Abstract

I will formulate the finite-volume thermodynamics of a massive integrable QFT in terms of a has of relativistic loops. The loops interact through scattering factors associated with their intersections. For the doubly periodic spacetime, after decoupling the pairwise interactions by a Hubbard-Stratonovich transformation, the sum over loops can be performed explicitly. The resulting effective theory becomes mean field type in the limit when one of the periods becomes asymptotically large. The mean field obeys the Thermodynamical Bethe Ansatz equations.

Speaker Intro

Ivan Kostov obtained his PhD in 1982 from the Moscow State University, with scientific advisers Vladimir Feinberg and Alexander Migdal. Then he worked in the group of Ivan Todorov at the INRNE Sofia, and since 1990 as a CNRS researcher at the IPhT, CEA-Saclay, France. Currently he is emeritus DR CNRS at IPhT and a visiting professor at UFES, Vitoria, Brazil.