Ground State Property of a One-Dimensional Bose–Hubbard Model Using Time-Evolving Body Decimation

We study the ground state property of the one-dimensional Bose–Hubbard model using an imaginary time evolving body decimation algorithm. The single-particle density matrix is numerically calculated for a Mott insulating system and a superfluid system separately. By plotting the chemical potential versus the filling n=N/L for U/J=20 and U/J=0.1, we identify the Mott gap for U/J=20 in filling n=1. Lastly, we investigate the occupation number of the Bloch state with quasimomentum for a system deep in the Mott phase and in the superfluid phase respectively. The results indicate Bose condensation in the quasimomentum space.