Testing whether Planck's radiation law applies at a very small scale

A recent discovery by William & Mary and University of Michigan researchers transforms our understanding of one of the most important laws of modern physics. The discovery, published in the journal Nature, has broad implications for science, impacting everything from nanotechnology to our understanding of the solar system.

"This changes everything, even our ideas about planetary formation," said Mumtaz Qazilbash, associate professor of physics at William & Mary and co-author on the paper. "The full extent of what this means is an important question and, frankly, one I will be continuing to think about."

Qazilbash and two W&M graduate students, Zhen Xing and Patrick McArdle, partnered with a team of engineers from the University of Michigan to test whether Planck's radiation law, a foundational scientific principle grounded in quantum mechanics, applies at the smallest length scales.

The other co-authors on the Nature paper include Dakotah Thompson, Linxiao Zhu, Rohith Mittapally, Seid Sadat, Pramod Reddy and Edgar Meyhofer. Qazilbash's research was funded by the National Science Foundation.
Through a series of experiments, the team was able to show Planck's law does not apply for objects smaller than a certain length scale—and the result is 100 times higher than what the law would predict. Qazilbash said the real challenge was not only provingthediscrepancy, but also explaining it.