Quantum noise spectroscopy as an incoherent imaging problem

Mankei Tsang, “Quantum noise spectroscopy as an incoherent imaging problem,” Physical Review A 107, 012611 (2023) [arXiv PDF].

People often asked us whether we can apply our quantum-inspired superresolution ideas to gravitational-wave detection. This paper shows that the answer is yes, if the goal is to detect a stochastic gravitational-wave background. This is because the two problems have the same random displacement model under the hood: randomly displaced photons in the case of imaging, and randomly displaced fields in the case of optomechanical detector. With the correspondence direct imaging = homodyne, SPADE = photon counting in the spectral modes, photon counting turns out to be far superior to homodyne in the same way SPADE is superior.