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Tails of Instability and Decay: a Hydrodynamic Perspective
by Olalla A. Castro-Alvaredo, Cecilia De Fazio, Benjamin Doyon, Aleksandra A. Ziółkowska
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Submission summary
| Authors (as registered SciPost users): | Olalla Castro-Alvaredo · Benjamin Doyon |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2103.03735v2 (pdf) |
| Date accepted: | 2022-03-23 |
| Date submitted: | 2021-12-03 11:56 |
| Submitted by: | Castro-Alvaredo, Olalla |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
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.
Author comments upon resubmission
List of changes
These have already been described in detail in our answer to the referee report.
Published as SciPost Phys. 12, 115 (2022)