title: PT symmetry via electromagnetically induced transparency.
abstract: We propose a scheme to realize parity-time (PT) symmetry via electromagnetically induced transparency (EIT). The system we consider is an ensemble of cold four-level atoms with an EIT core. We show that the cross-phase modulation contributed by an assisted field, the optical lattice potential provided by a far-detuned laser field, and the optical gain resulted from an incoherent pumping can be used to construct a PT-symmetric complex optical potential for probe field propagation in a controllable way. Comparing with previous study, the present scheme uses only a single atomic species and hence is easy for the physical realization of PT-symmetric Hamiltonian via atomic coherence.
authors: Hui-Jun
authors: HJ
authors: Li
authors: Jian-Peng
authors: JP
authors: Dou
authors: Guoxiang
authors: G
authors: Huang