Nonperturbative renormalization group treatment of amplitude fluctuations for |φ| 4 topological phase transitions

Year: 2017

Authors: Defenu N., Trombettoni A., Nbndori I., Enss T.

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; INFN, Sez Trieste, Via Bonomea 265, I-34136 Trieste, Italy; MTA DE Particle Phys Res Grp, POB 51, H-4001 Debrecen, Hungary; MTA Atomki, POB 51, H-4001 Debrecen, Hungary; Univ Debrecen, POB 105, H-4010 Debrecen, Hungary.

Abstract: The study of the Berezinskii-Kosterlitz-Thouless transition in two-dimensional |phi|(4) models can be performed in several representations, and the amplitude-phase (AP) Madelung parametrization is a natural way to study the contribution of density fluctuations to nonuniversal quantities. We introduce a functional renormalization group scheme in AP representation where amplitude fluctuations are integrated first to yield an effective sine-Gordon model with renormalized superfluid stiffness. By a mapping between the lattice XY and continuum |phi|(4) models, our method applies to both on equal footing. Our approach correctly reproduces the existence of a line of fixed points and of universal thermodynamics and it allows to estimate universal and nonuniversal quantities of the two models, finding good agreement with available Monte Carlo results. The presented approach is flexible enough to treat parameter ranges of experimental relevance.

Journal/Review: PHYSICAL REVIEW B

Volume: 96 (17)      Pages from: 174505-1  to: 174505-16

More Information: The authors wish to thank L. Benfatto, C. Castellani, N. Dupuis, G. Gori, Z. Gulacsi, H. Knorrer, J. Lorenzana, and I. Maccari for insightful discussions. We also thank M. Hasenbusch and N. Prokofev for useful correspondence. This work is part of and supported by the Deutsche Forschungsgemeinschaft Collaborative Research Centre SFB 1225 (ISOQUANT). T.E. thanks the Erwin-Schrodinger Institute in Vienna for hospitality during the initial stages of this work. This work was supported by the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences. A.T. and I. N. acknowledge financial support from Progetto Premiale ABNANOTECH. N.D. and A.T. thank the Institut Henri Poincare-Centre Emile Borel for hospitality, where the final part of this work was done during the trimester Stochastic Dynamics Out of Equilibrium.
KeyWords: 2-dimensional Xy Model; Monte-carlo; Coulomb Gas; Magnetization; Temperature; Equation
DOI: 10.1103/PhysRevB.96.174505

Citations: 21
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