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Center for Nonlinear Studies |
Open physical systems with balanced loss and gain exhibit a transition, absent in their solitary counterparts, which engenders modes that exponentially decay or grow with time and thus spontaneously breaks the parity-time (PT) symmetry. This PT-symmetry breaking is induced by modulating the strength or the temporal profile of the loss and gain, but also occurs in a pure dissipative system without gain. I will present the results of the first quantum simulation of PT-symmetry breaking using ultracold Li-6 atoms. We simulated static and Floquet dissipative Hamiltonians by generating state-dependent atom loss in a noninteracting Fermi gas. We showed that while the two-state system undergoes a single transition in the static case, its Floquet counterpart, with a periodic loss, undergoes PT-symmetry breaking and restoring transitions at vanishingly small dissipation strength. Our results demonstrate that Floquet dissipation offers a versatile tool for navigating PT phases. I will conclude the talk with theoretical results for signatures of PT symmetry breaking in quantum coherence and entanglement metrics for an interacting system of a few qubits.
Host: Avadh Saxena