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arXiv · 1912.05150

Probing the dynamical phase transition with a superconducting quantum simulator

Kai Xu·Zheng-Hang Sun·Wuxin Liu·Yu-Ran Zhang·Hekang Li·Hang Dong·Wenhui Ren·Pengfei Zhang·Franco Nori·Dongning Zheng·Heng Fan·H. Wang
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Abstract

Non-equilibrium quantum many-body systems, which are difficult to study via classical computation, have attracted wide interest. Quantum simulation can provide insights into these problems. Here, using a programmable quantum simulator with 16 all-to-all connected superconducting qubits, we investigate the dynamical phase transition in the Lipkin-Meshkov-Glick model with a quenched transverse field. Clear signatures of the dynamical phase transition, merging different concepts of dynamical criticality, are observed by measuring the non-equilibrium order parameter, nonlocal correlations, and the Loschmidt echo. Moreover, near the dynamical critical point, we obtain the optimal spin squeezing of $-7.0\pm 0.8$ decibels, showing multipartite entanglement useful for measurements with precision five-fold beyond the standard quantum limit. Based on the capability of entangling qubits simultaneously and the accurate single-shot readout of multi-qubit states, this superconducting quantum simulator can be used to study other problems in non-equilibrium quantum many-body systems.

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Kai Xu, Zheng-Hang Sun, Wuxin Liu, Yu-Ran Zhang, Hekang Li, Hang Dong, Wenhui Ren, Pengfei Zhang, Franco Nori, Dongning Zheng, Heng Fan, H. Wang. 2019-12-11. Probing the dynamical phase transition with a superconducting quantum simulator. https://doi.org/10.1126/sciadv.aba4935

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