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hep-th2021
Positivity Bounds without Boosts
Tanguy Grall, Scott Melville
We derive the first positivity bounds for low-energy Effective Field Theories (EFTs) that are not invariant under Lorentz boosts. "Positivity bounds" are the low-energy manifestati…
hep-th2020
The Cosmological Phonon: Symmetries and Amplitudes on Sub-Horizon Scales
Tanguy Grall, Sadra Jazayeri, David Stefanyszyn
In contrast to massless spinning particles, scalars are not heavily constrained by unitarity and locality. Off-shell, no gauge symmetries are required to write down manifestly loca…
hep-th2019
Symmetric Scalars
Tanguy Grall, Sadra Jazayeri, Enrico Pajer
We provide a complete classification of Poincaré-invariant scalar field theories with an enlarged set of classical symmetries to leading order in derivatives, namely for the so-cal…