Error estimates and specification parameters for functional renormalization

David Schnoerr, Igor Boettcher, Jan M. Pawlowski, Christof Wetterich

Research output: Contribution to journalArticlepeer-review

Abstract

We present a strategy for estimating the error of truncated functional flow equations. While the basic functional renormalization group equation is exact, approximated solutions by means of truncations do not only depend on the choice of the retained information, but also on the precise definition of the truncation. Therefore, results depend on specification parameters that can be used to quantify the error of a given truncation. We demonstrate this for the BCS–BEC crossover in ultracold atoms. Within a simple truncation the precise definition of the frequency dependence of the truncated propagator affects the results, indicating a shortcoming of the choice of a frequency independent cutoff function.
Original languageEnglish
Pages (from-to)83 - 99
Number of pages17
JournalAnnals of physics
Volume334
DOIs
Publication statusPublished - Jul 2013

Keywords

  • BCS–BEC crossover

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