CORDIS - EU research results

Super-conducting Quantum Information processing with Circuit QED

Final Activity Report Summary - SUPERQIP (Superconducting Quantum Information Processing with Circuit QED)

The realisation of computation that harnesses the power of quantum mechanics is a key goal in many areas of physics research today, and one which when finally achieved could revolutionize computing. Among the promising candidates for such a goal is an approach based on superconducting electrical circuits, with which fast progress has been made in the last few years. In this project a particular superconducting circuit architecture, known as Circuit QED, has been used to couple two superconducting quantum bits (qubits) to each other, through single microwave photons which live on a length of microwave transmission line on a chip. The two qubit 'entangled' states that were generated and characterized form the key component of a future quantum computer, and the method used is especially promising for scaling up to larger numbers of qubits.

Amongst a number of other novel experiments carried out in the scope of the project, a second highlight was the observation of an important quantum mechanical effect known as 'Berry's Phase', for the first time on an electronic chip. The result is a demonstration of the high level of control over a single quantum system that can now be achieved with superconducting circuits, and will allow further investigations of this interesting geometrical effect to be carried out in the future. Control of the phase of a qubit is also important for quantum computation, and using geometric effects to control it has potential for being more robust against errors.