IIMAS - FENOMEC
UNAM
Instanton calculus in quantum mechanics: quartic double-well and sine-Gordon potentials
Resumen:
In this talk we discuss specific problems for which perturbation theory
fails to explain physical properties even qualitatively. We then explain
how non-perturbative effects can be obtained by instanton calculus.
Feynman diagrams in the instanton background are used for the calculation
of the tunneling amplitude (the instanton density) in the three-loop
order. Unlike the two-loop contribution where all involved Feynman
integrals are rational numbers, we will show that in the three-loop case
they can contain irrational contributions as well.
Informes: coloquiomym@gmail.com, o al 5622-3564.