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  • Letter
  • Open Access

Observation of emergent Z2 gauge invariance in a superconducting circuit

Zhan Wang1,2,*, Zi-Yong Ge1,2,*, Zhongcheng Xiang1,*, Xiaohui Song1, Rui-Zhen Huang3, Pengtao Song1,2, Xue-Yi Guo1, Luhong Su1,2, Kai Xu1,4,5 et al.

Dongning Zheng1,2,4,5,† and Heng Fan1,4,5,6,‡

  • 1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • 2School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
  • 3Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
  • 4Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China
  • 5CAS Center for Excellence in Topological Quantum Computation, UCAS, Beijing 100190, China
  • 6Beijing Academy of Quantum Information Sciences, Beijing 100193, China

  • *These authors contributed equally to this work.
  • †dzheng@iphy.ac.cn
  • ‡hfan@iphy.ac.cn
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Phys. Rev. Research 4, L022060 – Published 17 June, 2022

DOI: https://doi.org/10.1103/PhysRevResearch.4.L022060

Abstract

Lattice gauge theories (LGTs) are one of the most fundamental subjects in many-body physics, and has recently attracted considerable research interests in quantum simulations. Here we experimentally investigate the emergent Z2 gauge invariance in a 1D superconducting circuit with 10 transmon qubits. By precisely adjusting staggered longitudinal and transverse fields to each qubit, we construct an effective Hamiltonian containing an LGT and gauge-broken terms. The corresponding matter sector can exhibit a localization, and there also exists a 3-qubit operator, of which the expectation value can retain nonzero for a long time in low-energy regimes. The above localization can be regarded as the confinement of matter fields, and the 3-body operator is the Z2 gauge generator. These experimental results demonstrate that, despite the absence of gauge structure in the effective Hamiltonian, Z2 gauge invariance can still emerge in low-energy regimes. Our work provides a method for both theoretically and experimentally studying the rich physics in quantum many-body systems with emergent gauge invariance.

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Phys. Rev. Research 4, L022060– Published 17 June, 2022
  • Received 17 November 2021
  • Revised 16 May 2022
  • Accepted 7 June 2022
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