2007/12/31 by Ferdinand Helmer, Matteo Mariantoni, Enrique Solano +1 · 1 citation
Physics and Astronomy · #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physreva.79.052115
published as Phys. Rev. A 79, 052115 (2009) · 4.5 pages, 3 figures
arxiv created 2008/05/30 · arxiv updated 2013/05/29
We analyze the detection of itinerant photons using a quantum non-demolition (QND) measurement. We show that the backaction due to the continuous measurement imposes a limit on the detector efficiency in such a scheme. We illustrate this using a setup where signal photons have to enter a cavity in order to be detected dispersively. In this approach, the measurement signal is the phase shift imparted to an intense beam passing through a second cavity mode. The restrictions on the fidelity are a consequence of the Quantum Zeno effect, and we discuss both analytical results and quantum trajectory simulations of the measurement process.