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

Springer eBooks

Collective Effects in Quantum Statistics of Radiation and Matter

Victor Nikolaevich Popov, Vladimir Sergeevich Yarunin

Published Jan 1, 1988• 43 citations
Publisher
DOI
10.1007/978-94-009-2983-8

Related papers

Collective effects in the quantum scattering of radiation

Vadim N. Tsytovich

Journal of Experimental and Theoretical Physics•Feb 1, 1996•0 citations

Collective phenomena in the interaction of radiation with matter

Vyacheslav I. Yukalov

The aim of this communication is to present in a concentrated form the main ideas of a method, developed by the author, for treating strongly nonequilibrium collective phenomena typical of the interaction of radiation with matter, as well as to give a survey of several applications of the method. The latter is called the Scale Separation Approach since its basic techniques rely on the possibility of separating different space-time scales in nonequilibrium statistical systems. This approach is rather general and can be applied to diverse physical problems, several of which are discussed here. These problems are: Superradiance of nuclear spins, filamentation in resonant media, semiconfinement of neutral atoms, negative electric current, and collective liberation of light.

arXiv:cond-mat/0002355•Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jan 14, 2000•0 citations

Optical coherence properties of collective molecular systems: A comparison of the statistical and quantum approaches

Izo I. Abram, Robin M. Hochstrasser

The formalism of collective (Dicke-like) states and operators is used to describe the relaxation of the initially prepared state of a material in the presence of a laser field. The material states are shown to be expressible as minimum uncertainty wave packets formed from those special collective states that couple with the radiation field. It is shown that these coherent states of matter exhibit all the features that are usually attributed to ensemble averages of two-level molecules in a conventional statistical picture. However, there are new features in the quantum mechanical model when there are correlations among the molecules in the ensemble. The loss of minimum uncertainty characteristics of the wave packet correspnds to the transverse (T2) relaxation of the statistical model. Different types of T2 processes can be defined corresponding to the decay of different orders of coherence of the wave packet. Only for the case that the system decays in all orders of coherence do the quantum and statistical results coincide. There is expected to be a transverse relaxation that preserves one or more orders of coherence. Experiments are suggested that can test these ideas. A particular case of the formalism of collective states applies to molecular crystals and it provides a quantum mechanical picture of the dephasing of molecular excitons in terms of orders of coherence analogous to the usual manner of describing states of the radiation field.

The Journal of Chemical Physics•Jul 1, 1981•12 citations

Quantum Statistics of Radiation in Random Media

Jan Peřina

Springer eBooks•Jan 1, 1991•0 citations

Quantum Statistics of Radiation in Random Media

Jan Peřina

Springer eBooks•Jan 1, 1984•0 citations

Cosmological Classical Branches: Operational classicality of primordial curvature perturbations from late-time matter records

Tomotaka Kuroda, Fumiya Sano, Yusuke Yamada

This paper addresses a fundamental unresolved problem in inflationary cosmology: what quantum-state structure makes the one-realization classical description used in late-time cosmology physically meaningful within unitary quantum theory? We identify a structure that supports such a description, which we call Cosmological Classical Branches (CCBs). After reheating, the curvature perturbation is a collective variable rather than an independent subsystem. This shifts the classicality problem from the reduced state of the curvature perturbation itself to records of primordial information in the post-reheating matter state. When distinct matter components respond to the same primordial realization and their conditional states become distinguishable across different realizations, they carry records of the information about the curvature perturbation. A record in one component makes the realization readable, while a compatible record in a disjoint component suppresses interference accessible to operations confined to the first component, forming CCBs. Conditioning on a physical record yields a one-realization description within a CCB, in which the resolved primordial value acts as a c-number label while the matter degrees of freedom remain quantum. We test this criterion using effective models of two radiation fluids during radiation domination and of photons and cold dark matter around radiation--matter equality. We also show that a CCB typical with respect to the primordial Born measure exhibits the expected one-realization statistics: mode averages approach the primordial two-point statistics at fixed nonzero wavenumber in the large-volume limit. Overall, these results provide an operational framework at the quantum-state level connecting the primordial quantum superposition to the one-realization cosmological history assumed in standard cosmology.

•Oct 10, 2026•0 citations
The aim of this communication is to present in a concentrated form the main ideas of a method, developed by the author, for treating strongly nonequilibrium collective phenomena typical of the interaction of radiation with matter, as well as to give a survey of several applications of the method. The latter is called the Scale Separation Approach since its basic techniques rely on the possibility of separating different space-time scales in nonequilibrium statistical systems. This approach is rather general and can be applied to diverse physical problems, several of which are discussed here. These problems are: Superradiance of nuclear spins, filamentation in resonant media, semiconfinement of neutral atoms, negative electric current, and collective liberation of light.
The formalism of collective (Dicke-like) states and operators is used to describe the relaxation of the initially prepared state of a material in the presence of a laser field. The material states are shown to be expressible as minimum uncertainty wave packets formed from those special collective states that couple with the radiation field. It is shown that these coherent states of matter exhibit all the features that are usually attributed to ensemble averages of two-level molecules in a conventional statistical picture. However, there are new features in the quantum mechanical model when there are correlations among the molecules in the ensemble. The loss of minimum uncertainty characteristics of the wave packet correspnds to the transverse (T2) relaxation of the statistical model. Different types of T2 processes can be defined corresponding to the decay of different orders of coherence of the wave packet. Only for the case that the system decays in all orders of coherence do the quantum and statistical results coincide. There is expected to be a transverse relaxation that preserves one or more orders of coherence. Experiments are suggested that can test these ideas. A particular case of the formalism of collective states applies to molecular crystals and it provides a quantum mechanical picture of the dephasing of molecular excitons in terms of orders of coherence analogous to the usual manner of describing states of the radiation field.
This paper addresses a fundamental unresolved problem in inflationary cosmology: what quantum-state structure makes the one-realization classical description used in late-time cosmology physically meaningful within unitary quantum theory? We identify a structure that supports such a description, which we call Cosmological Classical Branches (CCBs). After reheating, the curvature perturbation is a collective variable rather than an independent subsystem. This shifts the classicality problem from the reduced state of the curvature perturbation itself to records of primordial information in the post-reheating matter state. When distinct matter components respond to the same primordial realization and their conditional states become distinguishable across different realizations, they carry records of the information about the curvature perturbation. A record in one component makes the realization readable, while a compatible record in a disjoint component suppresses interference accessible to operations confined to the first component, forming CCBs. Conditioning on a physical record yields a one-realization description within a CCB, in which the resolved primordial value acts as a c-number label while the matter degrees of freedom remain quantum. We test this criterion using effective models of two radiation fluids during radiation domination and of photons and cold dark matter around radiation--matter equality. We also show that a CCB typical with respect to the primordial Born measure exhibits the expected one-realization statistics: mode averages approach the primordial two-point statistics at fixed nonzero wavenumber in the large-volume limit. Overall, these results provide an operational framework at the quantum-state level connecting the primordial quantum superposition to the one-realization cosmological history assumed in standard cosmology.