Light & Matter
Creating giant matter wave
As excitons cool to a fraction of a degree above absolute zero, they condense at the bottom of an electrostatic trap and spontaneously form coherent matter waves.
Exotic subatomic particles called excitons have been trapped and cooled to the point they formed a giant wave of matter, physicists report. Excitons exist in materials called semiconductors, which have a certain range of electrical conductivity that makes them essential for modern electronics. When light is shined on a semiconductor, it can kick out an electron from an atom, creating a bound state between the "hole" that's left and the detached electron, called an exciton. Now, researchers have cooled down excitons to the point that they form a single entity, a condensed state called an exciton condensate. And for the first time, the scientists have created this state within a trap in a lab. "Condensation in a trap is important because it provides an opportunity to control a condensate," research team leader Leonid Butov of the University of California, San Diego, told LiveScience. "This is a powerful opportunity to study the properties of this state of matter." Excitons exist in nature they are integral to photosynthesis, for example but the particular type being manipulated here is rare, and could potentially be useful for applications such as solar energy and super-fast computing. [Graphic: Nature's Tiniest Particles Explained] "It's interesting physics," Butov said. "It's fundamental properties of light and matter."
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