My research focuses on objects known as topological solitons. These are particle like lumps of energy that are self-sustaining and appear in many areas of physics. Examples of solitons include solitary waves in canals, certain types of pulses in optical fibres, vortices in superfluids and superconductors, and skyrmions in magnetic materials. A useful analogy for a soliton is to think of a washing line with fixed ends and pegs hanging from it. If the washing line is straight, then all of the pegs will hang down. However, if there is a twist in the line then the pegs will go round the twist and point upwards somewhere along the line. This point where the pegs point upwards can be moved along the washing line in either direction, but if the ends are fixed, we cannot get rid of the twist. The twist in the washing line is an example of a one-dimensional soliton known as a kink.

The first sighting of a soliton was by the Scottish civil engineer John Scott Russell who in 1834 observed that the bow wave of a canal boat kept moving at the same rate after the boat had stopped. This was a surprise as usually water waves will spread out and decrease in height as they travel. This is known as dissipation and is the expected behaviour for waves in most media. It took a while for the importance of Scott Russell’s observation to be apparent, but now we see similar structures in many areas of physics and beyond.

My soliton journey started during my PhD where I was studying mathematical models of vortices. Now, the term vortex likely brings to mind the image of water draining down a plug hole, or of a tornado. In both these cases we have a fluid, water and air respectively, that is rapidly rotating. If left on its own, the rate that these vortices spin at decreases and they disappear. However, the vortices that I studied were not quite the same as these. You may have heard of superfluidity, where you take helium and cool it down until it becomes a liquid with zero viscosity. Vortices in a superfluid are special as once they start spinning, they cannot stop. It turns out that there is some interesting mathematics that describes these superfluid vortices. Including a particular limit where the mathematical model becomes solvable, and we can explicitly write down a formula describing the vortex. This ability to explicitly solve a system is sometimes referred to as integrability, since one way to achieve this is literally to integrate the equations of motion.

Physics at Edge Hill

There are lots of opportunities to get involved in physics research at Edge Hill. The research project module in the final year of our physics degree, offers students the opportunity to engage with cutting-edge research carried out within the department. Research directions also influence what we teach and how we teach it.

As programme leader for physics I ensure that our teaching is interactive, focusing on the practical applications of physics to ensure that our students gain the necessary expertise to work in a wide range of industries. Teaching methods are designed in consultation with leading employers in the region. Benefitting from guest lectures delivered by industry experts.

Physics is the key to understanding how modern technology works and influences many other fields like engineering and other sciences. A physics degree gives you a solid foundation in critical thinking and technical skills and can prepare you for a range of careers from climate science and meteorology to education, engineering, and even medical physics. If you are captivated by the workings of the world and you like to ask how and why questions, then a physics degree is for you.

August 30, 2024