Astrometry in two-photon interferometry using Earth rotation fringe scan

TL;DR

This paper proposes a novel two-photon interferometry method using Earth rotation fringe scans to measure astronomical source positions with microarcsecond precision, potentially enabling long-baseline interferometry without phase-stable links.

Contribution

It introduces a Bayesian analysis approach for Earth rotation fringe scanning and demonstrates its feasibility for high-precision astrometry with modest telescope arrays.

Findings

Achieved $ ext{~}10~ ext{μas}$ astrometric precision in a few hours

Developed a Bayesian method consistent with Fisher matrix analysis

Identified candidate source pairs in the northern hemisphere

Abstract

Optical interferometers may not require a phase-stable optical link between the stations if instead sources of quantum-mechanically entangled pairs could be provided to them, enabling long baselines. We developed a new variation of this idea, proposing that photons from two different astronomical sources could be interfered at two decoupled stations. Interference products can then be calculated in post-processing or requiring only a slow, classical connection between stations. In this work, we investigated practical feasibility of this approach. We developed a Bayesian analysis method for the earth rotation fringe scanning technique and showed that in the limit of high signal-to-noise ratio it reproduced the results from a simple Fisher matrix analysis. We identify candidate stair pairs in the northern hemisphere, where this technique could be applied. With two telescopes with an effective collecting area of $\sim 2$ m$^2$, we could detect fringing and measure the astrometric separation of the sources at $\sim 10\,\mu$as precision in a few hours of observations, in agreement with previous estimates.