Far-field quantumstatistics oflight generated byacollection oftwo-level atomns

We study quantum statistics ofoptical fields inthefarzoneof alight source consisting ofa numberofuncorrelated atoms.The quantumstatistics ofsuchasystem canbeuniversal undercertain conditions. Atypical optics communication problem, whether classical orquantum, isconcerned withstudying theproperties oflight atareceiver suchasa photodetector etc., which isusually located inthefarzoneofalight source. Oneofthefundamental issues inthis context isthechange ofstatistical properties ofoptical fields onfree space propagation fromthesource tothe receiver. Theissue isveryimportant foroptical communications andimagingapplications. Thiscircumstance explains muchinterest inthetopic of correlation-induced spectal changes whichwasadvanced byWVolf notlong ago.Inparticular, Wolfhasdiscovered precise conditions thathavetobe imposed onthesource forittogenerate light whosenormalized spectrum inthefarzoneisthesameasthatinthesource plane [1]. Thisresult was followed byaflurry oftheoretical andexperimental activity (for areview see[2]). Toourknowledge, however, theworkonthechange oflight statistics onfree space propagation tothefar-zone hassofarbeenlimited tosecondorder correlation functions oftheoptical fields such astheir spectra. Thisisa