February 13, 2008

‘Superfluids’ Might Solve Two Universal Mysteries

At last month's Cosmology Meets Condensed Matter conference in London, it emerged that space-time could be simulated in the lab using strange, unique substances known as "superfluids", which flow without resistance and can even climb up the walls of jars.

The equations governing the particles inside the superfluids are similar to those that represent the early universe, said Ray Rivers at Imperial College London. "We hope that we can use these to check things in the lab that frankly we don't have any hope of seeing through astrophysical observations."

Tanmay Vachaspati of Princeton University thinks that studying superfluid helium-3 could help solve the two mysteries of why the universe is made almost entirely of matter rather than antimatter, and from where the huge magnetic fields that span galaxies originate.

Cosmologists believe that equal amounts of matter and antimatter should have been created in the early universe. But since matter and antimatter obliterate each other, something must have happened to create the excess of matter we see in the universe today.  

Vachaspati said perhaps some of the antimatter was converted to matter through a process involving virtual particles, which momentarily pop out of the vacuum before disappearing again. Among these would have been magnetic monopoles, hypothetical particles carrying a single magnetic charge.  As the monopoles disappear, they force nearby antimatter to become matter.

The monopoles, says Vachaspati, could also leave behind a trace of twisted magnetic field lines. These lines would have been stretched out as the universe expanded, giving rise to galactic magnetic fields. 

These traces in the early universe would be hard to spot in the cosmic microwave background left behind by the big bang, but superfluid helium-3 could provide a way to test the idea, said Vachaspati.

Spin a container of the stuff, and vortices are created whose edges share similar dynamics to monopoles, including their disappearing act. This means that the twisted field lines would be visible in the arrangement of superfluid particles left when the vortices disappear. "I really want to encourage experimentalists to look for this," he added.


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Imperial College London

Princeton University

New Scientist