English

Sarma phase in relativistic and non-relativistic systems

Quantum Gases 2015-01-26 v2 High Energy Physics - Phenomenology Nuclear Theory

Abstract

We investigate the stability of the Sarma phase in two-component fermion systems in three spatial dimensions. For this purpose we compare strongly-correlated systems with either relativistic or non-relativistic dispersion relation: relativistic quarks and mesons at finite isospin density and spin-imbalanced ultracold Fermi gases. Using a Functional Renormalization Group approach, we resolve fluctuation effects onto the corresponding phase diagrams beyond the mean-field approximation. We find that fluctuations induce a second order phase transition at zero temperature, and thus a Sarma phase, in the relativistic setup for large isospin chemical potential. This motivates the investigation of the cold atoms setup with comparable mean-field phase structure, where the Sarma phase could then be realized in experiment. However, for the non-relativistic system we find the stability region of the Sarma phase to be smaller than the one predicted from mean-field theory. It is limited to the BEC side of the phase diagram, and the unitary Fermi gas does not support a Sarma phase at zero temperature. Finally, we propose an ultracold quantum gas with four fermion species that has a good chance to realize a zero-temperature Sarma phase.

Keywords

Cite

@article{arxiv.1409.5232,
  title  = {Sarma phase in relativistic and non-relativistic systems},
  author = {I. Boettcher and T. K. Herbst and J. M. Pawlowski and N. Strodthoff and L. von Smekal and C. Wetterich},
  journal= {arXiv preprint arXiv:1409.5232},
  year   = {2015}
}

Comments

version published in Phys.Lett.B; 10 pages, 5 figures