We present a theory of Raman scattering in the Hubbard model. The scattering of light has two contributions. One gives rise to scattering by spin degrees of freedom in the insulating case where the general form of the scattering Hamiltonian is derived. The fluctuations of the ``chiral'' spin operator ${\mathrm{\ensuremath{\Sigma}}}_{{\mathit{S}}_{\mathit{i}}}$\ensuremath{\cdot}( ${\mathrm{S}}_{\mathit{i}}$ \ifmmode\times\else\texttimes\fi{} ${\mathrm{S}}_{\mathit{k}}$ ) are shown to contribute in the ${\mathit{B}}_{2\mathit{g}}$ scattering geometry. The other contributes in the doped case and is shown to probe the fluctuations of the ``stress tensor.'' This quantity is not conserved, and hence its fluctuations at small q inherent in optical experiments need not be small, in striking contrast to density fluctuations in usual metals.We present a theory of Raman scattering in the Hubbard model. The scattering of light has two contributions. One gives rise to scattering by spin degrees of freedom in the insulating case where the general form of the scattering Hamiltonian is derived. The fluctuations of the ``chiral'' spin operator ${\mathrm{\ensuremath{\Sigma}}}_{{\mathit{S}}_{\mathit{i}}}$\ensuremath{\cdot}(${\mathrm{S}}_{\mathit{i}}$\ifmmode\times\else\texttimes\fi{}${\mathrm{S}}_{\mathit{k}}$) are shown to contribute in the ${\mathit{B}}_{2\mathit{g}}$ scattering geometry. The other contributes in the doped case and is shown to probe the fluctuations of the ``stress tensor.'' This quantity is not conserved, and hence its fluctuations at small q inherent in optical experiments need not be small, in striking contrast to density fluctuations in usual metals.

Physical Review LettersAug 20, 1990286 citations

On a theory of light scattering from a Bose-Einstein condensate

V. M. Ezhova, L. V. Gerasimov, Dmitriy V. Kupriyanov

We consider a quantum theory of elastic light scattering from a macroscopic atomic sample existing in the Bose-Einstein condensate (BEC) phase. Following the second quantized formalism we introduce a set of coupled and closed diagram equations for the polariton propagator contributing to the T -matrix and scattering amplitude. Our approach allows us to follow important density corrections to the quasi-energy structure caused by static interaction and radiation losses associated with incoherent scattering in the case of near resonance excitation.We consider a quantum theory of elastic light scattering from a macroscopic atomic sample existing in the Bose-Einstein condensate (BEC) phase. Following the second quantized formalism we introduce a set of coupled and closed diagram equations for the polariton propagator contributing to the T -matrix and scattering amplitude. Our approach allows us to follow important density corrections to the quasi-energy structure caused by static interaction and radiation losses associated with incoherent scattering in the case of near resonance excitation.

arXiv:1602.07562Journal of Physics Conference SeriesNov 1, 20164 citations

Elements of Quantum Scattering Theory

Brian J. McParland

Springer eBooksAug 6, 20131 citation

Intensity correlation function for a resonant weak light field scattered by a many-particle system. The bunched and antibunched components

A. A. Villaeys, Karl F. Freed

The authors present a weak light field, scattering theoretical description of the intensity autocorrelation function for the scattered light from a many-atom (molecule) system. The theory considers both resonant and near-resonant scattering for atoms with many sublevels in both the ground and electronically excited states, and it incorporates the effects of the finite coherence time of the incident radiation. The theory is derived using incident two-photon wave packets with spatial dispersion among the target atoms. Purely anti-bunching contributions arise from single-atom-two-photon scattering and from successive two-atom-two-photon scattering events. However, there are interleaved two-atom-two-photon scattering processes which provide purely bunching contributions since both atoms may be scattering at the same time. Path length differences in the successive two-atom scatterings can also induce some bunching character to the correlation function. The dependence of the risetime and decay of the intensity correlation function upon the atomic excited state lifetimes and the coherence time of the incident light emphasises the correlation between photons which have been coherently and/or incoherently scattered.The authors present a weak light field, scattering theoretical description of the intensity autocorrelation function for the scattered light from a many-atom (molecule) system. The theory considers both resonant and near-resonant scattering for atoms with many sublevels in both the ground and electronically excited states, and it incorporates the effects of the finite coherence time of the incident radiation. The theory is derived using incident two-photon wave packets with spatial dispersion among the target atoms. Purely anti-bunching contributions arise from single-atom-two-photon scattering and from successive two-atom-two-photon scattering events. However, there are interleaved two-atom-two-photon scattering processes which provide purely bunching contributions since both atoms may be scattering at the same time. Path length differences in the successive two-atom scatterings can also induce some bunching character to the correlation function. The dependence of the risetime and decay of the intensity correlation function upon the atomic excited state lifetimes and the coherence time of the incident light emphasises the correlation between photons which have been coherently and/or incoherently scattered.

Journal of Physics B Atomic and Molecular PhysicsJul 28, 19802 citations

The Quantum Theory of Scattering

Pure and applied physicsJan 1, 1970332 citations

{\mathrm{S}}_{\mathit{i}}

\ifmmode\times\else\texttimes\fi{}

{\mathrm{S}}_{\mathit{k}}

) are shown to contribute in the

{\mathit{B}}_{2\mathit{g}}

scattering geometry. The other contributes in the doped case and is shown to probe the fluctuations of the ``stress tensor.'' This quantity is not conserved, and hence its fluctuations at small q inherent in optical experiments need not be small, in striking contrast to density fluctuations in usual metals.