Amplitude constraints on dark energy

TL;DR

This paper explores how fundamental physical principles impose constraints on dark energy models through scattering amplitude bounds, linking low-energy observations to high-energy theory consistency.

Contribution

It applies positivity bounds from scattering amplitudes to a dark energy EFT, connecting theoretical constraints with cosmological data.

Findings

Positivity bounds restrict dark energy EFT parameters.

Comparison with observations tests model viability.

Highlights the role of causality and unitarity in cosmology.

Abstract

This talk gives a short introduction to the ``UV/EFT correspondence", which uses scattering amplitudes to relate the Effective Field Theory (EFT) coefficients probed by low-energy measurements to properties of the underlying high-energy (UV) completion. This includes recent ``positivity bounds" on EFT coefficients, which are the low-energy signatures of causality and unitarity in the UV. To illustrate their phenomenological impact, I apply these bounds to a simple EFT for dark energy and compare with recent cosmological observations.