Nonlinear atom-photon-interaction-induced population inversion and inverted quantum phase transition of Bose-Einstein condensate in an optical cavity

Zhao, Xin; Ni, Lei; Liang, J.-Q.

doi:10.1103/physreva.90.023622

Cited by 22 publications

(11 citation statements)

References 43 publications

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“…When spin dissipation is absent 3 , 21 , 23 , 27 , 69 or acts collectively on all qubits at once, one can significantly simplify the problem by treating the qubits as a single, collective spin, which allows to obtain the quantum state of the qubits. This is not possible here, since the dissipation acts on each qubit individually 25 , 26 , 29 .…”

Section: Resultsmentioning

confidence: 99%

Dissipation-induced bistability in the two-photon Dicke model

Garbe

Wade

Minganti

et al. 2020

Sci Rep

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The Dicke model is a paradigmatic quantum-optical model describing the interaction of a collection of two-level systems with a single bosonic mode. Effective implementations of this model made it possible to observe the emergence of superradiance, i.e., cooperative phenomena arising from the collective nature of light-matter interactions. Via reservoir engineering and analogue quantum simulation techniques, current experimental platforms allow us not only to implement the Dicke model but also to design more exotic interactions, such as the two-photon Dicke model. In the Hamiltonian case, this model presents an interesting phase diagram characterized by two quantum criticalities: a superradiant phase transition and a spectral collapse, that is, the coalescence of discrete energy levels into a continuous band. Here, we investigate the effects of both qubit and photon dissipation on the phase transition and on the instability induced by the spectral collapse. Using a mean-field decoupling approximation, we analytically obtain the steady-state expectation values of the observables signaling a symmetry breaking, identifying a first-order phase transition from the normal to the superradiant phase. Our stability analysis unveils a very rich phase diagram, which features stable, bistable, and unstable phases depending on the dissipation rate. The Dicke model 1 describes the interaction of a collection of two-level systems with a single bosonic mode. In the thermodynamic limit, this model exhibits a superradiant phase transition at zero temperature 1-5. Namely, the ground-state number of photons changes non analytically from zero to finite values as the light-matter coupling strength is increased across a critical value. The relevance of the Dicke model to capture the physics of light-matter coupling near the critical point is the object of an ongoing debate. In particular, an obstacle to the observation of a superradiant phase transition arises due to the presence of the so-called diamagnetic term. In this regard, resolutions of gauge ambiguities have been recently proposed, such as employing modified unitary transformations or going beyond the two-level system description 6-9. It is possible, however, to circumvent this controversy entirely by using driven systems and bath engineering to simulate effective Hamiltonians. Thanks to this approach, it was possible to observe the superradiant phase transition in several platforms, in particular atomic systems in cavity 10-12 , and trapped ions 13,14. Other proposals have been put forward, using NV centers array 15 , or superconducting circuits 16. In general, the implementation of analogue quantum simulations 17,18 provides an ideal playground to test driven-dissipative physics in a controlled setting. Their experimental feasibility has motivated increasing research efforts devoted to the study of driven-dissipative quantum optical models, as it is known that noise and dissipation can drastically change the properties of the steady-state phase diagrams and the emergence of p...

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Section: Resultsmentioning

confidence: 99%

Dissipation-induced bistability in the two-photon Dicke model

Garbe

Wade

Minganti

et al. 2020

Sci Rep

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“…In this paper we provide analytic solutions for the macroscopic quantum state (MQS) for the spinboson system in terms of the recently developed spin coherent variational method [48,73,78,79]. The meaning of MQS in the present paper is that the variational wave function is considered as a product of boson and spin coherent states seen in the followings.…”

Section: Spin Coherent-state Variational Methodsmentioning

confidence: 99%

Collective atomic-population-inversion and stimulated radiation for two-component Bose-Einstein condensate in an optical cavity

2017

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In this paper we investigate the ground-state properties and related quantum phase transitions for the two-component Bose-Einstein condensate in a single-mode optical cavity. Apart from the usual normal and superradiant phases, multi-stable macroscopic quantum states are realized by means of the spin-coherent-state variational method. We demonstrate analytically the stimulated radiation from a collective state of atomic population inversion, which does not exist in the normal Dicke model with single-component atoms. It is also revealed that the stimulated radiation can be generated only from one component of atoms and the other remains in the ordinary superradiant state. However, the order of superradiant and stimulated-radiation states is interchangeable between two components of atoms by tuning the relative atom-field couplings and the frequency detuning as well.

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“…Thus |ψ 1 , and |ψ 2 are stable states of normal phase with zero average photon-number. While |ψ 0 is the ground state of superradiant phase [64][65][66]. We solve in the present paper the dynamic equation of motion for the given initial entangled states and then study the time-evolution of measuring outcome-correlations.…”

Section: Stationary Solutions and Entangled Statesmentioning

confidence: 99%

“…which are known as the spin coherent states [64][65][66] of north-and south-pole gauges. Here, n = (sin θ n cos Φ n , sin θ n sin Φ n , cos θ n ) with n = a, b is a unit vector parameterized by the polar and azimuthal angles (θ n , Φ n ).…”

Section: Measuring Outcome Correlation and Bell's Inequalitymentioning

confidence: 99%

Entanglement dynamics for two spins in an optical cavity – field interaction induced decoherence and coherence revival

Bai¹,

Gao²,

Li³

et al. 2017

Opt. Express

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Abstract:We in this paper study quantum correlations for two neutral spin-particles coupled with a single-mode optical cavity through the usual magnetic interaction. Two-spin entangled states for both antiparallel and parallel spin-polarizations are generated under the photon coherent-state assumption. Based on the quantum master equation we derive the time-dependent quantum correlation of Clauser-Horne-Shimony-Holt (CHSH) type explicitly in comparison with the well known entanglement-measure concurrence. In the two-spin singlet state, which is recognized as one eigenstate of the system, the CHSH correlation and concurrence remain in their maximum values invariant with time and independent of the average photon-numbers either. The correlation varies periodically with time in the general entangled-states for the low average photon-numbers. When the photon number increases to a certain value the oscillation becomes random and the correlations are suppressed below the Bell bound indicating the decoherence of the entangled states. In the high photon-number limit the coherence revivals periodically such that the CHSH correlation approaches the upper bound value at particular time points associated with the cavity-field period.

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Nonlinear atom-photon-interaction-induced population inversion and inverted quantum phase transition of Bose-Einstein condensate in an optical cavity

Cited by 22 publications

References 43 publications

Dissipation-induced bistability in the two-photon Dicke model

Dissipation-induced bistability in the two-photon Dicke model

Collective atomic-population-inversion and stimulated radiation for two-component Bose-Einstein condensate in an optical cavity

Entanglement dynamics for two spins in an optical cavity – field interaction induced decoherence and coherence revival

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