Photon Statistics of Cavity Modes with Atom and Nonlinear Crystal Coupled To Squeezed Vacuum Reservoirs

Abebe Yeshaw, Misrak Getahun

Abebe Yeshaw, Misrak Getahun

We examine the cavity modes with a nonlinear crystal and a lambda-type three-level atom coupled to the squeezed vacuum reservoir. The expectation values of the cavity and atomic variables at steady state have been used to determine quadrature variances and logarithmic negativity. The cavity modes exhibit quadrature squeezing and entanglement according to the criteria. The existence of a nonlinear crystal in the cavity and squeezed vacuum reservoir coupling the cavity modes increases the degree of squeezing and entanglement. The coupling constant for atom and cavity modes reduces both the degree of squeezing and entanglement. Furthermore, Duan et al. and logarithmic negativity criteria for entanglement are directly proportional to the variance of the minus quadrature.

Perry R. Rice, Chris Baird

Prem Kumar, Jianming Huang

Adagn Addisu Dabulo, Misrak Getahun

Abstract We investigate the steady-state photon statistics and quantum properties of a cascade three-level atom coupled to a two-mode squeezed-vacuum reservoir. The mean photon number, photon-number correlations, second-order coherence, and quadrature fluctuations are examined as functions of the stimulated-emission decay constant and the squeezing parameter. The system exhibits two distinct regimes: a squeezing-dominated regime, governed by reservoir-induced correlations, and a cavity-dynamics-dominated regime, characterized by strong gain–loss competition. Enhanced squeezing increases photon generation, intermodal correlations, and intracavity energy through correlated photon-pair injection while reducing vacuum fluctuations. Conversely, stronger stimulated emission induces nonlinear amplification, asymmetric photon distributions, and sequential emission dynamics. A transition from super-Poissonian to sub-Poissonian statistics is observed, indicating the coexistence of photon antibunching and continuous-variable quantum correlations. Furthermore, atom–cavity interactions modify the generalized uncertainty bounds, revealing fundamental limitations on achievable squeezing imposed by higher-order noise processes. These findings demonstrate that engineered reservoirs and cascade atomic systems provide versatile control of nonclassical light for quantum communication, precision metrology, and continuousvariable quantum information processing.

Chimdessa Gashu Feyisa

The quantum and statistical properties of light generated by an external classical field in a correlated emission laser with a parametric amplifier and coupled to a squeezed vacuum reservoir are investigated using the combination of the master and stochastic differential equations. First, the solutions of the cavity-mode variables and correlation properties of noise forces associated to the normal ordering are obtained. Next, applying the resulting solutions, the mean photon number of the separate cavity modes and their crosscorrelation, smallest eigenvalue of the symplectic matrix, mean photon number, intensity difference fluctuation, photon number variance, and intensity correlation are derived for the cavity-mode radiation. The entanglement produced is studied employing the logarithmic negativity criterion. It is found that pumping atoms from the lower energy state to excited state, introducing the nonlinear crystal into the cavity and coupling the system to a biased noise fluctuation, generate a bright and strong squeezing and entanglement with enhanced statistical properties although the atoms are initially in the ground state.