Statistical and phase properties and number-phase uncertainty relations are systematically investigated for photon states associated with the Holstein-Primakoff realization of the SU(1,1) Lie algebra. Perelomov's SU(1,1) coherent states and the eigenstates of the SU(1,1) lowering generator (the Barut-Girardello states) are discussed. A recently developed formalism, based on the antinormal order...

We study gauge fixing in the generalized Gupta-Bleuler quantization. In this method physical states are defined to be simultaneous null eigenstates of a set of quantum invariants. We apply the method to a solvable model proposed by Friedberg, Lee, Pang and Ren and show that no Gribov-type copies appears by construction. Gauge fixing is significant in quantization of gauge theories. Gribov ambig...

A new lightweight gas-particle mixture generator for fire-extinguishing purposes is designed such as to keep the generator and aerosol temperatures low by including a Phase Change Materials (PCM) component. The new generator performances have been studied experimentally and compared to the corresponding performances of a traditional design. The temperature evolution profiles of this gas-particl...