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Single-particle momentum spectra for a dynamically evolving one-dimensional Bose gas are analysed in the semi-classical wave limit. Representing one of the simplest correlation functions these give information about possible universal…

Quantum Gases · Physics 2012-07-06 Maximilian Schmidt , Sebastian Erne , Boris Nowak , Dénes Sexty , Thomas Gasenzer

Historically, there is little faith in particle tracking velocimetry (PTV) as a tool to make quantitative measurements of thermal counterflow in He II, since tracer particle motion is complicated by influences from the normal fluid,…

Other Condensed Matter · Physics 2019-02-13 Brian Mastracci , Wei Guo

Recently, it has been experimentally confirmed that non-equilibrium dynamics of phase separation in strongly ferromagnetic Bose-Einstein condensates of $^7$Li atoms obey the dynamic scaling law belonging to the binary-fluid universality…

Quantum Gases · Physics 2025-06-19 Ryuta Ito , Hiromitsu Takeuchi

We study the dynamics of a Bose-Einstein condensate (BEC) in a one dimensional optical lattice in the limit of weak atom-atom interactions. Numerically we find that a BEC may develop a pulsating instability in which atoms nearly…

Other Condensed Matter · Physics 2009-09-29 Uttam Shrestha

A model to explain the statistics of the velocity gradients in the dissipation range of a turbulent flow is presented. The experimentally observed non-gaussian statistics is theoretically predicted by means of a thermodynamical analogy…

Statistical Mechanics · Physics 2007-05-23 Jacopo Bellazzini

We study the detailed out of equilibrium time evolution of a homogeneous Bose-Einstein condensate.We consider a nonrelativistic quantum theory for a self-interacting complex scalar field, immersed in a thermal bath, as an effective…

Soft Condensed Matter · Physics 2009-10-31 Daniel G. Barci , E. S. Fraga , Rudnei O. Ramos

An inverse turbulent cascade in a periodic square box produces a coherent system-sized vortex dipole. We study the statistics of its motion by carrying out direct numerical simulations performed for various bottom friction $\alpha$, pumping…

Fluid Dynamics · Physics 2024-01-25 Vladimir Parfenyev

The velocity fluctuations for point vortex models are studied for the {\alpha}-turbulence equations, which are characterized by a fractional Laplacian relation between active scalar and the streamfunction. In particular, we focus on the…

Fluid Dynamics · Physics 2019-09-11 Giovanni Conti , Gualtiero Badin

The dynamics of a Bose-Einstein condensate is studied theoretically in a combined periodic plus harmonic external potential. Different dynamical regimes of stable and unstable collective dipole and Bloch oscillations are analysed in terms…

Other Condensed Matter · Physics 2007-05-23 Joachim Brand , Andrey R. Kolovsky

Mathematical results on some models describing the motion of a tracer particle through a Bose-Einstein condensate are described. In the limit of a very dense, very weakly interacting Bose gas and for a very large particle mass, the dynamics…

Analysis of PDEs · Mathematics 2015-05-20 Juerg Froehlich , Zhou Gang , Avy Soffer

We derive a set of equations that describe the shape and behaviour of a single perturbed vortex line in a Bose-Einstein condensate. Through the use of a matched asymptotic expansion and a unique coordinate transform a relation for a…

Quantum Gases · Physics 2013-05-30 Lyndon Koens , Andrew M. Martin

We use the quantum kinetic theory to calculate the steady state and the fluctuations of a trapped Bose-Einstein condensate at finite temperature. The system is divided in a condensate and a non-condensate part. A quantum mechanical…

Statistical Mechanics · Physics 2009-10-30 D. Jaksch , C. W. Gardiner , K. M. Gheri , P. Zoller

Turbulent emulsions are ubiquitous in chemical engineering, food processing, pharmaceuticals, and other fields. However, our experimental understanding of this area remains limited due to the multi-scale nature of turbulent flow and the…

Fluid Dynamics · Physics 2025-04-08 Yaning Fan , Yi-Bao Zhang , Jinghong Su , Lei Yi , Cheng Wang , Chao Sun

Indistinguishability of particles is normally considered to be an inherently quantum property which cannot be possessed by a classical theory. However, Saunders has argued that this is incorrect, and that classically indistinguishable…

Statistical Mechanics · Physics 2007-05-23 Daniel Gottesman

A perturbative way to investigate superfluid properties of various systems under nonuniform potential is presented. We derive the perturbation expansion of the superfluid fraction, which indicates how liquid exhibits nonclassical rotational…

Quantum Gases · Physics 2016-12-21 Shinji Koshida , Yusuke Kato

We review fundamental problems involved in liquid theory including both classical and quantum liquids. Understanding classical liquids involves exploring details of their microscopic dynamics and its consequences. Here, we apply the same…

Statistical Mechanics · Physics 2025-01-28 K. Trachenko

By constructing a hydrodynamic canonical formalism, we show that the occurrence of an arbitrary density-dependent gauge potential in the meanfield Hamiltonian of a Bose-condensed fluid invariably leads to nonlinear flow-dependent terms in…

Quantum Gases · Physics 2021-01-06 Y. Buggy , L. G. Phillips , P. Öhberg

The possibility to derive an equation for the mean velocity field in turbulent flow by using classical statistical mechanics is investigated. An application of projection operator technique available in the literature is used for this…

Classical Physics · Physics 2007-05-23 J. Piest

We study the hydrodynamic forces acting on a small impurity moving in a two-dimensional Bose-Einstein condensate at non-zero temperature. The condensate is modelled by the damped-Gross Pitaevskii (dGPE) equation and the impurity by a…

We simulate the motion of a massive object through a dilute Bose-Einstein condensate by numerical solution of the non-linear Schr\"odinger equation coupled to an equation of motion for the object. Under a constant applied force, the object…

Condensed Matter · Physics 2009-10-31 T. Winiecki , C. S. Adams