янв 12, 2017

Now for a really cool micro-drum solo: Boffins chill gizmo below quantum limit

Neat microwave trick could be key to reaching absolute zero


Physicists working at the US National Institute of Standards and Technology (NIST) have developed a way to theoretically cool an object to absolute zero.
This groundbreaking technique, detailed in Nature today, has been used to chill a vibrating aluminium membrane to 360 microKelvin, a temperature below the "quantum limit." That 360µK reading is just a smidge away from zero Kelvin or absolute zero, the point where molecular activity stops.
This quantum limit was believed to be the lowest temperature you could practically go according to the laws of physics. Now NIST's boffins say they have broken that barrier using superconductors and microwaves.
Several techniques have been used in the past to super-cool objects, but this new technique from NIST reaches lower temperatures by reducing pesky quantum fluctuations – random variations in energy – that result in heat. The key is to "squeeze light" out of a tiny aluminium drum.

"There is a quantum limit on how cold one could ever cool an object using light. While laser cooling – or sideband cooling – is a well-known technique for cooling, the quantum noise of the light means that you can never get perfectly cold, even in principle," John Teufel, who led the experiment and is coauthor of a paper on the research, told The Register.

The Register
by Katyanna Quach