Observation of Strong and Weak Thermalization in a Superconducting Quantum Processor

Fusheng Chen; Zheng-Hang Sun; Ming Gong; Qingling Zhu; Yu-Ran Zhang; Yulin Wu; Yangsen Ye; Chen Zha; Shaowei Li; Shaojun Guo; Haoran Qian; He-Liang Huang; Jiale Yu; Hui Deng; Hao Rong; Jin Lin; Yu Xu; Lihua Sun; Cheng Guo; Na Li; Futian Liang; Cheng-Zhi Peng; Heng Fan; Xiaobo Zhu; Jian-Wei Pan

doi:10.1103/PhysRevLett.127.020602

Observation of Strong and Weak Thermalization in a Superconducting Quantum Processor

Phys Rev Lett. 2021 Jul 9;127(2):020602. doi: 10.1103/PhysRevLett.127.020602.

Authors

Fusheng Chen^{1

2

3}, Zheng-Hang Sun^{4

5}, Ming Gong^{1

2

3}, Qingling Zhu^{1

2

3}, Yu-Ran Zhang⁶, Yulin Wu^{1

2

3}, Yangsen Ye^{1

2

3}, Chen Zha^{1

2

3}, Shaowei Li^{1

2

3}, Shaojun Guo^{1

2

3}, Haoran Qian^{1

2

3}, He-Liang Huang^{1

2

3}, Jiale Yu^{1

2

3}, Hui Deng^{1

2

3}, Hao Rong^{1

2

3}, Jin Lin^{1

2

3}, Yu Xu^{1

2

3}, Lihua Sun^{1

2

3}, Cheng Guo^{1

2

3}, Na Li^{1

2

3}, Futian Liang^{1

2

3}, Cheng-Zhi Peng^{1

2

3}, Heng Fan^{4

5

7

8}, Xiaobo Zhu^{1

2

3}, Jian-Wei Pan^{1

2

3}

Affiliations

¹ Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
² Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China.
³ Shanghai Research Center for Quantum Sciences, Shanghai 201315, China.
⁴ Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁵ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
⁶ Theoretical Quantum Physics Laboratory, RIKEN Cluster for Pioneering Research, Wako-shi, Saitama 351-0198, Japan.
⁷ Songshan Lake Materials Laboratory, Dongguan 523808, Guangdong, China.
⁸ CAS Center for Excellent in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.

PMID: 34296924
DOI: 10.1103/PhysRevLett.127.020602

Abstract

We experimentally study the ergodic dynamics of a 1D array of 12 superconducting qubits with a transverse field, and identify the regimes of strong and weak thermalization with different initial states. We observe convergence of the local observable to its thermal expectation value in the strong-thermalizaion regime. For weak thermalization, the dynamics of local observable exhibits an oscillation around the thermal value, which can only be attained by the time average. We also demonstrate that the entanglement entropy and concurrence can characterize the regimes of strong and weak thermalization. Our work provides an essential step toward a generic understanding of thermalization in quantum systems.