40 research outputs found
Entangler and analyzer for multiphoton maximally entangled states using weak nonlinearities
In the regime of weak nonlinearity we present two general feasible schemes.
One is an entangler for generating any one of the -photon
Greenberger-Horne-Zeilinge (GHZ) states and Bell states. After the interactions
with cross-Kerr nonlinear media, a phase gate followed by a measurement on the
probe beam, and appropriate local operations via classical feed-forward, one
can obtain the desired states in a nearly deterministic way. Another scheme is
an analyzer for multiphoton maximally entangled states, which is taken as a
further application of the above entangler. In this scheme, all of the
-photon GHZ states can, nearly deterministically, be discriminated.
Furthermore, an efficient two-step nondestructive Bell-state analyzer is
designed.Comment: 7 pages, 6 figure
Multi-photon entanglement and interferometry
Multi-photon interference reveals strictly non-classical phenomena. Its
applications range from fundamental tests of quantum mechanics to photonic
quantum information processing, where a significant fraction of key experiments
achieved so far comes from multi-photon state manipulation. We review the
progress, both theoretical and experimental, of this rapidly advancing
research. The emphasis is given to the creation of photonic entanglement of
various forms, tests of the completeness of quantum mechanics (in particular,
violations of local realism), quantum information protocols for quantum
communication (e.g., quantum teleportation, entanglement purification and
quantum repeater), and quantum computation with linear optics. We shall limit
the scope of our review to "few photon" phenomena involving measurements of
discrete observables.Comment: 71 pages, 38 figures; updated version accepted by Rev. Mod. Phy