Phase Diagram of the One-Dimensional t-U-X Model with Different Hubbard Interactions

俊 张

Zhiguo Wang, Yumei Zhang, Chen Hong

In the framework of nonperturbative quantum field theory, the critical phenomena of one-dimensional extended Hubbard model (EHM) at half-filling are discussed from weak to intermediate interactions. After the EHM being mapped into two decoupled sine-Gordon models, the ground state phase diagram of the system is derived in an explicit way. It is confirmed that the coexisting phases appear in different interaction regimes which cannot be found by conventional theoretical methods. The diagram shows that there are seven different phase regions in the ground state, which seems not to be the same as previous discussions, especially the boundary between the phase separation and condensed phase regions. The phase transition properties of the model between various phase regions are studied in detail.

R. T. Scalettar, Eugene Loh, James E. Gubernatis +5 more

Masaki Tezuka, Ryotaro Arita, Hideo Aoki

Till D. Kühner, H. Monien

The zero-temperature phase diagram of the one-dimensional Bose-Hubbard model with nearest-neighbor interaction is investigated using the density-matrix renormalization group. Recently normal phases without long-range order have been conjectured between the charge-density wave phase and the superfluid phase in one-dimensional bosonic systems without disorder. Our calculations demonstrate that there is no intermediate phase in the one-dimensional Bose-Hubbard model but a simultaneous vanishing of crystalline order and appearance of superfluid order. The complete phase diagrams with and without nearest-neighbor interaction are obtained. Both phase diagrams show reentrance from the superfluid phase to the insulator phase.

H. Q. Lin, Eduardo R. Gagliano, David K Campbell +2 more