One-way Einstein–Podolsky–Rosen steering with the aid of the thermal noise in a correlated emission laser

Abstract

We present to use the thermal noise as an effective way to manipulate the direction of Einstein–Podolsky–Rosen (EPR) steering. In particular, a system of three-level cascade laser is under our consideration, in which the atoms are prepared in an initial superposition of the upper excited level and ground level and the cavity modes are damped by the thermal bath. It is found that the thermal noise plays a constructive role in realizing the one-way EPR steering and expanding the parameter region of the steady-state asymmetric steering. In the absence of the thermal noise, two-way steering mainly occurs due to the injected atomic coherence that is quite helpful for entanglement enhancement. Surprisingly, when the thermal noise is involved, the one-way steering substitutes for two-way steering and it can be obtainable in most parameter region. Actually, the thermal noise significantly increases the mean number of the emitted photon pairs and enlarges the intensity difference between two cavity modes, which leads to the striking asymmetry in the mean photon numbers and then induces the unidirectional steerability from the mode generated by the upper transition to the mode in the low transition. The present scheme may provide a resource in a long-distance quantum network for quantum secret sharing protocol.