Quantum limits on detection sensitivity of a linear detector with feedback

TL;DR

This paper establishes fundamental quantum limits on the detection sensitivity of linear detectors, including bounds relevant for atomic force microscopes and gravitational wave detection, highlighting the ultimate quantum limit and a generalized lower bound.

Contribution

It derives new quantum bounds on detection sensitivity for linear detectors, extending understanding of fundamental measurement limits in quantum systems.

Findings

Detection sensitivity is bounded by quantum limits.

The ultimate quantum limit applies to force detection.

A generalized lower bound is derived for displacement detection.

Abstract

We show that the detection sensitivity of a linear detector is lower bounded by some quantum limits. For the force detection, relevant for atomic force microscopes, the lower bound is given by the so-called ultimate quantum limit. For the displacement detection, relevant for detecting gravitational waves, a generalized lower bound is obtained.