Intensity Correlations for Stars

The pioneering experiments of intensity correlations by Hanbury-Brown and Twiss more than 50-years ago not only allowed to measure the angular diameter of many bright stars, but it also motivated Roy Glauber to develop his quantum formalism of photon statistics.

The advent of direct optical interferences of light collected by different telescopes developed in the beginning of the 70s, with superior performances in terms of signal to noise ratio and correspondingly reduced required observation time put an end to these first attempts of intensity correlation imaging for astrophysics.

State of the art optical interference imaging is however limited by accessible baselines and the required mechanical precision for optical delay lines are limited in particular due to atmospheric fluctuations and at short wavelengths.

In IC4Stars we will use modern photon counting techniques to perform quantum optics measurements and probe quantum systems in astrophysics.

A first target will be a quantum degenerate Fermi gaz of electrons (a white dwarf) whose angular diameter is out of reach for direct optical imaging techniques.

A second goal will be the search for quantum sources of radiation by looking for random lasing in astrophysics, to be detected by second order photon correlation.