This morning Mrs. Pontiff read me a review out of the New York Times for the film “A Serious Man.” The opening paragraph of the review gives you an idea why she thought it might be relevant to me:
Did you hear the one about the guy who lived in the land of Uz, who was perfect and upright and feared God? His name was Job. In the new movie version, “A Serious Man,” some details have been changed. He’s called Larry Gopnik and he lives in Minnesota, where he teaches physics at a university. When we first meet Larry, in the spring of 1967, his tenure case is pending, his son’s bar mitzvah is approaching, and, as in the original, a lot of bad stuff is about to happen, for no apparent reason.
Cool, a physicist playing Job. But then she read me the second paragraph and it all soured for me:
At work, Larry specializes in topics like Schr√∂dinger’s Paradox and the Heisenberg Principle — complex and esoteric ideas that can be summarized by the layman, more or less, as “God knows.” Because we can’t. Though if he does, he isn’t saying much.
Egads New York Times (okay maybe that should be a singular “egad” given the context) what are you trying to do to this old physics curmudgeon and literature major pedant early in the morning, give him a heart attack?!?
Dear Mr. New York Times reviewer A. O. Scott, the proper words you were looking for here are “Schr√∂dinger’s Cat Paradox” and “Heisenberg’s Uncertainty Principle.” If you’re going to take a mocking tone in your review about “complex and esoteric ideas” it would be useful, you know, if you actually got the names of those “complex and esoteric ideas” correct. Second isn’t it sad how a film critic can get away with calling these two ideas “complex”? Compared to what Mr. Scott? Compared to the proof of the PCP theorem? Compared to doing a calculation in quantum field theory? Um, I don’t think so. And finally, because standing on this upside down can is getting kind of wobbly, isn’t it a little presumptuous of you to say that God knows the position and the momentum of a particle? I mean might it be that even God doesn’t know the hidden variables of our universe. Or even, heaven forbid, that there are no such variables, and that *gasp* he is not in control of the universe that he supposedly created?
The biologists had to wince through a whole heap of ignorant reviews when the Day the Earth Stood Still remake came out; that’s not to say the movie was any good, mind you, just that the people reviewing it couldn’t be bothered to Google a term before mouthing off about it. I suppose it’s only fair we physics people suffer too. . . .
My much harsher comments, because this fits right in to one of my pet peeves…
Pet peeves..haha 🙂
or, you know, that there is no god.
My room-mate went to the premier of this movie at the Landmark Theater in Culver City, and while he isn’t a physicist, he actually quite liked it. I’ve liked most of what the Coen brothers have produced in the past.
Personally I don’t really care much about movie critics and their two cents worth of gibber-gabber.
At work, Larry specializes in topics like Universal Gravitation and the Fluxions — complex and esoteric ideas that can be summarized by the layman, more or less, as “Apples fall on Isaac Newton, but transform into Fig Newtons.” Because we can’t find our butt with both hands. Though if we do, we aren’t saying much. Because our motto is: “All the Nonsense that Fits, We Print.”
It’s also no good to say that someone in the 1960s specializes ” in topics like Schrödinger’s Paradox and the Heisenberg Principle”[sic], unless the specialty was also known as “teaching physics to undergraduates.”
“…ideas that can be summarized by the layman, more or less, as ‘those guys over there at your local university know.’ ”
Right, the SCP is not literally “complex.” It is a subtle matter of principle and confuses lots of people IMO, including experts! For example, I have decried the attempt to use “decoherence” to solve the SCP. Decoherence just doesn’t solve the superposition problem, given that you imagine (if you’re a realist) that there really “are” say two extended wavefunctions in superposition, at the outset. It is said, that when these WF phases are scrambled and entangled, this is supposed to somehow provide a classical world or the equivalence of “collapse” (or, suspiciously phrased as “appearance of a classical world”, or “appearance of collapse”!)
Here is an admittedly simplistic decoherence argument, as I’ve seen (say, “SDA”), but its spirit misdirects the whole enterprise (as presented; if there’s a better way let me know – but that better way still has to work differently from this!): randomizing the phases of waves, leads to classical-style statistics. Uh, yeah, if there was something to make a “statistics” out of the waves to begin with – otherwise they’d just stay waves, in various phase relationships! Classical EM waves, if in various phase relationships, just superpose to one net field one time, another net field another time, etc. I’m sorry, the SDA is a circular argument. It’s a logical flaw, and physicists have no special permission to indulge it. Sure Nature is “weird”, but logical hygiene is what it is.
Consider that the SDA says in effect, “Suppose there are the waves in superposition. Then their phases are scrambled, and then the interference pattern isn’t there anymore.” But that involves assuming that the waves are both “really there” in order to make the point! We are still left with a superposition.
The SDA just deftly slips in the “hits” to compare coherent statistics with incoherent statistics, but getting hits from wave amplitudes of any kind – however well-organized their phases are, or aren’t – is what needs explaining. Otherwise, we have “amplitudes” distributed in space. We can’t measure those directly, but if you don’t believe they are real, then what made the “coherent” pattern of hits possible the other cases?
Nothing about the messiness of the relative phases can tell me why we don’t find them both, or why they localize instead of spreading out, etc. Of course, any one hit doesn’t show anything anyway, so that’s the other mistake: conflating and comparing different, admittedly variable instances, to the case and issues of any one instance. Yes, we use ensembles to show that waves are present in the coherent cases, but the validity of ensembles is based on the instances all being alike!
And entanglement doesn’t really help. It is ultimately a relation between eventual hits, whatever causes them. (Question – in what sense would entanglement even be meaningful, if the WF remained a superposition? What meaning of “up spin here means down spin there, and vice versa,” without “hits?”) See also SEoP link on that.
If you are a realist: the WFs are always there until some collapse process kicks one out and/or localizes one of them. If sometimes you can’t prove they must have been there – you couldn’t do that with any one “hit” anyway! – so what?
If you aren’t a realist: there’s no point in worrying about “what happens to the WF” anyway.
Hence, it just doesn’t answer any question to say of the states, “they don’t interfere anymore.” Just imagine too, using e.g. Schrodinger equations to create a graphical model of the evolution of the waves in space and time. Maybe color one state red, the other blue. As they spread out and interact with things, their phases change around, etc – but you will see red and blue regions continuing to change together, with no opportunity for either one of them to slip away, or for either to become localized, without some special intervention.
Re MWI, sometimes (why?) tied in with decoherence: consider say a Mach-Zehnder interferometer. Wouldn’t the WF split at the first beam splitter, making two “worlds” then – one having the bottom leg, the other; the top leg? Then the beams couldn’t recombine together to interfere (or even “seem to”) later, could they?
Don’t just trust me, see the criticisms made at Stanford Encyclopedia of Philosophy, at http://plato.stanford.edu/entries/qm-decoherence/:
E.g., at “3.1 Solving the measurement problem?”
The fact that interference is typically very well suppressed between localised states of macroscopic objects suggests that it is relevant to why macroscopic objects in fact appear to us to be in localised states. A stronger claim is that decoherence is not only relevant to this question but by itself already provides the complete answer. In the special case of measuring apparatus, it would explain why we never observe an apparatus pointing, say, to two different results, i.e., decoherence would provide a solution to the measurement problem. As pointed out by many authors, however (recently e.g., Adler 2003; Zeh 1995, pp. 14-15), this claim is not tenable.
Indeed, “God only knows” what happens to the initial superpositions of wavefunctions. We sure don’t, and decoherence can’t palm them away, either. BTW, visit my handle link and pitch in if you want …