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arXiv · 2111.14064

Leggett-Garg inequalities for testing quantumness of gravity

Akira Matsumura·Yasusada Nambu·Kazuhiro Yamamoto
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Abstract

In this study, we determine a violation of the Leggett-Garg inequalities due to gravitational interaction in a hybrid system consisting of a harmonic oscillator and a spatially localized superposed particle. The violation of the Leggett-Garg inequalities is discussed using the two-time quasiprobability in connection with the entanglement negativity generated by gravitational interaction. It is demonstrated that the entanglement suppresses the violation of the Leggett-Garg inequalities when one of the two times of the quasiprobability t_1 is chosen as the initial time. Further, it is shown that the Leggett-Garg inequalities are generally violated due to gravitational interaction by properly choosing the configuration of the parameters, including t_1 and t_2, which are the times of the two-time quasiprobability. The feasibility of detecting violations of the Leggett-Garg inequalities in hybrid systems is also discussed.

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Akira Matsumura, Yasusada Nambu, Kazuhiro Yamamoto. 2021-11-28. Leggett-Garg inequalities for testing quantumness of gravity. https://doi.org/10.1103/physreva.106.012214

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