@misc{indiciaeacdb84e79510,
  title = {Photon number density operator iE-circumflex},
  author = {M Hawton and T Melde},
  year = {1995},
  doi = {10.1103/physreva.51.4186},
  url = {https://pubmed.ncbi.nlm.nih.gov/9912094/},
  note = {Source identifier: 9912094}
}