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Joy Ghosh

Publications and source records attributed to Joy Ghosh.

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Tripartite Entanglement Generation in Atom-Coupled Dual Microresonators System

In this work, we investigate the emergence and control of genuine tripartite entanglement in a hybrid cavity quantum electrodynamics architecture consisting of two linearly coupled single mode resonators, one of which interacts coherently with a two level atom. An analytical framework is developed in a weak driving regime, where the system dynamically supports a delocalized hybrid excitation shared by the two photonic modes and the atomic degree of freedom. Tripartite concurrence fill has been used to characterize and identify parameter regimes of maximal multipartite quantum correlation that can be generated in this model. Additionally, we demonstrate how dissipative rates and detuning asymmetries govern the conversion of bipartite entanglement into a genuinely tripartite state, establishing a controllable transition from localized Jaynes Cummings correlations to delocalized photonic atomic entanglement networks. These findings outline a clear route to engineering steady state multipartite quantum resources in coupled cavity QED platforms, with direct relevance to quantum networking, distributed quantum information processing, and photonic state routing in scalable quantum architectures.

quant-ph

Cauchy-Schwarz and Bell Inequality Violations in Coupled Optomechanical Systems

Destructive interference-based photon-phonon antibunching can lead to violations of classical inequalities in optomechanical cavity systems. In this paper, we explore the violation of the classical Cauchy-Schwarz inequality by examining second-order auto-correlation and cross-correlation functions, as well as Bell's nonlocality, to analyze the quantum correlations of single photon-phonon excitations when the system is driven by two weak probe fields. We propose that the violation of the Cauchy-Schwarz inequality can serve as an indicator for the stronger nonclassical tests associated with Bell's theorem. Our system reveals strong quantum correlations of photon-phonon pairs with distinctive antidiagonal patterns of photon filtering. For numerical analysis, we consider a weak effective optomechanical coupling strength and various optical-to-mechanical field amplitude ratios that enable unconventional photon (phonon) blockades at resonance. The findings are significant for producing sub-Poissonian signals under optimal conditions and have potential applications in hybrid systems for generating on-demand single photon-phonon pairs.

quant-ph

Exceptional point induced quantum phase synchronization and entanglement dynamics in mechanically coupled gain-loss oscillators

The optomechanical cavity (OMC) system has been a paradigm in the manifestation of continuous variable quantum information over the past decade. This paper investigates how quantum phase synchronization relates to bipartite Gaussian entanglement in coupled gain-loss mechanical oscillators, where the gain and loss rates are engineered by driving the cavity with blue and red detuned lasers, respectively. We examine the role of exceptional point in a deterministic way of producing self-sustained oscillations that induce robust quantum correlations among quadrature fluctuations of the oscillators. Particularly, steady phase synchronization dynamics along with the entanglement phenomena are observed in the effective weak coupling regime above a critical driving power. These phenomena are further verified by observing the mechanical squeezing and phase space rotations of the Wigner distributions. Additionally, we discuss how the oscillators frequency mismatches and decoherence due to thermal phonons impact the system dynamics. These findings hold promise for applications in phonon-based quantum communication and information processing.

quant-ph