Critical velocity for vortex nucleation in a finite-temperature Bose gas

Stagg, George; Pattinson, R. W.; Barenghi, Carlo F.; Parker, N. G.

doi:10.1103/physreva.93.023640

Cited by 11 publications

(9 citation statements)

References 52 publications

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“…14 . Finally, the fundamental problem of vortex nucleation due to fast impurities has been thoroughly investigated at zero temperature [11][12][13] , but few results are known in the finite temperature regime 51,52 . In particular, the PGP model coupled with impurities (1) would be a suitable framework to address the impurity-vortex interaction at non-zero temperature.…”

Section: Discussionmentioning

confidence: 99%

Stochastic motion of finite-size immiscible impurities in a dilute quantum fluid at finite temperature

Giuriato,

Krstulovic

2020

Preprint

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The dynamics of an active, finite-size and immiscible impurity in a dilute quantum fluid at finite temperature is characterized by means of numerical simulations of the projected Gross-Pitaevskii equation. The impurity is modeled as a localized repulsive potential and described with classical degrees of freedom. It is shown that impurities of different sizes thermalize with the fluid and undergo a stochastic dynamics compatible with an Ornstein-Uhlenbeck process at sufficiently large time-lags. The velocity correlation function and the displacement of the impurity are measured and an increment of the friction with temperature is observed. Such behavior is phenomenologically explained in a scenario where the impurity exchanges momentum with a dilute gas of thermal excitations, experiencing an Epstein drag.

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Section: Discussionmentioning

confidence: 99%

Stochastic motion of finite-size immiscible impurities in a dilute quantum fluid at finite temperature

Giuriato,

Krstulovic

2020

Preprint

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“…The GPE is conventionally used to model a zero temperature condensate, but it is now established that, provided the modes of the gas are highly occupied, the gas evolves as an ensemble of modes, each of which follows (to leading order) the classical trajectory described by the GPE [21][22][23]. Various phenomena have been studied within this classical field formalism, including equilibration dynamics [12,13,15,24], critical temperatures [25], correlation functions [26], vortex nucleation [27][28][29][30] and decay of vortex rings [31], as well as extensions to binary condensates [32][33][34].…”

Section: Classical Field Methodsmentioning

confidence: 99%

Ultraquantum turbulence in a quenched homogeneous Bose gas

2016

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Using the classical field method, we study numerically the characteristics and decay of the turbulent tangle of superfluid vortices which is created in the evolution of a Bose gas from highly nonequilibrium initial conditions. By analysing the vortex line density, the energy spectrum and the velocity correlation function, we determine that the turbulence resulting from this effective thermal quench lacks the coherent structures and the Kolmogorov scaling; these properties are typical of both ordinary classical fluids and of superfluid helium when driven by grids or propellers. Instead, thermal quench turbulence has properties akin to a random flow, more similar to another turbulent regime called ultra-quantum turbulence which has been observed in superfluid helium.

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“…As the shedding of vortices causes the depletion of the condensate fraction, we would expect the presence of thermal effects to lower the critical velocity [15] which in turn would lead to the nucleation of more vortices, until the condensate is depleted. In fact, since the long term behaviour of the condensate fraction is to equilibriate, we deduce that the system stops shedding vortices.…”

Section: The Velocity Of the Condensate And Non-condensate Modesmentioning

confidence: 99%

“…As the velocity of the flow around the obstacle increases, there is a transition from the regular shedding of vortex dipole pairs to an irregular shedding of larger clusters of same-sign vortices, indicating that the system has become turbulent [3,12]. The transition to turbulence in superfluid flow past a potential obstacle has been the focus of recent theoretical [2,3,[13][14][15][16] and experimental [11,12,17,18] work. These works have investigated the effect of obstacle shape [14,19,20] and finite temperature effects [15,16] on the critical velocity for vortex nucleation past a single obstacle.…”

Section: Introductionmentioning

confidence: 99%

“…The transition to turbulence in superfluid flow past a potential obstacle has been the focus of recent theoretical [2,3,[13][14][15][16] and experimental [11,12,17,18] work. These works have investigated the effect of obstacle shape [14,19,20] and finite temperature effects [15,16] on the critical velocity for vortex nucleation past a single obstacle.…”

Section: Introductionmentioning

confidence: 99%

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Critical Velocity and Arrest of a Superfluid in a Point-Like Disordered Potential

Doran¹,

Groszek²,

Billam³

2022

Preprint

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Superfluid flow past a potential barrier is a well studied problem in ultracold Bose gases, however, fewer studies have considered the case of flow through a disordered potential. Here we consider the case of a superfluid flowing through a channel containing multiple point-like barriers, randomly placed to form a disordered potential. We begin by identifying the relationship between the relative position of two point-like barriers and the critical velocity of such an arrangement. We then show that there is a mapping between the critical velocity of a system with two obstacles, and a system with a large number of obstacles. By establishing an initial superflow through a point-like disordered potential, moving faster than the critical velocity, we study how the superflow is arrested through the nucleation of vortices and the breakdown of superfluidity, a problem with interesting connections to quantum turbulence and coarsening. We calculate the vortex decay rate as the width of the barriers is increased, and show that vortex pinning becomes a more important effect for these larger barriers.

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Critical velocity for vortex nucleation in a finite-temperature Bose gas

Cited by 11 publications

References 52 publications

Stochastic motion of finite-size immiscible impurities in a dilute quantum fluid at finite temperature

Stochastic motion of finite-size immiscible impurities in a dilute quantum fluid at finite temperature

Ultraquantum turbulence in a quenched homogeneous Bose gas

Critical Velocity and Arrest of a Superfluid in a Point-Like Disordered Potential

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