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Published August 1, 1980 | public
Journal Article

Quantum Nondemolition Measurements


Some future gravitational-wave antennas will be cylinders of mass ∼100 kilograms, whose end-to-end vibrations must be measured so accurately (10^(–19) centimeter) that they behave quantum mechanically. Moreover, the vibration amplitude must be measured over and over again without perturbing it (quantum nondemolition measurement). This contrasts with quantum chemistry, quantum optics, or atomic, nuclear, and elementary particle physics, where one usually makes measurements on an ensemble of identical objects and does not care whether any single object is perturbed or destroyed by the measurement. This article describes the new electronic techniques required for quantum nondemolition measurements and the theory underlying them. Quantum nondemolition measurements may find application elsewhere in science and technology.

Additional Information

© 1980 American Association for the Advancement of Science. For valuable discussions we thank C. M. Caves, R. W. P. Drever, and F. Ya. Khalili. For financial support we thank: (i) at Moscow University, the Ministry of Higher Education of the U.S.S.R.; (ii) at Caltech, the U.S. National Aeronautics and Space Administration (NGR 05-002-256 and a grant from PACE) and the U.S. National Science Foundation (AST76-80801 A02); (iii) for collaborative aspects of this work, the Cooperative Program in Physics between the U.S. National Academy of Sciences and the U.S.S.R. Academy of Sciences under the auspices of the U.S.-U.S.S.R. Joint Commission on Scientific and Technological Cooperation (contract NSF-C310, Task Order 379).

Additional details

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October 20, 2023