De Broglie wavelength of a non-local four-photon state

Autor(en)

Philip Walther, Jian-Wei Pan, Markus Aspelmeyer, Rupert Ursin, Sara Gasparoni, Anton Zeilinger

Abstrakt

Superposition is one of the most distinctive features of quantum theory and has been demonstrated in numerous single-particle interference experiments. Quantum entanglement, the coherent superposition of states in multi-particle systems, yields more complex phenomena. One important type of multi-particle experiment uses path-entangled number states, which exhibit pure higher-order interference and the potential for applications in metrology and imaging; these include quantum interferometry and spectroscopy with phase sensitivity at the Heisenberg limit, or quantum lithography beyond the classical diffraction limit. It has been generally understood that in optical implementations of such schemes, lower-order interference effects always decrease the overall performance at higher particle numbers. Such experiments have therefore been limited to two photons. Here we overcome this limitation, demonstrating a four-photon interferometer based on linear optics. We observe interference fringes with a periodicity of one-quarter of the single-photon wavelength, confirming the presence of a four-particle mode-entangled state. We anticipate that this scheme should be extendable to arbitrary photon numbers, holding promise for realizable applications with entanglement-enhanced performance.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Universität Heidelberg

Journal

Nature

Band

429

Seiten

158-161

Anzahl der Seiten

4

ISSN

0028-0836

DOI

https://doi.org/10.1038/nature02552

Publikationsdatum

05-2004

Peer-reviewed

Ja

ÖFOS 2012

103026 Quantenoptik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/e39a77fb-50b6-4e75-adf8-820d77f31f07