Entanglement of two hybrid optomechanical cavities composed of BEC atoms under Bell detection

Eghbali-Arani, Mohammad; Ameri, Vahid

doi:10.1007/s11128-016-1511-9

Cited by 8 publications

(8 citation statements)

References 30 publications

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“…This generates a strong atom-membrane entanglement close to the critical point. This behavior is manifest in a rising logarithmic negativity E N [43][44][45] at the critical point which is shown in Fig. 3(a).…”

Section: Collective Excitation Modesmentioning

confidence: 89%

Nonequilibrium Quantum Phase Transition in a Hybrid Atom-Optomechanical System

et al. 2018

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We consider a hybrid quantum many-body system formed by a vibrational mode of a nanomembrane, which interacts optomechanically with light in a cavity, and an ultracold atom gas in the optical lattice of the out-coupled light. The adiabatic elimination of the light field yields an effective Hamiltonian which reveals a competition between the force localizing the atoms and the membrane displacement. At a critical atom-membrane interaction, we find a nonequilibrium quantum phase transition from a localized symmetric state of the atom cloud to a shifted symmetry-broken state, the energy of the lowest collective excitation vanishes, and a strong atom-membrane entanglement arises. The effect occurs when the atoms and the membrane are non-resonantly coupled.Hybrid quantum systems combine complementary fields of physics, such as solid-state physics, quantum optics and atom physics, in one set-up. Recently, a hybrid atom-optomechanical system [1] has been realized experimentally [2] in which a single mechanical mode of a nanomembrane in an optical cavity is optically coupled to a far distant cloud of cold 87 Rb atoms residing in the optical potential of the out-coupled standing wave of the cavity light. When displaced, the membrane experiences the radiation pressure force of the cavity light, and in the bad-cavity limit, the field follows the membrane displacement adiabatically. This modulates the light phase which leads to a shaking of the atom gas in the lattice. The nanomechanical motion of the membrane then couples non-resonantly to the collective motion of the atoms. The aim is twofold [1][2][3][4][5][6][7]: The gas can cool the nanomembrane, and, emergent phenomena of the correlated quantum many-body system are of interest [8][9][10][11][12][13][14][15][16][17].State-of-the-art optomechanics [3-6] is nowadays able to realize optical feedback cooling [18,19] of the mechanical oscillator to its quantum-mechanical ground state [20,21]. Yet, the resolved sideband limit allows ground-state cooling only if the oscillator frequency exceeds the photon loss rate in the cavity [22][23][24]. Hence, cooling a macroscopic low-frequency nanomembrane close to its ground state is so far not possible. One promising alternative [1,7] is to utilize an ultracold atom gas, which has been demonstrated recently [2] by sympathetic cooling down to 650 mK. Current investigations aim to a coherent state transfer of robust quantum entanglement [15].Apart from cooling the nanomembrane, an interesting fundamental feature is the collective quantum-many body behavior of the hybrid system. For instance, the atom-atom interaction can in principle be coherently modulated by the back-action of the cavity light on the nanooscillator. By this, a long-range interaction emerges which resembles that of a dipolar Bose-Einstein condensate (BEC) [25]. In fact, a simpler hybrid quantum many-body system has also been implemented in the form of a BEC in an optical lattice inside a transversely pumped optical cavity. A Dicke quantum phase transition between a n...

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Section: Collective Excitation Modesmentioning

confidence: 89%

Nonequilibrium Quantum Phase Transition in a Hybrid Atom-Optomechanical System

et al. 2018

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“…From the set of equations (51)-(53), we find the equation of motion for the vector of the collective modes d d d d d d d , , , , , In order to determine the atom-membrane entanglement in the steady-state regime, we solve the Bogoliubov-de Gennes equation (57) in the long-time limit t  ¥. A possible measure to quantify the quantum entanglement between two different bare modes is the logarithmic negativity E  [36][37][38][39], which is evaluated from the reduced covariance matrix C x x xx 2 kl k l l k = á + ñˆˆˆ. Here, we adopted the shorthand notation x q q q p p p , , , , , t = a g s a g ŝ (ˆˆˆˆˆˆ) with the quadratures q…”

Section: Advantages Over Motional Coupling and Tuning Of The Asymmetrmentioning

confidence: 99%

Tuning the order of the nonequilibrium quantum phase transition in a hybrid atom-optomechanical system

2019

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We show that a hybrid atom-optomechanical quantum many-body system with two internal atom states undergoes both firstand second-order nonequilibrium quantum phase transitions (NQPTs). A nanomembrane is placed in a pumped optical cavity, whose outcoupled light forms a lattice for an ultracold Bose gas. By changing the pump strength, the effective membrane-atom coupling can be tuned. Above a critical intensity, a symmetry-broken phase emerges which is characterized by a sizeable occupation of the high-energy internal states and a displaced membrane. The order of this NQPT can be changed by tuning the transition frequency. For a symmetric coupling, the transition is continuous below a certain transition frequency and discontinuous above. For an asymmetric coupling, a first-order phase transition occurs.

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“…In this way, many theoretical [38][39][40] as well as experimental [41][42][43] analyzes have been performed in this line of research. Recently, some particular features of such systems have been discussed in [44][45][46]. The possible potential application of optomechanical system has been proposed in [47].…”

Section: Introductionmentioning

confidence: 99%

Quantum repeater protocol using an arrangement of QED–optomechanical hybrid systems

Ghasemi

Tavassoly

2019

J. Opt. Soc. Am. B

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In this paper we consider the quantum repeater protocol for distributing the entanglement to two distant three-level atoms. In this protocol, we insert six atoms between two target atoms such that the eight considered atoms are labeled by 1, 2, • • • 8, while only each two adjacent atoms (i, i + 1) with i = 1, 3, 5, 7 are entangled. Initially, the separable atomic pair states (1,4) and (5,8) become entangled by performing interaction between atoms (2,3) and (6,7) in two optomechanical cavities, respectively. Then, via performing appropriate interaction between atoms (4,5) in an optical cavity quantum electrodynamics (QED) approach, the target atoms (1,8) are finally become entangled. Throughout this investigation, the effects of mechanical frequency and optomechanical coupling strength to the field modes on the produced entanglement and the related success probability are evaluated. It is shown that, the time period of produced entanglement can be developed by increasing the mechanical frequency. Also, maximum of success probability of atoms (1,8) is increased by decreasing the optomechanical coupling strength to the field modes in most cases.

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Entanglement of two hybrid optomechanical cavities composed of BEC atoms under Bell detection

Cited by 8 publications

References 30 publications

Nonequilibrium Quantum Phase Transition in a Hybrid Atom-Optomechanical System

Nonequilibrium Quantum Phase Transition in a Hybrid Atom-Optomechanical System

Tuning the order of the nonequilibrium quantum phase transition in a hybrid atom-optomechanical system

Quantum repeater protocol using an arrangement of QED–optomechanical hybrid systems

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