Bounds on photon scattering

Abstract

We study 2-to-2 scattering amplitudes of massless spin one particles in $d=4$ space-time dimensions, like real world photons. We define a set of non-perturbative observables (Wilson coefficients) which describe these amplitudes at low energies. We use full non-linear unitarity to construct various novel numerical bounds on these observables. For completeness, we also rederive some bounds using positivity only. We discover and explain why some of these Wilson coefficients cannot be bounded.

39 pages + appendices, 20 figures

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Cited by in corpus (7)

• Massive Gravity is not Positive
• Positivity Bounds on parity-violating scalar-tensor EFTs
• Non-Forward UV/IR Relations
• Lectures in Quantum Gravity
• Strings from Almost Nothing
• Positivity bounds in scalar-QED EFT at one-loop level
• Primal S-matrix bootstrap with dispersion relations