Happy Saint Patrick's Day!

Have fun, but take care of yourself and everybody else ...

It's Talk Like a Physicist Day!

Greetings ....

Well, (in my time zone, folks, and still in many others!) it's Talk Like a Physicist Day, Pi day, Bee writes about the PI gym (at the Perimeter Institute) albeit two days earlier, and Albert Einstein's 129th birthday! First, one cool way to talk like a physicist is to never refer directly to "zero" or "one." Instead, say the quantity is vanishingly small, or vanishes, and say "unity" instead of "one."

Second, here's the weird little story I heard years ago about someone who got in trouble for talking like a physicist, and was one as well (assuming it really happened ...): If you run a red light and it goes to court, beware of trying the apocryphal (?) tack of claiming that Doppler blue shift made the red light look green (or yellow.) Supposedly the physicist who posed that excuse some years ago faced a scientifically literate judge, to his dismay. The judge calculated that the driver had to be going around 100,000,000 mph, and fined him accordingly! It’s not always wise or clever to talk like a physicist, even if you are one.
(Does anyone remember when/where they head that one?)

A quantum measurement paradox: the reallocation by measurement problem

I spend lots of time thinking about weird foundational issues in quantum mechanics (I used to be in top Google hit for "quantum measurement paradox"), and do I have a deal for anyone else like me. I have been thinking of this problem for awhile, and the post Many Worlds, Many Headaches on Uncertain Principles stimulated me to post a version of it. If you want something really strange and "after the fact" about measurement, please consider my following proposal: In a Mach-Zehnder interferometer, insert a gray filter G into leg L2. Given a traditional stream of light, that alters the amplitudes delivered to the beam-splitter/recombiner R. With a 25% transmitting filter, the L2 amplitude is 0.5 of that in L1 (which itself is sqrt (0.5) of the original pre-split input.) Hence, with symmetrical R, we get an output mix rather than all A channel output. We can adjust R to a compensatory split so that output is again all A channel. Using individual photons, the statistics should be the same. FEL optical physicist Michelle Shinn of J-Lab agreed with me that's so, despite the weirdness of the photon's wave function in L2 being attenuated by the chance that it could have been absorbed, even if it wasn't (well, superposition of absorption and not-absorption in the dye molecules in the filter, etc, right?) Also, as G gets darker, this has to be the limiting factor approaching the results of an opaque stop in L2. But what happens if we can find out whether a photon has been absorbed in the filter?

Consider an opaque stop: the stop clearly "reallocates" the WF all into L1, in a manner akin to the Renninger negative result problem, even though no actual "measurement" is taken। But there, a photon will just never get through. However, G may or may not absorb a photon, something we can in principle check on (There are semi-transparent optical detectors, no? Just consider film for example.) Now, while G is still "deciding" (in a state of superposition) whether it will absorb or not, it makes sense to consider the L2 wave to be attenuated relative to L1. Maybe that's the normal time scale to allow interference in R before that happens. But, after a certain time, if we check G carefully to look for evidence of absorption, it should be settled: absorption or not. If it did, there's no paradox. But if we find "no absorption," why in the world should the L2 wave continue attenuated? The measurement result was "no" for G, so there is no longer "a chance" that the photon might end up there. The filter might as well have been clear glass, right? If so, then the interference at R would be different (it would follow normal equal-balance rules instead.)

The really weird thing is, that reallocation should take place as soon as the absorption/detection issue is settled. If so, we could manipulate the pattern of hits (with sequential photon shots) at the output by looking for evidence of absorption in the filter, which would start rearranging the WF as per Renninger etc. In principle, there's nothing to stop this from being a true FTL signal, since manipulating G (or perhaps the distance to R) causes noticeable effects (not distant signal correlations) at R. Sure, that's problematical, but you can't just blow off the supposed effect on the WF of the negative measurement in G, can you? Have fun.
(I also just put this up on sci.optics, sci.physics, etc.)

Not Even Wrong?

Science In Crisis: Not Even Wrong

This is an interesting take on a "scientifically incorrect" jeremiad: that string theory/s are not really the it thing. (Well, have they produced testable predictions yet? Or rather, successfully tested predictions? Actually, the millimeter dimension theories did, but we didn't find the sub-mm deviations from Newton's 1/r^2.) Check out the post, and the book it's about (Peter Woit's new book, Not Even Wrong: The Failure of String Theory and the Continuing Challenge to Unify the Laws of Physics...) when it becomes generally available in a few months. While you're here, check out my synopsis of how I showed that space must have three large dimensions without needing string theory etc. - just self-consistency for extrapolated electromagnetism.

- NB

Why 3-D?

Hello folks, and long-time no-be-seen.

I recently listened to an interview on Public Radio with physicist Lisa Randall. She is a top theorist on foundational theory of why the universe is the way it is. That means string, branes, and such. One of the venerable questions is: why is space three-dimensional? It may seem natural to have three dimensions of space and one of time, but mathematically there can be any number of dimensions (think of specifying points using 4, 10, etc. variables.) Physicists, including Lisa, say they can't see why space *had* to have three dimensions. (Check out http://arxiv.org/abs/hep-th/0506053 ) However, they have come up with reasons why three large-scale dimensions would be more likely to expand out of a larger set (usually thought of as 10 or 11) of original, perhaps tiny dimensions. Below follows a statement adapted from my post to http://www.radioopensource.org/the-holy-grail-of-physics/ in response to the interview, and outlining my own efforts to answer this question. (I’ll also find out if the automatic editing puts in links for me.) Also, happy Cinco de Mayo, late as it is!

I have been working myself on the question, why are there three *large* dimensions of space? (There are probably more, like a total of 10 or 11 space dimensions, but the rest are curled up very small or otherwise inaccessible.) After extrapolating electromagnetic interactions to spaces of other dimensions, I found at least two arguments:

1. In spaces with other than one or three dimensions, an oscillating charge does not project the same *average* field along the axis of oscillation as the rest value. That is due to two things: the combination of "projection" of its retarded distance - where it would be had it continued at the velocity it had when light left it - and the distortion of the field due to Lorentz contraction, which weakens it to
gamma^(1-N) the value it has at rest. N is the number of large space dimensions. (We also must take into account the Doppler shift of projection intervals. Heh, it’s not quite as complicated as it sounds.) Remember that the Coulombic electric field intensity is given as E = qr^(1-N) due to field spreading. This amplifies the effect of the oscillating charge’s apparent position being close (projected from approaching cycle) to a second “target” charge at rest. It increasingly swamps the weakening effect of the gamma factor as N goes above three and is incorrect when N = 2. That would impose a net force on a second "target" charge unequal to that on the oscillating charge, and violate conservation of momentum and energy. The one-dimensional case is ruled out due to infinite potential energy as is the 2-D case (why didn’t A. K. Dewdney realize that about the 2-D Planiverse?)

2. Let two charges be connected by a reasonably rigid rod. Then, accelerate the rod along its length. The combined force between the charges will be derived from the sort of considerations given in (1.), as the projected field of each charge catches up to the other charge. Then we must take into account the extra force created by the action of acceleration on the relativistic stress-correction to the momentum and energy of the rod. Only in three dimensions of space does that equal in net the effective inertia the charges should have given their potential energy. (In higher dimensions, taking the integral of f = q1q2/r^(N-1), that potential w.r.t. infinity is: -q1q2r^(2-N)/(2-N). )

I hope I can publish the full development of this before long. I don’t think anyone else has an explicit proof that N *must* equal three, only reasons it was more likely to form, or oddities like being unfriendly to life, distorted wave propagation (see Barrow and Tipler’s _The Anthropic Cosmological Principle_ for great discussion of this.)

Neil Bates

Welcome to Tyrannogenius!

Hello, visitors!

My name is Neil Bates, and I welcome you to Tyrannogenius - the first post of my first blog. I'm just introducing myself here, and will have more to say later. However, to give you a taste...

1. I like scientific paradoxes, and I propose them too. Enter "quantum measurement paradox" into Google, and a thread I started on sci.physics.research (a quality, refereed newsgroup) comes up first. I'll describe the paradox in these pages later.

2. The great philosophical questions interest me greatly. I think that the unwit I call "Witlesstein" is one of the worst philosophers ever. Someday I will post a refutation of his undeservedly renowned "beetle-in-a-box" argument against private languages. (It's mostly an indulgence of logical positivism. Hey - can you logical positivists tell me what the operational meaning of "things continue to exist even while not being observed" is? Nor can we find out what happened yesterday because of quantum uncertainty, but we don't pretend things aren't a definite way to be today for the sake of the poor bastards of tomorrow who can't do a Laplacian track-back...)

Well, that's all folks 'til next time!