New photon-counting formula in thermo field dynamics

摘要

We show that the probability distribution p(m, T) of registering m photoelectrons can be explained in Thermo Field Dynamics theory as a matrix element of thermo entangling operator e(1-xi) a(dagger) (a) over tilde (dagger) between = vertical bar m > vertical bar (m) over tilde > where vertical bar(m) over tilde > is a fictitious Fock state. Based on this, the new integration formula for calculating p(m, T), which involves both Laguerre polynomial and the characteristic function chi(eta) of rho, is obtained. This provides us with convenience for evaluating photoelectric counting probability for various optical fields.