Landau criterion for an anisotropic Bose-Einstein condensate

Yu, Zeng-Qiang

doi:10.1103/physreva.95.033618

Cited by 14 publications

(14 citation statements)

References 38 publications

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“…Thus, its contribution to the drag force (25) does not vanish. A similar suppression of the dissipationless motion has been found in the uniform plane-wave phase [44].…”

Section: Drag Force and Energy Dissipation In The Stripe Phasesupporting

confidence: 78%

“…( 26) it follows that the critical speed v ℓ,c can depend on the direction v of the motion. This effect has already been addressed in several works [44][45][46][47], which focused on the uniform plane-wave and zero-momentum phases. It has also been found that the drag force can be not parallel to v, and the critical velocity can be different from the sound velocity even in the directions perpendicular to the condensation momentum.…”

Section: Drag Force and Energy Dissipation In The Stripe Phasementioning

confidence: 89%

“…where v is a unit vector along v identifying the direction of the motion of the impurity. Equation ( 26) coincides with a generalized version of the Landau criterion for superfluidity that takes into account the anisotropy of the system under consideration [44]. For an isotropic superfluid it reduces to the traditional form v c,ℓ = min q ω ℓ,q /q independent of v [37].…”

Section: Drag Force and Energy Dissipation In The Stripe Phasementioning

confidence: 97%

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Drag Force and Superfluidity in the Supersolid Stripe Phase of a Spin-Orbit-Coupled Bose-Einstein Condensate

Martone¹,

SHLYAPNIKOV²

2018

Zh. Eksp. Teor. Fiz.

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The phase diagram of a spin-orbit-coupled two-component Bose gas includes a supersolid stripe phase, which is featuring density modulations along the direction of the spin-orbit coupling. This phase has been recently found experimentally [J. Li et al., Nature (London) 543, 91 (2017)]. In the present work we characterize the superfluid behavior of the stripe phase by calculating the drag force acting on a moving impurity. Because of the gapless band structure of the excitation spectrum, the Landau critical velocity vanishes if the motion is not strictly parallel to the stripes, and energy dissipation takes place at any speed. Moreover, due to the spin-orbit coupling, the drag force can develop a component perpendicular to the velocity of the impurity. Finally, by estimating the time over which the energy dissipation occurs, we find that for slow impurities the effects of friction are negligible on a time scale up to several seconds, which is comparable with the duration of a typical experiment.

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“…Thus, its contribution to the drag force (25) does not vanish. A similar suppression of the dissipationless motion has been found in the uniform plane-wave phase [44].…”

Section: Drag Force and Energy Dissipation In The Stripe Phasesupporting

confidence: 78%

Section: Drag Force and Energy Dissipation In The Stripe Phasementioning

confidence: 89%

Section: Drag Force and Energy Dissipation In The Stripe Phasementioning

confidence: 97%

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Drag Force and Superfluidity in the Supersolid Stripe Phase of a Spin-Orbit-Coupled Bose-Einstein Condensate

Martone¹,

SHLYAPNIKOV²

2018

Zh. Eksp. Teor. Fiz.

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“…The Landau criterion [2] then relates the anisotropy of the excitation spectrum to the breakdown of superfluidity, since quasiparticles cannot be emitted by an impurity moving at a velocity v smaller than the critical velocity v c = min[ ω(k)/k ] in an isotropic fluid. For anisotropic interactions the excitation wavevector k does not necessarily coincide with the direction of movementv of the impurity [13]. In its generalized form the Landau crite-rion therefore becomes v c = min[ ω(k)/(k ·v) ].…”

mentioning

confidence: 99%

Anisotropic Superfluid Behavior of a Dipolar Bose-Einstein Condensate

Wenzel¹,

Böttcher²,

Schmidt³

et al. 2018

Phys. Rev. Lett.

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We present transport measurements on a dipolar superfluid using a Bose-Einstein condensate of ^{162}Dy with strong magnetic dipole-dipole interactions. By moving an attractive laser beam through the condensate we observe an anisotropy in superfluid flow. This observation is compatible with an anisotropic critical velocity for the breakdown of dissipationless flow, which, in the spirit of the Landau criterion, can directly be connected to the anisotropy of the underlying dipolar excitation spectrum. In addition, the heating rate above this critical velocity reflects the same anisotropy. Our observations are in excellent agreement with simulations based on the Gross-Pitaevskii equation and highlight the effect of dipolar interactions on macroscopic transport properties, rendering dissipation anisotropic.

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“…Utilizando interação com lasers podemos proporcionar acoplamento entre as componentes do espinor que descrevem o condensado. Embora recentes, já acumula uma lista crescente de temas estudados da qual fazem parte solitons [13,14,15], estudo de vórtices [16], verificação experimental para 2 [17] ou os 3 [18], entre outros [19,20,21].…”

Section: Rudimentos Da Condensação De Bose-einstein E Estrutura Hiperunclassified

Condensados de Bose-Einstein com interação spin-órbita

Andriati¹

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Nesta dissertação são estudados Condensados de Bose-Einstein deátomos com pseudo-spin 1/2 cuja dinâmica orbital está acoplada a estes dois níveis de energia internos. A geração de tal sistemaé possível induzindo transições entre os subníveis m f = −1 e m f = 0 do estado hiperfino atômico f = 1 usando um arranjo de lasers, os quais também introduzem junto uma dependência espacial dada por suas fases, as quais estão relacionadas a posição doátomo no campo, levando assimà interação acoplando spin eórbita.É considerado então um sistema unidimensional efetivo na mesma direção do acoplamento dos lasers, onde são estudado diferentes observáveis do estado fundamental, para uma varredura dos parâmetros presentes na equação, dando origem a três fases diferenciadas pela distribuição do momento. Foram determinadas estas fases do estado fundamental para interação atrativa, sendo elas modulada(striped), onda plana e de momento nulo, mostrando a localização onde cada uma ocorre no domínio de parâmetros da equação, através de diagramas de fase. São também mostrados, separadamente, observáveis relevantes como momento e desbalanço entre os estados internos nestas transições, os quais apresentaram variações bruscas, ditando valores críticos nos parâmetros, onde ocorrem. Posteriormenté e estudado a dinâmica através de soluções do tipo sóliton, as quais não se propagam linearmente e são ditadas por oscilações do centro de massa e das populações, explorando diferentes situações iniciais.

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Landau criterion for an anisotropic Bose-Einstein condensate

Cited by 14 publications

References 38 publications

Drag Force and Superfluidity in the Supersolid Stripe Phase of a Spin-Orbit-Coupled Bose-Einstein Condensate

Drag Force and Superfluidity in the Supersolid Stripe Phase of a Spin-Orbit-Coupled Bose-Einstein Condensate

Anisotropic Superfluid Behavior of a Dipolar Bose-Einstein Condensate

Condensados de Bose-Einstein com interação spin-órbita

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