Tunable Nonreciprocal Quantum Transport through a Dissipative Aharonov-Bohm Ring in Ultracold Atoms

Abstract

We report the experimental observation of tunable, non-reciprocal quantum transport of a Bose-Einstein condensate in a momentum lattice. By implementing a dissipative Aharonov-Bohm (AB) ring in momentum space and sending atoms through it, we demonstrate a directional atom flow by measuring the momentum distribution of the condensate at different times. While the dissipative AB ring is characterized by the synthetic magnetic flux through the ring and the laser-induced loss on it, both the propagation direction and transport rate of the atom flow sensitively depend on these highly tunable parameters. We demonstrate that the non-reciprocity originates from the interplay of the synthetic magnetic flux and the laser-induced loss, which simultaneously breaks the inversion and the time-reversal symmetries. Our results open up the avenue for investigating non-reciprocal dynamics in cold atoms, and highlight the dissipative AB ring as a flexible building element for applications in quantum simulation and quantum information. arXiv:2001.01859v1 [cond-mat.quant-gas]

Emergent PT symmetry in a double-quantum-dot circuit QED setup

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“…(Note that in other setups loss-induced lasing can occur without any exceptional point [111].) This explicitly requires a gain medium and cannot be observed in the existing experiments in the quantum regime [60][61][62][63][64][65][66][67][68][69], none of which features a gain medium. The real and imaginary parts of the eigenvalues of H eff as a function of κ 2 are plotted in Fig.…”

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Non-Hermitian Floquet Phases with Even-Integer Topological Invariants in a Periodically Quenched Two-Leg Ladder

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