Enhanced CV Entanglement Quantification in a CEL with Parametric Amplifier and Coupled to Squeezed Vacuum

Abstract

Externally induced entanglement amplification in a coherently pumped correlated emission laser (CEL) with parametric amplifier and coupled to a two-mode squeezed vacuum reservoir is presented. The combination of the master equation and stochastic differential equation is employed to investigate the entanglement of the two-mode light generated by the quantum system. The resulting solutions of the correlation properties of noise forces associated with the normal ordering are used to find the mean photon number of the cross-correlated mode and separate cavity modes, quadrature fluctuations, smallest eigenvalue of the symplectic matrix, and photon number correlation function. It is found that pumping atoms from the lower energy state to excited state results in a robust entanglement that remains in its maximum strength over a wide range of the strong classical driving radiation. The introduction of the nonlinear crystal into the linear cavity, and coupling the system to the two-mode squeezed vacuum environment lead to a significant enhancement of entanglement of the cavity light. The enhanced entanglement is quantified employing logarithmic negativity, Cauchy-Schwarz inequality, and Duan et al. criteria. It has been observed that an intense light can be produced where the entanglement is strong.

Quantum Langevin approach for superradiant nanolasers

“…( 42) and n A (N ) from Eq. ( 43) into the energy conservation law (52). By solving the latter equation, we can determine the population inversion N .…”

“…Quadratures of the polarization have been used in Lamb's semiclassical laser theory [30], while quadratures of the electromagnetic field were used, for example, in the analysis of the driven Van der Pol oscillator applied to lasers in [36] and in quantum optics to squeezed states of the radiation field [50]. Symmetric and anti-symmetric combinations of the quadratures of a quantum field are also used in entanglement criteria [51,52]. Our work is an extension since, to our knowledge, quadratures as well as their S/A combinations for both the lasing field and polarization combined have not been used in laser theory before.…”