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Quantum Non-Demolition Measurements: Concepts, Theory and Practice


Affiliations
1 Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
 

This is a limited overview of quantum non-demolition (QND) measurements, with brief discussions of illustrative examples meant to clarify the essential features. In a QND measurement, the predictability of a subsequent value of a precisely measured observable is maintained and any random back-action from uncertainty introduced into a non-commuting observable is avoided. The fundamental ideas, relevant theory and the conditions and scope for applicability are discussed with some examples. Precision measurements have indeed gained from developing QND measurements and some implementations in quantum optics, gravitational wave detectors and spin-magnetometry are discussed.

Keywords

Back-Action Evasion, Gravitational Waves, Quantum Non-Demolition, Standard Quantum Limit, Squeezed Light.
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  • Quantum Non-Demolition Measurements: Concepts, Theory and Practice

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Authors

C. S. Unnikrishnan
Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India

Abstract


This is a limited overview of quantum non-demolition (QND) measurements, with brief discussions of illustrative examples meant to clarify the essential features. In a QND measurement, the predictability of a subsequent value of a precisely measured observable is maintained and any random back-action from uncertainty introduced into a non-commuting observable is avoided. The fundamental ideas, relevant theory and the conditions and scope for applicability are discussed with some examples. Precision measurements have indeed gained from developing QND measurements and some implementations in quantum optics, gravitational wave detectors and spin-magnetometry are discussed.

Keywords


Back-Action Evasion, Gravitational Waves, Quantum Non-Demolition, Standard Quantum Limit, Squeezed Light.

References





DOI: https://doi.org/10.18520/cs%2Fv109%2Fi11%2F2052-2060