Exploring the quantum critical behaviour in a driven Tavis-Cummings circuit

M. Feng*, Y. P. Zhong, T. Liu, L. L. Yan, W. L. Yang, J. Twamley, H. Wang

*Corresponding author for this work

Research output: Contribution to journalArticle

24 Citations (Scopus)
19 Downloads (Pure)

Abstract

Quantum phase transitions play an important role in many-body systems and have been a research focus in conventional condensed-matter physics over the past few decades. Artificial atoms, such as superconducting qubits that can be individually manipulated, provide a new paradigm of realising and exploring quantum phase transitions by engineering an on-chip quantum simulator. Here we demonstrate experimentally the quantum critical behaviour in a highly controllable superconducting circuit, consisting of four qubits coupled to a common resonator mode. By off-resonantly driving the system to renormalize the critical spin-field coupling strength, we have observed a four-qubit nonequilibrium quantum phase transition in a dynamical manner; that is, we sweep the critical coupling strength over time and monitor the four-qubit scaled moments for a signature of a structural change of the system's eigenstates. Our observation of the nonequilibrium quantum phase transition, which is in good agreement with the driven Tavis-Cummings theory under decoherence, offers new experimental approaches towards exploring quantum phase transition-related science, such as scaling behaviours, parity breaking and long-range quantum correlations.

Original languageEnglish
Article number7111
Pages (from-to)1-7
Number of pages7
JournalNature Communications
Volume6
DOIs
Publication statusPublished - 14 May 2015

Bibliographical note

Copyright 2015 Macmillan Publishers Limited. First published in Nature Communications 6, Article number: 7111. The original publication is available at http://www.doi.org/10.1038/ncomms8111. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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