Thrice in the past six months, I have had someone tell me that scientific evidence shows that quantum particles behave like they’re sentient. Was there really a scientific study on this? Where are these New Agers getting this from?

They’re probably getting it from a misinterpretation of the double-slit experiment. (See the external links at the bottom for more info on this famous result).

Also, as scientists we call things a paradox at the drop of a hat more because ew like the word than anything else.  Unfortunately, this does not sit well upon the ears eegits and they tend to make a mountain out of even the most dwindlesome molehills.  The Einstein-Podolsky-Rosen “paradox” is actually in no way paradoxical.  And quantum uncertainty (another one guaranteed to get a fool fantasising), arises from the fact that in order to measure the position of the point of action of a quantum (more acurately where it is from one moment to the next) we have to take the average of multiple readings to get anywhere close to being accurate (the more readings on this one measurement we do, the more we pin down it’s position). However, it’s position is changing all the time and so is it’s momentum which also takes a lot of repeats (of an entirely different experiment) to pin it down with any kind of accuracy.  Hence the more accurately you know it’s positiion, the less you know about it’s momentum and where it’s going next, and conversely, the better you know it’s momentum and where it’s going to, the less well you know where it is.  These difficulties of measurement are partly to be expected in things that are osccilating wavelike things that are billions of times smaller than atoms.  Putting it in such mundane killjoy terms as I just did, they cease to sound as exciting as saying things like “they appear to have sentient qualities, but unfortunately they are nowhere near that exciting.  Very useful for modelling stuff though, but boring.  I once set a super-computer on an density functional theory minimisation calculation and it took five weeks to come to a final answer, which I then stuck in as a very small section of a paper in a journal.  And that kind of timespan is not unusual.

That may be part of it, but they say that our thoughts are making them behave differently?

I know… kind of like WTBDWK… But other people have been saying it too…

Well, the so-called Copenhagen Interpretation of QM has it that what ‘collapses the wavefunction’ into one determinate measure is, basically, a human mind observing what is going on ... that’s the whole notion of Schrödinger’s Cat; that there is no determinate fact of the matter as to whether the cat is alive or dead until an observer opens the box and sees what’s happened inside.

I think that this interpretation is incoherent. There are other, philosophically much clearer, interpretations of QM, including the Many-Worlds Interpretation and the Bohm Interpretation.

And a pretty definitive one for the Einstein-Podolsky-Rosen “paradox” by Bell (in his collected papers edicition) called “Bertleman’s Socks and the nature of quantum reality” or something like that.  In a different paper in that book he offers a very good mathematical rebuttal of the theory of local “Beables”.  All done in his inimitable sardonic style.

“Beables”?

Indeed, beables; it was his own theory as well.  Beables, indeed, as opposed to observables:

http://en.wikipedia.org/wiki/John_Stewart_Bell

Interesting. I see it is pronounced “be-ables” as in “that which is able to be”. Originally I thought it was “beables” like “beagles” or “baubles”.

I am not sure that the “many worlds” interpretation need be subjectivist, as the Wikipedia entry on Bell intimates. It could be that any causal interactions produce branches (not just interactions that count as “observations”) ... although not being in any sense a physicist or QM expert, I will leave this to others to decide ...

That was pretty much Bell’s initial idea and the many worlds thing did not come from him.  It was merely the idea that a quantum particle could have all kinds of states that are quantized such as spin, energy, magnetic moment etc. but some were observable and they only a subset of what was beable.  It was possible for a quantum to have many more facets of its behaviour that would be prescriptive of its subsequent behaviour than just the things that we could or had measured, in other words.  The idea was a reasonable sounding one that said that in order to predict a quantum’s behaviour we need to have all of the possible information about it not just some. Despite this sounding reasonable and being a good theory, Bell actually accepted reality and went on to say that his theory was wrong.  This is hard to do when you’ve pjutn your heart and soul into something and the initial results of painstaking work appeared to support your theory, to carry on doing work that you think will give further support to it and find that it doesn’t is quite gutting.  At this point many scientists (and Bell was more accurately a metaphysicist) would use wishful thinking to try and shore up their earlier results against the intrusion of these harsh realities.  Sportingly, he didn’t and went on to rebut his own ideas in the light of better evidence and, more so, clearer thinking.