Entanglement and the Mott transition in a rotating bosonic ring lattice

摘要: We use second- and fourth-order correlation functions accessible in time-of-flight images to investigate the effects of rotation on one-dimensional ultracold bosons confined a ring lattice. There exists critical frequency at which ground state weakly interacting integer-filled atomic gas is fragmented into macroscopic superposition two states with different circulation. The formation such quantum (``cat'') accompanied by opening gap spectrum, sudden rearrangement momentum distribution lowers threshold Mott insulator transition. show that both entangled character enhancement correlations can be detected density-density expanding cloud. Our studies demonstrate usefulness these for identifying physics cold systems.