Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Breakdown of superfluidity of an atom laser in a random environment

Mathias Albert, Tobias Paul, Nicolas Pavloff, P. Lebœuf

Published Mar 30, 2010• 0 citations
OpenAlex

Abstract

We consider a guided Bose-Einstein matter wave flowing through a disordered potential. We determine the critical velocity at which superfluidity is broken and compute its statistical properties. They are shown to be connected to extreme values of the random potential. Experimental implementations of this physics are discussed.

Related papers

Breakdown of the superfluidity of a matter wave in a random environment

Mathias Albert, Tobias Paul, Nicolas Pavloff +1 more

We consider a guided Bose-Einstein matter wave flowing through a disordered potential. We determine the critical velocity at which superfluidity is broken and compute its statistical properties. They are shown to be connected to extreme values of the random potential. Experimental implementations of this physics are discussed.

arXiv:1003.5808•Physical Review A•Jul 6, 2010•27 citations

Breakdown of superfluidity of an atom laser past an obstacle

Nicolas Pavloff

The one-dimensional flow of a continuous beam of Bose-Einstein condensed atoms in the presence of an obstacle is studied as a function of the beam velocity and of the type of perturbing potential (representing the interaction of the obstacle with the atoms of the beam). We identify the relevant regimes: stationary/time-dependent and superfluid/dissipative; the absence of drag is used as a criterion for superfluidity. There exists a critical velocity below which the flow is superfluid. For attractive obstacles, we show that this critical velocity can reach the value predicted by Landau's approach. Besides, for penetrable obstacles, it is shown that superfluidity is recovered at large beam velocity. Finally, enormous differences in drag occur when switching from repulsive to attractive potential.

arXiv:cond-mat/0206271•Physical Review A•Jul 19, 2002•123 citations

Transport properties of a Bose-Einstein condensate with tunable interactions in the presence of a disordered or single defect potential

D. Dries

Bose-Einstein condensates (BECs) have proven to be remarkable systems with which to study some of the foundational models of condensed matter physics. The observation of a critical velocity for the breakdown of superfluidity in a BEC and the superfluid to Mott insulator transition observed in a BEC trapped by an optical lattice are but two examples of the, by now, dozens of exciting results in this field, which combines theoretical tools from condensed matter physics with state-of-the-art experimental techniques from ultra-cold atomic physics. However, any real condensed matter system has to contend with the effects of disorder, a phenomena notably absent in the inherently clean BEC systems. We have developed and implemented a way to add well characterized disorder in a controlled way to the otherwise clean BEC system using the light field from a laser speckle pattern. Using this system, we have investigated the effects of disorder or a single Gaussian defect, on the collective dipole motion of a BEC of 7Li in an optical trap. In addition, we perform transport experiments on a weakly interacting BEC expanding in a disordered one-dimensional atom wave-guide. We have observed that in such a system, the wave nature of matter can lead to spectacular and counterintuitive phenomena. Specifically, we verify that this system exhibits Anderson localization, a phenomena fundamentally resulting from the interference of multiply scattered matter waves. In such a state, the localized gas behaves as an insulator in a regime where it is classically expected to be conducting.\nWe also present results of experiments regarding a repulsive BEC scattering from a semi-permeable, single defect potential. We investigate the transport properties of such a system with special emphasis on the velocity and defect strength dependent dissipation of the collective dipole motion of the BEC. Finally, we present the results of our experiments on the scattering properties of bright matter wave solitons. We have observed fragmentation of the soliton in a disordered potential as well as both splitting and recombination of a soliton after interacting with a single repulsive defect potential.

•Jan 1, 2010•0 citations

Critical velocity and arrest of a superfluid in a pointlike disordered potential

R. Doran, Andrew J. Groszek, T. P. Billam

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. Published by the American Physical Society 2024

arXiv:2201.11887•Physical Review A•Jan 5, 2024•1 citation

Full distribution of the superfluid fraction and extreme value statistics in a one-dimensional disordered Bose gas

Mathias Albert, Cord Axel Müller

The full statistical distribution of the superfluid fraction characterizing one-dimensional Bose gases in random potentials is discussed. Rare configurations with extreme fluctuations of the disorder potential can fragment the condensate and reduce the superfluid fraction to zero. The resulting bimodal probability distribution for the superfluid fraction is calculated numerically in the quasi-one-dimensional mean-field regime of ultracold atoms in laser speckle potentials. Using extreme value statistics, an analytical scaling of the zero-superfluid probability as a function of disorder strength, disorder correlation length, and system size is presented. It is argued that similar results can be expected for point-like impurities and that these findings are in reach for present-day experiments.

arXiv:1911.03256•Physical Review A•Feb 10, 2020•2 citations

Two-dimensional Bose gases in systems with pointlike disorder

Garrick, David

The effect of disorder on many-body physics is important for our understanding of real-world systems. In particular, the behaviour of phase transitions between superfluid, normal and insulating phases is an area with many unanswered questions and experimental evidence remains scarce in certain important cases. In this thesis, we focus on systems of two-dimensional (2D) Bose gases subjected to a pointlike disorder potential. We trap atoms in radiofrequency dressed potentials and apply the technique of multiple-radiofrequency dressing to create a double-well potential into which we load the ultracold atoms. Matter-wave interferometry allows us to directly probe the local relative phase and its fluctuations between the clouds in the two potential wells. A pointlike disordered optical potential is produced by a high-intensity laser beam which is shaped by a programmable mirror array and passes through clouds in both of the wells. We adiabatically apply disordered potentials of increasing strength to observe their effect on the superfluids in equilibrium in a double-well. We observe that above a critical disorder strength the superfluid undergoes a transition to the normal phase at a lower temperature than that of the disorder-free case, and we characterise this disorder-induced transition. We also study the flow of a 2D superfluid cloud around both a single defect and a random potential and measure the dissipation induced by the obstacles. The absence of dissipation is observed below a critical velocity in the case of a single defect but we find no such dissipationless regime for the disordered potential. We describe the development of a software simulation package for modelling cold-atom systems and the implementation of particle collisions, magnetic trapping and evaporative cooling. Finally, we report on the initial work towards construction of a new cold-atom apparatus, capable of faster sequence times and greater atom numbers, to continue our investigation of many-body physics.

•Jan 1, 2022•0 citations
The one-dimensional flow of a continuous beam of Bose-Einstein condensed atoms in the presence of an obstacle is studied as a function of the beam velocity and of the type of perturbing potential (representing the interaction of the obstacle with the atoms of the beam). We identify the relevant regimes: stationary/time-dependent and superfluid/dissipative; the absence of drag is used as a criterion for superfluidity. There exists a critical velocity below which the flow is superfluid. For attractive obstacles, we show that this critical velocity can reach the value predicted by Landau's approach. Besides, for penetrable obstacles, it is shown that superfluidity is recovered at large beam velocity. Finally, enormous differences in drag occur when switching from repulsive to attractive potential.
Bose-Einstein condensates (BECs) have proven to be remarkable systems with which to study some of the foundational models of condensed matter physics. The observation of a critical velocity for the breakdown of superfluidity in a BEC and the superfluid to Mott insulator transition observed in a BEC trapped by an optical lattice are but two examples of the, by now, dozens of exciting results in this field, which combines theoretical tools from condensed matter physics with state-of-the-art experimental techniques from ultra-cold atomic physics. However, any real condensed matter system has to contend with the effects of disorder, a phenomena notably absent in the inherently clean BEC systems. We have developed and implemented a way to add well characterized disorder in a controlled way to the otherwise clean BEC system using the light field from a laser speckle pattern. Using this system, we have investigated the effects of disorder or a single Gaussian defect, on the collective dipole motion of a BEC of 7Li in an optical trap. In addition, we perform transport experiments on a weakly interacting BEC expanding in a disordered one-dimensional atom wave-guide. We have observed that in such a system, the wave nature of matter can lead to spectacular and counterintuitive phenomena. Specifically, we verify that this system exhibits Anderson localization, a phenomena fundamentally resulting from the interference of multiply scattered matter waves. In such a state, the localized gas behaves as an insulator in a regime where it is classically expected to be conducting.\nWe also present results of experiments regarding a repulsive BEC scattering from a semi-permeable, single defect potential. We investigate the transport properties of such a system with special emphasis on the velocity and defect strength dependent dissipation of the collective dipole motion of the BEC. Finally, we present the results of our experiments on the scattering properties of bright matter wave solitons. We have observed fragmentation of the soliton in a disordered potential as well as both splitting and recombination of a soliton after interacting with a single repulsive defect potential.
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. Published by the American Physical Society 2024
The full statistical distribution of the superfluid fraction characterizing one-dimensional Bose gases in random potentials is discussed. Rare configurations with extreme fluctuations of the disorder potential can fragment the condensate and reduce the superfluid fraction to zero. The resulting bimodal probability distribution for the superfluid fraction is calculated numerically in the quasi-one-dimensional mean-field regime of ultracold atoms in laser speckle potentials. Using extreme value statistics, an analytical scaling of the zero-superfluid probability as a function of disorder strength, disorder correlation length, and system size is presented. It is argued that similar results can be expected for point-like impurities and that these findings are in reach for present-day experiments.
The effect of disorder on many-body physics is important for our understanding of real-world systems. In particular, the behaviour of phase transitions between superfluid, normal and insulating phases is an area with many unanswered questions and experimental evidence remains scarce in certain important cases. In this thesis, we focus on systems of two-dimensional (2D) Bose gases subjected to a pointlike disorder potential. We trap atoms in radiofrequency dressed potentials and apply the technique of multiple-radiofrequency dressing to create a double-well potential into which we load the ultracold atoms. Matter-wave interferometry allows us to directly probe the local relative phase and its fluctuations between the clouds in the two potential wells. A pointlike disordered optical potential is produced by a high-intensity laser beam which is shaped by a programmable mirror array and passes through clouds in both of the wells. We adiabatically apply disordered potentials of increasing strength to observe their effect on the superfluids in equilibrium in a double-well. We observe that above a critical disorder strength the superfluid undergoes a transition to the normal phase at a lower temperature than that of the disorder-free case, and we characterise this disorder-induced transition. We also study the flow of a 2D superfluid cloud around both a single defect and a random potential and measure the dissipation induced by the obstacles. The absence of dissipation is observed below a critical velocity in the case of a single defect but we find no such dissipationless regime for the disordered potential. We describe the development of a software simulation package for modelling cold-atom systems and the implementation of particle collisions, magnetic trapping and evaporative cooling. Finally, we report on the initial work towards construction of a new cold-atom apparatus, capable of faster sequence times and greater atom numbers, to continue our investigation of many-body physics.