Double peaks in the momentum distribution of cold polar molecules in the supersolid state

We study the checkerboard supersolid of hard-core bosonic polar molecules in a 2D square lattice. This supersolid shows a novel double-peak structure in the momentum distribution of bosons. The double peaks indicate coexistence of superfluidity and solidility. The corresponding peaks can be measured by the time-of-flight experiment and will become a clear evidence for the supersolid state. By exact quantum Monte Carlo calculations, we reveal temperature dependence of the momentum distribution in the supersolid phase. As a result, we observe successive developments of the two peaks.