Wednesday, October 5, 2011

Faster than Light Neutrinos: Quite possibly

When I first heard the report of faster than light neutrinos, I (a theoretical physicist) was sure it couldn't be true--especially after Martin Rees noted that there had been observed optical pulses coincident with neutrino pulses from distant, astronomical objects. So if neutrinos indeed did travel faster than light, the neutrino pulse would be way in advance of the optical pulse.

But then, I wondered if one could reconcile these two results and not do serious damage to relativity theory. I believe the answer is yes.

We need some mechanism whereby at any distance scale, the neutrino can be only a little in advance of the photon. Imagine this crude analogy (similar, actually to the old Ptolemy epicycles in the Earth-centric model). Think of some invisible 'thing' traveling at a fast speed. And this thing has an arm sticking out from it on which is a visible particle. And the arm is rotating around the thing in the direction of motion. When the arm has swung the visible particle ahead of the thing, the particle is then traveling a tad faster than the thing. Similarly, the particle is traveling a little slower than the thing when the arm is behind the thing. This periodic motion can, for example, be replicated by an extra, closed dimension with some 'selection' rules for, as an example, the neutrino. I'm not sure the closed dimension is the best way to go (it feels perhaps too similar to epicycles). But it can be made to work.

The question then is: Can a very small, oscillatory, velocity over c coexist with relativity theory. Again, I think the answer is yes.
The two big problems with faster than light travel are causality (i.e. in another reference frame the effect can happen before the cause), and the synchronization of clocks throughout the universe.

I don't think causality is a problem for very small time scales and elementary particles (the LHC result is 60 nanoseconds) as micro-causality (i.e. elementary particles traveling short distances) doesn't seem to hold.
And as to the synchronization of clocks, the fuzzy nature of measurements in quantum mechanics should (IMO) wash out any problems for such small time scales.

There's a somewhat jocular (but fruitful) conjecture attributed to Murry Gell-Mann that says if something is not absolutely forbidden by physics, it must occur. Perhaps a sometimes-fast neutrino should then exist. 

So I'm inclined to believe (or at least not disbelieve out of hand) the LHC results (there are some very good, careful, and cautious scientists working there).

But then again, as well as being a theoretical physicist, I'm also a science fiction writer, so maybe it's easier for me to willingly suspend my disbelief.

And as an SF writer, allow me to plug my latest SF anthology, available as a Kindle book through Amazon.
'SF++ Science Fiction Stories for Linux Geeks'.