Using mixed many-body particle states to generate exact PT-symmetry in a time-dependent four-well system

作者：Mathea Tina^*; Dast Dennis; Dizdarevic Daniel; Cartarius Holger; Main Joerg; Wunner Guenter

来源：Journal of Physics A-Mathematical and Theoretical, 2018, 51(31): 315303.

DOI：10.1088/1751-8121/aacaa3

• open quantum systems and decoherence
• PT-symmetric quantum systems
• Bose-Einstein condensates
• Bose-Hubbard model

Bose-Einstein condensates with balanced gain and loss in a double-well potential have been shown to exhibit PT-symmetric states. As proposed by Kreibich (2013 Phys. Rev. A 87 051601), in the mean-field limit the dynamical behaviour of this system, especially that of the PT-symmetric states, can be simulated by embedding it into a Hermitian four-well system with time-dependent parameters. In this paper we go beyond the mean-field approximation and investigate many-body effects in this system, which are in lowest order described by the single-particle density matrix. The conditions for PT symmetry in the single-particle density matrix cannot be completely fulfilled by using pure initial states. Here we show that it is mathematically possible to achieve exact PT symmetry in the four-well many-body system in the sense of the dynamical behaviour of the single-particle density matrix. In contrast to previous work, for this purpose, we use mixed initial states fulfilling certain constraints and use them to calculate the dynamics.

• 出版日期2018-8-3