Unraveling superradiance: Entanglement and mutual information in collective decay

Fuente: arXiv
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Main Authors: Zhang, Xin H. H., Malz, Daniel, Rabl, Peter
Format: Preprint
Published: 2025
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author Zhang, Xin H. H.
Malz, Daniel
Rabl, Peter
author_facet Zhang, Xin H. H.
Malz, Daniel
Rabl, Peter
contents We study the collective decay of an initially inverted ensemble of two-level emitters in two distinct scenarios: when coupled to a squeezed photonic reservoir and when interacting with a one-dimensional waveguide. Using a quantum-state diffusion approach to unravel the emission process, we investigate entanglement and classical correlations along individual quantum trajectories over time. This numerical analysis shows that despite an initial build-up of entanglement and a significant amount of entanglement due to either spin squeezing or dark states at late times, the essential features of the superradiant burst are well described by averages over fully factorizable states. We explain this observation in terms of an almost complete factorization of all 2-local observables, which we identify as a generic property of superradiant decay. Based on this insight, we provide a purely classical theory for the burst in squeezed superradiance, which is both intuitive and exact for a large number of emitters. Moreover, we find that our numerical approach also performs well in the presence of subradiant states, which dominate the slow residual decay of non-uniform ensembles at late times.
format Preprint
id arxiv_https___arxiv_org_abs_2505_13401
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unraveling superradiance: Entanglement and mutual information in collective decay
Zhang, Xin H. H.
Malz, Daniel
Rabl, Peter
Quantum Physics
Atomic Physics
We study the collective decay of an initially inverted ensemble of two-level emitters in two distinct scenarios: when coupled to a squeezed photonic reservoir and when interacting with a one-dimensional waveguide. Using a quantum-state diffusion approach to unravel the emission process, we investigate entanglement and classical correlations along individual quantum trajectories over time. This numerical analysis shows that despite an initial build-up of entanglement and a significant amount of entanglement due to either spin squeezing or dark states at late times, the essential features of the superradiant burst are well described by averages over fully factorizable states. We explain this observation in terms of an almost complete factorization of all 2-local observables, which we identify as a generic property of superradiant decay. Based on this insight, we provide a purely classical theory for the burst in squeezed superradiance, which is both intuitive and exact for a large number of emitters. Moreover, we find that our numerical approach also performs well in the presence of subradiant states, which dominate the slow residual decay of non-uniform ensembles at late times.
title Unraveling superradiance: Entanglement and mutual information in collective decay
topic Quantum Physics
Atomic Physics
url https://arxiv.org/abs/2505.13401