Formal expressions are given for the elements of the density matrix of an $n$ -level quantum system interacting with a polychromatic electromagnetic field and coupled to the modes of a photon reservoir. The interaction with the polychromatic field is treated in both the semiclassical and quantum approaches, and the expressions obtained for the density matrix in the two cases are compared. It is shown that in most physical situations one can use equivalently the semiclassical or the quantum approach with a simple form of the density matrix of the field at initial time.Formal expressions are given for the elements of the density matrix of an $n$-level quantum system interacting with a polychromatic electromagnetic field and coupled to the modes of a photon reservoir. The interaction with the polychromatic field is treated in both the semiclassical and quantum approaches, and the expressions obtained for the density matrix in the two cases are compared. It is shown that in most physical situations one can use equivalently the semiclassical or the quantum approach with a simple form of the density matrix of the field at initial time.

Physical Review AJun 1, 197714 citations

Quantum theory of RF resonances: the semiclassical limit

Stig Stenholm

The author attempts to show that, in contradiction with work by Chang and Stehle, the semiclassical description of RF resonance experiments is valid. The density matrix equation of motion is set up for a two-level atom interacting with a one-mode quantized field. The terms giving the semiclassical description are separated and the contributions arising from the rest are carefully evaluated. Corrections to the semiclassical treatment are found to be of order n 0 -2 , where n 0 is the average number of RF photons. In practice such corrections are negligible.The author attempts to show that, in contradiction with work by Chang and Stehle, the semiclassical description of RF resonance experiments is valid. The density matrix equation of motion is set up for a two-level atom interacting with a one-mode quantized field. The terms giving the semiclassical description are separated and the contributions arising from the rest are carefully evaluated. Corrections to the semiclassical treatment are found to be of order n 0 -2 , where n 0 is the average number of RF photons. In practice such corrections are negligible.

Journal of Physics B Atomic and Molecular PhysicsAug 1, 197320 citations

Semiclassical Representation of Photon Field and Laser-Matter Interaction

WORLD SCIENTIFIC eBooksSep 19, 20240 citations

Generalised semiclassical formalism for two-photon resonant problems

J.N. Elgin, G.H.C. New, K. E. Orkney

Optics CommunicationsAug 1, 197636 citations

Two-Photon Dynamics in Coherent Rydberg Atomic Ensemble

Bing He, A. V. Sharypov, Jiteng Sheng +2 more

We study the interaction of two photons in a Rydberg atomic ensemble under the condition of electromagnetically induced transparency, combining a semiclassical approach for pulse propagation and a complete quantum treatment for quantum state evolution. We find that the blockade regime is not suitable for implementing photon-photon cross-phase modulation due to pulse absorption and dispersion. However, approximately ideal cross-phase modulation can be realized based on relatively weak interactions, with counterpropagating and transversely separated pulses.We study the interaction of two photons in a Rydberg atomic ensemble under the condition of electromagnetically induced transparency, combining a semiclassical approach for pulse propagation and a complete quantum treatment for quantum state evolution. We find that the blockade regime is not suitable for implementing photon-photon cross-phase modulation due to pulse absorption and dispersion. However, approximately ideal cross-phase modulation can be realized based on relatively weak interactions, with counterpropagating and transversely separated pulses.

arXiv:1401.1540Physical Review LettersApr 4, 2014109 citations

Formal expressions are given for the elements of the density matrix of an

n

-level quantum system interacting with a polychromatic electromagnetic field and coupled to the modes of a photon reservoir. The interaction with the polychromatic field is treated in both the semiclassical and quantum approaches, and the expressions obtained for the density matrix in the two cases are compared. It is shown that in most physical situations one can use equivalently the semiclassical or the quantum approach with a simple form of the density matrix of the field at initial time.