Abstract
We have frozen the coherent evolution of a field in a cavity by repeated measurements of its photon number. We use circular Rydberg atoms dispersively coupled to the cavity mode for an absorption-free photon counting. These measurements inhibit the growth of a field injected in the cavity by a classical source. This manifestation of the quantum Zeno effect illustrates the backaction of the photon number determination onto the field phase. The residual growth of the field can be seen as a random walk of its amplitude in the two-dimensional phase space. This experiment sheds light onto the measurement process and opens perspectives for active quantum feedback.
- Received 21 July 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.180402
©2008 American Physical Society
Synopsis
Frozen light in a cavity
Published 30 October 2008
Successive and rapid measurements of a quantum system can prevent it from evolving in time. This quantum Zeno effect has now been demonstrated for light inside a cavity.
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