Quantum criticality of dipolar spin chains
Strongly Correlated Electrons
2011-11-28 v3 Statistical Mechanics
Abstract
We show that a chain of Heisenberg spins interacting with long-range dipolar forces in a magnetic field h perpendicular to the chain exhibits a quantum critical point belonging to the two-dimensional Ising universality class. Within linear spin-wave theory the magnon dispersion for small momenta k is [Delta^2 + v_k^2 k^2]^{1/2}, where Delta^2 \propto |h - h_c| and v_k^2 \propto |ln k|. For fields close to h_c linear spin-wave theory breaks down and we investigate the system using density-matrix and functional renormalization group methods. The Ginzburg regime where non-Gaussian fluctuations are important is found to be rather narrow on the ordered side of the transition, and very broad on the disordered side.
Cite
@article{arxiv.1108.6064,
title = {Quantum criticality of dipolar spin chains},
author = {Aldo Isidori and Annika Ruppel and Andreas Kreisel and Peter Kopietz and Alexander Mai and Reinhard M. Noack},
journal= {arXiv preprint arXiv:1108.6064},
year = {2011}
}
Comments
6 pages, 5 figures