Quantum physics is not something I claim to even remotely understand, not that it stops me from trying. One aspect that I do get, however, is Heisenberg’s uncertainty principle. It stipulates that we can never know how subatomic particles actually behave, because the very act of observing them affects their behavior.
This makes sense to me at a gut level – I mean, don’t you act differently if you know someone’s paying attention? Not that I’m implying that protons and such have emotions…but the instruments used to observe things so tiny have to exert some kind of electromagnetic force themselves (I think), or force the particles into a medium where their traces can be seen.
And that, dear readers, is pretty much the extent of my understanding of particle physics. So it was interesting to find this story: namely, that the uncertainty principle isn’t so – well, certain:
The principle has bedeviled quantum physicists for nearly a century, until recently, when researchers at the University of Toronto demonstrated the ability to directly measure the disturbance and confirm that Heisenberg was too pessimistic.
In order to overcome this hurdle, Rozema and his colleagues employed a technique known as weak measurement wherein the action of a measuring device is weak enough to have an imperceptible impact on what is being measured. Before each photon was sent to the measurement apparatus, the researchers measured it weakly and then measured it again afterwards, comparing the results. They found that the disturbance induced by the measurement is less than Heisenberg’s precision-disturbance relation would require.
The headline at the link pretty much writes itself: Scientists Cast Doubt On Heisenberg’s Uncertainty Principle.
So how do they know?