Dark Matter on a Chip

Researchers at Stanford University and University of Würzburg in Germany are hoping to catch dark matter on a chip.

As published last week in the online edition of Nature Physics and presented Sunday at the American Physical Society's meeting in Portland, Oregon, scientists are hoping to use a material similar to a computer chip—topological insulators—to test the existence of the axions, theoretical weak and lightweight particles that could be the dark matter that accounts for 23% of the universe.

A topological insulator is a material where electrons can travel easily on the exterior, but not the interior. This leads to unusual properties that may be important for applications such as spintronics.

And what makes all of this exciting for physicists is that they believe that the electromagnetic behavior of topological insulators is described by the very same mathematical equations that describe the behavior of axions.

According to Shoucheng Zhang of the Stanford Institute for Materials and Energy Science, "We can make observations in tabletop experiments that help us figure out the deeper mysteries of the universe."

Although dark matter is invisible, astrophysicists observe its gravitational effects on galaxies and light from distant parts of the Universe, among other things. With its very small mass and lack of electric charge, the axion is a candidate for a mysterious dark matter particle. But despite much effort, the axion has never been observed experimentally. If these experiments succeed, it will potentially make future large-scale searches easier.

“If we ‘see’ an axion in a tabletop experiment, it will be extremely illuminating,” Zhang said. “It will help shed light on the dark matter mystery.”

Image by Hubble Space Telescope courtesy of NASA and ESA