Breakdown of superfluidity in liquid helium

Superfluidity in Solid Helium-4

Superfluidity in a doped helium droplet.

Path-integral Monte Carlo calculations of the superfluid density throughout 4He droplets doped with linear impurities are presented. After deriving a local estimator for the superfluid density distribution, we find a decreased superfluid response in the cylindrically symmetric region of the first solvation layer. The helium in this region has a superfluid transition temperature similar to that ...

Breakdown of Counterflow Superfluidity in a Disordered QuantumHall Bilayer

We present a theory for the regime of coherent interlayer tunneling in a disordered quantum Hall bilayer at total filling factor one, allowing for the effect of static vortices. We find that the system consists of domains of polarized superfluid phase. Injected currents introduce phase slips between the polarized domains which are pinned by disorder. We present a model of saturated tunneling do...

Breakdown of superfluidity of an atom laser past an obstacle

The 1D 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 supe...

Color Superfluidity and Chiral Symmetry Breakdown in Dense Qcd Matter

We describe the interplay of two nonperturbative phenomena which should take place in the chirally invariant deconfined phase of QCD matter at finite density and T=0 : (i) Cooper-pair quark-quark ground-state condensation in appropriate channels should yield exotic sorts of color superfluidity, and (ii) quark-antiquark ground-state condensation should yield spontaneous breakdown of chiral symme...