Effects of Disorder on Superfluids

This paper was about the effects of disorder on superfluids and specifically how the the superfluid self-averages as we approach the SF-BG phase boundary. This is a critical question because it gives us insight into the robustness of superfluid to effects of disorder together with critical fluctuations. Top left image shows the superfluid fraction that measures the amount of superfluid in the system as we change the interaction strength (U/t) and the disorder strength ($\Delta/U$). Top right image shows how the superfluid fraction changes with interaction strength for different types of disorder distribution. Bottom image shows the self-averaging property of the system. It is remarkable that the superfluid can self-average even in the limit of critical fluctuations.