More nonlocality with less entanglement in a tripartite atom-optomechanical system

Abstract

We study quantum effects in hybrid atomic optomechanics in a system comprising a cloud of atoms and a mobile mirror mediated by a single-mode cavity. Tripartite nonlocality is observed in the atom-light-mirror system, as demonstrated by the violation of the Mermin-Klyshko (MK) inequality. It has been shown [C. Genes, et al., PRA 77, 050307 (R) (2008)] that tripartite entanglement is optimized when the cavity is resonant with the anti-Stokes sideband of the driving laser and the atomic frequency matches the Stokes one. However, we show that this is not the case for the nonlocality. The MK function achieves {\it minima} when the atoms are resonant with both the Stokes and anti-Stokes sidebands, and unexpectedly, we find violation of the MK inequality only in a parameter region where entanglement is far from being maximum. A negative relation exists between nonlocality and entanglement with consideration of the possibility of bipartite nonlocality in the violation of the MK inequality. We also study the non-classicality of the mirror by post-selected measurements, e.g. Geiger-like detection, on the cavity and/or the atoms. We show that with feasible parameters Geiger-like detection on the atoms can effectively induce mechanical non-classicality.

7 pages, 3 figures. Accepted for publication in the special issue "Quantum and Hybrid Mechanical Systems - From Fundamentals to Applications" in Annalen der Physik

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Cited by in corpus (10)

• Magnon-photon-phonon entanglement in cavity magnomechanics
• Perfect Transfer of enhanced entanglement and asymmetric steering in a cavity magnomechanical system
• Non-classical state generation in macroscopic systems via hybrid discrete-continuous quantum measurements
• Probing of nonlinear hybrid optomechanical systems via partial accessibility
• Enhanced entanglement of two optical modes in optomechanical systems via an optical parametric amplifier
• Einstein-Podolsky-Rosen steering and Bell nonlocality of two macroscopic mechanical oscillators in optomechanical systems
• Engineering single-phonon number states of a mechanical oscillator via photon subtraction
• Enhancing squeezing and nonclassicality of light in atom-optomechanical systems
• Enhancing the quantum entanglement and EPR steering of a coupled optomechanical system with a squeezed vacuum field
• Genuine multipartite nonlocality of permutationally invariant Gaussian states