News Archive
QIP IRC Conference 2006
The QIP IRC conference took place on the 26th and 27th of June 2006 at St Anne's College, Oxford.
Monday 26 June
10:15 Registration and coffee 11:00 Single photonics and quantum information - Professor Gerard Milburn,
Building and characterising a single photon source is a very active research objective of experimental quantum optics. Such sources have application in quantum key distribution and quantum computation, although the technical requirements for the latter are much more demanding. I review the theoretical description of single photon states and discuss a number of schemes to produce them. I will describe a new scheme for coherent communication with single photons states. This application at first sight seems surprising as single photons states have a zero average field amplitude. However the quantum coherence necessary to create single photon pulses provides a path to coherent communication based on fourth order interference rather than classical second order interference used in traditional coherent communication protocols. 12:00 Poster presentations
13:00 Lunch
14:00 Introduction to overview sessions - Professor Andrew Briggs,
14:15 Photons and QIP: the theoretical perspective - Professor Sir Peter Knight, Imperial College London A key focus of the Quantum Information Processing IRC is the coupling of "flying" to "stationary" qubits, one ingredient of a scalable quantum processor with distributed components. I will review progress being made in this area, and discuss current views on its prospects for the future. Stationary qubits come in many forms: quantum dots embedded in a solid state environment, superconducting circuits, laser-cooled trapped ions, cold atoms in optical lattices are all candidates for isolated qubits capable of being initialized, addressed and read out. Flying qubits are usually thought of as being photonic (although schemes do exist for shuttling massive carriers of quantum information in the form of ions and also of atom "heads"). To couple (and entangle) the two kinds usually requires a strong coupling necessitating a cavity with high finesse. I will review the current status of such attempts, and concentrate towards the end of my talk on the approach taken at Imperial to couple stationary cold atoms on an atom chip to fibre-based cavities which has a number of attractive features (mode-matching, high finesse, addressability and the possibility of scalability).
14:45 Demonstration of quantum telecloning of optical coherent states - Professor Sam Braunstein, University of York We demonstrate unconditional telecloning for the first time. In particular, we symmetrically and unconditionally teleclone coherent states of light from one sender to two receivers, achieving a fidelity for each clone of F=0.58±0.01, which surpasses the classical limit. This is a manipulation of a new type of multipartite entanglement whose nature is neither purely bipartite nor purely tripartite.
15:15 Recent progress in quantum computer architectures - Dr Simon Benjamin, University of Oxford In the period since the QIP IRC began, theoretical work has significantly broadened the range of physical systems that can support quantum computation. There has been exciting progress in highly distributed architectures where a very small quantum resource exists at each location and probabilistic measurement operations are employed to entangle remote sites. At the other extreme, we have seen progress in finding routes to exploit dense qubit arrays where individual units are too close to be addressed sepearately - ideas of efficient state transfer and 'mirroring' have matured into full QIP schemes. I will summarize some of this progress and pose the question of whether, in light of the new ideas and the strong UK contribution, the QIP IRC should make the realization of these schemes a key goal.
15:45 Developing electron spin quantum computing with carbon nanomaterials - Dr John Morton, University of Oxford Electron spin is emerging as a leading candidate for the embodiment of quantum information within a solid-state context. Carbon nanomaterials offer both well-defined electron spin qubits with exceptionally long coherence times, and also the means to arrange these qubits in one, two or three dimensions. I will present recent progress in the engineering of spin active carbon nanostructures and their use in development of techniques for electron spin quantum information processing. I will also describe the evolution of these techniques from the ensemble case towards the single spin limit.
16:15 Tea and breakout sessions
18:00 Posters and drinks reception
19:30 Dinner
Tuesday 27 June
09:00 Excitons in Self-Assembled Quantum Dots for Quantum Information Processing - Professor Maurice Skolnick, University of Sheffield Progress of the Excitons in Cavities grouping within the IRC will be summarised. On InAs quantum dots, notable achievements which will be presented include the observation of entangled photon pairs, coherent manipulation of exciton qubits, and the development of new techniques for controlled site positioning, important for maximising interactions between excitons and confined cavity photons. New modelling techniques to understand the factors controlling cavity Q factors have been developed, and applied to fabricated high Q micropillars and photonic crystals. Long term work on high stability quantum dots in wide band gap nitrides will be summarised. Progress against the goals set at the start of the IRC will be described.
09:30 Quantum Photonics - Professor John Rarity, University of Bristol I will review the progress in the area of quantum photonics. This includes the development of bright pair photon sources based on photonic crystal fiber and efficient triggered sources of single and entangled pair photons. These sources are being used to build photonic logic gates.
10:00 Quantum memories - Professor Ian Walmsley, University of Oxford I will discuss recent progress in quantum optical memories. These are essential components of long-distance quantum communications schemes and linear optical quantum computers. The general principles of operation, parameter ranges, and current state of the art in experiment will be reviewed.
10:30 Coffee
11:00 Vision for Years 4 and 5 of the QIP IRC
13:00 Lunch
14:00 Wrap up session and close
15:00 Tea
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