论文标题
热状态的量子速度极限
Quantum speed limit for thermal states
论文作者
论文摘要
量子速度限制是严格的估计，即量子系统的状态在量子演变过程中可以偏离初始状态的速度。大多数已知的量子速度限制，包括著名的Mandelstam-Tamm和Margolus-Levitin的限制，是适用于任意初始状态的一般界限。但是，当应用于多体系统的混合状态时，它们通常会显着高估量子进化的速度，并且无法在热力学极限中提供有意义的界限。在这里，我们得出了最初以热状态制备并在时间依赖的哈密顿量下进化的封闭系统的量子速度极限。该量子速度极限利用热状态的结构，尤其是明确取决于温度。在一系列的多体设置中，事实证明，它比一般量子速度限制更强大。
Quantum speed limits are rigorous estimates on how fast a state of a quantum system can depart from the initial state in the course of quantum evolution. Most known quantum speed limits, including the celebrated Mandelstam-Tamm and Margolus-Levitin ones, are general bounds applicable to arbitrary initial states. However, when applied to mixed states of many-body systems, they, as a rule, dramatically overestimate the speed of quantum evolution and fail to provide meaningful bounds in the thermodynamic limit. Here we derive a quantum speed limit for a closed system initially prepared in a thermal state and evolving under a time-dependent Hamiltonian. This quantum speed limit exploits the structure of the thermal state and, in particular, explicitly depends on the temperature. In a broad class of many-body setups it proves to be drastically stronger than general quantum speed limits.
