A note on Hall conductance and Hall conductivity in interacting Fermion systems

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Hauptverfasser: Teufel, Stefan, Wesle, Marius
Format: Preprint
Veröffentlicht: 2025
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author Teufel, Stefan
Wesle, Marius
author_facet Teufel, Stefan
Wesle, Marius
contents In this note we consider lattice fermions on $\mathbb{Z}^2$ with a gapped ground state and show how to apply the NEASS approach to linear response to derive a formula for the Hall conductance in terms of the ground state expectation of a commutator of modified step functions. This formula is usually derived by a charge pumping argument going back to Laughlin. Here we show that it can also be obtained as the linear response coefficient of the microscopic current response to an adiabatic increase of the chemical potential on a half plane (or more generally on any cone-like region). Indeed, in a manner reminiscent of the bulk-boundary correspondence, we show that raising the chemical potential in any cone-like region gives rise to a current that flows along its boundary and is nearly linear in the increase in chemical potential. We also discuss the connection with the double commutator formula with modified position operators for the Hall conductivity derived in arXiv:2411.06967 as the linear response coefficient of the macroscopic current response to the adiabatic application of a constant electric field.
format Preprint
id arxiv_https___arxiv_org_abs_2506_13581
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A note on Hall conductance and Hall conductivity in interacting Fermion systems
Teufel, Stefan
Wesle, Marius
Mathematical Physics
Quantum Physics
81V70, 81V74
In this note we consider lattice fermions on $\mathbb{Z}^2$ with a gapped ground state and show how to apply the NEASS approach to linear response to derive a formula for the Hall conductance in terms of the ground state expectation of a commutator of modified step functions. This formula is usually derived by a charge pumping argument going back to Laughlin. Here we show that it can also be obtained as the linear response coefficient of the microscopic current response to an adiabatic increase of the chemical potential on a half plane (or more generally on any cone-like region). Indeed, in a manner reminiscent of the bulk-boundary correspondence, we show that raising the chemical potential in any cone-like region gives rise to a current that flows along its boundary and is nearly linear in the increase in chemical potential. We also discuss the connection with the double commutator formula with modified position operators for the Hall conductivity derived in arXiv:2411.06967 as the linear response coefficient of the macroscopic current response to the adiabatic application of a constant electric field.
title A note on Hall conductance and Hall conductivity in interacting Fermion systems
topic Mathematical Physics
Quantum Physics
81V70, 81V74
url https://arxiv.org/abs/2506.13581