Monday, November 21, 2011

Trifecta of Amazing Science News

This has quietly been an incredible week for science news. For one thing, we had a repeat of the neutrino experiment that I discussed earlier which confirmed the special-relativity-busting faster-than-light result. It might be worth pointing out of these two senses in which this experiment causes problems for understanding of both neutrinos and special relativity.

You might recall from the “Ghost Particle” documentary that we watched that the two teams resolve the anomaly of the missing neutrinos by theorizing that neutrinos “change flavors” as they pass through space, and that Ray Davis's giant neutrino counter was only set up to detect one of their three flavors. The fact that neutrinos could change implied something that no one really suspected given how weekly neutrinos interact with matter: that they have mass. For if they were massless, and traveling at the speed of light, special relativity would imply that they cannot “experience” the passage of time and therefore cannot change their qualities (as they appear to do). So the discovery that they are traveling faster than light conflicts with special relativity twice over: it conflicts with the tenet that nothing can travel faster than light and relativistic interpretation of the neutrino count anomaly experienced by Ray Davis. While I'm a non-expert on this, it seems to me that if this result is right, it implies not only trouble for special relativity (one of the best confirmed theories in the history of science) but the reinstatement of the puzzle of the solar neutrinos!

Of course, questions remain and many people are not willing to accept even this confirmed result as falsifying special relativity (even though on the surface that is exactly what it appears to do). It will be very interesting to keep an eye on this debate. We might be witnessing another scientific revolution in progress. But interestingly, it is impossible to know whether that's the case. Think about this point in the context of other scientific revolutions — like the Copernican revolution. It seems to me that this supports one of Feyerabend's points: the benefit of hindsight can have a distorting effect when we are interested in thinking about the justification of accepting certain scientific theories at a given time. . . . 

There was also a fascinating feature in Nature about physicists at the Large Hadron Collider at CERN starting to close in on where they suspect the Higgs Field Boson (one of the remaining lynchpins of the so-called "Standard Model" of particle physics) must be hiding. They're remaining a little tight-lipped so far (basically, the experiments are done and they're attempting to analyze their data right now). But I found this little video interviewing many of the researchers quite interesting. (For background on the Higgs Field — how it fits in with the standard model —, check out this short video prepared by Fermilab.)

Finally, I wanted to bring your attention to a "seismic" discovery in Quantum Mechanics (QM) that is directly relevant to our discussion of the realism/anti-realism debate. There has been a longstanding question of how to interpret the equations of QM: should we think of them as representing reality or merely offering us a tool for modeling certain (weird) observable features of it? There have been a few camps on this question that have waxed and waned in popularity through the years. But a recent theorem strongly implies that we should be realists about the "wavefunction" in QM — a feature of QM to which many physicists want to take an instrumentalist approach, treating it as a mere statistical tool. We knew from a previous important result in QM (Bell's Theorem) that QM implies action at a distance for particles that get "entangled" (if we treat it realistically). This new result shows that "if a quantum wavefunction were purely a statistical tool, then even quantum states that are unconnected across space and time would be able to communicate with each other. As that seems very unlikely to be true, the researchers conclude that the wavefunction must be physically real after all." Note the structure of the reasoning here:

(1) If S, then U
(2) not-U
(3) therefore, not-S

(3) is supposed to give us the realist result: if a statistical interpretation of the wavefunction is not true, then we must interpret it realistically; the new theorem is (1); (2) is an assumption. So this also connects with the Duhem-Quine thesis. (1) only implies (3) with the help of (2). But while (2) is indeed quite plausible, perhaps one could simply deny it and accept that "even quantum states that are unconnected across space and time would be able to communicate with each other". After all, that is basically what people did in response to Bell's Theorem: they simply accepted what many found unacceptably spooky: instantaneous action at a distance

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