Abstract
Measurement is integral to quantum information processing and communication; it is how information encoded in the state of a system is transformed into classical signals for further use. In quantum optics, measurements are typically destructive, so that the state is not available afterwards for further steps. Here we show how to measure the presence or absence of the vacuum in a quantum optical field without destroying the state, implementing the ideal projections onto the respective subspaces. This not only enables sequential measurements, useful for quantum communication, but it can also be adapted to create novel states of light via bare raising and lowering operators.
- Received 27 November 2012
DOI:https://doi.org/10.1103/PhysRevLett.110.210504
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© 2013 American Physical Society
Synopsis
Measuring Nothing
Published 23 May 2013
Transitions in an atom can allow nondestructive measurement of the quantum vacuum state.
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