Ring exchange, the exciton Bose liquid, and bosonization in two dimensions
Ring exchange, the exciton Bose liquid, and bosonization in two dimensions
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环交换、激子玻色液体和二维玻色化
DOI：
10.1103/physrevb.66.054526
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发表时间：
2002
影响因子：
3.7
通讯作者：
M. Fisher
中科院分区：
文献类型：
--
作者：
A. Paramekanti;L. Balents;M. Fisher
在高T_c铜酸盐的激励下，我们考虑了一个通过环交换在正方形晶格上运动的玻色子Cooper对的模型。我们发现，这个模型在传统的反铁磁Mott绝缘体和构成高温超导自旋-电荷分离场景的完全去禁闭的分馏相之间提供了一个天然的中间基点。结果表明，这种环模型存在一个稳定的二维临界相，即激子玻色液体~EBL！EBL是一种可压缩的态，具有无间隙但未凝聚的玻色子和“涡旋”激发，幂定律超导和电荷有序关联，以及宽谱函数。我们借助精确的斑块对偶变换来表征EBL，这促使了EBL的普遍低能量描述。该描述是关于一对双玻色相场的，并且是众所周知的一维玻色化方法的直接模拟。通过对环模型的精确对偶形式的数值模拟，验证了低能描述的有效性。讨论了与高T_c超导体的关联以及对其他系统的各种扩展，包括二维费米环模型的玻色化。
Motivated by the high-Tc cuprates, we consider a model of bosonic Cooper pairs moving on a square lattice via ring exchange. We show that this model offers a natural middle ground between a conventional antiferromagnetic Mott insulator and the fully deconfined fractionalized phase that underlies the spin-charge separation scenario for high-Tc superconductivity. We show that such ring models sustain a stable critical phase in two dimensions, the exciton Bose liquid ~EBL!. The EBL is a compressible state, with gapless but uncondensed boson and ‘‘vortex’’ excitations, power-law superconducting and charge-ordering correlations, and broad spectral functions. We characterize the EBL with the aid of an exact plaquette duality transformation, which motivates a universal low-energy description of the EBL. This description is in terms of a pair of dual bosonic phase fields, and is a direct analog of the well known one-dimensional bosonization approach. We verify the validity of the low-energy description by numerical simulations of the ring model in its exact dual form. The relevance to the high-Tc superconductors and a variety of extensions to other systems are discussed, including the bosonization of a two-dimensional fermionic ring model.