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New postdoctoral researcher

1 February 2017

We are happy to welcome Alexios Michailidis who is joining the group after doing his PhD at University of Nottingham.

Alexios is working on many-body localisation and numerical simulations of quantum many-body systems using matrix-product states and tensor networks.




Merry Christmas and Happy New Year!

22 December 2016

Merry Christmas and Happy New Year!

 

Photo: Theory group getting ready for Christmas party and playing shuffleboard.




PhD position available: "Quantum computing with photonic networks"

16 December 2016

 

Funded PhD position available for project on "Quantum computing with photonic networks" in close collaboration with the Oxford Quantum Technology Hub NQIT.

 

Please contact Almut Beige [A.Beige@leeds.ac.uk] for more information.




PhD position: Photoactive molecular complexes

9 December 2016

Contact: Dr. Arend G. Dijkstra (a.g.dijkstra@leeds.ac.uk)

In our group, we use models to understand how molecular systems use light to function. These models are compared with state of the art optical experiments, which allow us to probe the fundamental motions of electrons and nuclei that take place on femtosecond to picosecond time scales. Inspiration for our work comes from biological systems. Our work uses mathematics and computer programming. The projects are suitable for chemistry, physics and mathematics graduates. The first project is about photosynthesis. How is the energy that is collected by plants and bacteria from sunlight transported? It turns out that answering this question requires a detailed description of the pigment molecules that interact with the light, as well as of the protein and solvent environment. In this project, you will build a new model of the energy transport mechanism. The model will be based on quantum mechanics of an electronic system interacting with vibrations. A main goal of the project is to accurately determine the parameters that describe real systems, from either simulation or comparison to experiment.

 

The second project is about photo switching. Some of the fastest events in biology occur within the eye. As in photosynthesis, electrons are excited by light absorption, However, in the primary step in vision the nuclear motion induced by electronic excitation is very large. Cis-trans isomerization in the rhodopsin molecule completely changes the structure. The system clearly explores parts of the potential energy surface far away from equilibrium, such that a harmonic description is completely invalid. This is also the case in man-made photo switches. This is a challenging regime for models that treat both the electronic and the nuclear motion under the influence of the protein environment. This project aims at developing a new theory to describe quantum decoherence and friction outside the harmonic approximation.

 

References

[1] Dijkstra, A. G. and Tanimura. Y., New J. Phys. 14, 073027 (2012);

[2] Prokhorenko, V. I., Picchiotti, A., Pola, M., Dijkstra, A. G. and Miller, R. J. D., J. Phys. Chem. Lett. 7, 4445 (2016);

[3] Dijkstra, A. G., Wang, C., Cao, J. and Fleming, G. R., J. Phys. Chem. Lett. 6, 627 (2015).




New paper in Nature Communications on exchanging Majorana zero modes

31 October 2016

Nature Communications 7, Article number: 13194 (2016)

 

Experimental Simulation of the Exchange of Majorana Zero Modes

 

Majorana zero modes are an eagerly anticipated resource for quantum information processing as they offer immunity to noise, but they are difficult to create and control experimentally. In collaboration with theorists and experimentalists from Hefei University of Science and Technology in China, Dr Jiannis Pachos from the Theoretical Physics Group in Leeds demonstrated in a recent publication in Nature Communications a fundamental property of Majorana fermions: their non-trivial statistics. This was performed with a quantum simulation of a superconducting chain with linear optics. This system provided the degree of controllability that enabled the manipulation of Majorana quasiparticles and the demonstration of their anyonic statistics. A popular version of the article has been published in 2Physics.




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