We propose a scheme to realize parity-time (\(\mathcal{PT}\)) 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 \(\mathcal{PT}\)-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 \(\mathcal{PT}\)-symmetric Hamiltonian via atomic coherence.

http://arxiv.org/abs/1307.2695
Quantum Physics (quant-ph)