Criticality and phase diagram of quantum long-range O(N) models

Article

关键词: RENORMALIZATION-GROUP;    DERIVATIVE EXPANSION;    SPHERICAL MODEL;    FIELD-THEORY;    COLD ATOMS;    LATTICE;    FERROMAGNETS;    PROPAGATION;    CROSSOVER;    SIMULATOR;   

DOI  :  10.1103/PhysRevB.96.104432

来源: SCIE

【 摘 要 】

Several recent experiments in atomic, molecular, and optical systems motivated a huge interest in the study of quantum long-range systems. Our goal in this paper is to present a general description of their critical behavior and phases, devising a treatment valid in d dimensions, with an exponent d + sigma for the power-law decay of the couplings in the presence of an O(N) symmetry. By introducing a convenient ansatz for the effective action, we determine the phase diagram for the N-component quantum rotor model with long-range interactions, with N = 1 corresponding to the Ising model. The phase diagram in the sigma-d plane shows a nontrivial dependence on sigma. As a consequence of the fact that the model is quantum, the correlation functions are anisotropic in the spatial and time coordinates for sigma smaller than a critical value, and in this region the isotropy is not restored even at criticality. Results for the correlation length exponent nu, the dynamical critical exponent z, and a comparison with numerical findings for them are presented.

【 授权许可】

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