Quantum Optics and Laser Science

William Irvine
William worked as a UROP student in the Ion Trap group (QOLS) with Dr Segal and Prof Thompson on an experiment that studied the phenomenon of “quantum jumps” which takes place when a single atomic particle is laser cooled to very low temperatures in an ion trap and interacts with coherent laser radiation.  The work was published in Journal of Physics B. 

Michael Feyereisen
Michael arranged an internship in a nonlinear optics lab in the South of France, where his group set up an optically injected laser system to study "rogue waves" in the laser intensity. Demonstrating the presence of these events in this system for the first time, they also showed that these events are the deterministic result of a nonlinear process. The work was published in Physical Review Letters."

Martin Asprusten and Simon Worthington
Martin Asprusten and Simon Worthington worked for their MSci project with Prof Richard Thompson on simulations of the motion of small numbers of atomic ions held in a Penning trap and under the influence of laser cooling.  They found that the ions form into a small crystal in the trap, which was an expected result.  They also found that the crystal rotates and that the speed of rotation depends in many cases only on the parameters of the laser beam and not on the trap itself.  This was an unexpected result and led to the formulation of some new theoretical ideas about the laser cooling process.  The theory results and the confirmation by simulations were published in the Journal of Applied Physics B in November 2013.

Jacob Craigie and Ali Hammad
Jacob Craigie and Ali Hammad worked with Vitali Averbukh and Bridgette Cooper on application of Stieltjes-Chebyshev moment theory to quasi-exponential decay in quantum mechanical systems of discrete energy levels. Their research continued after the formal completion of the 3rd year project and led to a publication in the Journal of Chemical Physics http://aip.scitation.org/doi/full/10.1063/1.4884785 (2014) that sheds light on the mechanism of the breakdown of molecular orbital picture of ionisation in the inner valence region.

Renjie Yun
Renjie Yun, while being an undergraduate in our department, worked with Vitali Averbukh and Marco Ruberti on molecular photoionisation.  Renjie co-authored two papers:
M.  Ruberti, R. Yun, K. Gokhberg, S. Kopelke, L. S. Cederbaum, F. Tarantelli  and V. Averbukh,
Total molecular photoionization cross-sections by algebraic diagrammatic construction-Stieltjes-Lanczos method: Benchmark calculations 
J. Chem. Phys. 139, 144107 (2013);

M. Ruberti, R. Yun, K. Gokhberg, S. Kopelke, L. S. Cederbaum, F. Tarantelli, and V. Averbukh,
Total  photoionization cross-sections of excited electronic states by the  algebraic diagrammatic construction-Stieltjes-Lanczos method
J. Chem. Phys. 140, 184107 (2014).

Following the successful undergraduate research work, Renjie was awarded the competitive Lee Family Scholarship for pursuing a PhD under supervision of Vitali Averbukh.

Kwok-Ho Wan, Hlér Kristjánsson and Robert Gardner

Last summer, after finishing their second year of the undergraduate physics degree, Hlér Kristjánsson, Robert Gardner and Kwok-Ho Wan worked as UROP students at the London Institute for Mathematical Sciences. They aimed to generalise tools in the Machine Learning paradigm to process quantum information. 

Along with their supervisors, they managed to simulate a quantum autoencoder (data compression device) and used a Quantum Neural Network to numerically rediscover the conventional quantum teleportation protocol given a suitable network structure. Finally, they also looked briefly at potential photonics implementations via photonic-modules. Their paper is available at; https://www.nature.com/articles/s41534-017-0032-4

Paul Micaelli and Charles Oliver

Paul Micaelli and Charles Oliver carried out their MSci final year project in 2016 on applying machine learning to the world’s first X-ray Free Electron Laser, the LCLS at SLAC, Stanford, California. Using diagnostic data from some experiments we had performed in 2015 to train their machine learning code they were able to demonstrate that the X-ray pulse characteristics on every shot can be accurately predicted. This was the first such demonstration and has important implications for future $1 billion scale machines (LCLS II in Stanford and Euro-XFEL in Hamburg) that operate at a high repetition rate and so cannot be accurately diagnosed on every shot otherwise. The work was published in Nature Communications 8, 15461 (2017) (supervisor Jon Marangos)

Jergus Strucka

Jergus Strucka carried out a first year summer internship in our laboratory working on the measurement of in vacuum liquid sheet jets of an unprecedentedly thin 1 micron thickness. These have many potential applications including ultrafast spectroscopy of photochemistry and sources for laser proton acceleration. Jergus developed an interferometric technique to measure the thickness. This work was published in Reviews of Scientific Instruments 88, 083117 (2017) (supervisor Jon Marangos)