Mainz 2017 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 16: Quantum Information: Concepts and Methods III
Q 16.1: Talk
Tuesday, March 7, 2017, 11:00–11:15, P 2
Witnessing Quantum Squeezing via Binary Homodyne Detection — Christian R. Müller1,2, •Kaushik Seshadreesan1,2, Gerd Leuchs1,2, and Christoph Marquardt1,2 — 1Max Planck Institute for the Science of Light, Erlangen, Germany. — 2Department of Physics, University of Erlangen-Nuremberg (FAU), Germany.
Ideal homodyne detection provides an observable with a continuous spectrum. In practical situations, however, the observed quantity is always discretized to some extent. This may be due to the specifics of the protocol, such as the discretization of phase space in CV-QKD, or also due to the limited resolution of the implemented analog-to-digital converter. We consider the extreme case of homodyne detection with a resolution of only 1 bit, i.e., where only the sign of the projected quadrature value is accessible. We illustrate the capacity of such a restricted homodyne detector by demonstrating that even extremely weak squeezing of coherent states can be witnessed. We derive the associated error probabilities in discriminating a coherent state from a weakly squeezed state and experimentally validate our findings. Furthermore, we discuss the possibility of detecting squeezed light transmitted in satellite communication with binary homodyne detectors.