Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis

We study the non-Fermi-liquid state formed by an isotropic, degenerate Fermi gas in two spatial dimensions interacting with a U(1) gauge field. Our calculation uses the functional renormalization group (fRG) with a soft frequency cutoff for the fermions. The fRG scheme we employ takes account of the...

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Main Authors: Thomas P. Sheerin, Chris A. Hooley
Format: Article
Language:English
Published: American Physical Society 2025-06-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.7.023216
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author Thomas P. Sheerin
Chris A. Hooley
author_facet Thomas P. Sheerin
Chris A. Hooley
author_sort Thomas P. Sheerin
collection DOAJ
description We study the non-Fermi-liquid state formed by an isotropic, degenerate Fermi gas in two spatial dimensions interacting with a U(1) gauge field. Our calculation uses the functional renormalization group (fRG) with a soft frequency cutoff for the fermions. The fRG scheme we employ takes account of the gauge symmetry, which imposes relations (modified Ward-Takahashi identities) between the couplings which constrain the RG flow. The critical exponents and couplings we find for the resulting non-Fermi liquid are mostly insensitive to whether we enforce the gauge symmetry constraints, which signifies either that the constraints are superfluous or that the frequency-cutoff scheme is particularly robust. The exception is the gauge-boson mass term, which is RG-relevant about the fixed point without the constraints but is irrelevant when they are enforced. The latter is physically accurate, as a gauge symmetry cannot be spontaneously broken. In addition, we find z=2 and Σ(ω,k_{F})∼ω^{1/2} for the boson dynamical exponent and scaling of the fermion self-energy, respectively. These results differ considerably from those of past works on the model, though we argue for their plausibility.
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spelling doaj-art-2c3fe8679ba14e0d8ee382ddbc5dc9b72025-08-20T01:57:51ZengAmerican Physical SocietyPhysical Review Research2643-15642025-06-017202321610.1103/PhysRevResearch.7.023216Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysisThomas P. SheerinChris A. HooleyWe study the non-Fermi-liquid state formed by an isotropic, degenerate Fermi gas in two spatial dimensions interacting with a U(1) gauge field. Our calculation uses the functional renormalization group (fRG) with a soft frequency cutoff for the fermions. The fRG scheme we employ takes account of the gauge symmetry, which imposes relations (modified Ward-Takahashi identities) between the couplings which constrain the RG flow. The critical exponents and couplings we find for the resulting non-Fermi liquid are mostly insensitive to whether we enforce the gauge symmetry constraints, which signifies either that the constraints are superfluous or that the frequency-cutoff scheme is particularly robust. The exception is the gauge-boson mass term, which is RG-relevant about the fixed point without the constraints but is irrelevant when they are enforced. The latter is physically accurate, as a gauge symmetry cannot be spontaneously broken. In addition, we find z=2 and Σ(ω,k_{F})∼ω^{1/2} for the boson dynamical exponent and scaling of the fermion self-energy, respectively. These results differ considerably from those of past works on the model, though we argue for their plausibility.http://doi.org/10.1103/PhysRevResearch.7.023216
spellingShingle Thomas P. Sheerin
Chris A. Hooley
Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis
Physical Review Research
title Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis
title_full Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis
title_fullStr Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis
title_full_unstemmed Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis
title_short Non-Fermi liquid induced by U(1) gauge-field interactions: A functional renormalization group analysis
title_sort non fermi liquid induced by u 1 gauge field interactions a functional renormalization group analysis
url http://doi.org/10.1103/PhysRevResearch.7.023216
work_keys_str_mv AT thomaspsheerin nonfermiliquidinducedbyu1gaugefieldinteractionsafunctionalrenormalizationgroupanalysis
AT chrisahooley nonfermiliquidinducedbyu1gaugefieldinteractionsafunctionalrenormalizationgroupanalysis