Atom Interferometry

There’s been some interest in our idea of testing dark energy with atom interferometry.  This is a collection of links to articles aimed at the general public:


The dark side of the Universe

I recently had a great time giving at talk at the National Museum of Scotland (a wonderful museum, you should go!) as part of the  Edinburgh Science Festival.  It was hosted by Prof. James Hough and the Royal Society and the audience were amazingly well informed, and asked lots of perceptive questions.


There is a video of my talk here.  Although I haven’t been able to bring myself to watch it yet!

Dark energy in Westminster

Somewhat belatedly this is my post about my Week in Westminster with the Royal Society Pairing scheme.  It appeared first on the Making Science Public blog.


When I told friends and colleagues that I was going to spend a Week in Westminster as part of the Royal Society MP-Scientist pairing scheme the response, more often than not, was: “Why would you want to do that?”  To be fair to them the connections between my research into the nature of Dark Energy and the day to day work of parliament and government are not at all obvious.

Dark Energy

One of the most startling things we have learnt about the Universe in the last decade is that the speed with which galaxies are moving away from one another is now beginning to accelerate. Nothing in the physics that we understand can explain this observation. There must be a new, mysterious substance in the Universe which behaves unlike anything we know. We call this substance Dark Energy.  In my research I try to build theoretical models for what dark energy might be; it’s very difficult to make a model that is self-consistent, explains what the Universe is doing on the largest scales and is in agreement with the physics that we have measured precisely on Earth.  We still don’t have a successful theory yet, but we’re working on it!

I wanted to take part in the pairing scheme partly because it seemed like an amazing opportunity to try to understand the complex organisations that influence so much of our lives, but I also wanted to go to find out more about how the government views fundamental science at a time when our funding seems ever more precarious.

The Royal Society has been running this successful scheme since 2001 and this year 36 scientists (including my colleague at Nottingham Philip Moriarty who blogged about his experiences in an earlier post) from all career stages took part and were paired up with MPs, civil servants or a Lord.  We spent two days learning about the many different roles that science plays in parliament and then I spent two days shadowing Lilian Greenwood, MP for Nottingham South and Shadow Rail Minster.

Dark time?

The difference that stood out for me most between the world of Westminster and the world of academic research was the time scales that we work to.  There are few hard deadlines in the world of research and the papers that I publish can be the result of anything from six months to a few years’ worth of work.  By contrast the focus of parliament is continually shifting from one topic to another, and if you want to contribute to a particular debate you have to grab you chance when it arises or lose it, meaning you need to be able to acquire and process information very rapidly

I experienced this directly on Thursday morning.  When I met Lilian in the lobby of Portcullis House she told me that she was planning on attending questions to the Minister for Business, Innovation and Skills (BIS) in half an hour and did I want to try to think up a question she could ask to the Minster on the importance of fundamental science.  Having to marshal my thoughts into a concise and coherent argument in the space of about 15 minutes and then seeing the result of that half an hour when Lilian asked our question in the chamber, was challenging and so different to the way that I normally work.  I’m very proud of the question that Lilian asked:

“Does the Minister agree that investing in fundamental research is vital to inspire the next generation of scientists and engineers and to create conditions for the serendipitous discoveries of the future?”

Fundamental physics

It sums up all of the reasons that I think doing fundamental research, even into something as seemingly far removed from daily life as dark energy, is important and everything that I feel is missing in the current drive to connect the research done in Universities ever closer with industry.  The response from David Willetts, Minister for Universities and Science, was a little disappointing:

“I completely agree with the hon. Lady, which is why the Government support fundamental research. Only last week I went to the launch of £250 million of public money for centres of doctoral training run by the Engineering and Physical Sciences Research Council.”

It’s great to hear that the Minister agrees that fundamental research is important, but it’s unfortunate that he chose to back this up with the example of the new CDTs that all have industry involved as a partner or a co-creator.

Fundamental relations

A number of times during my week in Westminster I heard the relationship between government and science today compared to the relationship between the media and science 10 years ago.  Both sides mistrust and misunderstand one another and so communication is difficult.  But just as our relationship with the media has changed for the better, I’m convinced science and government can learn to work well with one another and the Royal Society Pairing Scheme is a great way of making that happen.

Study physics girls and start a revolution!

I’m cross posting something I wrote for the UoN Press Office blog on the recent IoP report about the lack of women in Physics.  You can find the original here.


Cosmologist tells girls to reach for the stars!

In many ways I am the worst person to write about why young women chose not to study physics because I have been studying physics since I picked my A-levels in 1999. I’ve never regretted that decision, it was the first step on a path that has allowed me to travel the world, study some of the biggest mysteries in the Universe and has led me to where I am now – a Research Fellow at The University of Nottingham.

So why don’t more young women start along this path?

According to a report published by the Institute of Physics the answer is that in a majority of schools young people are still being given the message that some subjects are for girls and some are for boys, and physics is definitely for boys.

Who hung the ‘no girls allowed’ sign on the door of the physics club house?

The answer seems to be sexism. In 2011 the Institute of Physics found that 46% of schools with female students sent no girls on to do A-level physics (compare with 14% for boys). Today’s report tells us that schools with a gender imbalance in physics also had significant gender imbalances in other subjects including those where girls were in the majority. I doubt whether there are many teachers today saying out loud to their students that boys should do physics and girls should do psychology. The message comes in subtle, sneaky, cultural ways that are hard to spot and even harder to counter.

Why does it matter?

The young women who are choosing not to do physics get just as good grades at GCSE as their male friends. If something puts them off studying physics further we are both limiting their opportunities and losing out on many brilliant future scientists and engineers.

There is some good news in the IoP report though. They find that a small number of schools show that it is possible to counteract gender imbalances by actively engaging with the issues. The statistics I quoted above can be changed, but it requires us all to acknowledge there’s a problem and to actively try to change it. We need to challenge gender stereotypes when we see them and we need to talk to young people, both boys and girls, about the imperfect world we live in and how they can help to change that.

Choose physics girls and start a revolution

To any young woman who is thinking about what A-levels to study – I say: Choose Physics and start a Revolution. Society is still trying to tell you what you should be doing, and that some things are not for you. This really is your opportunity to change the world. If you’ve ever looked up at the night sky and been awed by the stars, I promise you that they only become more beautiful the more you understand about what they are and where they’ve come from. There’s still so much that we don’t know about the Universe and so many ways in which physics will change the world we live in. Don’t let anybody tell you that you shouldn’t be a part of that.

Questions in Parliament

This week I’ve been taking part in the Royal Society pairing scheme for Scientists and MPs.  By far the best thing that happened during my ‘Week in Westminster’ is that my local MP, Lilian Greenwood, asked a question in the House of Commons to the Minister for Buisness, Innovation and Skills about the importance of fundamental research.

Here’s the transcript of her question and the reply from David Willetts, the Minister for Universities and Science:

Lilian Greenwood (Nottingham South) (Lab): Does the Minister agree that investing in fundamental research is vital to inspire the next generation of scientists and engineers and to create conditions for the serendipitous discoveries of the future?

Mr Willetts: I completely agree with the hon. Lady, which is why the Government support fundamental research. Only last week I went to the launch of £250 million of public money for centres of doctoral training run by the Engineering and Physical Sciences Research Council.

I’m planning to write more about my experiences on the scheme over the next couple of days.

The answer is no

There is a piece of folk law in physics that says:

“If a paper or talk has a title that is a question the answer is no.”

This concept also exists in journalism where it is known as Betteridge’s law of headlines

“Any headline which ends in a question mark can be answered by the word no.”


In my experience the law holds much more often than not.  However, last week I made an attempt to flout it by giving a talk at Queen Mary where the title was “Can you detect dark energy in the laboratory?”, and I argued that the answer was “possibly” or even “probably, given enough time and the right experiment”.

A much more striking counter example to this rule is a paper by Einstein with the title “Ist die Trägheit eines Körpers von seinem Energieinhalt abhängig?” which can be translated as “Does the Inertia of a Body Depend Upon Its Energy Content?”

Einstein showed that the answer to this question is “yes” and that gives us the famous relationship between mass and energy:

E=mc² .

The Low Energy Frontier of High Energy Particle Physics

I recently went to The Daresbury Laboratory for a meeting on the Low-Energy Frontier of High Energy Physics.  The Low-Energy Frontier is the idea that small scale experiments can tell us about high energy physics by doing low energy measurement with extreme precision.  This is in contrast to particle coliders which study high energy physics by producing particles with very high energies and then smashing them together to make a big mess and looking for new particles in that mess.

Low energy experiments are much smaller and cheaper than particle colliders, and yet they can put very stringent constraints on high energy physics.  Their downside is that each individual experiment can only look for one very particular type of new physics, whereas a particle collider, in principle, can cover all the different possibilities at once (if you know what to look for).


One type of low-energy frontier experiment that I find very exciting are the attempts to shine light through walls.  If there are new types of particle, called axion-like particles (ALPs),  that interact with photons then in a magnetic field a photon from a laser beam can change into an ALP.  Then it turns out that ALPs can pass through walls which are impermeable to photons.  On the far side of the wall you use another magnet to transform the ALP back into a photon which you then try to detect with a very sensitive camera.  No one has seen light shining through walls yet but many experiments, including a new one at the Daresbury laboratory which uses microwaves instead of laser light, are trying hard.


It was a great meeting, but slightly spoiled by the ratio of men to women being 23:1 (and I was the 1).