Speaker: Prof. Sir Peter Knight FRS

Kavli Royal Society International Centre, Chicheley Hall and Blackett Laboratory, Imperial College London

Abstract:

How can one utilize the laws of quantum mechanics to process information in a manner beyond the capability of classical physics? Our group at Imperial has been pursuing this idea of quantum information processing and quantum computing for some years. I will review the basic ideas, and then explore ways in which we can use these ideas to simulate quantum processes. A major growth area of quantum information science is the potential to realize Feynman’s early idea of simulating quantum processes. With a given quantum resource: an array of qubits that can be manipulated with external couplings, one can simulate efficiently quantum processes which occur naturally but which cannot easily be simulated by classical methods, given the size of the state space involved.  One approach to this is to employ a quantum walk algorithm, and I will describe how this can explore state space faster than a classical random walk.

And this will bring me to the second part of my talk: there is evidence that nature utilises quantum coherence of this kind in early stage photosynthesis. To uncover this, we needed ultra-fast laser nonlinear spectroscopy, and that’s where the Laser Consortium at Imperial has stepped in to provide insights as part of our attosecond collaboration, bringing together the whole group.  Newly developed capabilities in ultrafast laser technology have enabled us to follow motion at the quantum level, with many dramatic advances in laser science, which have taken us from the microsecond time resolution progressively down through nanoseconds, picoseconds, femtoseconds and now to attoseconds.  Quantum computing is hard to realise, due to the fragility of quantum superpositions in dissipative environments; yet biology seems to use quantum coherence in wet and warm environments in a robust manner. This is one of the most surprising aspects we have uncovered in the group’s research over the past few years.

This will be the last colloquium of this academic year

Please direct enquiries about Departmental Colloquia to Ingo & Ned, i.mueller-wodarg@imperial.ac.uk n.ekins-daukes@imperial.ac.uk