Collective modes of a one-dimensional trapped Bose gas in the presence of the anomalous density

Boudjemâa, Abdelâali

doi:10.1103/physreva.94.053629

Cited by 13 publications

(13 citation statements)

References 52 publications

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“…Combining the expressions ofm j andñ j and using the fact that 2N (x) + 1 = coth(x/2), we obtain I kj = coth 2 (ε kj /2T ). For a noninteracting Bose gas where the anomalous density vanishes, I kj = coth 2 (E kj /2T ) [54]. For an ideal trapped case, the Heisenberg invariant keeps the same form as Eq.…”

Section: Tdhfb Theorymentioning

confidence: 93%

“…In addition, the TDHFB equations allow us to examine the role of anomalous fluctuations in the phenomenon of phase separation in trapped dual Bose condensates. The anomalous density has a crucial contribution in the stability, excitations, superfluidity, and solitons in a single component BEC [45,46,[54][55][56][57][58][59][60]. Based on experimentally relevant parameters, we demonstrate that a large anomalous density may lead to a transition from miscible to immiscible regime.…”

Section: Introductionmentioning

confidence: 97%

“…Although the above theories received great success in describing the behavior of two-component BECs, much remains to be investigated regarding effects of quantum and thermal fluctuations on the phase separation and collective excitations of such mixtures. The present work deals with the static and the dynamic properties of homogeneous and inhomogeneous Bose-Bose mixtures at finite temperature using the TDHFB theory [44][45][46][47][48][49][50][51][52][53][54][55]. Our scheme provides an excellent starting point to study the dynamics of Bose systems and has been successfully tested against experiments in a wide variety of problems namely, collective modes, vortices, solitons and Bose polarons.…”

Section: Introductionmentioning

confidence: 99%

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Quantum and thermal fluctuations in two-component Bose gases

Boudjemâa

2018

Phys. Rev. A

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We study the effects of quantum and thermal fluctuations on Bose-Bose mixtures at finite temperature employing the time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory. The theory governs selfconsistently the motion of the condensates, the noncondensates and of the anomalous components on an equal footing. The finite temperature criterion for the phase separation is established. We numerically analyze the temperature dependence of different densities for both miscible and immiscible mixtures. We show that the degree of the overlap between the two condensates and the thermal clouds is lowered and the relative motion of the centers-of-mass of the condensed and thermal components is strongly damped due to the presence of the pair anomalous fluctuations. Our results are compared with previous theoretical and experimental findings. On the other hand, starting from our TDHFB equations, we develop a random-phase theory for the elementary excitations in a homogeneous mixture. We find that the normal and anomalous fluctuations may lead to enhance the excitations and the thermodynamics of the system.

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Section: Tdhfb Theorymentioning

confidence: 93%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Quantum and thermal fluctuations in two-component Bose gases

Boudjemâa

2018

Phys. Rev. A

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“…. Expanding the density and the phase in the basis of the excitations: [27,30,36]). Assuming small density fluctuations, we then obtain for the excitation spectrum of homogeneous gas…”

Section: Lhymentioning

confidence: 99%

Two-dimensional quantum droplets in dipolar Bose gases

Boudjemâa

2019

New J. Phys.

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We calculate analytically the quantum and thermal fluctuations corrections of a dilute quasi-twodimensional Bose-condensed dipolar gas. We show that these fluctuations may change their character from repulsion to attraction in the density-temperature plane owing to the striking momentum dependence of the dipole-dipole interactions. The dipolar instability is halted by such unconventional beyond mean field corrections leading to the formation of a droplet phase. The equilibrium features and coherence properties exhibited by such droplets are deeply discussed. At finite temperature, we find that the equilibrium density crucially depends on the temperature and on the confinement strength and thus, a stable droplet can exist only at ultralow temperature due to the strong thermal fluctuations.

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“…the mean-field energy is repulsive while the beyond mean-field term is attractive [11]. A major advantage of 1D problem which reflected in a supression of three-body losses [12], is that a stable droplet can survive even in strongly-interacting regime due to the boosted role played by quantum fluctuations [13,14]. Difference between bright solitons and quantum droplets have been highlighted in [7,15].…”

Section: Introductionmentioning

confidence: 99%

Quantum droplets in one-dimensional Bose-Bose mixtures: beyond the Lee-Huang-Yang description

Boudjemâa,

Abbas

2023

New J. Phys.

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The static and dynamic properties of self-bound quantum droplets in a one-dimensional Bose-Bose mixture are discussed in the spirit of the Hartree–Fock-Bogoliubov theory. This latter enables us to provide beyond the Lee-Huang-Yang (LHY) quantum corrections to the equation of state at both zero and finite temperatures. In the uniform case our results for the ground-state energy and the critical temperature are confirmed through comparison with Quantum Monte-Carlo simulation and with available theoretical results. The density profiles are supported by numerical simulations of the generalized Gross-Pitaevskii equation which selfconsistently includes higher-order terms originating from the normal and anomalous fluctuations under the local density approximation. We show that the density exhibits a dip near its center in the flat-top plateau region for large interspecies interactions. We exemplify the impact of the beyond LHY corrections on the spatiotemporal evolution of the self-bound droplet in the presence of excitation induced by periodic density modulation. It is found that higher-order corrections may lead to the formation of a train of small droplets. We then extend our study for the case of inhomogeneous droplets in quasi one-dimensional Bose mixtures.

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Collective modes of a one-dimensional trapped Bose gas in the presence of the anomalous density

Cited by 13 publications

References 52 publications

Quantum and thermal fluctuations in two-component Bose gases

Quantum and thermal fluctuations in two-component Bose gases

Two-dimensional quantum droplets in dipolar Bose gases

Quantum droplets in one-dimensional Bose-Bose mixtures: beyond the Lee-Huang-Yang description

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