Tails of Instability and Decay: a Hydrodynamic Perspective
arXiv:2103.03735 · doi:10.21468/SciPostPhys.12.3.115
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.
arXiv comment24 pages, 9 figures and 3 tables. In the revised version, the paper format has changed from a letter to a longer paper which now included the original supplementary material and a new discussion in section 5
References in corpus (45)
- From Quantum Chaos and Eigenstate Thermalization to Statistical Mechanics and Thermodynamics
- Relaxation in a Completely Integrable Many-Body Quantum System: An Ab Initio Study of the Dynamics of the Highly Excited States of Lattice Hard-Core Bosons
- Evolution of Entanglement Entropy in One-Dimensional Systems
- Quantum many-body systems out of equilibrium
- Time-dependence of correlation functions following a quantum quench
- Review of AdS/CFT Integrability: An Overview
- Equilibration, thermalisation, and the emergence of statistical mechanics in closed quantum systems
- Transport in Out-of-Equilibrium XXZ Chains: Exact Profiles of Charges and Currents
- Quench dynamics and relaxation in isolated integrable quantum spin chains
- Emergent hydrodynamics in integrable quantum systems out of equilibrium
- Real time confinement following a quantum quench to a non-integrable model
- Generalized HydroDynamics on an Atom Chip
- Quasilocal charges in integrable lattice systems
- Solvable Hydrodynamics of Quantum Integrable Systems
- Nonequilibrium quantum dynamics and transport: from integrability to many-body localization
- Large-scale description of interacting one-dimensional Bose gases: generalized hydrodynamics supersedes conventional hydrodynamics
- Conformal field theory out of equilibrium: a review
- Hilbert-Space Fragmentation from Strict Confinement
- Lecture notes on Generalised Hydrodynamics
- A geometric viewpoint on generalized hydrodynamics
- Experimental Observation of Bethe Strings
- Signatures of rare states and thermalization in a theory with confinement
- The Symmetric Space and Homogeneous sine-Gordon Theories
- Yang-Baxter integrable models in experiments: from condensed matter to ultracold atoms
- Entanglement Oscillations near a Quantum Critical Point
- Thermodynamic Bethe Ansatz of the Homogeneous Sine-Gordon models
- Integrable Quantum Field Theories with Unstable Particles
- Solitonic Integrable Perturbations of Parafermionic Theories
- Semi-classical spectrum of the Homogeneous sine-Gordon theories
- Identifying the Operator Content, the Homogeneous Sine-Gordon models
- Introducing iFluid: a numerical framework for solving hydrodynamical equations in integrable models
- Mass scales and crossover phenomena in the Homogeneous Sine-Gordon Models
- Euler-scale dynamical correlations in integrable systems with fluid motion
- Experimental realization of the Yang-Baxter Equation via NMR interferometry
- Decoupling the SU(N)_2-homogeneous Sine-Gordon model
- Search for Chargino and Neutralino Production at sqrt(s) = 192-209 GeV at LEP
- Small x Phenomenology: Summary and status 2002
- Integrable scattering theories with unstable particles
- K_{e3} decays and CKM unitarity
- Form Factors of the Homogeneous Sine-Gordon models
- Renormalization group flow with unstable particles
- Exact mass-coupling relation for the homogeneous sine-Gordon model
- On the Hydrodynamics of Unstable Excitations
- On the mass-coupling relation of multi-scale quantum integrable models
- The Staircase Model: Massless Flows and Hydrodynamics