Friday, January 16, 2009

quantum hindsight got contacts

From ScienceDaily: Physicists Resolve Confounding Paradox Of Quantum Theory

Science is fun, especially quantum theory (nice I'm saying that when I really don't understand it, huh?). One of the things early quantum physicists discovered is that observing particles move changes how they act. (Check out this awesome video describing the "double slit experiment" performed in the 1920s. It's very easy to understand and features a superhero scientist. Sweet.)

So, according to this article, in the '90s people started thinking they could measure particles without interacting with them, "[b]ut when Lucien Hardy proposed that one could never reliably make inferences about past events which hadn't been directly observed, a paradox emerged which suggested that whenever one attempted to reason about the past in this way they would be led into error." So hindsight is blind?

However, scientists at the University of Toronto combined the ideas of "interaction-free measurement" with something call weak measurement, "a tool whereby the presence of a detector is less than the level of uncertainty around what is being measured, so that there is an imperceptible impact on the experiment."

I have to say, I don't understand the specifics. (I really need to take some college-level physics.) But, it basically sounds to me like scientists will now be able to see what particles are doing when they're supposed to be acting like matter but are pretending to be energy. And then for the why. Then maybe the why of particles getting stage fright?

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