Interaction of a cavity mode with coherent light in a closed cavity coupled to thermal reservoir

Shambel Derso

Published Jun 25, 2026• 0 citations

Abstract

In this thesis, we investigate the quantum optical properties of a single cavity mode interacting with an external classical coherent driving field inside a closed cavity, which is coupled to a thermal reservoir via a single-port mirror. We establish a mathematically comprehensive framework utilizing both the Master Equation under the density operator formalism and the Quantum Langevin Equation under the Heisenberg picture. By analyzing the system with an arbitrary ordering of reservoir noise operators, we derive the steady-state P-representation of the quasi-probability distribution. Employing this quasi-probability distribution, we analytically compute the mean photon number, photon number variance, photon number distribution, and the second-order intensity correlation function. Our findings establish that the interaction of the cavity mode with the coherent drive in the presence of thermal fluctuations exhibits strictly super-Poissonian statistics. The mean photon number and photon number variance scale monotonically with both the strength of the external coherent drive and the average thermal photon occupation of the reservoir. Furthermore, we prove that the produced cavity field does not exhibit quadrature squeezing, confirming that the presence of thermal noise effectively destroys quantum squeezing in this configuration. Finally, the input-output is evaluated to verify the preservation of the commutation relations of the formalism output field. Keywords: Quantum Optics, Master Equation, Fokker-Planck, Quantum Langevin Equation, P- function, Photon Statistics, Super-Poissonian, Squeezing.

DOI: 10.20372/nadre:25219

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