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Title: Discontinuity of the magnetization in one-dimensional 1/absolute value x-y/sup 2/ Ising and Potts models

Journal Article · · J. Stat. Phys.; (United States)
DOI:https://doi.org/10.1007/BF01022985· OSTI ID:7180343

Results from percolation theory are used to study phase transitions in one-dimensional Ising and q-state Potts models with couplings of the asymptotic form J/sub x,y/ approx. = const/absolute value x-y/sup 2/. For translation-invariant systems with well-defined lim/sub x ..-->.. infinity/x/sup 2/J/sub x/ = J/sup +/ (possibly O or infinity) we establish: (1) there is no long-range order at inverse temperatures ..beta.. with ..beta..J/sup +/ less than or equal to1. (2) If ..beta..J/sup +/ > q, then by sufficiently increasing J/sub 1/ the spontaneous magnetization M is made positive. (3) In models with 0 < J/sup +/ < infinity the magnetization is discontinuous at the transition point (as originally predicted by Thouless), and obeys M(..beta../sub c/) less than or equal to 1/(..beta../sub c/J/sup +/)/sup 1/2. (4) For Ising (q =2) models with J/sup +/ < infinity, it is noted that the correlation function decays as (..beta..) approx. = c(..beta..)/absolute value x-y/sup 2/ whenever ..beta.. < ..beta../sub c/. Points 1-3 are deduced from previous percolation results by utilizing the Fortuin-Kasteleyn representation, which also yields other results of independent interest relating Potts models with different values of q.

Research Organization:
New York Univ., NY (USA)
OSTI ID:
7180343
Journal Information:
J. Stat. Phys.; (United States), Vol. 50:1-2
Country of Publication:
United States
Language:
English