We study an imaginary stark ladder model and propose a realization of the in dissipative chain with linearly increasing site-dependent dissipation strength. Due to existence $K$-symmetry passive $\mathcal{PT}$ symmetry, exhibits quite different feature from its Hermitian counterpart. With increase strength, system first undergoes $\mathcal{PT}$-symmetry breaking transition, shifted eigenvalues ...

We investigate the effects of quantum fluctuations in a parity-time($\mathcal{PT}$) symmetric two-species Bose-Einstein Condensate(BEC). It is found that $\mathcal{PT}$-symmetry, though preserved by macroscopic condensate, can be spontaneously broken its Bogoliubov quasi-particles under fluctuations. The associated $\mathcal{PT}$-breaking transitions spectrum conveniently tuned interaction anis...

Parity-time (PT) symmetry and broken in micro-/nanophotonic structures have been investigated extensively as they bring new opportunities to control the flow of light based on non-Hermitian optics. Previous studies focused situations PT-symmetry loss-loss or gain-loss coupling systems. Here, we theoretically predict gain-gain gain-lossless PT-broken from phase diagram, where boundaries between ...