Far-Field Signatures of a Two-Body Bound State in Collective Emission from Interacting Two-Level Atoms on a Lattice

TL;DR

This paper investigates the far-field emission signatures of a two-body bound state in a chain of interacting two-level atoms, revealing distinctive spectral features that indicate the presence of such bound states without requiring individual atom control.

Contribution

It provides analytical and spectral analysis of two-body bound states in collective emission from a lattice of atoms, highlighting observable far-field signatures.

Findings

Distinct angular decay patterns for bound states

Unique steady-state emission spectra indicating bound states

Method to determine two-body wavefunction momentum distribution

Abstract

The collective emission from a one-dimensional chain of interacting two-level atoms is investigated. We calculate the light scattered by dissipative few-excitation eigenstates in the far-field, and in particular focus on signatures of a lattice two-body bound state. We present analytical results for the angle-resolved, temporal decay of the scattered light intensity. Moreover, we find that the steady-state emission spectrum that emerges when the system is probed by a weak, incoherent driving field exhibits a distinct signature for the existence of a bound state, and allows to determine the momentum distribution of the two-body relative wavefunction. Intriguingly, our study does not rely on single-atom addressability and/or manipulation techniques.