论文标题
通过全局旋转旋转来加速耗散量子旋转系统对平稳性的方法
Accelerating the approach of dissipative quantum spin systems towards stationarity through global spin rotations
论文作者
论文摘要
我们考虑开放的量子系统，其动力学受到时间独立的马尔可夫·林德布拉德主方程的控制。这样的系统将其固定状态接近一个时间尺度，该时间表由主方程动力学的发电机的光谱差异确定。在最近的论文[Carollo等人，物理学。莱特牧师。 127，060401（2021）]证明，在某些情况下，可以通过对初始状态进行单一转换来指数级加速平稳性的方法。这种现象可以被视为所谓的mpemba效应的量子版本。初始状态的转换消除了其与具有最慢衰减速率的开放系统动力学的动力学模式的重叠，因此决定了光谱间隙。尽管在某些情况下可以完全构建这种转换，但实践中实施挑战。在这里，我们表明，通过全球统一自旋旋转构建的更简单的转换可以指数速度加速放松。我们使用简单的耗散量子自旋系统证明了这一点，这些系统与基于捕获的原子和离子的当前量子仿真和计算平台相关。
We consider open quantum systems whose dynamics is governed by a time-independent Markovian Lindblad Master equation. Such systems approach their stationary state on a timescale that is determined by the spectral gap of the generator of the Master equation dynamics. In the recent paper [Carollo et al., Phys. Rev. Lett. 127, 060401 (2021)] it was shown that under certain circumstances it is possible to exponentially accelerate the approach to stationarity by performing a unitary transformation of the initial state. This phenomenon can be regarded as the quantum version of the so-called Mpemba effect. The transformation of the initial state removes its overlap with the dynamical mode of the open system dynamics that possesses the slowest decay rate and thus determines the spectral gap. While this transformation can be exactly constructed in some cases, it is in practice challenging to implement. Here we show that even far simpler transformations constructed by a global unitary spin rotation allow to exponentially speed up relaxation. We demonstrate this using simple dissipative quantum spin systems, which are relevant for current quantum simulation and computation platforms based on trapped atoms and ions.
