Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:cond-mat/0411302

Entanglement Production under Collective Radiation

Vyacheslav I. Yukalov

Published Nov 11, 2004• 3 citations
arXivHTMLPDF

Abstract

The relation is studied between the entanglement production and collective radiation by an ensemble of atoms. Entanglement production is quantified by means of a general measure introduced earlier by the author. Primary emphasis is placed on the entanglement generated by pseudospin density matrices. The problem of collective atomic radiation can be described by the pseudospin evolution equations. These equations define the evolutional entanglement generated by the related density matrices. Under conditions of superradiant emission, the entanglement production exhibits sharp peaks at the delay time, where the intensity of radiation is maximal. The possibility of regulating the occurrence of such peaks by punctuated superradiance is discussed, which suggests the feasibility of {\it punctuated entanglement production}.

DOI
10.48550/arxiv.cond-mat/0411302

Related papers

Coherent dynamics of radiating atomic systems in pseudospin representation

Vyacheslav I. Yukalov

The aim of this review is twofold. Firstly, a general approach is presented which can provide a unified description of the dynamics of radiating systems of different natures. Both atomic systems and spin assemblies can be treated within the same mathematical method, which is based on a pseudospin (or spin) representation of the evolution equations. The approach is applicable to all stages of radiation dynamics, including the most difficult initial quantum stage, where coherence is not yet developed. This makes it possible to study the process of coherent self-organization from the chaotic quantum stage. Secondly, the approach is illustrated by applying it to the description of several coherent phenomena. Different types of superradiance are characterized: pure superradiance, triggered superradiance, pulsing and punctuated superradiance. The theory of such interesting effects as triggering dipolar waves, turbulent photon filamentation, collective liberation of light, pseudospin atomic squeezing, and operator entanglement production is presented.

arXiv:1408.6073•Laser Physics•Aug 15, 2014•12 citations

Extensive mixed-state entanglement in kinetically constrained superradiance

Lucas Winter, Jan Kumlin, Thomas Pohl +1 more

Dicke superradiance by an ensemble of quantum emitters produces a collective burst of radiation, but no entanglement in the mixed state of the emitters. We show that adding a local kinetic constraint between the emitters generates extensive mixed-state entanglement, while otherwise preserving all key features of Dicke superradiance. Specifically, for any local Boolean constraint, we analytically derive a lower bound for the emission rate which implies a peak intensity $\propto N^2$ and a peak time $\propto (\log N)/N$ with number of spins $N$. This effect enables the superradiantly accelerated preparation of entangled dark states. Hereby, Hilbert-space fragmentation of the Dicke ladder leads to an exponentially branching decay tree that generates a hierarchy of dark states. Importantly, these disconnected manifolds include exponentially many long-range entangled singlet dark states. The explored kinetic constraints and superradiant dynamics can be realized in neutral-atom arrays coupled to an optical cavity, and we suggest a simple and accessible witness to detect the predicted mixed-state entanglement in such experiments. Moreover, we show that entanglement generation is robust against atomic decay and collective dephasing, and should be observable under recently reported experimental conditions. Our results, thereby, offer a general framework and experimentally viable approach for the dissipative engineering of entangled dark states enhanced by superradiance.

quant-pharXiv:2605.16131•May 18, 2026•0 citations

Absence of entanglement growth in Dicke superradiance

Nico S. Bassler

Dicke superradiance describes an ensemble of N permutationally invariant two-level systems collectively emitting radiation with a peak radiated intensity scaling as N 2 . Individual Dicke states are typically entangled. However, the density matrix during superradiant decay is a mixture of such states, raising the subtle question of whether the total state is entangled or separable. We resolve this by showing analytically that for any N , starting from the fully excited state, the collective decay preserves separability for all times. This answers a longstanding question on the role of entanglement in Dicke superradiance and underscores that, despite collective dissipation, separable states remain separable under these dynamics.

arXiv:2504.13646•Physical Review A•Nov 13, 2025•3 citations

Quantum statistics of single-mode radiation emitted by superradiant Dicke states

Anirudh Yadav, Deniz D. Yavuz

We study the quantum statistics of single-mode radiation emitted by an atomic ensemble when the ensemble is initially prepared in a superradiant Dicke state. We show that while the radiation is well approximated by the Glauber coherent state at early times in the evolution, the emission can be truly quantum at later times. In particular, one can observe a large amount of photon-number squeezing in the emission under certain conditions; even a Fock state can be produced. We discuss the quantum statistics of the emission for various parameters, including different initial conditions for the atomic ensemble. To obtain these results, we have developed a formalism where we are able to calculate the quantum statistics of the emission over long time scales even when the number of atoms in the ensemble is quite large.

arXiv:2508.09962•Physical Review A•Nov 17, 2025•0 citations

Quantum statistics of superradiant pulses

Fritz Haake, Roy J. Glauber

We investigate the statistical aspects of the cooperative emission of radiation by a system of many atoms. By solving the equation of motion for a suitably defined quasiprobability distribution which represents the density operator of the atoms, we find explicit expressions for the expectation values of products of atomic observables. The system is found to exhibit large quantum fluctuations for the most highly excited initial states of the atoms. For all others it exhibits nearly classical behavior. Previous numerical evaluations of the radiated intensity and its variance are found to be in good agreement with the present results.

IEEE Journal of Quantum Electronics•Jun 1, 1972•1 citation

Quantum Statistics of Superradiant Pulses

Fritz Haake, Roy J. Glauber

We investigate the statistical aspects of the cooperative emission of radiation by a system of many atoms. By solving the equation of motion for a suitably defined quasiprobability distribution which represents the density operator of the atoms, we find explicit expressions for the expectation values of products of atomic observables. The system is found to exhibit large quantum fluctuations for the most highly excited initial states of the atoms. For all others it exhibits nearly classical behavior. Previous numerical evaluations of the radiated intensity and its variance are found to be in good agreement with the present results.

Physical Review A•Mar 1, 1972•112 citations
The relation is studied between the entanglement production and collective radiation by an ensemble of atoms. Entanglement production is quantified by means of a general measure introduced earlier by the author. Primary emphasis is placed on the entanglement generated by pseudospin density matrices. The problem of collective atomic radiation can be described by the pseudospin evolution equations. These equations define the evolutional entanglement generated by the related density matrices. Under conditions of superradiant emission, the entanglement production exhibits sharp peaks at the delay time, where the intensity of radiation is maximal. The possibility of regulating the occurrence of such peaks by punctuated superradiance is discussed, which suggests the feasibility of {\it punctuated entanglement production}.
The aim of this review is twofold. Firstly, a general approach is presented which can provide a unified description of the dynamics of radiating systems of different natures. Both atomic systems and spin assemblies can be treated within the same mathematical method, which is based on a pseudospin (or spin) representation of the evolution equations. The approach is applicable to all stages of radiation dynamics, including the most difficult initial quantum stage, where coherence is not yet developed. This makes it possible to study the process of coherent self-organization from the chaotic quantum stage. Secondly, the approach is illustrated by applying it to the description of several coherent phenomena. Different types of superradiance are characterized: pure superradiance, triggered superradiance, pulsing and punctuated superradiance. The theory of such interesting effects as triggering dipolar waves, turbulent photon filamentation, collective liberation of light, pseudospin atomic squeezing, and operator entanglement production is presented.
Dicke superradiance by an ensemble of quantum emitters produces a collective burst of radiation, but no entanglement in the mixed state of the emitters. We show that adding a local kinetic constraint between the emitters generates extensive mixed-state entanglement, while otherwise preserving all key features of Dicke superradiance. Specifically, for any local Boolean constraint, we analytically derive a lower bound for the emission rate which implies a peak intensity ∝N2\propto N^2∝N2 and a peak time ∝(log⁡N)/N\propto (\log N)/N∝(logN)/N with number of spins NNN. This effect enables the superradiantly accelerated preparation of entangled dark states. Hereby, Hilbert-space fragmentation of the Dicke ladder leads to an exponentially branching decay tree that generates a hierarchy of dark states. Importantly, these disconnected manifolds include exponentially many long-range entangled singlet dark states. The explored kinetic constraints and superradiant dynamics can be realized in neutral-atom arrays coupled to an optical cavity, and we suggest a simple and accessible witness to detect the predicted mixed-state entanglement in such experiments. Moreover, we show that entanglement generation is robust against atomic decay and collective dephasing, and should be observable under recently reported experimental conditions. Our results, thereby, offer a general framework and experimentally viable approach for the dissipative engineering of entangled dark states enhanced by superradiance.
Dicke superradiance describes an ensemble of N permutationally invariant two-level systems collectively emitting radiation with a peak radiated intensity scaling as N 2 . Individual Dicke states are typically entangled. However, the density matrix during superradiant decay is a mixture of such states, raising the subtle question of whether the total state is entangled or separable. We resolve this by showing analytically that for any N , starting from the fully excited state, the collective decay preserves separability for all times. This answers a longstanding question on the role of entanglement in Dicke superradiance and underscores that, despite collective dissipation, separable states remain separable under these dynamics.
We study the quantum statistics of single-mode radiation emitted by an atomic ensemble when the ensemble is initially prepared in a superradiant Dicke state. We show that while the radiation is well approximated by the Glauber coherent state at early times in the evolution, the emission can be truly quantum at later times. In particular, one can observe a large amount of photon-number squeezing in the emission under certain conditions; even a Fock state can be produced. We discuss the quantum statistics of the emission for various parameters, including different initial conditions for the atomic ensemble. To obtain these results, we have developed a formalism where we are able to calculate the quantum statistics of the emission over long time scales even when the number of atoms in the ensemble is quite large.
We investigate the statistical aspects of the cooperative emission of radiation by a system of many atoms. By solving the equation of motion for a suitably defined quasiprobability distribution which represents the density operator of the atoms, we find explicit expressions for the expectation values of products of atomic observables. The system is found to exhibit large quantum fluctuations for the most highly excited initial states of the atoms. For all others it exhibits nearly classical behavior. Previous numerical evaluations of the radiated intensity and its variance are found to be in good agreement with the present results.
We investigate the statistical aspects of the cooperative emission of radiation by a system of many atoms. By solving the equation of motion for a suitably defined quasiprobability distribution which represents the density operator of the atoms, we find explicit expressions for the expectation values of products of atomic observables. The system is found to exhibit large quantum fluctuations for the most highly excited initial states of the atoms. For all others it exhibits nearly classical behavior. Previous numerical evaluations of the radiated intensity and its variance are found to be in good agreement with the present results.