ISSN:
1572-9613
Keywords:
Ising spins
;
XY spins
;
domain walls
;
quenched disorder
;
random field
;
random anisotropy
;
random potential
;
non-Gaussian thermal fluctuations
;
Imry-Ma argument
;
exact correlation functions
;
replica trick
;
random walks
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Exact identities are derived for a family of models including (a) a domain wall in a random field Ising model (RFIM), and (b) the random anisotropyXY model in the no-vortex approximation. In particular, the second moment of thermal fluctuations is not affected by frozen randomness. It is checked in a one-dimensional model that higher moments are on the contrary strongly enhanced. Thus, thermal fluctuations are strongly non-Gaussian. This reflects excursions between remote potential wells in the phase space. It is shown exactly that the Imry-Ma argument yields a correct evaluation of the field-induced fluctuations for the one-dimensional model.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01015318
