Criticality and phase diagram of quantum long-range O(N) models
Year: 2017
Authors: Defenu N., Trombettoni A., Ruffo S.
Autors Affiliation: Heidelberg Univ, Inst Theoret Phys, D-69120 Heidelberg, Germany; CNR, IOM DEMOCRITOS Simulat Ctr, Via Bonomea 265, I-34136 Trieste, Italy; SISSA, Via Bonomea 265, I-34136 Trieste, Italy; Ist Nazl Fis Nucl, Sez Trieste, I-34151 Trieste, Italy.
Abstract: 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.
Journal/Review: PHYSICAL REVIEW B
Volume: 96 (10) Pages from: 104432-1 to: 104432-11
KeyWords: Renormalization-group; Derivative Expansion; Spherical Model; Field-theory; Cold Atoms; Lattice; Ferromagnets; Propagation; Crossover; SimulatorDOI: 10.1103/PhysRevB.96.104432Citations: 79data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-10-20References taken from IsiWeb of Knowledge: (subscribers only)