Strongly-interacting bosons at 2D-1D dimensional crossover

Quantum gases at dimensional crossover exhibit fruitful physics which reflects special properties of non-integer dimensions. While various fascinating researches have been carried out in the tight-binding limit [1-3], the smooth dimensional crossover for strongly-interacting bosons in continuous lattice, which is beyond mean-field theory and strongly adapted to current generation of experiments, is rarely studied. In this talk, I will present our study about strongly-interacting bosons under continuous potential at 2D-1D dimensional crossover [4]. Using exact quantum Monte Carlo calculations, we investigate this dimensional crossover by computing longitudinal and transverse superfluid fractions as well as the superfluid correlation as a function of temperature, interactions and potential. We find the special behavior of longitudinal superfluidity at the crossover which signatures the interplay of dimensionalities. Moreover, we show the correlation function evolves from a Berezinskii-Kosterlitz-Thouless (BKT) to Tomonaga-Luttinger liquid (TLL) type, with the coexistence of 2D and 1D behaviors appearing at the dimensional crossover. In the end, I will discuss how the consequences of the dimensional crossover can be investigated in cold atomic gases experiments.