Universality and two-body losses: lessons from the effective non-Hermitian dynamics of two particles

TL;DR

This paper analyzes the late-time behavior of two particles with two-body losses in one dimension, revealing universal decay laws and exact decay rates using non-Hermitian Hamiltonian models.

Contribution

It provides an exact analytical study of the decay dynamics of two particles with losses, uncovering universal power-law decay behaviors in both continuum and lattice systems.

Findings

Decay as t^{-1/2} when particles start far apart

Decay as t^{-3/2} when particles initially overlap

Logarithmic correction in lattice case

Abstract

We study the late-time dynamics of two particles confined in one spatial dimension and subject to two-body losses. The dynamics is exactly described by a non-Hermitian Hamiltonian that can be analytically studied both in the continuum and on a lattice. The asymptotic decay rate and the universal power-law form of the decay of the number of particles are exactly computed in the whole parameter space of the problem. When in the initial state the two particles are far apart, the average number of particles in the setup decays with time $t$ as $t^{-1/2}$; a different power law, $t^{-3/2}$, is found when the two particles overlap in the initial state. These results are valid both in the continuum and on a lattice, but in the latter case a logarithmic correction appears.