Researchers demonstrate Heisenberg uncertainty principle at macro level

[Bill Angel]

http://phys.org/news/2013-02-heisenberg-uncertainty-principle-macro.html

 

http://www.livescience.com/27137-uncertainty-principle-measured-macro-scale.html

 

If you have access to the online version of Science Magazine:

http://www.sciencemag.org/content/339/6121/801.full

 

Here is the abstract from the actual scientific paper:

 

 

The quantum mechanics of position measurement of a macroscopic object is typically inaccessible because of strong coupling
to the environment and classical noise. In this work, we monitor a mechanical resonator subject to an increasingly
strong continuous position measurement and observe a quantum mechanical back-action force that rises in accordance with the Heisenberg
uncertainty limit. For our optically based position measurements, the back-action takes the form of a fluctuating
radiation pressure from the Poisson-distributed photons in the coherent measurement field, termed radiation pressure shot noise.
We demonstrate a back-action force that is comparable in magnitude to the thermal forces in our system. Additionally, we observe
a temporal correlation between fluctuations in the radiation force and in the position of the resonator.

 

Here is the description for the illustration from the actual paper:

(A) Canonical picture of continuous position measurement. RPSN (black), thermal motion (brown), and zero point motion
(orange) combine to give the expected measurement result (blue). The dashed line represents the effective displacement
noise from the shot noise–limited imprecision of an optical measurement.

 

(B) Photocurrent spectra. The photocurrent spectral densities (blue) and (red), as well as the noise floors,

including detector noise and the dominant shot noise (gray), are shown.

(C) Experimental setup. Beams are combined and separated with polarizing
beam splitters (PBS) and detected directly on photodetectors
(PD). The inset photograph shows an in situ image of the square membrane and optical mode spot, with blue dashed
lines indicating the nodes of the (2,2) mechanical mode. The inset diagram at right shows laser-cavity detunings.

 

[imatfaal]

There is a German team working at Max Planck Inst on a similar set up - I will drag up a link