Lattice twist operators and vertex operators in sine-Gordon theory in one dimension

Article

关键词: NEAREST-NEIGHBOR INTERACTIONS;    MECHANICAL POSITION-OPERATOR;    HUBBARD CHAIN;    EXTENDED SYSTEMS;    PHASE-DIAGRAM;    SPIN CHAINS;    MODEL;    LOCALIZATION;    POLARIZATION;    TRANSITIONS;   

DOI  :  10.1103/PhysRevB.65.153110

来源: SCIE

【 摘 要 】

In one dimension, the exponential position operators introduced in a theory of polarization are identified with the twist operators appearing in the Lieb-Schultz-Mattis argument, and their finite-size expectation values z(L)((q)) measure the overlap between the q-fold degenerate ground state and an excited state. Insulators are characterized by z(infinity)not equal0, and different states are distinguished by the sign of z(L). We identify z(L) with ground-state expectation values of vertex operators in the sine-Gordon model. This allows an accurate detection of quantum phase transitions in the universality classes of the Gaussian and the SU(2)(1) Wess-Zumino-Novikov-Witten models. We apply this theory to the half-filled extended Hubbard model and obtain agreement with the level-crossing method.

【 授权许可】

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