Coherence in the Sky: Precision Astrometry with Intensity Interferometry.

In the era of a wealth of data from the sky, new perspectives can lead to parametric improvements in discovery reach. I will discuss a surprising feature of the second-order coherence of light that opens new directions for detection: intensity interferometry. By recording photon counts rather than electromagnetic fields at a telescope, optical intensity interferometers admit longer baselines and thus can achieve greater precision on bright sources than traditional interferometers. I will describe the Extended-Path Intensity Correlator (EPIC): a proposed telescope array that extends the scope of intensity interferometry. Combined with technological advances, EPIC can achieve unprecedented precision in astrometry with applications including exoplanet detection, astrometric microlensing, and black hole measurements.