Physicists at Harvard have built a radio receiver out of building blocks the size of two atoms. It is, almost certainly, the tiniest radio receiver in the world.
And since it's a radio, it can play whatever you want to send its way, including Christmas music, as this video by the Harvard team that designed it makes clear:
Electrical engineering professor Marko Loncar and graduate student Linbo Shao applied basic radio engineering principles to a very small-scale machine.
As Leah Burrows, spokeswoman for Harvard's John A. Paulson School of Engineering and Applied Sciences, explains:
"Radios have five basic components: a power source, a receiver, a transducer to convert the high-frequency electromagnetic signal in the air to a low-frequency current, a tuner, and a speaker or headphones to convert the current to sound."
With those five components as a starting point, let's consider the inner workings of the tiny radio, where there is a diamond crystal made of carbon atoms.