Research generalities (I)

I thought I’d explain a bit about what I do in my research. This will be a general overview really, I’ll probably go into specifics at another time…

I’m currently working on experimental investigations into Macroscopic Quantum Tunneling in superconductors at mK temperatures, for qubit (quantum computing) and microwave applications. Specifically I look at Josephson Junctions, although there are other systems in which the phenomenon can be observed.

Why is this interesting?

Well, superconductors are one of the few examples of a system exhibiting a macroscopic quantum wavefunction. That is, a macroscopic number of electrons (for example 10^6 rather than the few in an atom or likewise) form a coherent quantum state, and you can make measurements of quantum variables by measuring more familiar quantities such as voltage and magnetic flux. Which is what I do. More about this on a later date I feel.

Here is a picture of a typical experimental setup:

This shows the dilution refrigerator (one of the group’s fridges) up and running. The temperature is 105mK, not sure if it’s possible to read that or not 🙂 It actually looks a bit swankier now, I have a nicer rackmount and some microwave kit and things, this photo is quite old!

Here’s a picture of the inside of the inner vacuum can showing some of the wiring and the filtering of the DC lines:

The device to be measured is in the centre of the copper box at the bottom, well shielded from the environment which would cause decoherence in qubits and add unwanted noise in the MQT experiments.

At the moment we are measuring some novel junction systems in addition to improving the measurement system for conventional Niobium junctions.

I’ll put some more pictures up soon, of the devices and different fridges. I have lots 🙂 You’ll have to excuse my slight biasing towards the dilution refrigerator though (colloquially known as Frosty) because I spent the majority of my PhD working on this piece of apparatus so I have a slight emotional attachment!


I suppose I’d better use the first post to explain a little about this blog.
I’m a University Research Fellow working in Experimental Condensed Matter Physics at the University of Birmingham, UK.

I’ve decided that I spend enough time both practicing physics and reading about interesting developments in various related fields that I can contribute a little to the ever-increasing pool of information freely available here on the ‘blogosphere’ and the internet in general. Why a blog? I like to post things as I find them, and I enjoy a dynamic, interactive medium. Why cake? Well, I like cake, and I always think that mulling over a difficult physics problem always seems easier with a nice cup of tea and a slice of cake.

So what could one potentially expect from this blog?

News from the lab – I haven’t been able to find many blogs written from an experimentalist’s point of view, so I thought I’d write my own. Expect to find pictures of lovely lab equipment and interesting devices along with stories of experiment success and tales from those days where it just won’t work (more often the case).

Physics developments – I like to think that I am ‘fairly’ in touch with the wider perspective of advancements in the field of physics (particularly solid state physics) so I hope that I can do some good explaining these to both a scientific and a non-scientific audience.

Book reviews – I’m quite interested in popular science and the public understanding of science in general, so I will potentially be writing comments on any books I read of this sort.

Links – I like to hunt down interesting, unusual and comical Physics and Engineering related links on the world wide web.

Cake – There may also be random posts pertaining to cake.