The role of entanglement in calibrating optical quantum gyroscopes

TL;DR

This paper investigates how entanglement affects the calibration accuracy of optical quantum gyroscopes, revealing that optimal inter-interferometer entanglement can enhance calibration precision.

Contribution

It introduces a generalized multi-position testing procedure for quantum interferometers and analyzes the complex role of entanglement between them for improved calibration.

Findings

Entanglement within a single interferometer is crucial for operation.

Optimal inter-interferometer entanglement depends on specific parameter values.

Properly chosen entangled states can provide measurable calibration improvements.

Abstract

We consider the calibration of an optical quantum gyroscope by modeling two Sagnac interferometers, mounted approximately at right angles to each other. Reliable operation requires that we know the angle between the interferometers with high precision, and we show that a procedure akin to multi-position testing in inertial navigation systems can be generalized to the case of quantum interferometry. We find that while entanglement is a key resource within an individual Sagnac interferometer, its presence between the interferometers is a far more complicated story. The optimum level of entanglement depends strongly on the sought parameter values, and small but significant improvements may be gained from choosing states with the optimal amount of entanglement between the interferometers.