Keldysh field theory of spin- and valley-distinguished polariton nonlinearities in transition-metal dichalcogenide monolayers
Abstract
Electrons in transition-metal dichalcogenides (TMDs) possess valley and spin degrees of freedom, which leads to rich exciton and exciton-polariton physics with nontrivial scattering dynamics and enhanced nonlinearities, presenting a key mechanism for photonic devices. Yet, existing descriptions of bosonization and polariton interactions in TMD-based systems overlook the valley degree of freedom as well as the various particles' spins combinations. In this work, we derive a nonequilibrium field-theory approach in the path integral formalism that allows to track all the polariton nonlinearities in the strong coupling regime. We demonstrate that, when all the bright and dark exciton species are considered, the TMD monolayer-based polariton systems feature sixteen different nonlinear contributions due to interactions and even more saturation-related terms. Strikingly, while the interactions of excitons within one valley are overall dominant, we show that the contribution to the blueshift from spin-dark excitons is much higher than that from bright intravalley excitons.
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BibTeX
@misc{grudinina2026keldysh,
title = {{Keldysh field theory of spin- and valley-distinguished polariton nonlinearities in transition-metal dichalcogenide monolayers}},
author = {Anna M. Grudinina and Nina S. Voronova},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.22242},
eprint = {2606.22242},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.22242},
}
RIS
TY - UNPB
TI - Keldysh field theory of spin- and valley-distinguished polariton nonlinearities in transition-metal dichalcogenide monolayers
AU - Anna M. Grudinina
AU - Nina S. Voronova
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2606.22242
UR - https://arxiv.org/abs/2606.22242
AB - Electrons in transition-metal dichalcogenides (TMDs) possess valley and spin degrees of freedom, which leads to rich exciton and exciton-polariton physics with nontrivial scattering dynamics and enhanced nonlinearities, presenting a key mechanism for photonic devices. Yet, existing descriptions of bosonization and polariton interactions in TMD-based systems overlook the valley degree of freedom as well as the various particles' spins combinations. In this work, we derive a nonequilibrium field-theory approach in the path integral formalism that allows to track all the polariton nonlinearities in the strong coupling regime. We demonstrate that, when all the bright and dark exciton species are considered, the TMD monolayer-based polariton systems feature sixteen different nonlinear contributions due to interactions and even more saturation-related terms. Strikingly, while the interactions of excitons within one valley are overall dominant, we show that the contribution to the blueshift from spin-dark excitons is much higher than that from bright intravalley excitons.
ER -