Usha Devi A R, Rajagopal A K
Department of Physics, Bangalore University, Bangalore 560 056, India.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Jul;80(1 Pt 1):011136. doi: 10.1103/PhysRevE.80.011136. Epub 2009 Jul 27.
A pure quantum state of large number N of oscillators, interacting via harmonic coupling, evolves such that any small subsystem n<<N of the global state approaches equilibrium. This provides a different example where stability emerges as natural phenomena under quantum dynamics alone, with no necessity to bring in any additional statistical postulates. Mixing of equilibrated subsystems consisting of 1,2,...,n<<N clearly indicates that small subsystems are entangled with the rest of the state, i.e., the bath. Every single mode oscillator is found to relax in a mixed density matrix of the Boltzmann canonical form. In two oscillator stationary subsystems, intraentanglement within the "system" oscillators is found to exist when the magnitude of the squeezing parameter of the bath is comparable in magnitude with that of the coupling strength.
大量N个通过谐波耦合相互作用的振子的纯量子态会发生演化，使得全局态中任何远小于N的小子系统n趋近于平衡态。这提供了一个不同的例子，即在仅量子动力学作用下，稳定性作为一种自然现象出现，无需引入任何额外的统计假设。由1、2、...、n（远小于N）组成的平衡子系统的混合清楚地表明，小子系统与态的其余部分（即热库）纠缠在一起。发现每个单模振子都在玻尔兹曼正则形式的混合密度矩阵中弛豫。在两个振子的定态子系统中，当热库的压缩参数的大小与耦合强度的大小相当时，发现“系统”振子内部存在纠缠。
