Statistical Physics seminars coming up

[Cond.Matt. & Stat.Mech.Section]

 JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR

 

 

Monday, 4 June -   2:00 p.m.

 



SISSA, Santorio Building,    Room 128 (1st Floor)

 

 

Olalla CASTRO ALVAREDO     ( City University London )

 
 

"Entanglement entropy of    one-dimensional quantum systems"

 

Abstract

 

In this talk I will review some of the work on Entanglement Entropy that I have carried out in collaboration with various authors since 2007. For general 1d Quantum Field Theories, the central objects are Twist Fields whose correlation functions are directly related to the entropy. In the context of Quantum Spin Chains, Twist Operators play a similar role and products thereof can be related to the twist fields in the continuous limit.

Once the entropy has been expressed in terms of correlation functions of these fields (or operators on the chain) one may exploit the powerful tools of integrable quantum models to establish new results. We may study both the short- and long-distance behaviours of the entropy in various kinds of theories, study the matrix elements of twist fields (or twist operators) on their own right, or investigate the features of other correlation functions involving the twist field. In my talk I will try to touch on the main results we have obtained when addressing some of these problems.



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JOINT ICTP/SISSA STATISTICAL PHYSICS SEMINAR

 

Tuesday, 5 June   -   11:30 hrs.

 



Luigi Stasi Seminar Room -    ICTP Leonardo Building - 1st floor


 

Benjamin DOYON   ( King's College London )

 


"Star-figures in conformal loop ensembles:   The stress tensor and some of its descendants"

 


Abstract

 

Consider the clusters of same-sign spins in the Ising model. In the scaling limit at criticality, their boundaries become (countably) infinitely many loops that don't intersect, and the Boltzman weight becomes a probability measure for these loop configurations. Conformal loop ensemble (CLE) is a one-parameter family of measures on such loop configurations with properties of locality and conformal invariance. It includes the measure obtained from the scaling limit of the critical Ising model, but also measures corresponding to all central charges between 0 and 1. It is believed that this loop description contains all the information of the usual local-operator CFT, in particular about minimal models. In this talk I will tell you how to represent the stress tensor and some of its descendants as random variables in CLE. The random variables essentially measure how likely it is that loops be separated by some specific closed curves that look like stars (with a bit of imagination); these stars are made to "rotate" at various angular velocities. It is interesting that the star-figure random variables in principle give definitions for the associated stress-tensor descendants even beyond CFT. This talk will be very elementary: I'll introduce all necessary notions, and if time permits I will give you an idea of how the proof works.