Tails of Instability and Decay: a Hydrodynamic Perspective
Olalla A. Castro-Alvaredo, Cecilia De Fazio, Benjamin Doyon, Aleksandra A. Ziółkowska
SciPost Phys. 12, 115 (2022) · published 31 March 2022
- doi: 10.21468/SciPostPhys.12.3.115
- Submissions/Reports
Abstract
In the context of quantum field theory (QFT), unstable particles are associated with complex-valued poles of two-body scattering matrices in the unphysical sheet of rapidity space. The Breit-Wigner formula relates this pole to the mass and life-time of the particle, observed in scattering events. In this paper, we uncover new, dynamical signatures of unstable excitations and show that they have a strong effect on the non-equilibrium properties of QFT. Focusing on a 1+1D integrable model, and using the theory of Generalized Hydrodynamics, we study the formation and decay of unstable particles by analysing the release of hot matter into a low-temperature environment. We observe the formation of tails and the decay of the emitted nonlinear waves, in sharp contrast to the situation without unstable excitations. We also uncover a new phenomenon by which a wave of a stable population of unstable particles may persist without decay for long times. We expect these signatures of the presence of unstable particles to have a large degree of universality. Our study shows that the out-of-equilibrium dynamics of many-body systems can be strongly affected not only by the spectrum, but also by excitations with finite life-times.
Cited by 3
Authors / Affiliations: mappings to Contributors and Organizations
See all Organizations.- 1 Olalla A. Castro-Alvaredo,
- 1 Cecilia De Fazio,
- 2 Benjamin Doyon,
- 3 Aleksandra A. Ziolkowska