PT-symmetric optical potentials in a coherent atomic medium

We propose that a coherently prepared four-level atomic medium can provide a versatile platform for realizing parity-time (PT) symmetric optical potentials. Different types of PT -symmetric potentials are proposed by appropriately tuning the exciting optical fields and the pertinent atomic parameters. Such reconfigurable and controllable systems may open up new avenues in observing PT -related phenomena with appreciable gain-loss contrast in coherent atomic media.