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SUMMARY:Resurgence at work in the principal chiral model - Aleksey Cherman
  (FTPI)
DTSTART:20131003T120000Z
DTEND:20131003T130000Z
UID:TALK47632@talks.cam.ac.uk
CONTACT:Dr Dorigoni
DESCRIPTION:I will discuss the physical role of non-perturbative saddle po
 ints of path integrals in theories without instantons\, using the example 
 of the asymptotically free two-dimensional principal chiral model (PCM). S
 tandard topological arguments based on homotopy considerations suggest no 
 role for non-perturbative saddles in such theories. However\, resurgence t
 heory\, which unifies perturbative and non-perturbative physics\, predicts
  the existence of several types of non-perturbative saddles associated wit
 h features of the large-order structure of perturbation theory. These poin
 ts are illustrated in the PCM\, where we found new non-perturbative `fract
 on' saddle point field configurations\, and give a quantum interpretation 
 of previously discovered `uniton' unstable classical solutions. The fracto
 ns lead to a semi-classical realization of IR renormalons in the circle-co
 mpactified theory\, and yield the microscopic mechanism of the mass gap of
  the PCM.
LOCATION:Potter Room (first floor\, Pav. B)
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