General Spin-1 Dynamics During Inflation: Microcausality Constraints and Cosmological Collider Signals
Abstract
We construct the general theory of a spin-1 field propagating on an inflationary background consistent with scale invariance, rotations, Bunch-Davies conditions and microcausality. Our Boostless Proca theory generalises the usual massive Proca theory to a Lagrangian with 5 free parameters: 4 corresponding to parity-even terms and a single parity-odd term. We impose three degrees of freedom from the outset and find that microcausality, the statement that field operators vanish outside the lightcone, requires the kinetic terms to be gauge invariant. We couple this spin-1 state to the inflaton and study the signatures it imprints on cosmological correlators. We find no new signals for the bispectrum meaning that the known signals are the most general thereby providing a very clean model-independent probe of new physics in this leading form of non-Gaussianity. For the trispectrum and higher-point functions, the boostless Proca theory produces new shapes with all 5 parameters in principle measurable.
Related
- Cosmological constraints on single-field inflation models from ACT/SPT data and observations at sub-Mpc scales
- Stochastic dynamics of cosmological inflation in general relativity
- Exploring the Observational Constraints and Cosmological Dynamics in f(Q,L_m) Gravity
- Analytical Cosmological Collider at Strong Mixing in Laplace Space
- Hubble Susceptibility: Beyond Effective-Mass Spectroscopy in the Cosmological Collider
BibTeX
@misc{cheung2026general,
title = {{General Spin-1 Dynamics During Inflation: Microcausality Constraints and Cosmological Collider Signals}},
author = {Trevor Cheung and Carlos Duaso-Pueyo and David Stefanyszyn and Dong-Gang Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10693},
eprint = {2610.10693},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10693},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - General Spin-1 Dynamics During Inflation: Microcausality Constraints and Cosmological Collider Signals
AU - Trevor Cheung
AU - Carlos Duaso-Pueyo
AU - David Stefanyszyn
AU - Dong-Gang Wang
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10693
UR - https://arxiv.org/abs/2610.10693
AB - We construct the general theory of a spin-1 field propagating on an inflationary background consistent with scale invariance, rotations, Bunch-Davies conditions and microcausality. Our Boostless Proca theory generalises the usual massive Proca theory to a Lagrangian with 5 free parameters: 4 corresponding to parity-even terms and a single parity-odd term. We impose three degrees of freedom from the outset and find that microcausality, the statement that field operators vanish outside the lightcone, requires the kinetic terms to be gauge invariant. We couple this spin-1 state to the inflaton and study the signatures it imprints on cosmological correlators. We find no new signals for the bispectrum meaning that the known signals are the most general thereby providing a very clean model-independent probe of new physics in this leading form of non-Gaussianity. For the trispectrum and higher-point functions, the boostless Proca theory produces new shapes with all 5 parameters in principle measurable.
ER -