title: Clash of kinks: phase shifts in colliding nonintegrable solitons.
abstract: We derive a closed-form expression for the phase shift experienced by (1+1)-dimensional kinks colliding at ultrarelativistic velocities (γv>>1), valid for arbitrary periodic potentials. Our closed-form expression is the leading-order result of a more general scattering theory of solitary waves described in a related paper [Phys. Rev. D 88, 105024 (2013)]. This theory relies on a small kinematic parameter 1/(γv)<<1 rather than a small parameter in the Lagrangian. Our analytic results can be directly extracted from the Lagrangian without solving the equation of motion. Based on our closed-form expression, we prove that kink-kink and kink-antikink collisions have identical phase shifts at leading order.
authors: Kavli Institute for Cosmology and Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, United Kingdom.
authors: Mustafa A
authors: MA
authors: Amin
authors: Physics Department, Theoretical Particle Physics and Cosmology Group, King's College London, Strand, London WC2R 2LS, United Kingdom.
authors: Eugene A
authors: EA
authors: Lim
authors: IOP and GRAPPA, Universiteit van Amsterdam, Science Park 904, 1090 GL Amsterdam, Netherlands.
authors: I-Sheng
authors: IS
authors: Yang