TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.12.3.115
TI  - Tails of Instability and Decay: a Hydrodynamic Perspective
PY  - 2022/03/31
UR  - https://www.scipost.org/SciPostPhys.12.3.115
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 12
IS  - 3
SP  - 115
A1  - Castro-Alvaredo, Olalla A.
AU  - De Fazio, Cecilia
AU  - Doyon, Benjamin
AU  - Ziolkowska, Aleksandra A.
AB  - 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.
ER  -

@Article{10.21468/SciPostPhys.12.3.115,
	title={{Tails of Instability and Decay: a Hydrodynamic Perspective}},
	author={Olalla A. Castro-Alvaredo and Cecilia De Fazio and Benjamin Doyon and Aleksandra A. Ziółkowska},
	journal={SciPost Phys.},
	volume={12},
	pages={115},
	year={2022},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.12.3.115},
	url={https://scipost.org/10.21468/SciPostPhys.12.3.115},
}