Optical transmission singularities in light propagation through double active barrier structure

Propagation of the electromagnetic wave through a system with complex permittivity is investigated. The system consists of two media, one is passive and surrounds the two barrier slabs made out of the second material with complex dielectric constant. Expression for transmission probability is obtained along with equation which allows calculation of the resonant frequency. Analytical expressions for reflection and absorption probabilities are acquired as well. It will be shown, if the frequency is given, that the transmission probability (along with reflection and absorption probabilities) approaches infinity for one particular value of the dielectric constant with negative imaginary part, which is used to describe active media. Furthermore, conditions for appearance of these transmission singularities are obtained.

STABILITY OF MONOPOLE CONDENSATION IN SU(2) QCD

We propose to resolve the controversy regarding the stability of the monopole condensation in QCD by calculating the imaginary part of the one-loop effective action perturbatively. We calculate the imaginary part perturbatively to the order g2 with two different methods, with Feynman diagram and with Schwinger's method. Our result shows that with the magnetic background the effective action has no imaginary part, but with the electric background it acquires a negative imaginary part. This strongly indicates a stable monopole condensation in QCD.