Martin J, Georgeot B, Shepelyansky D L
Université de Toulouse, F-31062 Toulouse, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Jun;79(6 Pt 2):066205. doi: 10.1103/PhysRevE.79.066205. Epub 2009 Jun 12.
We study numerically the coupling between a qubit and a Bose-Einstein condensate (BEC) moving in a kicked optical lattice using Gross-Pitaevskii equation. In the regime where the BEC size is smaller than the lattice period, the chaotic dynamics of the BEC is effectively controlled by the qubit state. The feedback effects of the nonlinear chaotic BEC dynamics preserve the coherence and purity of the qubit in the regime of strong BEC nonlinearity. This gives an example of an exponentially sensitive control over a macroscopic state by internal qubit states. At weak nonlinearity quantum chaos leads to rapid dynamical decoherence of the qubit. The realization of such coupled systems is within reach of current experimental techniques.
我们使用格罗斯 - 皮塔耶夫斯基方程对一个量子比特与在受踢光学晶格中运动的玻色 - 爱因斯坦凝聚体（BEC）之间的耦合进行了数值研究。在BEC尺寸小于晶格周期的情况下，BEC的混沌动力学由量子比特状态有效控制。在强BEC非线性区域，非线性混沌BEC动力学的反馈效应保持了量子比特的相干性和纯度。这给出了一个通过内部量子比特状态对宏观状态进行指数敏感控制的例子。在弱非线性情况下，量子混沌导致量子比特的快速动力学退相干。这种耦合系统的实现是当前实验技术能够达到的。
