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arXiv · 0912.3665

Nonperturbative Renormalisation Group: Applications to the few and many-body systems

B. Krippa
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Abstract

We consider the applications of functional renormalisation group to few and many-body systems. As an application to the few-body dynamics we study the ratio between the fermion-fermion scattering length and the dimer-dimer scattering length for systems of few nonrelativistic fermions. We find a strong dependence on the cutoff function used in the renormalisation flow for a two-body truncation of the action. Adding a simple three-body term substantially reduces this dependence. In the context of many-body physics we study the dynamics of both symmetric and asymmetric many-fermion systems using the same functional renormalisation technique. It is demonstrated that functional renormalisation group gives sensible and reliable results and provides a solid theoretical ground for the future studies. Open questions as well as lines of further developments are discussed.

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B. Krippa. 2009-12-18. Nonperturbative Renormalisation Group: Applications to the few and many-body systems. https://doi.org/10.1051/epjconf%2F20100302003

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