Deterministic conversion of a thermal state to a quasi-Fock state and the dynamics of number state-multi-atom interactions

Abstract The Fock state is widely regarded as the most nonclassical quantum state of light and has great potential in the areas of quantum computation and quantum sensing. Numerous methods have been proposed to generate Fock states and extremely number-squeezed states, or quasi-Fock states. In order to utilize natural light for quantum technologies, it is necessary to develop methods for transforming classical light into quasi-Fock states. Thus, we demonstrated that through the collective interaction of light and atoms in the Tavis-Cummings model, we can amplify classical light, such as thermal states and coherent states, into quasi-Fock states. To analyze this process, we introduce theoretical tools for studying number state-multi-atom interactions and provide a comprehensive analysis of Tavis-Cummings dynamics, rather than relying on extensions of the Jaynes-Cummings model. Our results reveal that the emergence of nearly sinusoidal emission-absorption oscillations, periodic oscillation of photon number variance, and intrinisic nonlinear effects collectively establilshes the necessary condition for deterministic conversion of classical light into quasi-Fock states.