3 papers
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…
gr-qc2020
Inflation in Motion: Unitarity Constraints in Effective Field Theories with Broken Lorentz Symmetry
Tanguy Grall, Scott Melville
During inflation, there is a preferred reference frame in which the expansion of the background spacetime is spatially isotropic. In contrast to Minkowski spacetime, observables ca…
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…