2001/06/03 by Axel Gelfert, Gelfert, Axel
Physics and Astronomy · #Condensed Matter (cond-mat) #FOS: Physical sciences #cond-mat
paper · pdf · doi:10.48550/arxiv.cond-mat/0106031
100 pages
arxiv created 2001/06/03 · arxiv updated 2009/11/30
Starting from general considerations concerning phase transitions and the many-body problem, a pedagogical introduction to the Mermin-Wagner theorem is given. Particular attention is paid to how the Mermin-Wagner theorem fits in with more general methods in many-particle physics. An attempt at an assessment of its validity for approximative methods is made by contrasting the results obtained within Onsager reaction-field theory and those obtained by the well-known Tyablikov method.