New photon-counting formula in thermo field dynamics
Gang Ren, Jian-ming Du, Hai-jun Yu, Hong-Yi Fan · Journal of Modern Optics · 2016
We show that the probability distribution pm,T of registering m photoelectrons can be explained in Thermo Field Dynamics theory as a matrix element of thermo entangling operator e1-ξa†a~† between ρ=∑mm,m~ρ and m,m~=mm~ where m~ is a fictitious Fock state. Based on this, the new integration formula for calculating pm,T, which involves both Laguerre polynomial and the characteristic function χη of ρ, is obtained. This provides us with convenience for evaluating photoelectric counting probability for various optical fields.