less than sqrt(hbar)

[John Denker <jsd@AV8N.COM>]

Stefan Jeglinski wrote:

> Based purely on the
> abstract, it is not clear that the design, in detail, could be
> realized in any implementation in 1984, or now, 20 years later. Or
> that it was intended to be implemented.

Guess again.  It took a lot less than 20 years.
  Phys. Rev. Lett. 55, 2409–2412 (1985)
  http://prola.aps.org/abstract/PRL/v55/i22/p2409_1

Colder than cold.  Blacker than black.

Put a zero-temperature black body in front of the detector
and the noise level goes *up*.  Been there, done that, not
gonna forget it anytime soon.