## Thermodynamics of balanced and slightly spin-imbalanced Fermi gases at unitarity

In this article we present a Monte Carlo calculation of the critical temperature and other thermodynamic quantities for the unitary Fermi gas with a population imbalance (unequal number of fermions in the two spin components). We describe an improved worm-type algorithm that is less prone to autocorrelations than the previously available methods and show how this algorithm can be applied to simulate the unitary Fermi gas in presence of a small imbalance. Our data indicate that the critical temperature remains almost constant for small imbalances h={Delta}{mu}/{epsilon}{sub F} < or approx. 0.2. We obtain the continuum result T{sub c}=0.171(5){epsilon}{sub F} inmore »