2013/06/30 by Junya Otsuki, Yoshio Kuramoto · 15 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Condensed matter physics #Ferromagnetism #Goldstone boson #Heisenberg model #Magnon #Mean field theory #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum #Quantum and electron transport phenomena #Quantum fluctuation #Quantum mechanics #Spin (aerodynamics) #Statistical physics #Symmetry breaking #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.88.024427
published in Physical Review B 88(2) (American Physical Society) · 8 pages, 5 figures
openalex publication_date 2013/07/30 · arxiv created 2013/08/01 · arxiv updated 2013/08/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.