On the measurement of a weak classical force coupled to a harmonic oscillator: experimental progress

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Reviews of Modern Physics

DOI:https://doi.org/10.1103/RevModPhys.68.755· OSTI ID:287012

Bocko, M F ^[1]; Onofrio, R ^[2]

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1. Department of Electrical Engineering, University of Rochester, Rochester, New York 14627 (United States)
2. Dipartimento di Fisica `Galileo Galilei`, Universita di Padova, I-35131 Padova (Italy)

Several high-precision physics experiments are approaching a level of sensitivity at which the intrinsic quantum nature of the experimental apparatus is the dominant source of fluctuations limiting the sensitivity of the measurements. This quantum limit is embodied by the Heisenberg uncertainty principle, which prohibits arbitrarily precise simultaneous measurements of two conjugate observables of a system but allows one-time measurements of a single observable with any precision. The dynamical evolution of a system immediately following a measurement limits the class of observables that may be measured repeatedly with arbitrary precision, with the influence of the measurement apparatus on the system being confined strictly to the conjugate observables. Observables having this feature, and the corresponding measurements performed on them, have been named quantum nondemolition or back-action evasion observables. In a previous review (Caves {ital et} {ital al}., 1980, Rev. Mod. Phys. {bold 52}, 341) a quantum-mechanical analysis of quantum nondemolition measurements of a harmonic oscillator was presented. The present review summarizes the experimental progress on quantum nondemolition measurements and the classical models developed to describe and guide the development of practical implementations of quantum nondemolition measurements. The relationship between the classical and quantum theoretical models is also reviewed. The concept of quantum nondemolition and back-action evasion measurements originated in the context of measurements on a macroscopic mechanical harmonic oscillator, though these techniques may be useful in other experimental contexts as well, as is discussed in the last part of this review. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 287012
• Journal Information: Reviews of Modern Physics, Journal Name: Reviews of Modern Physics Journal Issue: 3 Vol. 68; ISSN RMPHAT; ISSN 0034-6861
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CLASSICAL MECHANICS
CORRELATION FUNCTIONS
EXPERIMENTAL DATA
FORCES
HARMONIC OSCILLATORS
LIMITING VALUES
MEASURE THEORY
MEASURING METHODS
OBSERVABLES
QUANTUM MECHANICS
REVIEWS
STATISTICAL MECHANICS
UNCERTAINTY PRINCIPLE