Viennot David, Aubourg Lucile
Institut UTINAM (CNRS UMR 6213, Université de Franche-Comté, Observatoire de Besançon), 41bis Avenue de l'Observatoire, BP1615, 25010 Besançon cedex, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Jun;87(6):062903. doi: 10.1103/PhysRevE.87.062903. Epub 2013 Jun 7.
We study the dynamics of a quantum spin ensemble controlled by trains of ultrashort pulses. To model disturbances of the kicks, we consider that the spins are submitted to different kick trains which follow regular, random, stochastic, or chaotic dynamical processes. These are described by dynamical systems on a torus. We study the quantum decoherence and the population relaxation of the spin ensemble induced by these classical dynamical processes disturbing the kick trains. For chaotic kick trains we show that the decoherence and the relaxation processes exhibit a signature of chaos directly related to the Lyapunov exponents of the dynamical system. This signature is a horizon of coherence, i.e., a preliminary duration without decoherence followed by a rapid decoherence process.
我们研究了由超短脉冲序列控制的量子自旋系综的动力学。为了模拟脉冲的扰动，我们考虑自旋受到不同的脉冲序列影响，这些序列遵循规则、随机、随机或混沌动力学过程。这些过程由环面上的动力学系统描述。我们研究了由这些干扰脉冲序列的经典动力学过程引起的自旋系综的量子退相干和布居弛豫。对于混沌脉冲序列，我们表明退相干和弛豫过程呈现出与动力学系统的李雅普诺夫指数直接相关的混沌特征。这个特征是一个相干视界，即一个没有退相干的初始持续时间，随后是一个快速退相干过程。
