Speaker
Description
Nonclassical correlations between different bosonic modes constitute one of the key signatures of quantum behavior in hybrid quantum systems and play an important role in quantum information processing, quantum communication, and quantum sensing. In particular, inter-mode quantum correlations provide valuable insight into the transfer and redistribution of quantum excitations in coupled light--matter systems.
In this work, we investigate a driven quantum system consisting of a superconducting microwave resonator capacitively coupled to a quantum micromechanical resonator and interacting with a two-level atom. To describe the coupled dynamics, we introduce a hybrid photon-phonon supermode by applying a balanced linear transformation to the photonic and phononic fields. This representation enables a direct comparison of the quantum statistical properties of the photonic, phononic, and hybrid excitations.
To characterize the correlations between different modes, we evaluate the second-order two-mode correlation functions $g^{(2)}_{ab}(0)$, $g^{(2)}_{ac}(0)$, and $g^{(2)}_{bc}(0)$. In addition, we calculate the corresponding two-mode principal squeeze variances and perform a comparative analysis of the correlation properties in all mode pairs. Particular attention is devoted to the influence of hybridization on the emergence of nonclassical inter-mode correlations and quantum noise reduction.
Our results demonstrate that the hybrid mode modifies the quantum statistical behavior of the system, leading to enhanced nonclassical correlations and stronger two-mode squeezing over extended parameter regions compared with the purely photonic and phononic modes. These findings provide further insight into the role of hybrid photon--phonon excitations in engineering multimode quantum states and may be relevant for future applications in quantum information processing and quantum metrology.
Keywords: second-order two-mode correlation functions, two-mode principal squeezing, hybrid photon-phonon modes, nonclassical states.