Channel-loss-independent quantum-enhanced interferometer

TL;DR

This paper introduces a quantum interferometer that maintains high phase sensitivity despite large channel loss, using practical detectors and states, improving long-baseline angular resolution for remote star observations.

Contribution

It presents a novel quantum interferometry scheme that is loss-independent and feasible with current technology, enhancing long-distance astronomical measurements.

Findings

Fisher information remains constant under large channel loss.

Achieves better angular resolution than previous quantum methods.

Uses only mature, practical components like threshold detectors and coherent or squeezed states.

Abstract

We propose a channel-loss-independent quantum-enhanced interferometer. In our scheme, the Fisher information for phase difference of weak light from a remote star remains constant under arbitrarily large channel loss, and the angular resolution of our method is better than that of prior quantum-enhanced methods in the long-baseline regime. Moreover, our method requires only threshold detectors and tunable coherent state or two-mode squeezed state sources, both of which are matured technologies nowadays.