The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform

N. Pavloff - One of the best experts on this subject based on the ideXlab platform.

  • solution of the riemann problem for Polarization Waves in a two component bose einstein condensate
    Physical Review E, 2017
    Co-Authors: T. Congy, A. M. Kamchatnov, Sergey K Ivanov, N. Pavloff
    Abstract:

    We provide a classification of the possible flows of two-component Bose-Einstein condensates evolving from initially discontinuous profiles. We consider the situation where the dynamics can be reduced to the consideration of a single Polarization mode (also denoted as "magnetic excitation") obeying a system of equations equivalent to the Landau-Lifshitz equation for an easy-plane ferromagnet. We present the full set of one-phase periodic solutions. The corresponding Whitham modulation equations are obtained together with formulas connecting their solutions with the Riemann invariants of the modulation equations. The problem is not genuinely nonlinear, and this results in a non-single-valued mapping of the solutions of the Whitham equations with physical wave patterns as well as the appearance of interesting elements-contact dispersive shock Waves-that are absent in more standard, genuinely nonlinear situations. Our analytic results are confirmed by numerical simulations.

  • Dispersive hydrodynamics of nonlinear Polarization Waves in two-component Bose-Einstein condensates
    SciPost Physics, 2016
    Co-Authors: T. Congy, A. M. Kamchatnov, N. Pavloff
    Abstract:

    We study one dimensional mixtures of two-component Bose-Einstein condensates in the limit where the intra-species and inter-species interaction constants are very close. Near the mixing-demixing transition the Polarization and the density dynamics decouple. We study the nonlinear Polarization Waves, show that they obey a universal (i.e., parameter free) dynamical description, identify a new type of algebraic soliton, explicitly write simple wave solutions, and study the Gurevich-Pitaevskii problem in this context.

  • nonlinear Polarization Waves in a two component bose einstein condensate
    Physical Review A, 2014
    Co-Authors: A. M. Kamchatnov, Yaroslav V Kartashov, Pierreelie Larre, N. Pavloff
    Abstract:

    A two-component Bose-Einstein condensate whose dynamics is described by a system of coupled GrossPitaevskii equations accommodates Waves with different symmetries. A first type of Waves corresponds to excitations for which the motion of both components is locally in phase. For the second type of Waves, the two components have a counterphase local motion. When the values of the inter- and intracomponent interaction constants are different, the long-wavelength behavior of these two modes corresponds to two types of sound with different velocities. In the limit of weak nonlinearity and small dispersion, the first mode is described by the well-known Korteweg-de Vries equation. In the same limit, we show that the second mode can be described by the Gardner equation if the values of the two intracomponent interaction constants are sufficiently close. This leads to a rich variety of nonlinear excitations (solitons, kinks, algebraic solitons, breathers) which do not exist in the Korteweg-de Vries description. DOI: 10.1103/PhysRevA.89.033618 PACS number(s): 03.75.Mn, 47.37.+q, 71.36.+c

A. M. Kamchatnov - One of the best experts on this subject based on the ideXlab platform.

  • solution of the riemann problem for Polarization Waves in a two component bose einstein condensate
    Physical Review E, 2017
    Co-Authors: T. Congy, A. M. Kamchatnov, Sergey K Ivanov, N. Pavloff
    Abstract:

    We provide a classification of the possible flows of two-component Bose-Einstein condensates evolving from initially discontinuous profiles. We consider the situation where the dynamics can be reduced to the consideration of a single Polarization mode (also denoted as "magnetic excitation") obeying a system of equations equivalent to the Landau-Lifshitz equation for an easy-plane ferromagnet. We present the full set of one-phase periodic solutions. The corresponding Whitham modulation equations are obtained together with formulas connecting their solutions with the Riemann invariants of the modulation equations. The problem is not genuinely nonlinear, and this results in a non-single-valued mapping of the solutions of the Whitham equations with physical wave patterns as well as the appearance of interesting elements-contact dispersive shock Waves-that are absent in more standard, genuinely nonlinear situations. Our analytic results are confirmed by numerical simulations.

  • Dispersive hydrodynamics of nonlinear Polarization Waves in two-component Bose-Einstein condensates
    SciPost Physics, 2016
    Co-Authors: T. Congy, A. M. Kamchatnov, N. Pavloff
    Abstract:

    We study one dimensional mixtures of two-component Bose-Einstein condensates in the limit where the intra-species and inter-species interaction constants are very close. Near the mixing-demixing transition the Polarization and the density dynamics decouple. We study the nonlinear Polarization Waves, show that they obey a universal (i.e., parameter free) dynamical description, identify a new type of algebraic soliton, explicitly write simple wave solutions, and study the Gurevich-Pitaevskii problem in this context.

  • nonlinear Polarization Waves in a two component bose einstein condensate
    Physical Review A, 2014
    Co-Authors: A. M. Kamchatnov, Yaroslav V Kartashov, Pierreelie Larre, N. Pavloff
    Abstract:

    A two-component Bose-Einstein condensate whose dynamics is described by a system of coupled GrossPitaevskii equations accommodates Waves with different symmetries. A first type of Waves corresponds to excitations for which the motion of both components is locally in phase. For the second type of Waves, the two components have a counterphase local motion. When the values of the inter- and intracomponent interaction constants are different, the long-wavelength behavior of these two modes corresponds to two types of sound with different velocities. In the limit of weak nonlinearity and small dispersion, the first mode is described by the well-known Korteweg-de Vries equation. In the same limit, we show that the second mode can be described by the Gardner equation if the values of the two intracomponent interaction constants are sufficiently close. This leads to a rich variety of nonlinear excitations (solitons, kinks, algebraic solitons, breathers) which do not exist in the Korteweg-de Vries description. DOI: 10.1103/PhysRevA.89.033618 PACS number(s): 03.75.Mn, 47.37.+q, 71.36.+c

N N Rosanov - One of the best experts on this subject based on the ideXlab platform.

  • population density gratings induced by few cycle optical pulses in a resonant medium
    Scientific Reports, 2017
    Co-Authors: R M Arkhipov, M V Arkhipov, I Babushkin, Ayhan Demircan, Uwe Morgner, A V Pakhomov, N N Rosanov
    Abstract:

    Creation, erasing and ultrafast control of population density gratings using few-cycle optical pulses coherently interacting with resonant medium is discussed. In contrast to the commonly used schemes, here the pulses do not need to overlap in the medium, interaction between the pulses is mediated by excitation of Polarization Waves. We investigate the details of the dynamics arising in such ultrashort pulse scheme and develop an analytical theory demonstrating the importance of the phase memory effects in the dynamics.

  • ultrafast creation and control of population density gratings via ultraslow Polarization Waves
    Optics Letters, 2016
    Co-Authors: R M Arkhipov, M V Arkhipov, I Babushkin, Ayhan Demircan, Uwe Morgner, N N Rosanov
    Abstract:

    In the regime of resonant coherent light–matter interaction, light pulses may interact with each other indirectly via a Polarization wave created by the other pulse. We show that such interaction allows fast creation and erasing of high-contrast dynamic population density gratings, as well as control of their period in a few-cycle regime. Our scheme uses counter-propagating optical pulses, which do not cross each other in the medium. The mechanism is able to work with pulse durations up to the single-cycle limit. Somewhat surprisingly, ultrafast grating wave vector control requires the generation of Polarization Waves with the phase velocity much smaller than that of light.

R M Arkhipov - One of the best experts on this subject based on the ideXlab platform.

  • population density gratings induced by few cycle optical pulses in a resonant medium
    Scientific Reports, 2017
    Co-Authors: R M Arkhipov, M V Arkhipov, I Babushkin, Ayhan Demircan, Uwe Morgner, A V Pakhomov, N N Rosanov
    Abstract:

    Creation, erasing and ultrafast control of population density gratings using few-cycle optical pulses coherently interacting with resonant medium is discussed. In contrast to the commonly used schemes, here the pulses do not need to overlap in the medium, interaction between the pulses is mediated by excitation of Polarization Waves. We investigate the details of the dynamics arising in such ultrashort pulse scheme and develop an analytical theory demonstrating the importance of the phase memory effects in the dynamics.

  • ultrafast creation and control of population density gratings via ultraslow Polarization Waves
    Optics Letters, 2016
    Co-Authors: R M Arkhipov, M V Arkhipov, I Babushkin, Ayhan Demircan, Uwe Morgner, N N Rosanov
    Abstract:

    In the regime of resonant coherent light–matter interaction, light pulses may interact with each other indirectly via a Polarization wave created by the other pulse. We show that such interaction allows fast creation and erasing of high-contrast dynamic population density gratings, as well as control of their period in a few-cycle regime. Our scheme uses counter-propagating optical pulses, which do not cross each other in the medium. The mechanism is able to work with pulse durations up to the single-cycle limit. Somewhat surprisingly, ultrafast grating wave vector control requires the generation of Polarization Waves with the phase velocity much smaller than that of light.

Sergey K Ivanov - One of the best experts on this subject based on the ideXlab platform.

  • solution of the riemann problem for Polarization Waves in a two component bose einstein condensate
    Physical Review E, 2017
    Co-Authors: T. Congy, A. M. Kamchatnov, Sergey K Ivanov, N. Pavloff
    Abstract:

    We provide a classification of the possible flows of two-component Bose-Einstein condensates evolving from initially discontinuous profiles. We consider the situation where the dynamics can be reduced to the consideration of a single Polarization mode (also denoted as "magnetic excitation") obeying a system of equations equivalent to the Landau-Lifshitz equation for an easy-plane ferromagnet. We present the full set of one-phase periodic solutions. The corresponding Whitham modulation equations are obtained together with formulas connecting their solutions with the Riemann invariants of the modulation equations. The problem is not genuinely nonlinear, and this results in a non-single-valued mapping of the solutions of the Whitham equations with physical wave patterns as well as the appearance of interesting elements-contact dispersive shock Waves-that are absent in more standard, genuinely nonlinear situations. Our analytic results are confirmed by numerical simulations.