Characterizing the nature of superfluid to Mott-insulator transitions via microwave spectroscopy

Superfluid to Mott-insulator quantum phase transitions can be first order or second order in a spin-1 sodium spinor Bose-Einstein condensate confined by a three-dimensional optical lattice. This is mainly due to the antiferromagnetic nature of spin-dependent interactions in the sodium system. We experimentally demonstrate that the nature of the phase transitions in spinor condensates can be characterized via microwave spectroscopy in a quantum quench scenario. A comparison between our observations and the mean-field theory is also discussed.