Why can't we get physical?

Libby Heaney, 22, is probing nature's most bizarre mysteries. She started her PhD in physics at Leeds University six months ago, with a group of world-leading quantum scientists. She wants to understand why certain tiny particles can pair up and "feel" their twins even if they are literally separated by an ocean.

That's quite a challenge, considering she only has three years to do it before the funding guillotine drops. Libby and her peers belong to an endangered species, according to a report issued in January by an international panel of scientists.

The report, "International Perceptions of UK Research in Physics and Astronomy", warns that the UK's ability to produce adequate numbers of professional physicists is coming under threat. The past 15 years saw one in three university physics departments close, while others live on in uncertainty.

Another report, from the Higher Education Policy Institute (HEPI), revealed a 2 per cent fall in postgraduate student numbers in the physical sciences between 1996 and 2002, while the number of PhD students fell by 9 per cent, according to the Roberts review of 2002.

"The fall comes at a time when everything else is going up," says Tom Sastry, the author of the HEPI report in 2004. "If subjects such as physics are falling during the current boom in postgraduate education, one wonders how they will fare in normal times."

So what makes PhD students like Heaney tick, and what is she up against? Her passion for physics was fired during her undergraduate days at Imperial College London. "I was fascinated by all the weird stuff that happens in relativity and quantum physics," she says.

Only in her third year did she decide that her interest was solid enough to see her through the marathon of a physics PhD and to delay repaying thousands of pounds in undergraduate loans. And, over the next three years, she will need all her self-motivation and bundles of dogged determination on top.

"The key thing to realise is that physics PhDs often go in six-month chunks," remembers Daron Walker, 35, of his own PhD on superconductors at Cambridge. Today, Walker dons a new hat as a senior policy adviser with the Department of Trade and Industry (DTI). "There will be periods where you make great progress, followed by months on end when experiments don't work. Progress can be like climbing a staircase."

The physics PhD is an uncharted journey. The first shock to the systems of fresh-faced PhD entrants comes from the expectation that they will now think for themselves. "It's the first time when students move away from exam-style problems where everything has a clear answer. They now have to solve real problems, to break them down into manageable chunks," says Professor Vlatko Vedral, 34, the head of Leeds University's new quantum information group, which supervises Libby Heaney.

And the bar is set high. Only fresh contributions to physics earn the coveted "Dr". With all the easy problems now calculated, measured and calculated again, the only way forward is narrow specialisation. So time spent choosing a research topic that genuinely excites you is crucial - "all the more so because it is the only period in your life when you'll have the free time to work mainly on what interests you. After that, your freedom decreases rapidly," Vedral says.

The choice of research group and supervisor can make the difference between three years of excitement or misery. Visit different groups, talk to students and get a feel for what they do. "Physics is a co-operative enterprise," Vedral says. "Make sure the group you are about to join is open and friendly, and discussion is encouraged. Check out how many discussion areas and coffee machines there are."

A recent PhD graduate in biophysics, who wishes to remain unnamed, had a miserable time at a top UK institution's biomedical engineering department. His supervisor spun out a company that swallowed up all his efforts. "A good supervisor will assist you to get a PhD. A bad one will seek to further his agenda or expand his list of publications at the expense of your time and effort. Don't let that happen," he warns.

Even when everything goes to plan, students sometimes discover that the life of a researcher is not for them. Ben Fletcher, who is finishing his PhD on the behaviour of cold atoms at Oxford University, says: "When I started my PhD, I was convinced I wanted to be an academic. After 18 months of actual laboratory work, I realised that I wouldn't be very happy doing it for a living. I want a career that's less narrowly focused, maybe in the commercial world or the civil service."

Academia has a tough time keeping its best students. It is well known that pay is better on the outside. But that view masks the other major complaint - about the grim career prospects of post-doctoral researchers. They often work for years on short-term contracts, while their pay after tax is little better than the average £13,000 a year of PhD students.

On the job market, Fletcher will get off to a flying start whichever career he picks. Physicists' logical and fact-based approach to problem-solving, plus their technical abilities and project management skills, are prized by employers. After all, a PhD is one long project. That makes physicists the third-highest earners after doctors and lawyers.

At the DTI, Walker has covered policy areas from telecommunications to energy. "I wanted to make use of my physics skills, but also to broaden out," he says. "They help me to understand the analysis necessary to make policy for energy markets, to talk credibly about technologies and to follow what people are telling me."

Would Walker recommend the physics PhD to others? "I had a great time. I got to spend a year in Paris, and I met my wife during my PhD. It's not all about money, after all."

Libby Heaney is following in illustrious footsteps. Exactly 50 years ago, Sir Peter Mansfield's path took similar turns, eventually leading to a Nobel Prize in 2003 for the invention of magnetic resonance imaging (MRI). "My interest was sparked during my undergraduate physics project, using magnetism to detect buried clay objects," Mansfield remembers. The technique today saves thousands of people from the surgeon's knife. But it needed dogged determination and some luck to turn that into the MRI scanner.