What I've been reading

Not as far into the book as I'd like to be, simply because I've been feeling so drained lately. Still, I enjoy it when I get the chance to focus.

We can make measurements which observe the position of an electron, or we can make measurements which tell us which way it is moving, and in either case we can make the measurements as accurate as we like. But trying to measure the position very accurately blurs the electron's momentum, by a quantifiable amount, and vice versa.

This is not, as some textbooks still mistakenly suggest, solely a result of the practical difficulty of making measurements. It is not simply because in measuring the position of the electron (perhaps by bouncing photons off it) we give it a kick, which changes its momentum. A quantum object does not have a precisely defined momentum and a precisely defined position. The electron itself does not 'know' within certain limits where it is or where it is going. Exaggerating only slightly, if it knows exactly where it is, it doesn't know where it is going at all; if it knows exactly where it is going, it doesn't have the faintest idea where it is.

--John Gribbin, Schrödinger's Kittens and the Search for Reality (pp. 16-17)

My first reaction when reading this bit was that there's a metaphor for human life in there, probably one involving too many self-help books. The more you observe a quantum entity, the more "real" it is in a classical sense. An unobserved particle does not obey the laws of Newtonian physics. While the probability may be low, an unobserved particle could be on Mars--in fact, in some sense, it is, even if the probability wave suggests it's having more effect on that cup of tea sitting on your desk. But once you start looking for something, it has to decide where it is. Your examined entity becomes much more real, but much less free.

I deeply resent having to look at my life, catalog what I can and cannot do, determine and record for the benefit of others that X is possible and Y is not. Maybe because I don't want this life to be real. Maybe because I want things to have the chance to change.

After a discussion of an experiment showing that a watched quantum pot never boils:

If, as quantum theory suggests, the world only exists because it is being observed, then it is also true that the world only changes because it is not being observed all the time. (p. 135)

Quantum theory is tasty. I don't understand it, mind, but it's yummy all the same. So's relativity.

The Lorentz transformations tell us that time stands still for an object moving at the speed of light. From the point of view of the photon, of course, it is everything else that is rushing past at the speed of light. And under such extreme conditions, the Lorentz-Fitzgerald contraction reduces the distances between all objects to zero. You can either say that time does not exist for an electromagnetic wave, so that it is everywhere along its path (everywhere in the Universe) at once; or you can say that distance does not exist for an electromagnetic wave, so that it 'touches' everything in the universe at once.

This is an enormously important idea, which I have never seen given due attention. From the point of view of a photon, it takes no time at all to cross the 150 million km from the Sun to the Earth (or to cross the entire Universe), for the simple reason that this space interval does not exist for the photon. (p. 79-80)

Something timeless (eternal) and existing everywhere? No wonder light is such a common metaphor for God.

Language, under God

Since hearing about the U.S. Supreme Court decision to make no decision about that controversial phrase in the Pledge of Allegiance, you have surely been saying to yourself, "Yes, fine, we've heard all the lawyers and pundits jabbering on about the case. But what is the linguistic perspective?"

Well, dear reader, if you followed the languagelog feed, you would know.

One nation [head], under God [adjunct]
Dysfunctional Shift
Never say never
Out with Under God

So now you know.

(Also on the religious language front, there's the ridiculousness of the Unitarians being referred to as a "controversial cult", but those of you on my favorite mailing list have already heard about that one.)