Momentum Distribution and Contact of the Unitary Fermi gas

Understand

We calculate the momentum distribution n(k) of the Unitary Fermi Gas using Quantum Monte Carlo calculations at finite temperature T/\epsilon_F as well as in the ground state.

• At large momenta k/k_F, we find that n(k) falls off as C/k^4, in agreement with the Tan relations.
• From the asymptotics of n(k), we determine the contact C as a function of T/\epsilon_F and present a comparison with theory.
• At low T/\epsilon_F, we find that C increases with temperature, and we tentatively identify a maximum around T/\epsilon_F \simeq 0.4.