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Title: Error estimates and specification parameters for functional renormalization

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.
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Institute for Theoretical Physics, University of Heidelberg, D-69120 Heidelberg (Germany)
  2. (Germany)
Publication Date:
OSTI Identifier:
22220746
Resource Type:
Journal Article
Resource Relation:
Journal Name: Annals of Physics (New York); Journal Volume: 334; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; APPROXIMATIONS; ATOMS; EQUATIONS; ERRORS; FREQUENCY DEPENDENCE; FUNCTIONS; MATHEMATICAL SOLUTIONS; PROPAGATOR; RENORMALIZATION