## Séminaire de Physique Théorique

**An introduction to resurgent theory and some new aspects in Stokes phenomena**

Akira Shudo (Tokyo)

Thursday 19 May 2011 14:00 - Tours - Salle 1180 (Bât E2)

**Résumé :**

The saddle point method is known to be a widely used technique to approximately evaluate integrals. A difficulty in applying it in general lies in the fact that not all of the saddles point solutions necessarily contribute. This is because the so-called Stokes phenomenon occurs in the parameter space of given integrals, and the number of contributing saddles changes when one crosses Stokes lines. The discovery of Stokes phenomena dates back to the 19th century, but its understanding remains in a heuristic level until resurgent theory has been developed. We here introduce an idea of resurgent theory, particularly emphasizing on its new aspects which are related with the saddle point method for the case with more than two saddles.

**Liens :**