Quantum correlations in optomechanical crystals (original) (raw)

Probing Quantum Correlations in a Hybrid Optomechanical System

International Journal of Theoretical Physics

Refining coherence is a central challenge in quantum simulations and experiments on optomechanical cavities. Here we suggest a scheme of two coupled optomechanical cavities to enhance the intracavity entanglement. The couplings are established between the optical modes through a photon hopping process and between the mechanical resonators by the phonon tunneling process. Both cavities are driven by classical light. The generated quantum correlations inside each cavity are explored in terms of strength couplings with two different quantum measures, namely, logarithmic negativity and quantum steering. These will allow us to analyze the various aspects of these quantum measures and see the interest in their applications. Also, the stability conditions are examined in terms of the coupling strengths. Consequently, it is shown that the intracavity-entanglement degree can be quantified, and it is found that the generated entanglement can be improved with an appropriate choice of the photon and phonon hopping strengths. The calculations were performed within the recent experimentally accessible parameters.

Quantum Effects in Optomechanical Systems

Advances in Atomic, Molecular, and Optical Physics, Vol 57, 2009

The search for experimental demonstrations of the quantum behavior of macroscopic mechanical resonators is a fastly growing field of investigation and recent results suggest that the generation of quantum states of resonators with a mass at the microgram scale is within reach. In this chapter we give an overview of two important topics within this research field: cooling to the motional ground state, and the generation of entanglement involving mechanical, optical and atomic degrees of freedom. We focus on optomechanical systems where the resonator is coupled to one or more driven cavity modes by the radiation pressure interaction. We show that robust stationary entanglement between the mechanical resonator and the output fields of the cavity can be generated, and that this entanglement can be transferred to atomic ensembles placed within the cavity. These results show that optomechanical devices are interesting candidates for the realization of quantum memories and interfaces for continuous variable quantum communication networks.

Multimode circuit optomechanics near the quantum limit

Nature Communications, 2012

The coupling of distinct systems underlies nearly all physical phenomena. A basic instance is that of interacting harmonic oscillators, giving rise to, for example, the phonon eigenmodes in a lattice. Of particular importance are the interactions in hybrid quantum systems, which can combine the benefits of each part in quantum technologies. Here we investigate a hybrid optomechanical system having three degrees of freedom, consisting of a microwave cavity and two micromechanical beams with closely spaced frequencies around 32 MHz and no direct interaction. We record the first evidence of tripartite optomechanical mixing, implying that the eigenmodes are combinations of one photonic and two phononic modes. We identify an asymmetric dark mode having a long lifetime. Simultaneously, we operate the nearly macroscopic mechanical modes close to the motional quantum ground state, down to 1.8 thermal quanta, achieved by back-action cooling. These results constitute an important advance towards engineering of entangled motional states.

Strong coupling and long-range collective interactions in optomechanical arrays

Arxiv preprint arXiv:1202.6210, 2012

We investigate the collective optomechanics of an ensemble of scatterers inside a Fabry-Pérot resonator and identify an optimized configuration where the ensemble is transmissive, in contrast with the usual reflective optomechanics approach. In this configuration, the optomechanical coupling of a specific collective mechanical mode can be several orders of magnitude larger than the singleelement case, and long-range interactions can be generated between the different elements since light permeates throughout the array. This new regime should realistically allow for achieving strong single-photon optomechanical coupling with massive resonators, realizing hybrid quantum interfaces, and exploiting collective long-range interactions in arrays of atoms or mechanical oscillators. arXiv:1202.6210v2 [quant-ph]

Quantum information at the interface of light with atomic ensembles and micromechanical oscillators

Quantum Information Processing, 2011

This article reviews recent research towards a universal light-matter interface. Such an interface is an important prerequisite for long distance quantum communication, entanglement assisted sensing and measurement, as well as for scalable photonic quantum computation. We review the developments in light-matter interfaces based on room temperature atomic vapors interacting with propagating pulses via the Faraday effect. This interaction has long been used as a tool for quantum nondemolition detections of atomic spins via light. It was discovered recently that this type of light-matter interaction can actually be tuned to realize more general dynamics, enabling better performance of the light-matter interface as well as rendering tasks possible, which were before thought to be impractical. This includes the realization of improved entanglement assisted and backaction evading magnetometry approaching the Quantum Cramer-Rao limit, quantum memory for squeezed states of light and the dissipative generation of entanglement. A separate, but related, experiment on entanglement assisted cold atom clock showing the Heisenberg scaling of precision is described. We also review a possible interface between collective atomic spins with nano-or micromechanical oscillators, providing a link between atomic and solid state physics approaches towards quantum information processing.

Unconventional phonon blockade via atom-photon-phonon interaction in hybrid optomechanical systems

Optics Express, 2022

Phonon nonlinearities play an important role in hybrid quantum networks and on-chip quantum devices. We investigate the phonon statistics of a mechanical oscillator in hybrid systems composed of an atom and one or two standard optomechanical cavities. An efficiently enhanced atom-phonon interaction can be derived via a tripartite atom-photon-phonon interaction, where the atom-photon coupling depends on the mechanical displacement without practically changing a cavity frequency. This novel mechanism of optomechanical interactions, as predicted recently by Cotrufo et al. [Phys. Rev. Lett. 118, 133603 (2017)10.1103/PhysRevLett.118.133603], is fundamentally different from standard ones. In the enhanced atom-phonon coupling, the strong phonon nonlinearity at a single-excitation level is obtained in the originally weak-coupling regime, which leads to the appearance of phonon blockade. Moreover, the optimal parameter regimes are presented both for the cases of one and two cavities. We comp...

Distributing fully optomechanical quantum correlations

Physical Review A, 2011

We present a scheme to prepare quantum correlated states of two mechanical systems based on the pouring of pre-available all-optical entanglement into the state of two micro-mirrors belonging to remote and noninteracting optomechanical cavities. We show that, under realistic experimental conditions, the protocol allows for the preparation of a genuine quantum state of a composite mesoscopic system whose non-classical features extend beyond the occurrence of entanglement. We finally discuss a way to access such mechanical correlations.