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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

As Contributors: Olalla Castro-Alvaredo · Benjamin Doyon
Arxiv 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
Academic field: Physics
Specialties:
  • High-Energy Physics - Theory
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.

Published as SciPost Phys. 12, 115 (2022)



Author comments upon resubmission

This is the revised manuscript, which addresses the referees criticisms/comments.

List of changes

These have already been described in detail in our answer to the referee report.


Reports on this Submission

Anonymous Report 2 on 2022-2-18 (Invited Report)

Report

The authors have addressed most points raised by the referees. I still disagree with some of the statements made by the authors, but nothing that should prevent publication. I recommend publication in Scipost Physics.

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Anonymous Report 1 on 2022-2-3 (Invited Report)

Report

The authors have addressed all my concerns and I am happy to recommend the manuscript for publication in SciPost.

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