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hep-th2026
On the Asymptotic Causal Structure in Gravitational EFTs
Bruno Bucciotti, Paolo Creminelli, Alessandro Longo +2
It is usually assumed that a healthy EFT should not allow superluminal propagation. In the presence of gravity, however, the notion of superluminality becomes subtle, since there i…
hep-th2025
Analyticity and positivity of Green's functions without Lorentz
Paolo Creminelli, Alessandro Longo, Borna Salehian +1
We study the properties imposed by microcausality and positivity on the retarded two-point Green's function in a theory with spontaneous breaking of Lorentz invariance. We assume i…
hep-th2023
Non-analyticity of the -matrix with spontaneously broken Lorentz invariance
Paolo Creminelli, Matteo Delladio, Oliver Janssen +2
We study the -matrix of Goldstones in the renormalizable theory of a complex scalar at finite charge, i.e. in a state that breaks Lorentz invariance. The theory is weakly…