Dynamical mean-field theory for quantum spin systems: Test of solutions for magnetically ordered states

Junya Otsuki, Yoshio Kuramoto

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

A spin version of dynamical mean-field theory is extended for magnetically ordered states in the Heisenberg model. The self-consistency equations are solved with high numerical accuracy by means of the continuous-time quantum Monte Carlo with bosonic baths coupled to the spin. The resultant solution is critically tested by known physical properties. In contrast with the mean-field theory, soft paramagnons appear near the transition temperature. Moreover, the Nambu-Goldstone mode (magnon) in the ferromagnetic phase is reproduced reasonably well. However, antiferromagnetic magnons have an energy gap in contradiction to the Nambu-Goldstone theorem. The origin of this failure is discussed in connection with the artificial first-order nature of the transition.

Original languageEnglish
Article number024427
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume88
Issue number2
DOIs
Publication statusPublished - Jul 30 2013
Externally publishedYes

Fingerprint

Mean field theory
magnons
Superconducting transition temperature
baths
Energy gap
theorems
Physical properties
physical properties
transition temperature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

@article{9f8f754f001e401899988a75887dd990,
title = "Dynamical mean-field theory for quantum spin systems: Test of solutions for magnetically ordered states",
abstract = "A spin version of dynamical mean-field theory is extended for magnetically ordered states in the Heisenberg model. The self-consistency equations are solved with high numerical accuracy by means of the continuous-time quantum Monte Carlo with bosonic baths coupled to the spin. The resultant solution is critically tested by known physical properties. In contrast with the mean-field theory, soft paramagnons appear near the transition temperature. Moreover, the Nambu-Goldstone mode (magnon) in the ferromagnetic phase is reproduced reasonably well. However, antiferromagnetic magnons have an energy gap in contradiction to the Nambu-Goldstone theorem. The origin of this failure is discussed in connection with the artificial first-order nature of the transition.",
author = "Junya Otsuki and Yoshio Kuramoto",
year = "2013",
month = "7",
day = "30",
doi = "10.1103/PhysRevB.88.024427",
language = "English",
volume = "88",
journal = "Physical Review B-Condensed Matter",
issn = "1098-0121",
publisher = "American Physical Society",
number = "2",

}

TY - JOUR

T1 - Dynamical mean-field theory for quantum spin systems

T2 - Test of solutions for magnetically ordered states

AU - Otsuki, Junya

AU - Kuramoto, Yoshio

PY - 2013/7/30

Y1 - 2013/7/30

N2 - A spin version of dynamical mean-field theory is extended for magnetically ordered states in the Heisenberg model. The self-consistency equations are solved with high numerical accuracy by means of the continuous-time quantum Monte Carlo with bosonic baths coupled to the spin. The resultant solution is critically tested by known physical properties. In contrast with the mean-field theory, soft paramagnons appear near the transition temperature. Moreover, the Nambu-Goldstone mode (magnon) in the ferromagnetic phase is reproduced reasonably well. However, antiferromagnetic magnons have an energy gap in contradiction to the Nambu-Goldstone theorem. The origin of this failure is discussed in connection with the artificial first-order nature of the transition.

AB - A spin version of dynamical mean-field theory is extended for magnetically ordered states in the Heisenberg model. The self-consistency equations are solved with high numerical accuracy by means of the continuous-time quantum Monte Carlo with bosonic baths coupled to the spin. The resultant solution is critically tested by known physical properties. In contrast with the mean-field theory, soft paramagnons appear near the transition temperature. Moreover, the Nambu-Goldstone mode (magnon) in the ferromagnetic phase is reproduced reasonably well. However, antiferromagnetic magnons have an energy gap in contradiction to the Nambu-Goldstone theorem. The origin of this failure is discussed in connection with the artificial first-order nature of the transition.

UR - http://www.scopus.com/inward/record.url?scp=84881124080&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84881124080&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.88.024427

DO - 10.1103/PhysRevB.88.024427

M3 - Article

AN - SCOPUS:84881124080

VL - 88

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 2

M1 - 024427

ER -