Gain-assisted superluminal light propagation through a Bose-Einstein condensate cavity system

TL;DR

This paper demonstrates gain-assisted superluminal light propagation in a Bose-Einstein condensate cavity system, showing controllable group velocity and amplification without population inversion, a phenomenon not observed in traditional two-level atomic systems.

Contribution

It introduces a novel mechanism for superluminal light in BEC cavity systems via cross-Kerr nonlinearity, distinct from conventional atomic systems.

Findings

Superluminal propagation controlled by pump Rabi frequency.

Gain-assisted superluminal light without population inversion.

Effect of cavity decay rate on phase dispersion slope.

Abstract

The propagation of a probe laser field in a cavity optomechanical system with a Bose-Einstein condensate is studied. The transmission properties of the system are investigated and it is shown that the group velocity of the probe pulse field can be controlled by Rabi frequency of the pump laser field. The effect of the decay rate of the cavity photons on the group velocity is studied and it is demonstrated that for small values of the decay rates, the slope of phase dispersion switches from positive to negative just by changing the Rabi frequency of the pump field. Then, the gain-assisted superluminal light propagation due to the cross-Kerr nonlinearity is established in cavity optomechanical system with a Bose-Einstein condensate. Such behavior can not appear in the pump-probe two-level atomic systems in the normal phase. We also find that the amplification is achieved without inversion in the population of the quantum energy levels.