Quantum Squeezing and Entanglement in Continuously‐Monitored Generalized Dicke Model with Single‐Emitter's Decay

ABSTRACT In this paper, we investigate steady‐state quantum squeezing and entanglement in a generalized Dicke model, which features Jaynes–Cummings (JC) and anti–Jaynes–Cummings (AJC) interactions with different strengths, by taking into account of single‐atom spontaneous emission and continuous homodyne detection of the cavity field. We find that a reduction in the strength of the AJC interaction can lead to atomic squeezing, which is otherwise absent when the strengths of the two interactions are equal. Likewise, cavity‐field squeezing and atom‐field entanglement can be enhanced as the strength of the AJC interaction is reduced. Furthermore, continuous measurement is shown to significantly enhance both the squeezing and entanglement in both normal and superradiant phases. In addition, it is revealed that under certain conditions, single‐atom spontaneous emission can also improve the squeezing and entanglement. Our results reveal distinctive characteristics of quantum correlations in the open Dicke model and suggest a promising route for realizing robust nonclassical states in such systems.