受驱克尔腔耗散相变附近的增强量子测温
Enhanced quantum thermometry near a dissipative phase transition in a driven Kerr cavity
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中文总结 AI 辅助
该研究针对耦合热库的受驱耗散克尔腔，利用其耗散相变的有限尺寸前兆，通过优化相干驱动实现了温度估计量子费舍尔信息的显著增强，为电路量子电动力学平台的量子测温提供了可调资源。
中文摘要 AI 辅助
我们研究耦合到热库的受驱耗散克尔腔中的量子测温问题。该系统呈现出耗散相变的有限尺寸前兆，其特征是李雅普诺夫间隙出现明显极小值，且在临界驱动强度下，平均光子数等稳态物理观测量会发生陡变。我们表明，该区域会显著提升用于温度估计的量子费舍尔信息（QFI）。通过采用有效双分支描述，我们发现这种增强源于温度诱导的光子数分布权重因子在低光子数分支与高光子数分支之间的重新分布，该过程由有效二元费舍尔信息描述。通过优化相干驱动，增强响应可在扩展的低温、低热占据区域持续存在，并产生有利的相对温度不确定度界。这些结果表明，克尔腔平台中耗散相变的有限尺寸前兆是可调非平衡量子测温的有用资源。我们进一步证明，预测的测温增强在与电路量子电动力学（circuit-QED）平台兼容的参数区域内是可实现的。
英文摘要
We investigate quantum thermometry in a driven--dissipative Kerr cavity coupled to a thermal reservoir. The system exhibits a finite-size precursor of a dissipative phase transition, characterized by a pronounced minimum of the Liouvillian gap and a sharp jump in the steady-state physical observables such as average photon number at the critical driving strength. We show that this regime leads to strong enhancement of the quantum Fisher information (QFI) for temperature estimation. Using an effective two-branch description, we show that the enhancement originates from temperature-induced redistribution of the weight factors in photon number distribution between low- and high-photon-number branches, which is described by an effective binary Fisher information. By optimizing the coherent drive, the enhanced response persists over an extended low-temperature, low-thermal-occupation regime and yields a favorable relative temperature-uncertainty bound. These results identify finite-size precursors of dissipative phase transitions in Kerr-cavity platforms as useful resources for tunable nonequilibrium quantum thermometry. We further show that the predicted thermometric enhancement is accessible in a parameter regime compatible with circuit quantum electrodynamics (circuit-QED) platforms.
