EQUIP: Entanglement in quantum information processing and communication

• Research unit: EU RFP
• Project number: 99.0467

Key words (English)

Quantum information processing

Alternative project number (English)

EU project number: IST-1999-11053

Research programs (English)

EU-programme: 5. Frame Research Programme - 1.2.8 Generic R&D activities

Short description (English)

See abstract

Partners and International Organizations (English)

Coordinator: Universität Potsdam (D)

Abstract (English)

This theoretical project gathers a very large group of European experts in quantum information theory. In 2001 two collaborations produced success. First, together with colleagues at Bristol University, UK, and at the ULB, Belgium, a generalization of the famous Bell inequality to quantum systems of arbitrary dimensions was discovered. This work appeared in Phys. Rev. Lett. in early January 2002 and was highlighted by Nature. Recall that Bell inequalities are the quantitative side of the phenomenon called quantum non-locality. The second collaboration was within Switzerland with colleagues from the ETHZ, Prof. U. Maurer and his student M. Fitzi. We developped a quantum solution to an old problem in distributed computing. In its simplest form, a sender has to broadcast some information to two receivers, but they have access only to pairwise communication channels. Unlike quantum key distribution, here the goal is not secrecy but agreement, and the adversary (one of the receivers or the sender himself) is not outside but inside the game. Using only classical channels this problem is probably impossible. The solution uses pairwise quantum channels and entangled qutrits (i.e. 3- dimensional quantum systems). This is the first example of a quantum communication protocol requiring quantum systems of dimension larger than two (i.e. not qubits). This work appeared in Phys. Rev. Lett. 87,19, 2001, and has been accept by Eurocrypt 2002.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 99.0467