Log-correlated Gaussian fields: study of the Gibbs measure

50 mins 19 secs,  731.42 MB,  MPEG-4 Video  640x360,  29.97 fps,  44100 Hz,  1.93 Mbits/sec
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Description: Zindy, O (Université Pierre & Marie Curie-Paris VI)
Thursday 19 March 2015, 11:30-12:30
 
Created: 2015-03-20 17:06
Collection: Random Geometry
Publisher: Isaac Newton Institute
Copyright: Zindy, O
Language: eng (English)
Distribution: World     (downloadable)
Explicit content: No
Aspect Ratio: 16:9
Screencast: No
Bumper: UCS Default
Trailer: UCS Default
 
Abstract: Co-author: Louis-Pierre ARUIN (CUNY)

Gaussian fields with logarithmically decaying correlations, such as branching Brownian motion and the two-dimensional Gaussian free field, are conjectured to form universality class of extreme value statistics (notably in the work of Carpentier & Le Doussal and Fyodorov & Bouchaud). This class is the borderline case between the class of IID random variables, and models where correlations start to affect the statistics. In this talk, I will describe a general approach based on rigorous works in spin glass theory to describe features of the Gibbs measure of these Gaussian fields. I will focus on the two-dimensional discrete Gaussian free field. At low temperature, we show that the normalized covariance of two points sampled from the Gibbs measure is either 0 or 1. This is used to prove that the joint distribution of the Gibbs weights converges in a suitable sense to that of a Poisson-Dirichlet variable.
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