Quantum coherence and ground-state phase transition in a four-chain Bose–Hubbard model  

作　　者：Ji-Guo Wang Lin-Qi Guo Ya-Fei Song 

机构地区：[1]Department of Mathematics and Physics,Shijiazhuang TieDao University,Shijiazhuang 050043,China [2]Institute of Applied Physics,Shijiazhuang TieDao University,Shijiazhuang 050043,China

出　　处：《Communications in Theoretical Physics》2021年第8期182-188,共7页理论物理通讯（英文版）

基　　金：the NSF of China under Grant No.11904242;the NSF of Hebei province under Grant No.A2019210280。

摘　　要：We study the quantum coherence and ground-state phase transition of a four-chain Bose–Hubbard model with the long-range interaction. In a special four-chain Bose–Hubbard model,i.e., each chain only has one optical potential, four types of the ground-state phases are discovered. The effects of the disorder, the on-site interaction and the long-range interaction on the quantum coherence are studied. For the system without the long-range interaction, the quantum coherence changes from one periodic oscillation to two periodic oscillations as the onsite interaction increases. By considering the long-range interaction, the quantum coherence goes back to one periodic oscillation again. The on-site interaction itself suppresses the quantum coherence, both the on-site interaction and long-range interaction together enhance the quantum coherence with the weak disorder. If the disorder strength is increased beyond a critical value,they start to suppress the quantum coherence. In a regular four-chain Bose–Hubbard model, i.e.,each chain has many optical potentials, the ground-state phase transitions are obtained by using the cluster Gutzwiller mean-field method. Exotic ground-state phases are found, i.e., superfluid phase, integer Mott insulator phase, supersolid phase and loophole insulator phase. The combination of the loophole insulator phase and the supersolid phase expands the lobes with the half-integer filling per site for the small ratio β = t_(‖)/t_(⊥).

关 键 词：Bose-Hubbard model quantum coherence ground-state phase transition 

分 类 号：O469[理学—凝聚态物理]