Studying a common material at room temperature, researchers bring quantum behavior “closer to our daily life.”
When a guitar string is plucked, it vibrates as any vibrating object would, rising and falling like a wave, as the laws of classical physics predict. But under the laws of quantum mechanics, which describe the way physics works at the atomic scale, vibrations should behave not only as waves, but also as particles. The same guitar string, when observed at a quantum level, should vibrate as individual units of energy known as phonons.
Now scientists at MIT and the Swiss Federal Institute of Technology have for the first time created and observed a single phonon in a common material at room temperature.
Until now, single phonons have only been observed at ultracold temperatures and in precisely engineered, microscopic materials that researchers must probe in a vacuum. In contrast, the team has created and observed single phonons in a piece of diamond sitting in open air at room temperature. The results, the researchers write in a paper published today in Physical Review X, “bring quantum behavior closer to our daily life.”
“There is a dichotomy between our daily experience of what a vibration is — a wave — and what quantum mechanics tells us it must be — a particle,” says Vivishek Sudhir, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research. “Our experiment, because it is conducted at very tangible conditions, breaks this tension between our daily experience and what physics tells us must be the case.”
Credit: “Scientists observe a single quantum vibration under ordinary conditions”, Jennifer Chu, MIT News Office