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Project Prizes 2014

Our final year undergraduate students all undertake a major project exploring some aspects of physics/astrophysics. We recently held a celebration and presentation session for those students judged to have attained most highly in the project modules. Project coordinator Dr Donatella Cassettari commented at the event on the high standards seen across all the projects, and that it was lovely to be able to celebrate the "best" project students at this gathering.

Head of School Prof Andrew Cameron presented winners with a certificate. Winners, project coordinators, project supervisors, and the Head of School are pictured above.

The BSc Physics project winner was Eugene Valassakis. He was presented with his certificate by Head of School Prof Andrew Cameron (left). Eugene's project work was supervised by Dr Andrea di Falco (right) and was in the area of Surface Plasmon Polaritons. Surface Plasmon Polaritons (SPPs) are electromagnetic excitations confined at a metal-dielectric interface, which are coupled with electron oscillations within the metal. Finding ways to excite SPPs in more efficient and less restrictive ways (in terms of allowed angles of incidence or wavelength) is still a matter of research. This project consisted in the fabrication and investigation of curved, polymer based prisms that display potential to form such non-restrictive couplers.

The picture alongside shows bottom left one such polymer prism on top of a silver surface. The light comes in from the right at the foot of the picture. The plasmonic excitation at the silver surface can be seen as a vertical line this side of the prism. This effect can also be seen by the darker part of the reflection at the top of the picture.

 

Physics MPhys Project Joint Winner was Phil Ireland, who worked with the supervision of Dr Donatella Cassettari and Dr Graham Bruce on optical traps for cold atoms.

Holographic optical traps have recently emerged as a novel method of generating continuous intensity distributions aimed at trapping and manipulating ultracold atomic ensembles. The optical pattern is created by the diffraction of a laser beam by a device called a spatial light modulator (SLM), which can be used to display a phase pattern. The laser beam is imprinted with the phase profile and after focusing the diffracted light with a lens, the intensity distribution observed in the focal plane of the lens is directly linked to the phase pattern displayed on the SLM. As such, altering the phase pattern will dynamically change the intensity profile at the focal plane, and one can imagine forming any desired optical pattern at the focal plane of the lens if the corresponding phase pattern can be realised on the SLM. The light changes the potential energy for the atoms, and if these diffraction patterns can be done well, then there is the prospect of generating fully arbitrary optical traps for future work with cold atoms.

Phil worked on an algorithm that optimised the phase pattern on the SLM to produce a Gaussian ring in the focal plane of the lens. His work took a pattern that had a 16% deviation from ideal to one that had just a 3% deviation, as shown above.

 

Martynas Prokopas was the co-winner of the MPhys physics project prize. Martynas tells us "My project was about constructing and testing a functional Light Sheet microscope. I constructed my system based on a published layout and then programmed a LabView interface that is capable of controlling the system without any mechanical interaction from the user. My system is capable of creating 3D images of small samples with micrometer resolution. Below is a sample measurement of a cell strainer, which is a mesh of wires positioned 40 micrometers apart. (picture is 500 micrometers across)". Martynas's work was supervised by Prof Kishan Dholakia.

 

The joint prize winners for theoretical physics were Zoe Ashwood and Max Schulz. Both were supervised by theoretical physicist Dr Jonathan Keeling. Zoe is pictured above with (right) her supervisor and our Head of School. Zoe's project looked at theory relevant to the photon Bose-Einstein condensation experiment that was conducted at the University of Bonn in 2010. While an ideal gas model can effectively describe some aspects of the experiment, there are also some signs that photons are interacting. Through the 14 weeks of the project Zoe investigated properties of a model of photon BEC that incorporated so-called 'thermal lensing' interactions.

Max is pictured receiving his certificate from the Head of School, accompanied by the coordinator of the theoretical physics projects, Dr Chris Hooley. The project looked at simulating the steady state of a lossy Rabi-Hubbard Hamiltonian via the method of Matrix Product States (MPS) as applied to light-matter interactions that may be relevant to quantum simulation.

The lossy Rabi-Hubbard model describes one form of light matter interaction, where the photon field of a cavity can interact with a two-level system (qubit) via two different terms, g and g'. Furthermore, photons are allowed to hop between cavities via J. At the same time, in order to predict experiments realistically, we include photon losses via the term .

Before making large experimental efforts in building such a cavity system, it is interesting to solve the Hamiltonian describing this system theoretically. This is impossible with brute force, but Matrix Product States are a mathematical formalism that allows us to 'disect' the very large tensors needed to describe superpositions in Quantum Physics (and hence making computational solutions impossible) and bring them into a form that allows one to cut out information that is essentially unnecessary. This makes the simulation of complicated many-body Hamiltonians possible in one dimension.

Extending the Matrix Product Formalism to be able to treat a multi-operator space as occupied by the Rabi-Hubbard model, we were able to show that an interesting phase boundary between a normal 'insulating' phase at low J and a superfluid phase at larger J survives as predicted prior by Mean Field Calculations for this cavity system.

 

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Martha Tabor won the prize for the best astrophysics project. She is seen here getting her certificate from the Head of School, accompanied by the coordinator of the astronomy projects, Prof Moira Jardine. Martha's project was supervised by Dr Anne-Marie Weijmans. Martha says "My project involved using integral field spectroscopy to decompose the bulge and disk of an early-type spiral galaxy. We know that spiral galaxies undergo star formation quenching to become elliptical galaxies, but how exactly this quenching occurs is not well understood. There are several possible reasons, each of which will have a different effect on the bulge and on the disk. This means that by looking at the stellar ages and metallicites of the bulge and disk separately, the processes having an effect on this transition can begin to be understood. These parameters can be obtained using integral field spectroscopy, which effectively provides an image of the galaxy at a whole range of wavelengths. By fitting the sum of a bulge and disk profile to the image at each wavelength, spectral information for the bulge and disk separately can be obtained, in turn providing stellar population information. My target galaxy was NGC 6762, which is pictured alongside." -credit: the Sloan Digital Sky Survey.


Pictured above are prize winners Martha Tabor, Eugene Valassakis, Phil Ireland, Max Schulz, and Zoe Ashwood. Not present at the gathering was prize winner Martynas Prokopas.

 

First posted BDS 27.5.14