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Schlagwörter:
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MPINP:
Research group J. Evers – Division C. H. Keitel
Zusammenfassung:
The generation and verification of entanglement is one of the big remaining challenges
in x-ray quantum optics. We generalize a criterion for two-mode entanglement based
on a Bell inequality, which was put forward by Johansen. We show that the experimentally
simple criterion detects entanglement even for arbitrary losses behind the source.
Furthermore, a beamsplitter of arbitrary reflectivity can be used to generate two-mode
entanglement from a single-photon input. We investigate a range of other interesting
input states and find that states similar to the single-photon state produce entanglement
as well. The criterion thus provides a robust and practical benchmark for both theoretical
and experimental work on single-photon entanglement. By applying a post-selection
scheme, we demonstrate the importance of two-photon events in experiments, even for
very low event rates. The criterion’s possible experimental implementation at x-ray energies,
requiring only an interferometer and photodetectors, is discussed. We investigate
Mössbauer nuclei in a thin-film cavity as an interferometer and derive a scheme to extract
the first-order coherence g(1) from its Fano spectrum. Analyzing experimental data,
we show that thin-film cavity systems are capable of sufficiently high coherence for the
interferometry part of the criterion.
