# Formulating the Kramers Problem in Field Theory

#### Formulating the Kramers Problem in Field Theory

- Event time: 2:00pm
- Event date: 27th November 2019
- Speaker: Joel Mabillard (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Higgs Centre Seminar Room, Room 4305, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB

### Event details

The Kramers problem aims at deriving the rate at which a Brownian particle

escapes from a potential well. In this talk, I will define and derive the

Kramers escape rate for a scalar field, due to thermal fluctuations, and

discuss the applications for cosmology and other areas. In the presence of

such fluctuations, there is a non-vanishing probability for a field,

initially homogeneously located at a minimum of its potential, to escape

from the well. I will start with a review of the simpler problem of the

escape of a classical particle due to random forces. Then, I will discuss

the difficulties associated with a well-defined formulation of an escape

rate for a field and how these can be overcome. I will attempt to provide

a definition of the Kramers problem for a scalar field and present a

method to obtain the rate. Finally, I will conclude with some applications

of the formalism not only in cosmology but also in areas including

lattice gauge theory and condensed matter physics.

#### Event resources

### About Particle Physics Theory seminars

The Particle Physics Theory seminar is a weekly series of talks reflecting the diverse interests of the group. Topics include analytic and numerical calculations based on the Standard Model of elementary particle physics, theories exploring new physics, as well as more formal developments in gauge theories and gravity..