Nonequilibrium dynamics of vortex arrest in a finite-temperature Bose-Einstein condensate

Wright, Tod M.; Bradley, Ashton S.; Ballagh, R. J.

doi:10.1103/physreva.81.013610

Cited by 14 publications

(16 citation statements)

References 36 publications

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“…However, dynamical calculations within a pure PGPE formalism are able to provide useful insights into the dynamics of degenerate Bose-gas systems in situations where a precise identification of the method with the full field theory is impractical [45,58,66]. The PGPE has also been used to establish the connection between c-field methods and more traditional theoretical methods based on U(1) symmetry breaking [61,67].…”

Section: Projected Gross-pitaevskii Equation (Pgpe)mentioning

confidence: 99%

C-Field Methods for Non-Equilibrium Bose Gases

et al. 2013

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We review c-field methods for simulating the non-equilibrium dynamics of degenerate Bose gases beyond the mean-field Gross-Pitaevskii approximation. We describe three separate approaches that utilise similar numerical methods, but have distinct regimes of validity. Systems at finite temperature can be treated with either the closed-system projected Gross-Pitaevskii equation (PGPE), or the open-system stochastic projected GrossPitaevskii equation (SPGPE). These are both applicable in quantum degenerate regimes in which thermal fluctuations are significant. At low or zero temperature, the truncated Wigner projected Gross-Pitaevskii equation (TWPGPE) allows for the simulation of systems in which spontaneous collision processes seeded by quantum fluctuations are important. We describe the regimes of validity of each of these methods, and discuss their relationships to one another, and to other simulation techniques for the dynamics of Bose gases. The utility of the SPGPE formalism in modelling non-equilibrium Bose gases is illustrated by its application to the dynamics of spontaneous vortex formation in the growth of a Bose-Einstein condensate.

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Section: Projected Gross-pitaevskii Equation (Pgpe)mentioning

confidence: 99%

C-Field Methods for Non-Equilibrium Bose Gases

et al. 2013

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“…This definition in terms of correlations in the microcanonical density is an unambiguous measure of condensation in the simple equilibrium regimes in which it is applicable. Generalizations of this procedure based on short-time fluctuation statistics have been applied to more general scenarios involving, for example, broken rotational symmetries and nonequilibrium fields [15,[22][23][24].…”

Section: Microcanonical Interpretationmentioning

confidence: 99%

Temporal coherence, anomalous moments, and pairing correlations in the classical-field description of a degenerate Bose gas

2010

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The coherence properties of degenerate Bose gases have usually been expressed in terms of spatial correlation functions, neglecting the rich information encoded in their temporal behavior. In this article we show, using a Hamiltonian classical-field formalism, that temporal correlations can be used to characterize familiar properties of a finite-temperature degenerate Bose gas. The temporal coherence of a Bose-Einstein condensate is limited only by the slow diffusion of its phase, and thus the presence of a condensate is indicated by a sharp feature in the temporal power spectrum of the field. We show that the condensate mode can be obtained by averaging the field for a short time in an appropriate phase-rotating frame, and that for a wide range of temperatures, the condensate obtained in this approach agrees well with that defined by the Penrose-Onsager criterion based on one-body (spatial) correlations. For time periods long compared to the phase diffusion time, the field will average to zero, as we would expect from the overall U(1) symmetry of the Hamiltonian. We identify the emergence of the first moment on short time scales with the concept of U(1) symmetry breaking that is central to traditional mean-field theories of Bose condensation. We demonstrate that the short-time averaging procedure constitutes a general analog of the "anomalous" averaging operation of symmetry-broken theories by calculating the anomalous thermal density of the field, which we find to have form and temperature dependence consistent with the results of mean-field theories.

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“…While Hamiltonian vortex motion is well understood at the mean field level, dissipation plays a central role in the creation of spontaneous vortices [17] and solitons [18] during the BEC phase transition, in the formation of negative temperature states [11,[19][20][21][22], in the formation [7] and break-down [23] of persistent currents, and the frustrated equilibration of spinor condensates [24,25]. A variety of theoretical techniques have been used to study finite-temperature vortex dynamics [26,27], including phenomenological damping of the Gross-Pitaevskii equation [28][29][30], two-fluid models [31][32][33], the projected Gross-Pitaevskii equation [34][35][36] and related classical field theories [37,38], and the stochastic Gross-Pitaevskii equation [5,6,39,40]. However, the dissipative motion due to reservoir interactions of a quantum vortex have yet to be tested against experimental observations [41][42][43][44][45].…”

Section: Introductionmentioning

confidence: 99%

Reservoir interactions of a vortex in a trapped three-dimensional Bose-Einstein condensate

et al. 2016

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We simulate the dissipative evolution of a vortex in a trapped finite-temperature dilute-gas Bose-Einstein condensate using first-principles open-systems theory. Simulations of the complete stochastic projected GrossPitaevskii equation for a partially condensed Bose gas containing a single quantum vortex show that the transfer of condensate energy to the incoherent thermal component without population transfer provides an important channel for vortex decay. For the lower temperatures considered, this effect is significantly larger that the population transfer process underpinning the standard theory of vortex decay, and is the dominant determinant of the vortex lifetime. A comparison with the Zaremba-Nikuni-Griffin kinetic (two-fluid) theory further elucidates the role of the particle transfer interaction, and suggests the need for experimental testing of reservoir interaction theory. The dominance of this particular energetic decay mechanism for this open quantum system should be testable with current experimental setups, and its observation would have broad implications for the dynamics of atomic matter waves and experimental studies of dissipative phenomena.

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Nonequilibrium dynamics of vortex arrest in a finite-temperature Bose-Einstein condensate

Cited by 14 publications

References 36 publications

C-Field Methods for Non-Equilibrium Bose Gases

C-Field Methods for Non-Equilibrium Bose Gases

Temporal coherence, anomalous moments, and pairing correlations in the classical-field description of a degenerate Bose gas

Reservoir interactions of a vortex in a trapped three-dimensional Bose-Einstein condensate

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