The unavoidable interaction between thermal environments and quantum systems typically leads to the degradation of quantum coherence, which can be fought against by reservoir engineering. We propose the realization of a special mixture of thermal coherent states by coupling a thermal bath with a two-level system (TLS) that is longitudinally coupled to a resonator. We find that the state of the resonator is a special mixture of two oppositely displaced thermal coherent states, whereas the TLS remains thermal. This observation is verified by evaluating the second-order correlation coefficient for the resonator state. Moreover, we reveal the potential benefits of employing the mixture of thermal coherent states of the resonator in quantum thermometry. In this context, the resonator functions as a probe to measure the unknown temperature of a bath mediated by a TLS, strategically bridging the connection between the two. Our results show that the use of an ancillary-assisted probe may enhance the precision and broaden the applicable temperature range.

中文翻译：

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混合热相干态以提高量子测温法的精度和范围范围


热环境和量子系统之间不可避免的相互作用通常会导致量子相干性的退化，这可以通过油藏工程来对抗。我们提出了通过将热浴与纵向耦合到谐振器的两能级系统 （TLS） 耦合来实现热相干态的特殊混合物。我们发现谐振器的状态是两个相反位移的热相干态的特殊混合物，而 TLS 保持热状态。通过评估谐振器状态的二阶相关系数来验证这一观察结果。此外，我们揭示了在量子测温中采用谐振器的热相干态混合的潜在好处。在这种情况下，谐振器充当探针，测量由 TLS 介导的浴槽的未知温度，战略性地桥接两者之间的连接。我们的结果表明，使用辅助辅助探头可以提高精度并拓宽适用温度范围。