Fidelity matters: the birth of entanglement in the interference of Gaussian states

Abstract

We address the interaction of two Gaussian states interferring at a beam splitter and analyze the correlations exhibited by the resulting bipartite system. We demonstrate that nonlocal correlations (entanglement) arise if and only if the fidelity between the two input Gaussian states falls under a threshold value depending only on their purities and on the transmissivity of the beam splitter. Our result clarifies the role of squeezing as a prerequisite for entanglement and provide a tool to optimize the generation of entanglement by passive devices.

4 pages, 2 figures; revised version accepted for publication in Phys. Rev. Lett

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• Collapse and revival of quantum coherence for a harmonic oscillator interacting with a classical fluctuating environment
• Non-Gaussian quantum discord for Gaussian states
• Continuous-variable entanglement distillation and non-commutative central limit theorems
• Single- and two-mode quantumness at a beam splitter
• Observation of Anticorrelation with Classical Light in a Linear Optical System
• Almost local generation of EPR entanglement in non-equilibrium
• Quantum backflow effect and nonclassicality
• Exceptional point induced quantum phase synchronization and entanglement dynamics in mechanically coupled gain-loss oscillators
• Accessible precisions for estimating two conjugate parameters using Gaussian probes
• Maximum entanglement of formation for a two-mode Gaussian state over passive operations
• Experimental pre-assessing entanglement in Gaussian states mixing
• Entanglement generation through local field and quantum dissipation