Skip to main navigationSkip to main content
The University of Southampton
STAG Research Centre

Gravity seminar - Peter Millington (DATE/TIME CHANGE) Seminar

Time:
15:00 - 16:00
Date:
30 October 2013
Venue:
54/5A

For more information regarding this seminar, please email Adam Pound at a.pound@soton.ac.uk .

Event details

Perturbative non-equilibrium thermal field theory

We present a novel and fully perturbative formulation of non-equilibrium thermal field theory, applicable to the description of ultra-relativistic many-body systems across a range of disciplines. The diagrammatic perturbation series are built from non-homogeneous free propagators and explicitly time-dependent vertices, which together encode the absolute space-time dependence of the statistical background. This perturbative expansion is free of so-called pinch singularities, without ad hoc prescription or effective resummation of finite widths. Thus, this new approach does not suffer the mathematical pathologies previously thought to spoil truly perturbative treatments of non-equilibrium field theory. Arriving at a physically meaningful definition of particle number densities that does not rely on quasi-particle approximation, we derive master time evolution equations for statistical distribution functions, valid to all orders in perturbation theory and all orders in a gradient expansion. Truncating these transport equations in a perturbative loopwise sense, we successfully capture evolution on all timescales. Finally, with reference to a scalar model, we show that transient early-time behaviour is dominated by non-Markovian energy-violating processes, resulting from the systematic inclusion of finite-time effects.

Speaker information

Peter Millington, Manchester

Privacy Settings