Quantum nondemolition filters

J. W. Clark, C. K. Ong, T. J. Tarn, Garng Morton Huang

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

This is the second of two papers concerned with the formulation of a continuous-time quantum-mechanical filter. In the first paper, the invertibility of a quantum system coupled to a weak time-dependent classical field was studied. The physical system is modelled as an infinite-dimensional bilinear system. Necessary and sufficient conditions for invertibility were derived under the assumption that the output observable is a quantum nondemolition observable (QNDO), characterized by the classical property that its expected value is equal to its measured value. In this paper necessary and sufficient conditions are developed for an observable to qualify as a QNDO; if in addition the criteria for invertibility are met, the given observable defines a quantum nondemolition filter (QNDF). The associated filtering algorithm thus separates cleanly into the choice of output observable (a QNDO) and the choice of procedure for processing the measurement outcomes. This approach has the advantage over previous schemes that no optimization is necessary. Applications to demodulation of optical signals and to the detection and monitoring of gravitational waves are envisioned.

Original languageEnglish
Pages (from-to)33-55
Number of pages23
JournalMathematical Systems Theory
Volume18
Issue number1
DOIs
Publication statusPublished - 1 Dec 1985
Externally publishedYes

Fingerprint

Gravity waves
Demodulation
Filter
Monitoring
Processing
Invertibility
Necessary Conditions
Bilinear Systems
Infinite-dimensional Systems
Sufficient Conditions
Output
Gravitational Waves
Expected Value
Quantum Systems
Continuous Time
Filtering
Necessary
Optimization
Formulation

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Mathematics(all)
  • Computational Theory and Mathematics

Cite this

Quantum nondemolition filters. / Clark, J. W.; Ong, C. K.; Tarn, T. J.; Huang, Garng Morton.

In: Mathematical Systems Theory, Vol. 18, No. 1, 01.12.1985, p. 33-55.

Research output: Contribution to journalArticle

Clark, JW, Ong, CK, Tarn, TJ & Huang, GM 1985, 'Quantum nondemolition filters', Mathematical Systems Theory, vol. 18, no. 1, pp. 33-55. https://doi.org/10.1007/BF01699460
Clark, J. W. ; Ong, C. K. ; Tarn, T. J. ; Huang, Garng Morton. / Quantum nondemolition filters. In: Mathematical Systems Theory. 1985 ; Vol. 18, No. 1. pp. 33-55.
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