Experimental Measurement of the Quantum Metric Tensor and Related Topological Phase Transition with a Superconducting Qubit

A Berry curvature is an imaginary component of the quantum geometric tensor (QGT) and is well studied in many branches of modern physics; however, the quantum metric as a real component of the QGT is less explored. Here, by using tunable superconducting circuits, we experimentally demonstrate two me...

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Bibliographic Details
Published in:Physical review letters 2019-05, Vol.122 (21), p.210401-210401, Article 210401
Main Authors: Tan, Xinsheng, Zhang, Dan-Wei, Yang, Zhen, Chu, Ji, Zhu, Yan-Qing, Li, Danyu, Yang, Xiaopei, Song, Shuqing, Han, Zhikun, Li, Zhiyuan, Dong, Yuqian, Yu, Hai-Feng, Yan, Hui, Zhu, Shi-Liang, Yu, Yang
Format: Article
Language:English
Subjects:
Curvature
Mathematical analysis
Measurement methods
Phase transitions
Qubits (quantum computing)
Superconductivity
Tensors
Topology
Transition probabilities
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Summary:A Berry curvature is an imaginary component of the quantum geometric tensor (QGT) and is well studied in many branches of modern physics; however, the quantum metric as a real component of the QGT is less explored. Here, by using tunable superconducting circuits, we experimentally demonstrate two methods to directly measure the quantum metric tensor for characterizing the geometry and topology of underlying quantum states in parameter space. The first method is to probe the transition probability after a sudden quench, and the second one is to detect the excitation rate under weak periodic driving. Furthermore, based on quantum metric and Berry-curvature measurements, we explore a topological phase transition in a simulated time-reversal-symmetric system. The work opens up a unique approach to explore the topology of quantum states with the QGT.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.122.210401