Continuous-variable quantum steering in a Raman-driven quantum beat laser

In this work, we investigate continuous-variable (CV) quantum steering in a genuine bimodal active Raman-driven quantum beat laser (RDQBL) system. The lasing medium of the system is coupled to two external classical fields in Raman configuration and to two quantized cavity modes, the latter being initially prepared in arbitrary single-mode Gaussian states. Using the reduced density matrix of the evolved cavity modes, we derive and solve the dynamical equations analytically and numerically. We analyze the time evolution and strength of quantum steering in the two-mode Gaussian states against various system parameters, for instance, the intensity and relative phase of the classical Raman fields, the cavity decay rates, and the non-classicality and purity of the input cavity modes. Our results show that the cavity modes exhibit robust, tunable steerability across a wide range of parameters. We further demonstrate the intrinsic asymmetry of quantum steering, that is, an imbalance in the non-classicality of input modes ( τ 1 ≠ τ 2 ) leads to one-way directional steering. These findings establish the RDQBL system as a promising platform for controllable CV quantum steering with potential applications in secure quantum communication, quantum key distribution (QKD), quantum metrology, and asymmetric quantum networks.