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Observations of quantum turbulence in pure superfluid 4He in a rotating container are reported. New techniques of large-scale forcing (rotational oscillations of the cubic container) and detecting (monitoring ion transport along the axis of…

Other Condensed Matter · Physics 2012-09-25 P. M. Walmsley , A. I. Golov

The dynamics of superfluid 4He at and above the Landau quasiparticle regime is investigated by high precision inelastic neutron scattering measurements of the dynamic structure factor. A highly structured response is observed above the…

We have studied self-sustained, deformable, rotating liquid He cylinders of infinite length. In the normal fluid $^3$He case, we have employed a classical model where only surface tension and centrifugal forces are taken into account, as…

Mesoscale and Nanoscale Physics · Physics 2023-03-24 Martí Pi , Francesco Ancilotto , Manuel Barranco , Samuel L. Butler , José María Escartín

Kim and Chan have recently observed Non-Classical Rotational Inertia (NCRI) for solid $^4$He in Vycor glass, gold film, and bulk. Their low $T$ value of the superfluid fraction, $\rho_{s}/\rho\approx0.015$, is consistent with what is known…

Other Condensed Matter · Physics 2009-11-10 Wayne M. Saslow

Fluids consisting of hard platelike particles near a hard wall are investigated using density functional theory. The density and orientational profiles as well as the surface tension and the excess coverage are determined and compared with…

Statistical Mechanics · Physics 2009-11-07 L. Harnau , S. Dietrich

The onset mechanism of superfluidity is examined by taking the case of the capillary flow of liquid helium 4. In the capillary flow, a substantial fall of the shear viscosity has been observed in the normal phase (lambda point<T<3.7K). In…

Superconductivity · Physics 2008-09-01 Shun-ichiro Koh

I present here a microscopic theory for the superfluidity of $^4$He (He II) derived from experiments, and answer its essential questions. With a "momenton" model, the superfluid is shown to feature as a "harmonic superfluid". In which a new…

Condensed Matter · Physics 2007-05-23 J. X. Zheng-Johansson

The thermo-mechanical effect in superfluid helium is used to create an initial chemical potential difference, $\Delta \mu_0$, across a solid $^4$He sample. This $\Delta \mu_0$ causes a flow of helium atoms from one reservoir filled with…

Other Condensed Matter · Physics 2015-06-22 Ye. Vekhov , R. B. Hallock

The properties of a vortex in a rotating superfluid Fermi gas are studied in the unitary limit. A phenomenological approach based on Ginzburg-Landau theory is developed for this purpose. The density profiles, including those of the normal…

Other Condensed Matter · Physics 2009-11-11 Meng Gao , Hongyu Wu , Lan Yin

We propose a phenomenological equation for the vortex line density in rotating Bose-Einstein condensates as a function of the angular speed. This equation provides a simple description of the gross features of the increase in vortex number…

Other Condensed Matter · Physics 2007-12-12 Michele Sciacca , David Jou , Maria Stella Mongioví

The flow of superfluid helium at very low temperatures around an oscillating microsphere is known to be unstable slightly above the critical velocity. The flow pattern switches intermittently between potential flow and turbulence. From time…

Other Condensed Matter · Physics 2015-05-19 Wilfried Schoepe

The fact, that $^4$He atoms on different concentric circular paths around the axis of a quantum vortex move with identically equal angular momentum, which represents an important aspect of superfluidity of He-II, has been used to discover a…

Other Condensed Matter · Physics 2012-03-28 Yatendra S. Jain , Samrat Dey

The superfluid density near the superconducting transition is investigated in the presence of spatial inhomogeneity in the critical temperature. Disorder is accounted for by means of a random $T_c$ term in the conventional Ginzburg-Landau…

Superconductivity · Physics 2009-11-13 D. Dalidovich , A. J. Berlinsky , C. Kallin

We present a superfluid hydrodynamic model for the increase in moment of inertia, $\Delta I$, of molecules rotating in liquid $^4$He. The static inhomogeneous He density around each molecule (calculated using the Orsay-Paris liquid $^4$He…

Condensed Matter · Physics 2009-10-31 C. Callegari , A. Conjusteau , I. Reinhard , K. K. Lehmann , G. Scoles , F. Dalfovo

Evidence for a new type of superfluid phase in second-layer $^4$He on graphite has been obtained from simultaneous measurements of torsional-oscillator response and heat-capacity on exactly the same sample down to 30 mK, which resolve…

Other Condensed Matter · Physics 2026-01-12 Jun Usami , Hiroshi Fukuyama

Mixed $^3$He-$^4$He droplets created by hydrodynamic instability of a cryogenic fluid-jet may acquire angular momentum during their passage through the nozzle of the experimental apparatus. These free-standing droplets cool down to very low…

Quantum Gases · Physics 2020-08-12 Marti Pi , Francesco Ancilotto , Jose' Maria Escartin , Ricardo Mayol , Manuel Barranco

The probability of evaporation induced by $R^+$ and $R^-$ rotons at the surface of superfluid helium is calculated using time dependent density functional theory. We consider excitation energies and incident angles such that phonons do not…

Condensed Matter · Physics 2009-10-28 F. Dalfovo , A. Fracchetti , A. Lastri , L. Pitaevski , S. Stringari

An equation previously proposed to describe the evolution of vortex line density in rotating counterflow turbulent tangles in superfluid helium is generalized to incorporate nonvanishing barycentric velocity and velocity gradients. Our…

Other Condensed Matter · Physics 2009-11-13 David Jou , Michele Sciacca , Maria Stella Mongiovi'

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…

Materials Science · Physics 2023-11-15 Alberto Ambrosetti , Pier Luigi Silvestrelli , Luca Salasnich

We study the superfluid phase of the one-band attractive Hubbard model of fermions as a prototype of a strongly correlated s-wave fermion superfluid on a lattice. We show that the collective mode spectrum of this superfluid exhibits, in…

Superconductivity · Physics 2009-10-29 R. Ganesh , A. Paramekanti , A. A. Burkov