Phase diagram and pair Tomonaga-Luttinger liquid in a Bose-Hubbard model with flat bands

被引：78

作者：

Takayoshi, Shintaro ^{[1
]}

Katsura, Hosho ^{[2
]}

Watanabe, Noriaki ^{[3
,4
]}

Aoki, Hideo ^{[3
]}

机构：

[1] Natl Inst Mat Sci, Tsukuba, Ibaraki 3050047, Japan

[2] Gakushuin Univ, Dept Phys, Tokyo 1718588, Japan

[3] Univ Tokyo, Dept Phys, Tokyo 1130033, Japan

[4] Univ Tokyo, Kavli Inst Phys & Math Universe, Kashiwa, Chiba 2778583, Japan

来源：

PHYSICAL REVIEW A | 2013年 / 88卷 / 06期

关键词：

SURFACE-ENERGY; FERROMAGNETISM; FIELDS; STATES;

D O I：

10.1103/PhysRevA.88.063613

中图分类号：

O43 [光学];

学科分类号：

070207 ; 0803 ;

摘要：

To explore superfluidity in flat-band systems, we consider a Bose-Hubbard model on a cross-linked ladder with p flux, which has a flat band with a gap between the other band for noninteracting particles, where we study the effect of the on-site repulsion nonperturbatively. For low densities, we find exact degenerate ground states, each of which is a Wigner solid with nonoverlapping Wannier states on the flat band. At higher densities, the many-body system, when projected onto the lower flat band, can be mapped to a spin-chain model. This mapping enables us to reveal the existence of a Tomonaga-Luttinger liquid comprising pairs of bosons. Interestingly, the high- and low-density regions have an overlap, where the two phases coexist.

引用

页数：5

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