开放量子系统中加速度和温度的量子估计
Quantum estimation of acceleration and temperature in open quantum system
摘要：
在开放量子系统中，研究了作为探测器的二能级原子与给定环境相互作用的演化。对于闵可夫斯基真空中与无质量标量场耦合的匀加速二能级原子，当原子演化到一定时间后，发现加速度的量子费舍尔信息（QFI）存在一个峰值，这表明选择适当的加速度$a$可以获得最佳的估计精度.对于不同的原子初态参数$θ$，QFI有不同的行为，表现出周期性。但随着时间的演化，周期性逐渐消失，这意味着初态不能影响后来稳定的量子态。此外，添加边界后，我们观察到当原子靠近边界时，QFI的峰值增加，这表明QFI受到边界的保护。在此，QFI波动，并且在某一时刻可能存在两个峰值，这扩大了加速度的检测范围。因此，我们可以通过选择合适的位置和加速度$a$来提高加速度的估计精度。QFI相对于初始状态参数$θ$的周期性比之前的无界情况持续更长的时间，这表明初始状态受到边界的保护。最后，对于有边界的热浴，温度的QFI在某一时刻不超过一个峰值，这与有边界的加速度的QFI不同。周期性的持续时间也比无界情形长，这表明在两种情形下原子的初始量子态都受到边界的保护。
英文摘要：
In an open quantum system, we study the evolution of a two-level atom as a detector which interacts with given environments. For a uniformly accelerated two-level atom coupled to a massless scalar field in the Minkowski vacuum, when it evolves for a certain time, we find that there exists a peak value for the quantum Fisher information (QFI) of acceleration, which indicates that the optimal precision of estimation is achieved when choosing an appropriate acceleration $a$. QFI has different behaviors for different initial state parameters $θ$ of the atom, displaying periodicity. However, the periodicity fades away with the evolution of time, which means that the initial state cannot affect the later stable quantum state. Furthermore, adding a boundary, we observe that the peak value of QFI increases when the atom is close to the boundary, which shows that QFI is protected by the boundary. Here, QFI fluctuates, and there may exist two peak values with a certain moment, which expands the detection range of the acceleration. Therefore, we can enhance the estimation precision of acceleration by choosing an appropriate position and acceleration $a$. The periodicity of QFI with respect to the initial state parameter $θ$ lasts a longer time than the previous unbounded case, which indicates that the initial state is protected by the boundary. Finally, for a thermal bath with a boundary, QFI of temperature has no more than one peak value with a certain moment, which is different from QFI of acceleration with a boundary. The periodicity also lasts a longer time than unbounded case, which shows the initial quantum state of the atom is protected by the boundary for two cases.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
