Photon propagator, quantum

Quantum mechanics had exploded between 1923 and 1927. A. H. Compton, in 1923, had discovered the change in frequency of X-rays scattered from the electrons (the Compton effect).25 Compton and, independently, Debye had underlined the importance of this discovery in support of the Einstein conception of light-quanta or photon propagation in space.26... 

Kozhekin et al. [38] proposed a method of mapping of quantum states onto an atomic system based on the stimulated Raman absorption of propagating quantum light by a cloud of three-level atoms. Hald et al. [40] have experimentally observed the squeezed spin states of a system of three-level atoms driven by a squeezed held. The observed squeezed spin states have been generated via entanglement exchange with the squeezed held completely absorbed in the process. Fleishhauer et al. [39] have considered a similar system of three-level atoms and have found that quantum states of single-photon helds can be mapped onto collective states of the atomic system. In this case the quantum state of the held is stored in a dark state of the collective states of the system. 

The standard measurement of different properties of quantum electromagnetic radiation is based on the photodetection, which is field destructive. Following our consideration of the possibility of the Aharonov-Bohm effect at optical frequencies [100], we propose here a new nondemolition method of polarization measurement in which the linearly polarized longitudinal mode of the field is detected without any perturbation of its quantum state (Section VI.D). The estimation of physical conditions shows that such a measurement can be done either for the photons propagating through the fiber, or for the superradiant photons in radioband frequencies. 

FRET is a nonradiative process that is, the transfer takes place without the emission or absorption of a photon. And yet, the transition dipoles, which are central to the mechanism by which the ground and excited states are coupled, are conspicuously present in the expression for the rate of transfer. For instance, the fluorescence quantum yield and fluorescence spectrum of the donor and the absorption spectrum of the acceptor are part of the overlap integral in the Forster rate expression, Eq. (1.2). These spectroscopic transitions are usually associated with the emission and absorption of a photon. These dipole matrix elements in the quantum mechanical expression for the rate of FRET are the same matrix elements as found for the interaction of a propagating EM field with the chromophores. However, the origin of the EM perturbation driving the energy transfer and the spectroscopic transitions are quite different. The source of this interaction term... 

Conversely, a quantum yield

greater than unity cannot be achieved during a straightforward photochemical reaction, since the second law of photochemistry clearly says that one photon is consumed per species excited. In fact, values of > 1 indicate that a secondary reaction(s) has occurred. A value of > 2 implies that the product of the photochemical reaction is consumed by another molecule of reactant, e.g. during a chain reaction, with one photon generating a simple molecule of, say, excited chlorine, which cleaves in the excited state to generate two radicals. Each radical then reacts in propagation reactions until the reaction mixture is exhausted of reactant. 

M. Paulus, and O.J.F. Martin, A fully vectorial technique for scattering and propagation in three-dimensional stratified photonic structures. Optical and Quantum Electronics 33, 315-325 (2001). 

Einstein s laws of absorption and emission describe the operation of lasers. The luminescence of minerals, considered in this book, is a spontaneous emission where the luminescence is independent of incident radiation. In a stimulated emission the relaxation is accomplished by interaction with a photon of the same energy as the relaxation energy. Thus the quantum state of the excited species and the incident photon are intimately coupled. As a result the incident and the emitted photons will have the same phase and propagation direction. The emitted light of stimulated emission is therefore coherent as opposed to the... 

The energy-dependent speed of light is associated with the effect of the medium on the propagation of photon. The fluctuating refractive index of the medium induces this kind of the energy dependence. This kind of the medium has been considered, such as quantum gravity and the Maxwell vacuum with nonzero conductivity. So, it to make distinction between the contributions from standard model predictions as well as from other theories is needed. 

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