The role of polarization field terms in a model for a cavity quantum material

Fuente: arXiv
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Autori principali: Lloyd, Arwen, Stokes, Adam, Principi, Alessandro, Nazir, Ahsan
Natura: Preprint
Pubblicazione: 2026
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author Lloyd, Arwen
Stokes, Adam
Principi, Alessandro
Nazir, Ahsan
author_facet Lloyd, Arwen
Stokes, Adam
Principi, Alessandro
Nazir, Ahsan
contents Constructing models for cavity quantum materials requires a careful treatment of the light-matter coupling. In general, one must specify matrix elements constructed from the material wavefunctions, which are often unknown in a tight-binding framework. The Peierls substitution is often used to avoid introducing these additional parameters in the multi-center dipole (or Peiels) gauge, under the assumption that contributions from intraband and interband dipole moments can be neglected in the low-energy theory. We present the derivation of the Peierls gauge description in the passive view of canonical transformations. We construct a toy model for a multi-band system with two sites, which we couple to a uniform field in the Coulomb, dipole, and Peierls gauges. We find that the Peierls substitution can be justified as a low-energy, effectively single-band description in one dimension, but it misses both self-polarization corrections and the direct coupling needed to describe interband transitions in the full Peierls gauge theory. Moreover, the Coulomb, dipole, and Peierls gauges define distinct partitions of the composite system into the light and matter subsystems. We illustrate the implications of this subsystem relativity for physical observables and on the performance of orbital truncations in each gauge.
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id arxiv_https___arxiv_org_abs_2603_26917
institution arXiv
publishDate 2026
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spellingShingle The role of polarization field terms in a model for a cavity quantum material
Lloyd, Arwen
Stokes, Adam
Principi, Alessandro
Nazir, Ahsan
Mesoscale and Nanoscale Physics
Quantum Physics
Constructing models for cavity quantum materials requires a careful treatment of the light-matter coupling. In general, one must specify matrix elements constructed from the material wavefunctions, which are often unknown in a tight-binding framework. The Peierls substitution is often used to avoid introducing these additional parameters in the multi-center dipole (or Peiels) gauge, under the assumption that contributions from intraband and interband dipole moments can be neglected in the low-energy theory. We present the derivation of the Peierls gauge description in the passive view of canonical transformations. We construct a toy model for a multi-band system with two sites, which we couple to a uniform field in the Coulomb, dipole, and Peierls gauges. We find that the Peierls substitution can be justified as a low-energy, effectively single-band description in one dimension, but it misses both self-polarization corrections and the direct coupling needed to describe interband transitions in the full Peierls gauge theory. Moreover, the Coulomb, dipole, and Peierls gauges define distinct partitions of the composite system into the light and matter subsystems. We illustrate the implications of this subsystem relativity for physical observables and on the performance of orbital truncations in each gauge.
title The role of polarization field terms in a model for a cavity quantum material
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2603.26917