4 research outputs found
Quantum Phase Slips: from condensed matter to ultracold quantum gases
Quantum phase slips are the primary excitations in one-dimensional
superfluids and superconductors at low temperatures. They have been well
characterized in most condensed-matter systems, and signatures of their
existence has been recently observed in superfluids based on quantum gases too.
In this review we briefly summarize the main results obtained on the
investigation of phase slips from superconductors to quantum gases. In
particular we focus our attention on recent experimental results of the
dissipation in one-dimensional Bose superfluids flowing along a shallow
periodic potential, which show signatures of quantum phase slips.Comment: 10 pages, 6 figure
Velocity-dependent quantum phase slips in 1D atomic superfluids
Quantum phase slips are the primary excitations in one-dimensional
superfluids and superconductors at low temperatures but their existence in
ultracold quantum gases has not been demonstrated yet. We now study
experimentally the nucleation rate of phase slips in one-dimensional
superfluids realized with ultracold quantum gases, owing along a periodic
potential. We observe a crossover between a regime of temperature-dependent
dissipation at small velocity and interaction and a second regime of
velocity-dependent dissipation at larger velocity and interaction. This
behavior is consistent with the predicted crossover from thermally-assisted
quantum phase slips to purely quantum phase slips.Comment: 7 pages, 6 figure
Exploring quantum phase slips in 1D bosonic systems
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 experimental investigation of the dissipation in one-dimensional Bose superfluids flowing along a periodic potential, which show signatures of the presence of quantum phase slips. In particular, by controlling the velocity of the superfluid and the interaction between the bosons we are apparently able to drive a crossover from a regime of thermal phase slips into a regime of quantum phase slips. Achieving a good control of quantum phase slips in ultracold quantum gases requires to keep under control other phenomena such as the breaking of superfluidity at the critical velocity or the appearance of a Mott insulator in the strongly correlated regime. Here we show our current results in these directions