English

Ultra-cold fermions in real or fictitious magnetic fields: The BCS-BEC evolution and the type-I--type-II transition

Quantum Gases 2015-05-18 v2 Superconductivity

Abstract

We study ultra-cold neutral fermion superfluids in the presence of fictitious magnetic fields, as well as charged fermion superfluids in the presence of real magnetic fields. Charged fermion superfluids undergo a phase transition from type-I to type-II superfluidity, where the magnetic properties of the superfluid change from being a perfect diamagnet without vortices to a partial diamagnet with the emergence of the Abrikosov vortex lattice. The transition from type-I to type-II superfluidity is tunned by changing the scattering parameter (interaction) for fixed density. We also find that neutral fermion superfluids such as 6^6Li and 40^{40}K are extreme type-II superfluids, and that they are more robust to the penetration of a fictitious magnetic field in the BCS-BEC crossover region near unitarity, where the critical fictitious magnetic field reaches a maximum as a function of the scattering parameter (interaction).

Keywords

Cite

@article{arxiv.1003.2405,
  title  = {Ultra-cold fermions in real or fictitious magnetic fields: The BCS-BEC evolution and the type-I--type-II transition},
  author = {M. Iskin and C. A. R. Sa de Melo},
  journal= {arXiv preprint arXiv:1003.2405},
  year   = {2015}
}

Comments

4+ pages with 2 figures