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Cum laude physicist Tom O’Brien to research quantum chemistry by quantum computers

With defending his thesis ‘Applications of topology to Weyl semimetals and quantum computing’, the Leiden theoretical physicist Tom O'Brien has gained the rare 'cum laude' qualification. The freshly minted PhD has started a five year research programme on quantum algorithms for quantum chemistry, funded by Shell Research.

Femoco molecule

Quantum mechanical root nodules

Quantum computers exploit the fundamental laws of quantum mechanics, and can execute certain calculations much faster than ordinary computers will ever be able to. This includes calculations of the properties of complex molecules 

The Femoco molecule is one example. This molecule is embedded within the nitrogenase protein within some types of bacteria and cyanobacteria. These use the molecule to capture nitrogen from the air and use it in biologically useful molecules. These ‘nitrogen fixing’ bacteria can be found in the rood nodules of clover plants, famous for its ability to enrich the soil with nitrogen. Considering the importance of this process for agriculture, it is useful to understand how this process exactly works.

Tom O'Brien explains

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Quantum speedup

‘In nitrogen fixing, electrons move through the femoco molecule, but we don't have a clue as to how this happens in detail,’ says O’Brien. ‘It doesn't work for separate Femoco molecules, so it has something to do with how this is embedded within the wider protein. But calculating the full complex is a terribly difficult problem. Using classical computers, it will last much too long.’

Using a quantum computer, Femoco’s secret is probably within reach. Actually building a quantum computer is a project that physicists have been working on for years, among others at Delft Technical University. At least as important, however, is designing algorithms to really calculate the properties of molecules with the promised quantum speedup.

nitrogenase image: Jjsjjsjjs, CC BY-SA 3.0, wikimedia commons

Shell Research

Using funding by Shell Research, Leiden University started a research group that will design and research these algorithms, together with quantum chemists at Vrije Universiteit Amsterdam. Research leader O’Brien, who worked on quantum algorithms already during his PhD research, will start a five-year programme on quantum algorithms for quantum chemistry.

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