Quantum optomechanics with a mixture of ultracold atoms

Abstract

We study cavity optomechanics of a mixture of ultracold atoms with tunable nonlinear collisions. We show that atomic collisions provide linear couplings between fictitious condensate oscillators, leading to possibilities of achieving a globally coupled quantum optomechanical network with an integrated atom chip. Potential applications range from simulating collective nonequilibrium dynamics in fields well past physics to probing unique properties of quantum mixtures.PACS numbers: 03.75.Pp, 03.70.+k Recent years have witnessed rapid advances in the field of cavity optomechanics [1][2][3]. These advances have lead to striking demonstrations of quantum effects in mechanical objects at the mesoscale (single or two independent oscillators) [4], and opened up exciting new possibilities in developing integrated phononic circuits or coherent acoustic analogs of quantum nonlinear optics. Very recently, Lin et al . experimentally realized a direct mechanical coupling between two nano-oscillators and firstly observed remarkable effects of coherent mechanical wave mixing [5]. By establishing nearest-neighbor couplings in an optomechanical array [6], one can even synchronize vibrations of all elements [7]. For current nano-fabrication techniques, however, it remains a challenge to make a globally coupled optomechanical network, which has applications in simulating numerous important situations well past physics [8].In parallel to the approach to cavity optomechanics that relies on the advanced materials and processing techniques of the semiconductor industry and nanoscience, an alternative approach relies on the realization of optomechanics where momentum sideband or particle-hole excitations of an atomic Bose-Einstein condensate (BEC) [9][10][11] or a degenerate Fermi gas [12] play the role of the mechanical oscillator. In view of rapid advances in making and manipulating an ultracold mixture of two or more superfluids [13-18], here we probe the realization of multimode quantum acoustics [19], with linear mechanical couplings between the "BEC mirrors" arising from two-body atomic collisions. In contrast to the recently proposed nano-fabricated arrays with only nearest-neighbor couplings [7], our cold-atom system presents an interesting example of how to generate a multi-component quantum network with global couplings between different "mirror" modes.We consider a cigar-shaped n-component BEC trapped in an optical Fabry-Pérot cavity of length L, with the soft trapping direction parallel to the cavity axis z (see Fig. 1). We further assume that the trapping strength perpendicular to the cavity axis is sufficient to allow us to treat the system as quasi-1D, and to only consider excitations along the cavity axis [18]. Within the dipole and rotating-wave approximations, the atomic part of Hamil-

Optomechanical analog of two-color electromagnetically induced transparency: Photon transmission through an optomechanical device with a two-level system

“…It was also found that the EIT in a three-level atomic ensemble, interacting with a cavity field of an optomechanical system, can be significantly changed by an oscillating mirror [67]. Furthermore, the optomechanical coupling was studied in a system where a singlemode cavity field is coupled to an antiferromagnetic BoseEinstein condensate [68,69], where the mechanical element is provided by spin-wave excitations. It has also been theoretically shown that an optomechanical analogue of EIT can be controlled by a tunable superconducting qubit [70] or a twolevel atom [71,72], which is coupled to a cavity.…”

Mechanically modulated emission spectra and blockade of polaritons in a hybrid semiconductor-optomechanical system

“…( 40) for the resonant case ω c = ω ex are shown in red-dotted curves, while the energy structures with the numerically exact diagonalization of the Hamiltonian in Eq. (11) for each polariton subspace are shown in black-solid curves. The coincidence between the theoretical method and numerical one shows the validity of GRWA in the regime we are working with.…”

“…Various materials are used to construct optomechanical systems in order to increase or control optomechnaical coupling, but the detailed properties of the materials themselves are usually less considered. For example, there are studies that optomechanical systems are coupled to either two-level or other systems via either cavity fields [7][8][9][10][11] or mechanical resonators [12][13][14][15]. However, material properties of cavities and mechanical resonators in these studies are not studied.…”

Entangled-state engineering of vibrational modes in a multimembrane optomechanical system

“…The stationary entanglement between mechanical and cavity modes in the * yuxiliu@tsinghua.edu.cn optomechanical systems has been studied [35][36][37][38][39], and such continuous variable entanglement can be used to implement quantum teleportation [40][41][42]. Also both tripartite and bipartite entanglement between mechanical modes and other degrees of freedom can be generated in the optomechanical systems [43][44][45][46][47][48][49] or the hybrid optomechanical systems with an atomic ensemble [50][51][52][53][54][55][56][57][58][59] or a single-atom [60,61] inside the cavity. Moreover, the cavity field mediated entanglement between two macroscopic mechanical resonators in the steady state [62][63][64][65][66][67][68][69][70][71][72] has also been theoretically explored.…”