We consider the calculation of high energy hadron cascades induced by electron and photon beams in the GeV energy range. The most important source of high energy hadrons is the hadronic interaction of photons from the primary electron-photon shower. The hadronic interaction of high energy photons is described by the vector meson dominance model and by a Monte Carlo version of the dual multistri...

The process of pair creation by a photon in a strong magnetic field is investigated basing on the polarization operator in the field. The total probability of the process is found in a relatively simple form. The probability exhibits a ”saw-tooth” pattern because of divergences arising when the electron and positron are created at threshold of the Landau energy levels. The pattern will be washe...

Strong exciton-photon coupling is the result of a reversible exchange of energy between an excited state and a confined optical field. This results in the formation of polariton states that have energies different from the exciton and photon. We demonstrate strong exciton-photon coupling between light-harvesting complexes and a confined optical mode within a metallic optical microcavity. The en...

The advent of a next linear e e collider and back-scatterd laser beams will allow the study of a vast array of high energy processes of the Standard Model through the fusion of real and virtual photons and other gauge bosons. As examples, I discuss virtual photon scattering ! X in the region dominated by BFKL hard Pomeron exchange and report the predicted cross sections at present and future e ...

We study the prospects for probing the quark content of the photon using b tagging at high energy electron-photon colliders. We find that heavy quark tagging provides a sensitive and effective probe of the quark content of the photon. Using a 500 GeV ee NLC in electron-photon mode, the cross section for ebγ → eb can be measured to 10% with b tagging. This is sufficient to differentiate between ...

We study the porphyrin S1 ! S0 fluorescence and the photosensitized singlet oxygen Dg ! Rg phosphorescence, both originating from absorption of photons with energy less than the porphyrin S0 ! S1 transition energy. By measuring the excitation intensity dependence of fluorescence at lowered sample temperatures, we are able to discriminate between two parallel processes of one-photon hot-band abs...

The photosynthetic reaction center is one of the most complicated molecular complexes. Transducing photon energy to a transmembrane electrochemical potential difference for protons, it is the direct or indirect energy source for virtually all life. We show here that it operates in a simple, battery-like manner, with a maximum potential of 0.20 V. Intriguingly this is only one fifth of the energ...

In this work, we use Lorentz invariance violation (LIV) introduced as a generic modification to particle dispersion relations to study some consequences of single photon emission, known as vacuum Cherenkov radiation, and photon decay processes in cosmic and gamma rays. These processes are forbidden in a Lorentz invariant theory but allowed under the hypothesis of LIV. We show that the emission ...

The process of radiation from high-energy electron and electron-positron pair production by a photon in oriented single crystal is considered using the method which permits inseparable consideration of both coherent and incoherent mechanisms of photon emission from an electron and of pair creation by a photon and includes the action of field of axis (or plane) as well as the multiple scattering...