Friedrich-Alexander-Universität Erlangen-Nürnberg

Novel Quantum Receivers

Novel Quantum Receivers

Quantum state discrimination is one of the fundamental issues in optical communication and quantum signal detection. An important figure of merit here is the error rate. For a pair of coherent states, homodyne detection represents an effective way to achieve near-minimal error discrimination. A receiver based on photon counting would lead to even smaller error rates, provided if signal intensities are sufficiently large. In order to outperform the homodyne scheme also for smaller photon numbers, we have successfully implemented a novel detection scheme [1]. The scheme outperforms homodyne detection as well as all previous non-adaptive schemes using photon counting.

Usually quantum state discrimination has a deterministic outcome, which is erroneous due to the overlap of the wavefunction of the discriminated states. Another possibility is to allow for a probabilistic measurement outcome, meaning that inconclusive results are allowed. By extending the scheme in [1] with a photon number resolving detector and postselection, we showed that photon number resolving detectors are very useful in state discrimination [2] and outperform again the homodyne detection [3,4].


  1. Christoffer Wittmann, Masahiro Takeoka, Katiuscia N. Cassemiro, Masahide Sasaki, Gerd Leuchs,
    and Ulrik L. Andersen, Phys. Rev. Lett 101, 210501-4 (2008).
  2. Christoffer Wittmann, Ulrik L. Andersen, and Gerd Leuchs, J. Mod. Opt. 57, 213 (2010).
  3. C. Wittmann, U. L. Andersen, M. Takeoka, D. Sych, and G. Leuchs, Phys. Rev. Lett 104, 100505  (2010).
  4. C. Wittmann, U. L. Andersen, M. Takeoka, D. Sych, and G. Leuchs, Phys. Rev. A 81, 062338  (2010).


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