1. Experimental demonstration of spontaneous symmetry breaking with emergent multi-qubit entanglement
- Author
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Zheng, Ri-Hua, Ning, Wen, Lü, Jia-Hao, Yu, Xue-Jia, Wu, Fang, Deng, Cheng-Lin, Yang, Zhen-Biao, Xu, Kai, Zheng, Dongning, Fan, Heng, and Zheng, Shi-Biao
- Subjects
Quantum Physics - Abstract
Spontaneous symmetry breaking (SSB) is crucial to the occurrence of phase transitions. Once a phase transition occurs, a quantum system presents degenerate eigenstates that lack the symmetry of the Hamiltonian. After crossing the critical point, the system is essentially evolved to a quantum superposition of these eigenstates until decoherence sets in. Despite the fundamental importance and potential applications in quantum technologies, such quantum-mechanical SSB phenomena have not been experimentally explored in many-body systems. We here present an experimental demonstration of the SSB process in the Lipkin-Meshkov-Glick model, governed by the competition between the individual driving and intra-qubit interaction. The model is realized in a circuit quantum electrodynamics system, where 6 Xmon qubits are coupled in an all-to-all manner through virtual photon exchange mediated by a resonator. The observed nonclassical correlations among these qubits in the symmetry-breaking region go beyond the conventional description of SSB, shedding new light on phase transitions for quantum many-body systems., Comment: 27 pages, 18 figures
- Published
- 2024