Multimode mean-field model for the quantum phase transition of a Bose-Einstein condensate in an optical resonator

Kónya, G.; Szirmai, G.; Domokos, P.

doi:10.1140/epjd/e2011-20050-3

Cited by 24 publications

(46 citation statements)

References 42 publications

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“…where we have assumed the optical field mean value, α, to be a real number [24] and γ c is the dissipation of the collective density excitations of the BEC and ∆ = δ c − ξq s + ζQ s is the effective detuning. The dynamics of the quantum fluctuations can be described by the linearized QLEs which can be written in the compact matrix form,…”

Section: Dyanamics Of the Systemmentioning

confidence: 99%

Controllability of optical bistability, cooling and entanglement in hybrid cavity optomechanical systems by nonlinear atom–atom interaction

Dalafi

Naderi

Soltanolkotabi

et al. 2013

J. Phys. B: At. Mol. Opt. Phys.

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We investigate the effects of atomic collisions as well as optomechanical mirror-field coupling on the optical bistability in a hybrid system consisting of a Bose-Einstein condensate inside a driven optical cavity with a moving end mirror. It is shown that the bistability of the system can be controlled by the s-wave scattering frequency which can provide the possibility of realizing a controllable optical switch. On the other hand, by studying the effect of the Bogoliubov mode, as a secondary mechanical mode relative to the mirror vibrations, on the cooling process as well as the bipartite mirror-field and atom-field entanglements we find an interpretation for the cooling of the Bogoliubov mode. The advantage of this hybrid system in comparison to the bare optomecanical cavity with a two-mode moving mirror is the controllability of the frequency of the secondary mode through the s-wave scattering interaction.

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Section: Dyanamics Of the Systemmentioning

confidence: 99%

Controllability of optical bistability, cooling and entanglement in hybrid cavity optomechanical systems by nonlinear atom–atom interaction

Dalafi

Naderi

Soltanolkotabi

et al. 2013

J. Phys. B: At. Mol. Opt. Phys.

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“…Regarding the wavefunctions of the condensate, in steady state, we assume that they can be written in the form ψ b (x, t) = ψ b (x) exp(−iµ b t/h) and ψ c (x, t) = ψ c (x) exp(−iµ c t/h), with µ being the chemical potential; then the dynamical equations (5) and (6) in the absence of external trap potentials will become…”

Section: Critical Value Of Pump Strength For the Phase Transitionmentioning

confidence: 99%

“…An atomic gas inside a high-finesse optical cavity [1,2] may exhibit self-organization when it is subjected to a transverse laser pump [3][4][5][6][7]. In matter-cavity quantum electrodynamic (QED) systems, the mechanical effect of the electromagnetic fields on the motional states of atoms and the phase shift effect of atomic motion on the fields induce each other mutually in a self-consistent loop.…”

Section: Introductionmentioning

confidence: 99%

Raman superradiance and spin lattice of ultracold atoms in optical cavities

2013

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We investigate the synthesis of a hyperfine spin lattice in an atomic Bose-Einstein condensate, with two hyperfine spin components, inside a onedimensional high-finesse optical cavity, using off-resonant superradiant Raman scattering. Spatio-temporal evolution of the relative population of the hyperfine spin modes is examined numerically by solving the coupled cavity-condensate mean-field equations in the dispersive regime. We find, analytically and numerically, that beyond a certain threshold of the transverse laser pump, Raman superradiance and self-organization of the hyperfine spin components occur simultaneously and as a result a magnetic lattice is formed. The effects of an extra laser pump parallel to the cavity axis and the time dependence of the pump strength on the synthesis of a sharper lattice are also addressed.

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“…3C. We believe that in this region technical fluctuations, the dynamical change in the dispersive cavity shift (34), finite-N effects (35), and population of higher-order momentum states start to play a role.…”

mentioning

confidence: 93%

Real-time observation of fluctuations at the driven-dissipative Dicke phase transition

Brennecke

Mottl

Baumann

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

196

195

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We experimentally study the influence of dissipation on the driven Dicke quantum phase transition, realized by coupling external degrees of freedom of a Bose-Einstein condensate to the light field of a high-finesse optical cavity. The cavity provides a natural dissipation channel, which gives rise to vacuum-induced fluctuations and allows us to observe density fluctuations of the gas in real-time. We monitor the divergence of these fluctuations over two orders of magnitude while approaching the phase transition, and observe a behavior that deviates significantly from that expected for a closed system. A correlation analysis of the fluctuations reveals the diverging time scale of the atomic dynamics and allows us to extract a damping rate for the external degree of freedom of the atoms. We find good agreement with our theoretical model including dissipation via both the cavity field and the atomic field. Using a dissipation channel to nondestructively gain information about a quantum many-body system provides a unique path to study the physics of driven-dissipative systems.driven-dissipative phase transitions | critical behavior | Dicke model | quantum gas | cavity QED E xperimental progress in the creation, manipulation, and probing of atomic quantum gases has made it possible to study highly controlled many-body systems and to access their phase transitions. This unique approach to quantum many-body physics has substantiated the notion of quantum simulation for key models of condensed matter physics (1, 2). There has been increasing interest in generalizing such an approach to nonequilibrium zero-temperature or quantum phase transitions in driven-dissipative systems (3), as occurring in condensed matter systems coupled to light (4,5) or in open electronic systems (6, 7). Among the most tantalizing questions is how vacuum fluctuations from the environment influence the critical behavior at a phase transition via quantum backaction. Related to this question is whether driven-dissipative phase transitions give rise to new universal behavior, and under which conditions they exhibit classical critical behavior with an effective temperature (8-12).Coupling quantum gases to the field of an optical cavity is a particularly promising approach to realize a driven-dissipative quantum many-body system with a well-understood and controlled dissipation channel. A further advantage of this scheme is that the dissipation channel of the cavity mode can be directly used to investigate the system in a nondestructive way via the leaking cavity field (13). Combining the experimental setting of cavity quantum electrodynamics with that of quantum gases (14-18) led to the observation of quantum backaction heating caused by cavity dissipation (19,20), as well as to the realization of the nonequilibrium Dicke quantum phase transition (21). Here, we study the influence of cavity dissipation on the fluctuation spectrum at the Dicke phase transition by connecting these approaches. We nondestructively observe diverging fluctuations of the o...

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Multimode mean-field model for the quantum phase transition of a Bose-Einstein condensate in an optical resonator

Cited by 24 publications

References 42 publications

Controllability of optical bistability, cooling and entanglement in hybrid cavity optomechanical systems by nonlinear atom–atom interaction

Controllability of optical bistability, cooling and entanglement in hybrid cavity optomechanical systems by nonlinear atom–atom interaction

Raman superradiance and spin lattice of ultracold atoms in optical cavities

Real-time observation of fluctuations at the driven-dissipative Dicke phase transition

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