No-go theorem for passive single-rail linear optical quantum computing

Autor(en)

Lian-Ao Wu, Philip Walther, Daniel A. Lidar

Abstrakt

Photonic quantum systems are among the most promising architectures for quantum computers. It is well known that for dual-rail photons effective non-linearities and near-deterministic non-trivial two-qubit gates can be achieved via the measurement process and by introducing ancillary photons. While in principle this opens a legitimate path to scalable linear optical quantum computing, the technical requirements are still very challenging and thus other optical encodings are being actively investigated. One of the alternatives is to use single-rail encoded photons, where entangled states can be deterministically generated. Here we prove that even for such systems universal optical quantum computing using only passive optical elements such as beam splitters and phase shifters is not possible. This no-go theorem proves that photon bunching cannot be passively suppressed even when extra ancilla modes and arbitrary number of photons are used. Our result provides useful guidance for the design of optical quantum computers.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

University of the Basque Country, University of Southern California

Journal

Scientific Reports

Band

3

Anzahl der Seiten

6

DOI

https://doi.org/10.1038/srep01394

Publikationsdatum

03-2013

Peer-reviewed

Ja

ÖFOS 2012

103026 Quantenoptik, 103008 Experimentalphysik, 210006 Nanotechnologie, 103025 Quantenmechanik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/1b942c21-a6ad-4fa4-9950-9b71bf203d80