We investigate theoretically a quantum optomechanical realization of heat engine. In generic arrangement the coupling between cavity field and oscillating end-mirror results in polariton normal mode excitations whose character depends on pump detuning strength. By varying that it is possible to transform their from phonon-like photon-like, so they are predominantly coupled thermal reservoir phonons or photons, respectively. exploit fact effective temperatures these two reservoirs different...

An approach to fast entanglement generation based on Rydberg dephasing of collective excitations (spin-waves) in large, optically thick atomic ensembles is proposed. Long-range $1/r^3$ interactions are induced by microwave mixing opposite-parity states. Required long coherence times achieved via four-photon excitation and read-out wavelength spin-waves. The mechanism shown have favorable, approximately exponential, scaling for generation.

We propose a scheme that exploits the combined effects of nonlinear dynamics and dissipation to generate macroscopic quantum superpositions in massive optomechanical oscillators. The effective degenerate three-wave mixing interaction between mechanical optical cavity modes results from quadratic coupling, together with dissipation, can result existence dark superpositions. show analytically confirm numerically various be achieved deterministically, depending on initial state mechanics....

Coherent interconversion between optical and mechanical excitations in an optomechanical cavity can be used to engineer a quantum heat engine. This engine is based on Otto cycle cold photonic reservoir hot phononic [K. Zhang, F. Bariani, P. Meystre, Phys. Rev. Lett. 112, 150602 (2014)]. Building our previous work, we (i) develop detailed theoretical analysis of the work efficiency (ii) perform investigation thermodynamics underlying this scheme. In particular, analyze thermodynamic...

Because of their low energy content, microwave signals at the single-photon level are extremely challenging to measure. Guided by recent progress in optomechanics and hybrid optomechanical systems, we propose a multimode transducer that can detect intensities significantly below via adiabatic transfer signal optical frequency domain where measurement is then performed. The influence intrinsic quantum thermal fluctuations also discussed.

We investigate a hybrid quantum system consisting of cavity optomechanical device optically coupled to an ultracold gas. show that the dispersive properties gas can be used dramatically modify response mechanical resonator. examine schemes wherein resonator is either motional or spin degrees freedom In case, we find enhancement more than two orders magnitude in cooling due this interaction. Significantly, based on demonstrated parameters for device, identify regimes enable ground-state from...

A design of a quantum force sensor is proposed to achieve coherent noise cancellation (CQNC) by optically coupling mesoscopic mechanical resonator an ensemble ultracold atoms, which has the specific advantage allowing easy experimental realization CQNC reduce noises below standard limit.

We analyze theoretically measurement schemes of the mean output work and its fluctuations in a recently proposed optomechanical quantum heat engine [Zhang et al., Phys. Rev. Lett. 112, 150602 (2014)]. After showing that this can be operationally determined by continuous measurements intracavity photon number, we discuss both dispersive absorptive their back-action effects on efficiency engine. Both are found to reduce engine, but is qualitatively quantitatively different. For decreases as...

We theoretically study the optical properties of a gas ultracold, coherently dressed three-level atoms in Mott insulator phase an lattice. The vacuum state, band dispersion and absorption spectrum polariton field can be controlled real time by varying amplitude frequency dressing beam. In weak regime, system shows unique ultraslow-light propagation without absorption. presence fast modulation amplitude, we predict significant emission photon pairs parametric amplification polaritonic...

Conditions to achieve an unusually strong Rydberg spin-exchange interaction are investigated and proposed as a means generate pairwise entanglement realize swap-like quantum gate for neutral atoms. Ground-state is created by mapping entangled states ground using optical techniques. A protocol involving swap-gate operations predicted create global of chain $N$ atoms in time that independent $N$.

Rydberg spin-waves are optically excited in a quasi-one-dimensional atomic sample of Rb atoms. Pairwise spin-wave correlations observed by spatially selective transfer the quantum state onto light field and photoelectric correlation measurements light. The interpreted terms dephasing multiply long-range interactions.

We propose and analyze theoretically a cavity optomechanical analog of heat pump that uses polariton fluid to cool mechanical modes coupled single pre-cooled phonon mode via external modulation the substrate resonator. This approach permits arbitrary frequencies not limited by cavity-optical field detuning deep into quantum regime from room temperature.

A theory of Rydberg atom interactions is used to derive analytical forms for the spin wave pair correlation function in laser-excited cold-atom vapors. This controls quantum statistics light emission from dense, inhomogeneous clouds cold atoms various spatial dimensionalities. The results yield distinctive scaling behaviors on microsecond timescale, including generalized exponential decay. detailed comparison presented with a recent experiment cigar-shaped atomic ensemble [Y. Dudin and A....

We investigate a hybrid electromechanical system consisting of pair charged macroscopic mechanical oscillators coupled to small ensemble Rydberg atoms. The resonant dipole-dipole coupling between an internal atomic transition and the mechanics allows cooling its motional ground state with single atom despite considerable mass imbalance two subsystems. show that rich electronic spectrum atoms, combined their high degree optical control, paves way towards implementing various quantum-control...

The emission of light from a multiply excited atomic ensemble is examined and it shown how symmetric (spin-wave) nonsymmetric states excitation radiate into spatially separate field modes. This observation has potential application to single-photon generation spin-wave entanglement, since in the presence interactions can result isolated phase-matched mode.

We study radiation-matter interaction in a system of ultracold atoms trapped an optical lattice Mott insulator phase. develop fully general quantum model, and we perform calculations for one-dimensional geometry at normal incidence. Both two- three-level $Λ$ atomic configurations are studied. The polariton dispersion the reflectivity spectra characterized different regimes, both semi-infinite finite-size geometries. apply this model to propose photon energy lifter experiment: device which is...

We investigate hybrid optomechanical schemes involving cold atoms to improve cooling in the Doppler regime. focus on two specific examples of tunable three-level configurations: Electromagnetically Induced Transparency and Recoil Resonances.

We present a theoretical study of the dynamics light pulse propagating through multilayer system consisting alternating blocks electromagnetically induced transparency (EIT) media and vacuum. effect dynamical modulation EIT control field on shape wave packet. Interesting effects due to group velocity mismatch at interfaces are found. Modulation schemes that can be realized in ultracold atomic samples with standard experimental techniques proposed discussed. Calculations performed using...

We propose a scheme to prepare macroscopic quantum superpositions of motion in optomachanical nano- or micromechanical oscillators quadratically coupled an intracavity field. The nonlinear optomechanical coupling leads effective degenerate three-wave mixing interaction between the mechanical and cavity modes. result from combined effects dissipation. show analytically confirm numerically that various deterministic can be achieved, depending on initial state. effect damping is also studied...