Related papers: Dissipation in mesoscale superfluids
Using molecular dynamics simulations, we study supercritical fluids near the gas-liquid critical point under heat flow in two dimensions. We calculate the steady-state temperature and density profiles. The resultant thermal conductivity…
Turbulent drag of an oscillating microsphere, that is levitating in superfluid $^4$He at mK temperatures, is unstable slightly above a critical velocity amplitude $v_c$. The lifetime $\tau$ of the turbulent state is determined by the number…
We have examined superfluid properties of $^4$He confined to a nano-porous Gelsil glass that has nanopores 2.5 nm in diameter. The pressure-temperature phase diagram was determined by torsional oscillator, heat capacity and pressure…
Superfluidity is a well-characterized quantum phenomenon which entails frictionless-motion of mesoscopic particles through a superfluid, such as $^4$He or dilute atomic-gases at very low temperatures. As shown by Landau, the incompatibility…
A kinetic flux-splitting procedure used in conjunction with local thermodynamic equilibrium in a finite volume allows us to investigate numerically discrete-velocity gas flows. The procedure, outlined for a general discrete-velocity gas, is…
We consider a mean curvature flow in a cone, that is, a hypersurface in a cone which moves toward the opening with normal velocity equaling to the mean curvature, and the contact angle between the hypersurface and the cone boundary being…
We have studied the interaction of metastable $^4$He$_2^*$ excimer molecules with quantized vortices in superfluid $^4$He in the zero temperature limit. The vortices were generated by either rotation or ion injection. The trapping diameter…
We study the metastability and decay of multiply-charged superflow in a ring-shaped atomic Bose-Einstein condensate. Supercurrent corresponding to a giant vortex with topological charge up to q=10 is phase-imprinted optically and detected…
Resistance in superconductors arises from the motion of vortices driven by flowing supercurrents or external electromagnetic fields and may be strongly affected by thermal or quantum fluctuations. The common expectation borne out in…
To reveal a microscopic mechanism for the anomalous minimization and dependence of the superfluid critical velocity on a moving obstacle potential in a atomic Bose-Einstein condensate…
Miniature heaters are immersed in flows of quantum fluid and the efficiency of heat transfer is monitored versus velocity, superfluid fraction and time. The fluid is $^4$He helium with a superfluid fraction varied from 71% down to 0% and an…
In this work we study the process of depinning of a quantum of circulation trapped inside a disk by an applied two dimensional superflow. We use the Gross-Pitaevskii model to describe the neutral superfluid. The collective coordinate…
We formulate dissipative magnetohydrodynamic equations for finite-temperature superfluid and superconducting charged relativistic mixtures, taking into account the effects of particle diffusion and possible presence of Feynman-Onsager…
Quantum phase slips, i.e the primary excitations in one-dimensional superfluids at low temperature, have been well characterized in most condensed-matter systems, with the notable exception of ultracold quantum gases. Here we present our…
In superconductors where the coherence length is comparable to the Fermi wavelength, the electronic levels within a vortex core are quantized, and separated by energies of the order of the superconducting gap. The absence of a continuum…
We present a microscopic open quantum systems theory of thermally-damped vortex motion in oblate atomic superfluids that includes previously neglected energy-damping interactions between superfluid and thermal atoms. This mechanism couples…
Superfluid Turbulence is unusual and presents a challenge to fluid dynamicists because it consists of two coupled, inter penetrating turbulent fluids: the first is inviscid with quantised vorticity, the second is viscous with continuous…
We examine the transverse and longitudinal components of the drag force upon a straight vortex line due to the scattering of liquid $^4$He excitations. For this purpose, we consider a recently proposed Hamiltonian that describes the…
We propose a new theoretical approach to the excitation spectrum of superfluid ${^4}He$. It is based on the assumption that, in addition to the usual Feynman density fluctuations, there exist localized modes which describe the short range…
Driven by fundamental thermodynamic efficiency considerations, an emerging trend in the energy and propulsion systems is that the working fluid operates at a pressure above the critical pressure. Energy transport is thus accompanied by…