Technology & Science

Physicists create 'new state' of matter in a solid

An international team of physicists have coaxed particles into an exotic "fifth state" of matter at a higher temperature than ever before, according to new research.

An international team of physicistshave coaxed particles into an exotic "fifth state" of matter at a higher temperature than ever before, according to new research.

The research also represents the first time a Bose-Einstein condensate has been created in a solid, rather than in a super-cooled gas.

The Bose-Einstein condensate is a super-cooled state of matter in which all the atoms have the same energy and quantum characteristics, similar to the way all photons in a laser share the same characteristics.

This new form of matter was first predicted mathematically by Indian physicist S.N. Bose and Albert Einstein in 1924.

Three American physicists— Eric Cornell, Wolfgang Ketterle and Carl Wieman— first created a Bose-Einstein condensate in the lab in 1995 and shared the 2001 Nobel Prize for physics for their work.

This "controlled" matter could lead to more precise electronic components, quantum computers, advances in nanotechnology and "lasers" that use matter instead of light.

The Swiss research, led by Benoît Deveaud-Plédran of the École Polytechnique Fédérale de Lausanne, used exotic particles called polaritons to create a Bose-Einstein condensate.

Rubidium replaced by polaritons

The first Bose-Einstein condensate was created using rubidium atoms cooled to a tiny fraction of a degree above absolute zero, -273 C, the temperature at which all atomic motion stops.

Because polaritons are a billion times lighter than the rubidium atoms used in 1995, the particles condensed into a Bose-Einstein state at a much higher temperature: -254 C, about 19 degrees above absolute zero.

Also, in 1995 the condensate was made by cooling a gas until all the atoms reached the same quantum state. The polariton condensate was created within a solid semiconductor.

Deveaud said the (relatively) warm temperature of his condensate and the fact that it was made in the solid state will make it easier for future scientists to examine the strange properties of this new state of matter.

"It is exciting to envision exploring this magic without having to use an incredibly complex machine to get to temperatures just above absolute zero," said Deveaud in a statement.

Deveaud's condensate was short-lived, though. Polaritons are strange half-matter, half-light particles that only exist for a trillionth of a second. Even in that short time, though, the scientists were able to find evidence that the particles had reached the Bose-Einstein state.

The research was a collaboration between researchers in Lausanne, the University of Grenoble in France, Cambridge, Oxford and the Massachusetts Institute of Technology. The research appears in this week's issue of the journal Nature.

The practical applicationsof this new field of physics are a long way off, Deveaud said.

"We are still exploring the basic physics of this phenomenon," he said.