Finding the boson-number distributions in superconductors from photon   spectra emitted by supercurrent-carrying rings irradiated with far IR fields
  A theory of the IR-field-induced single-photon generation by the narrow thin-film superconducting rings made of the isotropic s-wave pairing type-II superconductors is presented. It is shown that statistical measurements of the energies of photons emitted by the same current-carrying ring prepared initially in the same quantum state, allow to find the number distribution of Cooper pairs in the superconductor. 
Alexander Agafonov
cond-mat.supr-con