halos KW - galaxies: formation KW - galaxies: ISM KW - intergalactic medium KW - quasars: absorption lines Y1 - 2011 U6 - https://doi.org/10.1051/0004-6361/201015566 SN - 0004-6361 VL - 528 IS - 4 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Müller, Markus P. A1 - Gross, David A1 - Eisert, Jens T1 - Concentration of Measure for Quantum States with a Fixed Expectation Value JF - Communications in mathematical physics N2 - Given some observable H on a finite-dimensional quantum system, we investigate the typical properties of random state vectors vertical bar psi >> that have a fixed expectation value < psi vertical bar H vertical bar psi > = E with respect to H. Under some conditions on the spectrum, we prove that this manifold of quantum states shows a concentration of measure phenomenon: any continuous function on this set is almost everywhere close to its mean. We also give a method to estimate the corresponding expectation values analytically, and we prove a formula for the typical reduced density matrix in the case that H is a sum of local observables. We discuss the implications of our results as new proof tools in quantum information theory and to study phenomena in quantum statistical mechanics. As a by-product, we derive a method to sample the resulting distribution numerically, which generalizes the well-known Gaussian method to draw random states from the sphere. Y1 - 2011 U6 - https://doi.org/10.1007/s00220-011-1205-1 SN - 0010-3616 VL - 303 IS - 3 SP - 785 EP - 824 PB - Springer CY - New York ER - TY - JOUR A1 - Mann, R. B. A1 - Young, M. B. A1 - Fuüntes-Schuller, I. T1 - A perturbative approach to inelastic collisions in a Bose-Einstein condensate JF - Journal of physics : B, Atomic, molecular and optical physics N2 - It has recently been discovered that for certain rates of mode-exchange collisions analytic solutions can be found for a Hamiltonian describing the two-mode Bose-Einstein condensate. We proceed to study the behaviour of the system using perturbation theory if the coupling constants only approximately match these parameter constraints. We find that the model is robust to such perturbations. We study the effects of degeneracy on the perturbations and find that the induced changes differ greatly from the non-degenerate case. We also model inelastic collisions that result in particle loss or condensate decay as external perturbations and use this formalism to examine the effects of three-body recombination and background collisions. Y1 - 2011 U6 - https://doi.org/10.1088/0953-4075/44/8/085301 SN - 0953-4075 VL - 44 IS - 8 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Valleriani, Angelo A1 - Zhang, Gong A1 - Nagar, Apoorva A1 - Ignatova, Zoya A1 - Lipowsky, Reinhard T1 - Length-dependent translation of messenger RNA by ribosomes JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - A simple measure for the efficiency of protein synthesis by ribosomes is provided by the steady state amount of protein per messenger RNA (mRNA), the so-called translational ratio, which is proportional to the translation rate. Taking the degradation of mRNA into account, we show theoretically that both the translation rate and the translational ratio decrease with increasing mRNA length, in agreement with available experimental data for the prokaryote Escherichia coli. We also show that, compared to prokaryotes, mRNA degradation in eukaryotes leads to a less rapid decrease of the translational ratio. This finding is consistent with the fact that, compared to prokaryotes, eukaryotes tend to have longer proteins. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevE.83.042903 SN - 1539-3755 VL - 83 IS - 4 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Tepper-Garcia, Thorsten A1 - Richter, Philipp A1 - Schaye, Joop A1 - Booth, C. M. A1 - Vecchia, Claudio Dalla A1 - Theuns, Tom A1 - Wiersma, Robert P. C. T1 - Absorption signatures of warm-hot gas at low redshift o vi JF - Monthly notices of the Royal Astronomical Society N2 - We investigate the origin and physical properties of O vi absorbers at low redshift (z = 0.25) using a subset of cosmological, hydrodynamical simulations from the OverWhelmingly Large Simulations (OWLS) project. Intervening O vi absorbers are believed to trace shock-heated gas in the warm-hot intergalactic medium (WHIM) and may thus play a key role in the search for the missing baryons in the present-day Universe. When compared to observations, the predicted distributions of the different O vi line parameters (column density, Doppler parameter, rest equivalent width W-r) from our simulations exhibit a lack of strong O vi absorbers, a discrepancy that has also been found by Oppenheimer & Dave. This suggests that physical processes on subgrid scales (e.g. turbulence) may strongly influence the observed properties of O vi systems. We find that the intervening O vi absorption arises mainly in highly metal enriched (10-1 < Z/Z(circle dot) less than or similar to 1) gas at typical overdensities of 1 < /<<>> less than or similar to 102. One-third of the O vi absorbers in our simulation are found to trace gas at temperatures T < 105 K, while the rest arises in gas at higher temperatures, most of them around T = 105.3 +/- 0.5 K. These temperatures are much higher than inferred by Oppenheimer & Dave, probably because that work did not take the suppression of metal-line cooling by the photoionizing background radiation into account. While the O vi resides in a similar region of (, T)-space as much of the shock-heated baryonic matter, the vast majority of this gas has a lower metal content and does not give rise to detectable O vi absorption. As a consequence of the patchy metal distribution, O vi absorbers in our simulations trace only a very small fraction of the cosmic baryons (< 2 per cent) and the cosmic metals. Instead, these systems presumably trace previously shock-heated, metal-rich material from galactic winds that is now mixing with the ambient gas and cooling. The common approach of comparing O vi and H i column densities to estimate the physical conditions in intervening absorbers from QSO observations may be misleading, as most of the H i (and most of the gas mass) is not physically connected with the high-metallicity patches that give rise to the O vi absorption. KW - methods: numerical KW - galaxies: formation KW - intergalactic medium KW - quasars: absorption lines KW - cosmology: theory Y1 - 2011 U6 - https://doi.org/10.1111/j.1365-2966.2010.18123.x SN - 0035-8711 VL - 413 IS - 1 SP - 190 EP - 212 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Schmidt, Hans-Jürgen T1 - Gauss-Bonnet lagrangian G lnG and cosmological exact solutions JF - Physical review : D, Particles, fields, gravitation, and cosmology N2 - For the Lagrangian L = G lnG where G is the Gauss-Bonnet curvature scalar we deduce the field equation and solve it in closed form for 3-flat Friedmann models using a state-finder parametrization. Further we show that among all Lagrangians F(G) this L is the only one not having the form G(r) with a real constant r but possessing a scale-invariant field equation. This turns out to be one of its analogies to f(R) theories in two-dimensional space-time. In the appendix, we systematically list several formulas for the decomposition of the Riemann tensor in arbitrary dimensions n, which are applied in the main deduction for n = 4. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevD.83.083513 SN - 1550-7998 VL - 83 IS - 8 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Beye, Martin A1 - Föhlisch, Alexander T1 - A soft X-ray approach to electron-phonon interactions beyond the Born-Oppenheimer approximation JF - Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy N2 - With modern soft X-ray methods, the whole field of electron-phonon interactions becomes accessible directly in the ultrafast time domain with ultrashort pulsed X-ray sources, as well as in the energy domain through modern highly resolving spectrometers. The well-known core-hole clock approach plays an intermediate role, resolving energetic and temporal features at the same time. In this perspective paper, we review several experiments to illustrate the modern advances in the selective study of electron-phonon interactions as fundamentally determining ingredients for materials properties. We present the different complementary approaches that can be taken with soft X-ray methods to conquer this field beyond the Born-Oppenheimer approximation. KW - Electron-phonon coupling KW - Resonant inelastic X-ray scattering KW - X-ray emission spectroscopy KW - Near edge X-ray absorption fine structure Y1 - 2011 U6 - https://doi.org/10.1016/j.elspec.2010.12.032 SN - 0368-2048 VL - 184 IS - 3-6 SP - 313 EP - 317 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Campbell, Earl T. T1 - Catalysis and activation of magic states in fault-tolerant architectures JF - Physical review : A, Atomic, molecular, and optical physics N2 - In many architectures for fault-tolerant quantum computing universality is achieved by a combination of Clifford group unitary operators and preparation of suitable nonstabilizer states, the so-called magic states. Universality is possible even for some fairly noisy nonstabilizer states, as distillation can convert many noisy copies into fewer purer magic states. Here we propose protocols that exploit multiple species of magic states in surprising ways. These protocols provide examples of previously unobserved phenomena that are analogous to catalysis and activation well known in entanglement theory. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevA.83.032317 SN - 1050-2947 VL - 83 IS - 3 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Schaefer, Edith A1 - Westendorf, Christian A1 - Bodenschatz, Eberhard A1 - Beta, Carsten A1 - Geil, Burkhard A1 - Janshoff, Andreas T1 - Shape oscillations of dictyostelium discoideum cells on ultramicroelectrodes monitored by impedance analysis JF - Small Y1 - 2011 U6 - https://doi.org/10.1002/smll.201001955 SN - 1613-6810 VL - 7 IS - 6 SP - 723 EP - 726 PB - Wiley-Blackwell CY - Malden ER -