scholarly journals Self-energy effects in functional renormalization group flows of the two-dimensionalt−t′Hubbard model away from van Hove filling

2015 ◽  
Vol 92 (23) ◽  
Author(s):  
Andreas Eberlein
Keyword(s):  
Renormalization Group ◽  
Hubbard Model ◽  
Functional Renormalization Group ◽  
Self Energy ◽  
Renormalization Group Flows

scholarly journals Multiloop functional renormalization group for the two-dimensional Hubbard model: Loop convergence of the response functions

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Agnese Tagliavini ◽  
Cornelia Hille ◽  
Fabian Kugler ◽  
Sabine Andergassen ◽  
Alessandro Toschi ◽  
...  
Keyword(s):  
Renormalization Group ◽  
Hubbard Model ◽  
Two Dimensional ◽  
Response Functions ◽  
Functional Renormalization Group ◽  
Self Energy ◽  
Numerical Effort ◽  
Physical Response ◽  
The Common ◽  
Made In

We present a functional renormalization group (fRG) study of the two dimensional Hubbard model, performed with an algorithmic implementation which lifts some of the common approximations made in fRG calculations. In particular, in our fRG flow; (i) we take explicitly into account the momentum and the frequency dependence of the vertex functions; (ii) we include the feedback effect of the self-energy; (iii) we implement the recently introduced multiloop extension which allows us to sum up all the diagrams of the parquet approximation with their exact weight. Due to its iterative structure based on successive one-loop computations, the loop convergence of the fRG results can be obtained with an affordable numerical effort. In particular, focusing on the analysis of the physical response functions, we show that the results become independent from the chosen cutoff scheme and from the way the fRG susceptibilities are computed, i.e., either through flowing couplings to external fields, or through a “post-processing” contraction of the interaction vertex at the end of the flow. The presented substantial refinement of fRG-based computation schemes paves a promising route towards future quantitative fRG analyses of more challenging systems and/or parameter regimes.

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