Towards the Fundamental Quantum Limit of Linear Measurements of Classical Signals

Haixing Miao, Rana Adhikari, Yiqiu Ma, Belinda Pang, Yanbei Chen

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

The quantum Cram\'er-Rao bound (QCRB) sets a fundamental limit for the measurement of classical signals with detectors operating in the quantum regime. Using linear-response theory and the Heisenberg uncertainty relation, we derive a general condition for achieving such a fundamental limit. When applied to classical displacement measurements with a test mass, this condition leads to an explicit connection between the QCRB and the Standard Quantum Limit which arises from a tradeoff between the measurement imprecision and quantum backaction; the QCRB can be viewed as an outcome of a quantum non-demolition measurement with the backaction evaded. Additionally, we show that the test mass is more a resource for improving measurement sensitivity than a victim of the quantum backaction, which suggests a new approach to enhancing the sensitivity of a broad class of sensors. We illustrate these points with laser interferometric gravitational wave detectors.
Original languageEnglish
Article number050801
JournalPhysical Review Letters
Volume119
DOIs
Publication statusPublished - 2 Aug 2017

Bibliographical note

revised version with supplemental materials added

Keywords

  • quant-ph

Fingerprint

Dive into the research topics of 'Towards the Fundamental Quantum Limit of Linear Measurements of Classical Signals'. Together they form a unique fingerprint.

Cite this