Coupled Dynamics for Superfluid $$^4\hbox {He}$$ 4 He in a Channel

Superfluid 4 He weak links

Superfluid He weak links

Dissipative dynamics of vortex lines in superfluid 4 He

We propose a Hamiltonian model that describes the interaction between a vortex line in superfluid He and the gas of elementary excitations. An equation of irreversible motion for the density operator of the vortex, regarded as a macroscopic quantum particle with a finite mass, is derived in the frame of Generalized Master Equations. This enables us to cast the effect of the coupling as a drag f...

Dispersion of Ripplons in Superfluid 4 He

A detailed study of the dispersion law of surface excitations in liquid 4He at zero temperature is presented, with special emphasis to the short wave length region. The hybridization mechanism between surface and bulk modes is discussed on a general basis, investigating the scattering of slow rotons from the surface. An accurate density functional, accounting for backflow effects, is then used ...

Acoustic Turbulence in Superfluid 4 He

Surprising behavior of the superfluid fraction for 4 He and 3 He - 4 He mixtures in 18 . 5 nm channels

We have obtained the superfluid fraction of He and mixtures confined in channels 0.0185μm×1.08μm×∞ . We compare this with film data L×∞ ×∞, and data for channels 0.0483μm×3.0μm×∞ . The behavior of the data in the smallest channels is quite different from what one might expect for a planar film of a given thickness. The transition is shifted to a lower temperature than expected; and, the overall...