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Irreversible phenomena like diffusion and thermalization obviously occur in our world, which is described by deterministic and time-reversible equations (Newton’s equations of motion or the Schrödinger equation in quantum mechanics). However, up to today we seem to lack the tools to describe and derive these phenomena rigorously (apart from a few special models). In physics, one usually models them by stochastic evolution equations and the transition from deterministic equations to stochastic ones remains a leap of faith. Our work treats one of the simplest possible models: a quantum particle interacting with a gas of bosons. With the help of a time-dependent renormalization group analysis, we prove diffusion.

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Wojciech de Roeck, Universität Heidelberg
Seminarraum Theoretische Physik
Contact: not specified