Profile

As a computational physicist, my job involves trying to understand very complicated imformation by applying simple rules in a computer program and then seeing if this makes the complicated things any easier to understand…  Sometimes this just results in me confusing myself, but I’ve managed to make some progress:)

I study the vibrations in crystalline materials, usually crystalline powders (common table salt is an example of a powder crystal, or ‘polycrystal’).  The usual way to do this is to get a big single crystal (like a diamond, or the big salt crystals you can grow in your airing cupboard with time and patience) and put it in a machine and fire neutrons at it.  These neutrons hit the atoms in the crystal and produce vibrations (just like ringing a bell) – we use big detectors to detect the neutrons as they bounce off the crystal atoms and from this we can ‘listen’ to the tones that are produced by these tiny bell-ringing hammers. This tells us all sorts of information about how the atoms stick together (the forces between them) and we can use this information to understand why materials have the properties they do.  Sometimes, we find very unexpected things – and these discoveries give us information on how the Universe (on the very small scale) operates as well as giving us information we need to design and build clever new materials that we can use to solve big problems.

However, most materials just don’t like to grow into big crystals, and prefer to remain as powdery small crystals, all jumbled up (just like the salt you put on your chips).  But with careful use of computer software, we can build up models of how the atoms stick together and move. We then use the computer to calculate what the machine would see if it were a real experiment.  If it’s the same -great, we can say that we understand how that material is stuck together.  But often, things are a bit different (or a lot different!).  In this case, we use the differences between the computer-predicted information and the real-life information we get from the neutron ‘bell-ringing’ machine to help us go backwards and change the models. The information the computer calculates is changed so it matches what the real machine (known as an ‘instrument’) sees.  If we do this carefully (which can take a while, even for a really big computer – and the computers used at neutron labs like ISIS are BIG), then we end up with a model of a material which explains what happens in the instrument AND gives us a way of understanding how that material sticks together and moves.  After all, the atoms in the crystal are really, really small so we can’t just poke them with a stick and watch the atoms move – we have to use our knowlege of physics to solve the problem.

This is what I do… I use computers, and my knowledge of physics, to try to understand what is going on in these neutron instruments and, in doing so, find new ways of getting simple understanding from complicated information.  I do this by writing software programs which I (and other scientists) can use to do this, and by going to neutron labs like ISIS to do the experiments and gather the information I need to test my computer ‘predictions’.  It might sound a bit boring, but it really isn’t – work is play for me (most of the time, anyway) and it’s great to be able to do something you love and get to pay your bills doing it!

I’ll come in to work (I tend to work late into the evening, so sometimes I’m not in work until midday!), put the kettle on and check my emails.  I work with other scientists all over the world, and we talk about the problems we have.  If I’m stuck (and that happens a lot), I can go read what other scientist have done (usually on the internet) or even ask other scientists what they think – this is called “collaboration” and it’s one of the most enjoyable parts of my job, because I’m never really alone.  I can always ask people for their opinions and they can do the same with me.  This part of the day usually takes an hour or two, depending on how many problems need to be sorted.

I teach University physics students, and also help PhD students (who have finished their first degrees and are now learning how to do research) with their work some days.  Most days, however, I get onto my computer, work out where I left off the previous day and get thinking.

My work involves trying to look at information (data) using lots of colourful plots and writing software programs to help me understand how atoms move together.  This usually requires a lot of concentration, but I really enjoy it – it’s very much like a big puzzle. I break down the big puzzle into lots of smaller puzzles and try to solve those before I put it back together again.  Just like when you’re playing a computer game and you’re really into it, you soon lose track of time and before you know it, it’s dark outside (even in the summer!) and my stomach tells me it’s time to feed it.  Then, once I start feeling tired, I make notes of where I’ve got to and off I go home.

Of course, some days I’m travelling to give talks to scientists around the world, or I’m visiting a lab to do an experiment or I’m off to visit a scientist I’m working with to see if he has a better way of solving a particularly stubborn puzzle.  But these, whilst common, are not really typical working days for me.  These are for me, my computer and my kettle:)