Monitored interacting Dirac fermions

Fuente: arXiv
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Main Authors: Müller, Thomas Martin, Buchhold, Michael, Diehl, Sebastian
Format: Preprint
Published: 2025
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author Müller, Thomas Martin
Buchhold, Michael
Diehl, Sebastian
author_facet Müller, Thomas Martin
Buchhold, Michael
Diehl, Sebastian
contents We analytically study interacting Dirac fermions, described by the Thirring model, under weak local particle number measurements with monitoring rate $γ$. This system maps to a bosonic replica field theory, analyzed via the renormalization group. For a nonzero attractive interaction, a phase transition occurs at a critical measurement strength $γ_c$. When $γ>γ_c$, the system enters a localized phase characterized by exponentially decaying density-density correlations beyond a finite correlation length; for $γ<γ_c$, the correlations decay algebraically. The transition is of BKT-type, reflected by a characteristic scaling of the correlation length. In the non-interacting limit, $γ_c\to0$ shifts to zero, reducing the algebraic phase to a single point in parameter space. This identifies weak measurements in the free case as an implicit double fine-tuning to the critical endpoint of the BKT phase transition. Along the non-interacting line, we compute the entanglement entropy from density-density correlation functions and find no entanglement transition at nonzero measurement strength in the thermodynamic limit.
format Preprint
id arxiv_https___arxiv_org_abs_2502_02645
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Monitored interacting Dirac fermions
Müller, Thomas Martin
Buchhold, Michael
Diehl, Sebastian
Statistical Mechanics
Disordered Systems and Neural Networks
Quantum Physics
We analytically study interacting Dirac fermions, described by the Thirring model, under weak local particle number measurements with monitoring rate $γ$. This system maps to a bosonic replica field theory, analyzed via the renormalization group. For a nonzero attractive interaction, a phase transition occurs at a critical measurement strength $γ_c$. When $γ>γ_c$, the system enters a localized phase characterized by exponentially decaying density-density correlations beyond a finite correlation length; for $γ<γ_c$, the correlations decay algebraically. The transition is of BKT-type, reflected by a characteristic scaling of the correlation length. In the non-interacting limit, $γ_c\to0$ shifts to zero, reducing the algebraic phase to a single point in parameter space. This identifies weak measurements in the free case as an implicit double fine-tuning to the critical endpoint of the BKT phase transition. Along the non-interacting line, we compute the entanglement entropy from density-density correlation functions and find no entanglement transition at nonzero measurement strength in the thermodynamic limit.
title Monitored interacting Dirac fermions
topic Statistical Mechanics
Disordered Systems and Neural Networks
Quantum Physics
url https://arxiv.org/abs/2502.02645