The principle of detailed balance between electrons and phonons in presence of excitonic effects
Abstract
Based on a many-body formulation, we derive an electron-phonon coupling including excitonic effects that preserves thermodynamic detailed balance between electronic and phononic scattering processes. We start from the microscopic electron-nucleus Hamiltonian, expand around the Born-Oppenheimer equilibrium geometry, and construct an effective action for the electronic and phononic propagators. From the same effective action, we derive both electronic and phononic self-energies in terms of a nonlocal vertex 𝒢s including excitonic effects, which generalizes the usual local interaction vertex gs. When electrons and phonons are well-defined quasiparticles in the screened-exchange approximation and 𝒢s is taken in its static limit, both self-energies reduce to Fermi-golden-rule expressions containing the same 𝒢s, thereby ensuring detailed balance. As an application, we compute electronic and phononic linewidths in graphene and illustrate this common-vertex construction. We analyze the competition between the reduced scattering phase space induced by the screened-exchange band structure and the enhancement of the electron-phonon vertex due to excitonic effects, finding that the vertex enhancement can compensate for and overcome the phase-space reduction in both electronic and phononic linewidths.
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BibTeX
@misc{guandalini2026principle,
title = {{The principle of detailed balance between electrons and phonons in presence of excitonic effects}},
author = {Alberto Guandalini and Giovanni Caldarelli and Francesco Mauri and Francesco Macheda},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.23403},
eprint = {2608.23403},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.23403},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The principle of detailed balance between electrons and phonons in presence of excitonic effects
AU - Alberto Guandalini
AU - Giovanni Caldarelli
AU - Francesco Mauri
AU - Francesco Macheda
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2608.23403
UR - https://arxiv.org/abs/2608.23403
AB - Based on a many-body formulation, we derive an electron-phonon coupling including excitonic effects that preserves thermodynamic detailed balance between electronic and phononic scattering processes. We start from the microscopic electron-nucleus Hamiltonian, expand around the Born-Oppenheimer equilibrium geometry, and construct an effective action for the electronic and phononic propagators. From the same effective action, we derive both electronic and phononic self-energies in terms of a nonlocal vertex 𝒢^s including excitonic effects, which generalizes the usual local interaction vertex g^s. When electrons and phonons are well-defined quasiparticles in the screened-exchange approximation and 𝒢^s is taken in its static limit, both self-energies reduce to Fermi-golden-rule expressions containing the same 𝒢^s, thereby ensuring detailed balance. As an application, we compute electronic and phononic linewidths in graphene and illustrate this common-vertex construction. We analyze the competition between the reduced scattering phase space induced by the screened-exchange band structure and the enhancement of the electron-phonon vertex due to excitonic effects, finding that the vertex enhancement can compensate for and overcome the phase-space reduction in both electronic and phononic linewidths.
ER -