We study finite-temperature phase structures of hard-core bosons in a two-dimensional optical lattice subject to an effective magnetic field by employing the gauged CP
1 model. Based on the extensive Monte Carlo simulations, we study their phase structures at finite temperatures for several values of the magnetic flux per plaquette of the lattice and mean particle density. Despite the presence of the particle number fluctuation, the thermodynamic properties are qualitatively similar to those of the frustrated
XY model, with only the phase as a dynamical variable. This suggests that cold-atom simulators of the frustrated
XY model are available irrespective of the particle filling at each site.
We study the dynamical properties of bosons in an optical lattice subject to a synthetic magnetic field at zero temperature. First, we consider a superfluid regime where the nearest-neighbor hopping is much larger than the on-site repulsion and a large number of bosons are occupied in each site. Then, the dynamics is well described by the discrete nonlinear Schrödinger equation. Second, we study the dynamics of hard-core bosons as a limit of the strong interparticle interaction by solving the truncated Green's functions for the boson and density operators. We discuss the evolution of the density and the vorticity, which are clearly distinct between two regimes.