Rotation sensing at the ultimate limit

TL;DR

This paper derives quantum states that reach the fundamental sensitivity limits for rotation sensing, promising significant improvements for next-generation quantum rotation sensors.

Contribution

It introduces optimal quantum states for rotation sensing that achieve the ultimate sensitivity limits dictated by quantum mechanics.

Findings

Optimal states for estimating rotation axis orientation

Optimal states for measuring rotation angle

Enhanced sensitivity approaching quantum limits

Abstract

Conventional classical sensors are approaching their maximum sensitivity levels in many areas. Yet these levels still are far from the ultimate limits dictated by quantum mechanics. Quantum sensors promise a substantial step ahead by taking advantage of the salient sensitivity of quantum states to the environment. Here, we focus on sensing rotations, a topic of broad application. By resorting to the basic tools of estimation theory, we derive states that achieve the ultimate sensitivities in estimating both the orientation of an unknown rotation axis and the angle rotated about it. The critical enhancement obtained with these optimal states should make of them an indispensable ingredient in the next generation of rotation sensors that is now blossoming.