Volume 114, Number 2, April 2016
|Number of page(s)||6|
|Published online||09 May 2016|
Quantum-dynamical phase transition and Fisher information in a non-Hermitian Bose-Hubbard dimer
1 School of Science, Zhejiang University of Science and Technology - Hangzhou, Zhejiang 310023, China
2 Department of Applied Physics, Zhejiang University of Technology - Hangzhou 310018, China
3 Laboratory of Quantum Engineering and Quantum Materials, SPTE, South China Normal University Guangzhou 510006, China
4 School of Science, Jiangnan University - Wuxi 214122, China
Received: 18 December 2015
Accepted: 26 April 2016
We study the dynamical properties in a non-Hermitian Bose-Hubbard dimer and show that the steady state consists mostly of the eigenstate whose eigenvalue has the largest imaginary part. A sharp phase transition occurs in the steady state and the phase transition occurs for a finite particle number, not for infinite ones, in contrast to the Hermitian system. We also investigate the quantum Fisher information and entanglement in two different phases. The results show that the steady state in the Josephson oscillation regime is fully N-particle entangled and the corresponding parameter sensitivity approaches the Heisenberg limit. In the self-trapping regime, the parameter sensitivity just scales as the shot-noise limit. Moreover, quantum Fisher information of the steady state is robust to the initial state, which indicates that the non-Hermitian dynamics takes more advantage than the Hermitian one for quantum metrology.
PACS: 03.67.-a – Quantum information / 03.75.Gg – Entanglement and decoherence in Bose-Einstein condensates / 05.30.Rt – Quantum phase transitions
© EPLA, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.