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Quantum Based Information Processing and Transfer Using Single Atoms and Photons

Objective

This project concerns the study of decoherence and entanglement of a variety of quantum systems (atoms, ions and cavities) with a view to the practical realisation of scaleable quantum registers for use in quantum computation and quantum communication. It comprises a many-pronged attack on the fundamental problem of decoherence of quantum systems, taking advantage of the varied and highly specialised experience of European groups in this area, including both experimental and theoretical work.

This proposal will result in:
- the demonstration of quantum gates using single ions and strings of ions trapped in different types of ion trap;
- the demonstration of trapping and cooling of single atoms for use in novel quantum gates;
- the realisation of novel quantum devices using techniques based on cavity QED; demonstrations of elementary quantum communications by bringing together aspects from the above areas.

Theoretical work will support and guide the experimental work undertaken. This proposal will result in Europe's continuing to take a lead in this scientifically and commercially important area. This project concerns the study of decoherence and entanglement of a variety of quantum systems (atoms, ions and cavities) with a view to the practical realisation of scaleable quantum registers for use in quantum computation and quantum communication. It comprises a many-pronged attack on the fundamental problem of decoherence of quantum systems, taking advantage of the varied and highly specialised experience of European groups in this area, including both experimental and theoretical work.

This proposal will result in:
- the demonstration of quantum gates using single ions and strings of ions trapped in different types of ion trap;
- the demonstration of trapping and cooling of single atoms for use in novel quantum gates;
- the realisation of novel quantum devices using techniques based on cavity QED; demonstrations of elementary quantum communications by bringing together aspects from the above areas.

Theoretical work will support and guide the experimental work undertaken. This proposal will result in Europe's continuing to take a lead in this scientifically and commercially important area.

OBJECTIVES
We will trap and laser cool small ensembles of atomic ions in different types of ion trap (end cap traps, linear traps and Penning traps) in order to study quantum decoherence, create quantum gates, perform simple algorithms and demonstrate quantum error correction schemes. A variety of approaches to the problem will ensure a thorough understanding of the fundamental issues. We will trap and laser cool single atoms and small numbers of atoms (using advanced techniques) in different optical traps (optical lattices, holographically generated light potentials and optical tweezers) for the investigation of novel neutral atom realisations of quantum gates as an alternative to trapped ions. We will investigate cavity QED in the microwave and optical regimes and will study entanglement of fields and atoms in this system. We will also use cavity QED techniques for the preparation of a "quantum switch" and a "photon pistol" (with free atoms), fundamental building blocks for quantum communication. We will also use trapped ions in cavities as an alternative approach to this problem. Experimental work in many of these areas will be complemented by related theoretical studies.

DESCRIPTION OF WORK
This project is organised under three main themes, with cross-theme links. The work is all highly technically demanding and is concentrated in areas where European groups are already at the forefront of international work. Collaborations made possible by EU funding will strengthen the individual groups and help advance the work rapidly. Under theme 1 (trapped ions), we will make a thorough investigation of trapped ions as potential realisations of quantum gates. For this we will investigate different species in different types of ion trap, using between 1 and 10 ions. In each case, state-of-the-art laser cooling techniques will be used to cool to the ground vibration states of motion of the ions. Entangled states (including Bell and GHZ states) will be generated and used for the investigation of decoherence. Quantum gates will be demonstrated and quantum error correction schemes investigated experimentally;

Under theme 2 (trapped neutral atoms) we will investigate small numbers (1-3) of trapped atoms as a potential novel system for the investigation of quantum decoherence and the realisation of quantum gates. This system has the prospect of very low decoherence rates and saleability to larger numbers of qubits. The atoms will be trapped in a variety of optical traps having different experimental advantages. Comparisons will be made with ion-trap schemes;

Theme 3 (Cavity QED) comprises a study of cavity QED in both conventional optical and microwave cavities and silica micro spheres. These will be used for studies of decoherence and for the generation of novel quantum devices. This scheme will be linked with theme 1 through cavity QED experiments with trapped ions, a particularly challenging technical area with enormous potential benefits including quantum communication. Finally, theoretical work underpins much of the experimental work proposed and provides extra links between the themes, in particular a study of entangled quantised motion.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

IMPERIAL COLLEGE OF SCIENCE, TECHNOLOGY AND MEDICINE
Address
South Kensington Campus
London
United Kingdom

Participants (10)

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
France
Address
3, Rue Michel-ange
75794 Paris Cedex 16
ECOLE NORMALE SUPERIEURE PARIS
France
Address
45, Rue D'ulm
75230 Paris Cedex 05
Eberhard-Karls-Universität Tübingen
Germany
Address
Wilhelmstraße 7
72074 Tübingen
INSTITUT FUER EXPERIMENTALPHYSIK DER UNIVERSITAET INNSBRUCK
Austria
Address
Technikerstrasse 25
6020 Innsbruck
LUDWIG-MAXIMILIANS-UNIVERSITAET MUENCHEN
Germany
Address
Geschwister-scholl-platz 1
80539 Muenchen
MAX-PLANCK GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V.
Germany
Address
Hofgartenstrasse 8
80539 Muenchen
NPL MANAGEMENT LIMITED
United Kingdom
Address
National Physical Laboratory, Queens Road
TW11 0LW Teddington, Middlesex
SLOVAK ACADEMY OF SCIENCES - INSTITUTE OF PHYSICS
Slovakia
Address
Dubravska Cesta 9
842 28 Bratislava
THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF OXFORD
United Kingdom
Address
University Offices, Wellington Square
OX1 2JD Oxford
UNIVERSITAET ULM
Germany
Address
Gruener Hof 5C
89073 Ulm