SciPost Submission Page

Quasi-particle functional Renormalisation Group calculations in the two-dimensional half-filled Hubbard model at finite temperatures

by D. Rohe, C. Honerkamp

Submission summary

As Contributors: Daniel Rohe
Arxiv Link: (pdf)
Date accepted: 2020-11-24
Date submitted: 2020-10-20 08:16
Submitted by: Rohe, Daniel
Submitted to: SciPost Physics
Academic field: Physics
  • Condensed Matter Physics - Theory
  • Condensed Matter Physics - Computational
Approaches: Theoretical, Computational


We present a highly parallelisable scheme for treating functional Renormalisation Group equations which incorporates a quasi-particle-based feedback on the flow and provides direct access to real-frequency self-energy data. This allows to map out the boundaries of Fermi-liquid regimes and to study the effect of quasi-particle degradation near Fermi liquid instabilities. As a first application, selected results for the two-dimensional half-filled perfectly nested Hubbard model are shown.

Current status:
Publication decision taken: accept

Editorial decision: For Journal SciPost Physics: Publish
(status: Editorial decision fixed and (if required) accepted by authors)

List of changes

* added content in reply to referee one -> see reply to referee
* added content in reply to referee two -> see reply to referee
* added content in reply to referee three -> see reply to referee

Reports on this Submission

Report 3 by Walter Metzner on 2020-11-18 Invited Report


The authors have replied satisfactorily to my questions and comments. The provided references on other real frequency fRG calculations are enough. Others can be found in the review by Dupuis et al. which they also cite.

I recommend publication in the present form.

  • validity: high
  • significance: high
  • originality: good
  • clarity: high
  • formatting: good
  • grammar: excellent

Anonymous Report 2 on 2020-11-12 Invited Report


The authors have corrected most part of the points which raised the critique of the Referees. I would suggest only technical corrections as mentioned below.

Requested changes

I suggest to replot Fig. 4 where the plot takes only 1/4 of the space of the figure. E.g., the legend can be made two column and/or put to the caption to give more space to the plot.

In Fig. 7 the vertical axis can be restricted by the interval 0.85-0.95 (or similar) to give more space for the plot.

The horizontal axis in Fig. 8 can be restricted by 2.25 giving also more space for the plot.

  • validity: good
  • significance: high
  • originality: high
  • clarity: good
  • formatting: good
  • grammar: excellent

Author Daniel Rohe on 2020-11-20
(in reply to Report 2 on 2020-11-12)

We thank the referee for these helpful final suggestions which will be implemented.

Anonymous Report 1 on 2020-11-6 Invited Report


This article presents a method that

1. extends the standard one-loop functional renormalization group approach by including quasiparticle-based feedback on the flow, and

2. allows the direct determination of the real frequency dependence of the single-particle self-energy.

3. This work is one of the few examples which presents real frequency behavior obtained with fRG and thus will be of interest to the community.


The authors' response to my previous comments is satisfactory. Publication can now be recommended.

  • validity: high
  • significance: high
  • originality: good
  • clarity: high
  • formatting: good
  • grammar: excellent

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