Squeezed Light Induced Symmetry Breaking Superradiant Phase Transition.
Squeezed Light Induced Symmetry Breaking Superradiant Phase Transition.
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DOI：
10.1103/physrevlett.124.073602
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发表时间：
2019-07
影响因子：
8.6
通讯作者：
Chengjie Zhu;L. Ping;Yaping Yang;G. Agarwal
中科院分区：
文献类型：
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作者：
Chengjie Zhu;L. Ping;Yaping Yang;G. Agarwal
我们从理论上研究了高质量腔中量子比特集体系统的量子相变，其中腔场通过光参量放大过程被压缩。我们证明了压缩光诱导对称性破缺可以导致量子相变而不需要超强耦合。利用标准平均场理论，导出了量子相变的条件。令人惊讶的是，我们发现，存在一个三临界点，一阶和二阶相变满足。在特定的原子-腔耦合强度下，一阶和二阶相变都可以通过非线性增益系数来控制，而非线性增益系数对泵浦场敏感。这些特征也导致光开关从正常阶段的超辐射阶段，通过增加泵浦场强度。这些相变的特征可以通过检测由压缩光强度控制的具有不同轮廓的相空间维格纳函数分布来观察。这种超辐射相变可以在各种量子系统中实现，包括光学腔中的原子、量子点和离子以及电路量子电动力学系统。
We theoretically investigate the quantum phase transition in the collective systems of qubits in a high quality cavity, where the cavity field is squeezed via the optical parametric amplification process. We show that the squeezed light induced symmetry breaking can result in quantum phase transition without the ultrastrong coupling requirement. Using the standard mean field theory, we derive the condition of the quantum phase transition. Surprisingly, we show that there exists a tricritical point where the first- and second-order phase transitions meet. With specific atom-cavity coupling strengths, both the first- and second-order phase transition can be controlled by the nonlinear gain coefficient, which is sensitive to the pump field. These features also lead to an optical switching from the normal phase to the superradiant phase by just increasing the pump field intensity. The signature of these phase transitions can be observed by detecting the phase space Wigner function distribution with different profiles controlled by the squeezed light intensity. Such superradiant phase transition can be implemented in various quantum systems, including atoms, quantum dots, and ions in optical cavities as well as the circuit quantum electrodynamics system.