We present a functional renormalization group analysis of a quantum critical point in a two-dimensional metal involving Fermi surface reconstruction due to the onset of spin density wave order. The critical theory is controlled by a fixed point in which the order parameter and fermionic quasiparticles are strongly coupled, and acquire spectral functions with a common dynamic critical exponent. ...

We consider the BCS-BEC (Bose-Einstein-condensate) crossover for a system of trapped Fermi atoms at finite temperature, both below and above the superfluid critical temperature, by including fluctuations beyond mean field. We determine the superfluid critical temperature and the pair-breaking temperature as functions of the attractive interaction between Fermi atoms, from the weak- to the stron...

In this work we study the behavior of relativistic ideal Bose and Fermi gases in two space dimensions. Making use of polylogarithm functions we derive a closed and unified expression for their densities. It is shown that both type of gases are essentially inequivalent, and only in the non-relativistic limit the spinless and equal mass Bose and Fermi gases are equivalent as known in the literature.

We use a bosonization approach to show that the momentum distribution nk of normal Fermi systems with sufficiently singular interactions is analytic in the vicinity of the non-interacting Fermi surface. These include singular density-density interactions that diverge in d dimensions stronger than |q|−2(d−1) for vanishing momentum transfer q, but also fermions that are coupled to transverse gaug...