Contractive States and the Standard Quantum Limit for Monitoring Free-Mass Positions
- 29 August 1983
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 51 (9) , 719-722
- https://doi.org/10.1103/physrevlett.51.719
Abstract
The familiar minimum-uncertainty wave packets for masses are generalized in analogy with the two-photon coherent states of the radiation field. The free evolution of a subclass of these states, the contractive states, leads to a narrowing of the position uncertainty in contrast with the usual minimum-uncertainty wave packets. As a consequence the standard quantum limit for monitoring the positions of a free mass can be breached. Further implications on quantum nondemolition measurements are discussed.Keywords
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