scholarly journals Photon engineering for quantum information processing

2003 ◽  
Vol 3 (special) ◽  
pp. 480-502
Author(s):  
A.B. U'Ren ◽  
K. Banaszek ◽  
I.A. Walmsley
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Interference ◽  
Quantum Information Processing ◽  
Logic Gate ◽  
Optical Systems ◽  
Two Photon ◽  
Entangled Photon Pairs ◽  
Available Technology ◽  
Photon States

We study distinguishing information in the context of quantum interference involving more than one parametric downconversion (PDC) source and in the context of generating polarization-entangled photon pairs based on PDC. We arrive at specific design criteria for two-photon sources so that when used as part of complex optical systems, such as photon-based quantum information processing schemes, distinguishing information between the photons is eliminated guaranteeing high visibility interference. We propose practical techniques which lead to suitably engineered two-photon states that can be realistically implemented with available technology. Finally, we study an implementation of the nonlinear-sign shift (NS) logic gate with PDC sources and show the effect of distinguishing information on the performance of the gate.

scholarly journals Synchronization of optical photons for quantum information processing

2016 ◽  
Vol 2 (5) ◽  
pp. e1501772 ◽  
Author(s):  
Kenzo Makino ◽  
Yosuke Hashimoto ◽  
Jun-ichi Yoshikawa ◽  
Hideaki Ohdan ◽  
Takeshi Toyama ◽  
...  
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
High Purity ◽  
Quantum Interference ◽  
Quantum Information Processing ◽  
Single Photon ◽  
Arrival Times ◽  
Optical Photons ◽  
Storage Times ◽  
First Time

A fundamental element of quantum information processing with photonic qubits is the nonclassical quantum interference between two photons when they bunch together via the Hong-Ou-Mandel (HOM) effect. Ultimately, many such photons must be processed in complex interferometric networks. For this purpose, it is essential to synchronize the arrival times of the flying photons and to keep their purities high. On the basis of the recent experimental success of single-photon storage with high purity, we demonstrate for the first time the HOM interference of two heralded, nearly pure optical photons synchronized through two independent quantum memories. Controlled storage times of up to 1.8 μs for about 90 events per second were achieved with purities that were sufficiently high for a negative Wigner function confirmed with homodyne measurements.

Quantum information processing with hyperentangled photon states

2006 ◽  
Vol 6 (4&5) ◽  
pp. 336-350
Author(s):  
S. P. Walborn ◽  
M. P. Almeida ◽  
P. H. Souto Ribeiro ◽  
C. H. Monken
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Degrees Of Freedom ◽  
Quantum Information Processing ◽  
Success Probability ◽  
Bell State ◽  
Multiple Degrees Of Freedom ◽  
Photon States ◽  
Probabilistic Nature ◽  
Bell State Measurements

We discuss quantum information processing with hyperentangled photon states - states entangled in multiple degrees of freedom. Using an additional entangled degree of freedom as an ancilla space, it has been shown that it is possible to perform efficient Bell-state measurements. We briefly review these results and present a novel deterministic quantum key distribution protocol based on Bell-state measurements of hyperentangled photons. In addition, we propose a scheme for a probabilistic controlled-not gate which operates with a 50% success probability. We also show that despite its probabilistic nature, the controlled-not gate can be used for an efficient, nonlocal demonstration of the Deutsch algorithm using two separate photons.

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