Observation of quantum-classical transition behavior of LGI in a dissipative quantum gas

• URL: http://arxiv.org/abs/2411.02910v1
• Date: Tue, 05 Nov 2024 08:52:42 GMT
• Title: Observation of quantum-classical transition behavior of LGI in a dissipative quantum gas
• Abstract summary: We apply the Leggett-Garg inequality (LGI) to a non-Hermitian system of ultracold Fermi gas with dissipation. Beyond a certain dissipation threshold, the LGI violation weakens, indicating a quantum-to-classical transition (QCT) This study provides a crucial stepping stone for using the LGI to explore the QCT in many-body open quantum systems.
• Score: 7.3471994064881665
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The Leggett-Garg inequality (LGI) is a powerful tool for distinguishing between quantum and classical properties in studies of macroscopic systems. Applying the LGI to non-Hermitian systems with dissipation presents a fascinating opportunity, as competing mechanisms can either strengthen or weaken LGI violations. On one hand, dissipation-induced nonlinear interactions amplify LGI violations compared to Hermitian systems; on the other hand, dissipation leads to decoherence, which could weaken the LGI violation. In this paper, we investigate a non-Hermitian system of ultracold Fermi gas with dissipation. Our experiments reveal that as dissipation increases, the upper bound of the third-order LGI parameter $K_3$ initially rises, reaching its maximum at the exceptional point (EP), where $K_3 = C_{21} + C_{32} - C_{31}$, encompassing three two-time correlation functions. Beyond a certain dissipation threshold, the LGI violation weakens, approaching the classical limit, indicating a quantum-to-classical transition (QCT). Furthermore, we observe that the LGI violation decreases with increasing evolution time, reinforcing the QCT in the time domain. This study provides a crucial stepping stone for using the LGI to explore the QCT in many-body open quantum systems.

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