Non-Hermitian dynamics and $\mathcal{PT}$-symmetry breaking in interacting mesoscopic Rydberg platforms

Abstract

We simulate the dissipative dynamics of a mesoscopic system of long-range interacting particles which can be mapped into non-Hermitian spin models with a PT symmetry. We find rich PTphase diagrams with PT -symmetric and PT -broken phases. The dynamical regimes can be further enriched by modulating tunable parameters of the system. We outline how the PT symmetries of such systems may be probed by studying their dynamics. We note that systems of Rydberg atoms and systems of Rydberg ions with strong dipolar interactions are particularly well suited for such studies. We show that for realistic parameters, long-range interactions allow the emergence of new PT -symmetric regions, generating new PT -phase transitions. In addition, such PT -symmetry phase transitions are found by changing the Rydberg atoms configurations. We monitor the transitions by accessing the populations of the Rydberg states. Their dynamics display oscillatory or exponential dependence in each phase.

Non-Hermitian quantum many-body scar

“…For the Hermitian QMBS realized in the Rydberg-atom quantum simulator [42], the symmetric coupling between the ground state and the Rydberg state is induced by a two-photon process via an intermediate level. Recently, much effort has been devoted to realizing the non-Hermiticity in cold-atom platforms [56][57][58][59][60][61][62], notably the Rydberg atoms [59,60]. When the coupling is experimentally tuned to be non-symmetric, such as through the three-level atoms with spontaneous decay [62], our results would be directly verified in experiments.…”

“…We find that the non-Hermitian QMBS become fragile as the non-Hermiticity strength increases in the real-spectrum region, but they still exhibit substantial stability. Our construction of the non-Hermitian QMBS may also be probed experimentally based on the newly developed measurement of the non-Hermiticity in ultracold-atom platforms [42,[56][57][58][59][60][61][62].…”