Yu Li, James Daniel F V
Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON, M5S 1A7, Canada.
Department of Physics, Harvard University, Cambridge, MA, 02138, USA.
Sci Rep. 2025 Aug 23;15(1):30984. doi: 10.1038/s41598-025-14825-z.
We develop a formally exact master equation to describe the evolution of the average density matrix of a closed quantum system driven by a stochastic Hamiltonian. The average over stochastic processes generally results in decoherence effects in closed system dynamics, in addition to the unitary evolution. We then show that, for an important class of problems in which the Hamiltonian is proportional to a Gaussian random process, the 2nd-order master equation yields exact dynamics. The general formalism is applied to study the examples of a two-level system, two atoms in a stochastic magnetic field and the heating of a trapped ion, where we find phenomena such as decoherence-induced disentanglement.
我们推导了一个形式上精确的主方程，用于描述由随机哈密顿量驱动的封闭量子系统平均密度矩阵的演化。除了幺正演化之外，随机过程的平均通常会在封闭系统动力学中导致退相干效应。然后我们表明，对于哈密顿量与高斯随机过程成正比的一类重要问题，二阶主方程能给出精确的动力学。我们将一般形式体系应用于研究二能级系统、处于随机磁场中的两个原子以及捕获离子的加热等例子，在这些例子中我们发现了诸如退相干诱导的纠缠消失等现象。
