Causality constraints for charged particles

Understand

In quantum systems with short-range interactions, causality imposes nontrivial constraints on low-energy scattering parameters.

• We investigate these causality constraints for systems where a long-range Coulomb potential is present in addition to a short-range interaction.
• The main result is an upper bound for the Coulomb-modified effective range parameter.
• We discuss the implications of this bound to the effective field theory for nuclear halo systems.