The solace of quantum

It would be fascinating to carry out a study of which aspects of science are most attractive in times of woe. When things are difficult, politicians are certainly happier to fund basic research rather than risk being seen trying - and failing - to address more immediate problems. The media are equally guilty: fundamental research can offer much-needed quirky, light stories. Essentially, we are currently desirous of X Factor- or Strictly Come Dancing flavoured science; we want something glitzy and distracting rather than something sober, sensible and improving.

So, why swim against the tide? Given that there's been a few interesting breakthroughs lately, let's discuss quantum theory. After all, it is endlessly diverting. Quantum theory describes how the world works at the atomic and subatomic scales. It is full of highly appealing weirdnesses. (Indeed, Brian Cox and Jeff Forshaw have just published a book on the subject, see page 38.)

These kinds of particles can be in two places at once. Their actions can be even more counterintuitive: they can travel through space in two different directions at once. They will choose to appear in experiments as waves rather than particles depending on how you choose to look at them. Make two of them interact and you can useone to change the state of the other instantaneously, even if they have since travelled to
opposite sides of the universe.

Even weirder is how quantum theory has something to say about what happenswhen there are no particles. Its equations declare there can be no such thing as empty space, because the quantum theory is governed by probability, andthere is never zero probability of something happening. So,
in quantum theory, supposedly empty space is populated by "virtual" particles that pop in and almost immediately out of existence.

It sounds fantastical, but a paper published by the journal Nature in November shows these particles do exist. In an ingenious experiment, Swedish physicists detected the energy that virtual particles radiate when you give them a kick.

Meanwhile, we have just been made to face another puzzling aspect of the quantum world. Physicists work with quantum theory's "wavefunction", the mathematical description of the particle's properties. It turns out that it's not just a mathematical description. A team of London based
physicists has revealed the wavefunction can affect the physical qualities of a particle.

Riding the waves

To get a flavour of how disturbing this discovery is - one researcher has described it as a "seismic" shift in the foundations of physics - imagine yourself as the particle, and the GPS location stored in the phone in your pocket as the wavefunction. If the London researchers are right, changing
those GPS co-ordinates will change the size of your nose or the colour of your eyes. Fundamentalphysical characteristics should not depend on a few numbers used to describe something aboutyou. Except, that is, if you live in the weird quantum world.

There is plenty more weirdness out there. A growing number of physicists now try to explain much of it through the "many worlds" idea, which says that the quantum particles have multiple existences in other, inaccessible universes. In these parallel universes every possible history
happens. There are universes, for instance, in which there is no recession - and no Simon Cowell.

There may even be a quantum world where the media focus on things that matter and politicians don't abdicate their responsibilities. But perhaps
that's stretching your credulity a little too far.

Michael Brooks's "Free Radicals: the Secret Anarchy of Science" is published by Profile Books (£12.99)

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 05 December 2011 issue of the New Statesman, The death spiral