Sunday, December 16, 2007

Another Post re: Sal Cordova

I really wasn't going to write about Sal Cordova's latest misunderstanding of quantum mechanics. Even though it's a long article, there didn't seem to be enough there to give me anything of substance to write about. But thanks to Blake Stacey's comment on my last post on Sal Cordova showing me that Tyler DiPietro had written a bit about the new post, I had enough to go on.

Remember this equation from before? It was never explained what any of this means. In Sal's recent article, we get something almost a little like mathematical information about the equation.

Sal writes,

That conceptual merging of all quantum systems is represented by the quantum system of the universe, or (for lack of a better term), the Universal Wave Function. Taking the Schrodinger equation and generalizing it for the entire universe, we have the universal wave function as derived by Barrow and Tipler: [picture] where the indexed Psi’s are the individual quantum systems, and the O’s are the “observations."
There is zero probability that Sal didn't just copy that out of a book. Why else would he capitalize "Universal Wave Function"? Does he know what a wave function is? Does he know what "observation" means? I sure don't, not in this context anyway.

Let's analyze this equation for a bit. Why would you multiply a wave function with this "observation"? Why sum them up? In fact, every time we see an index i we see a k, yet i and k are summed separately. Why? The product is over n, yet n only appears in the "observation." Why? What are these indices supposed to mean? What does any of this mean? Perhaps Sal should understand that math doesn't just pop out of nowhere like a child's birthday magic show: it needs to be derived. And preferably explained.

Sal then cites a respectable, peer-reviewed geocities page when he says, "Jenny Nielsen explains this beautifully in A Report on 'The Delayed Choice Experiment'.” Wait, did I say "cites"? I meant "reproduces the entire article."

For physically actualized systems, it appears then a measurement is essential for the system to be actualized.
I can only infer from this that Sal thinks before humans were around measuring everything, nothing in the universe is "actualized." When we're not looking, everything ceases to be.

For example, we see measurements defining the boundary conditions of a quantum system such as illustrated by the Nobel Prize winning experiment known as Stern Gerlach.
The Stern-Gerlach experiment has nothing to do with measurement, and everything to do with demonstrating spin. Well, I guess it does trivially have to do with measurement, as one needs to measure something to get any information from the experiment. However, I can assure you, the Stern-Gerlach experiment would run the same way whether someone was watching or not. The point of the experiment is that there is an intrinsic angular momentum to the electron and that it is quantized.

[John Barrow and Frank Tipler's book Anthropic Cosmological Principle] was hailed by the prestigious scientific journal Nature. However, in 1996, when Tipler came forward and said the “Ultimate Observer” was to be identified with the Judeo-Christian God, Tipler’s ideas were immediately ridiculed and his pay was cut.

In fact, I've found the review in question. But my university's online subscription to Nature only goes back to 01-01-87, and this article was published on 08-14-86. So close. I'll have to go to the library and track it down later.

In a comment on Tyler's article, Blake Stacey writes about a different review of Tipler.
Actually, a review of Tipler's Physics of Immortality, published in Nature, called that book "a masterpiece of pseudoscience ... the product of a fertile and creative imagination unhampered by the normal constraints of scientific and philosophical discipline". It's funny Cordova doesn't mention that review, isn't it?

So, another day, another butchering of quantum mechanics. Expect another soon enough.

6 comments:

Ben said...

Am I the only one who laughs that the equation say "Oink"?

Ben said...

"Sal then cites a respectable, peer-reviewed geocities page when he says, "Jenny Nielsen explains this beautifully in A Report on 'The Delayed Choice Experiment'.”

This line almost killed me. Also, you might want to increase the size of the XKCD comic. I have a hard time reading the text.

Blake Stacey said...

Quoting Sal Cordova:

Taking the Schrodinger equation and generalizing it for the entire universe, we have the universal wave function as derived by Barrow and Tipler: [picture] where the indexed Psi’s are the individual quantum systems, and the O’s are the “observations."

This is a very poor way of describing a superposition of eigenstates (which is what that copy-and-pasted equation is, AFAICT). The coefficient multiplying a particular eigenfunction, which here is the O multiplying a ψ, is not an "observation" in and of itself. That's gibberish. Such a number is actually the probability amplitude for finding the system in that eigenstate when an observation is made.

It's just poor phrasing, but it's the kind of poor phrasing made by somebody who doesn't know any quantum physics.

Flavin said...

I can understand the summing: it's taking a linear combination of the (presumably energy) eigenstates. And I can almost understand the product: I guess you're creating a combined wavefunction from the individual wavefunctions. Sure. In principle I can get those things.

What makes this equation nonsense is, as you said, the "observation." Also the unexplained indices. Is n supposed to represent all the particles in the universe, as Sal seems to imply? What could one possibly hope to gain by examining this state? To make a classical analogy, this would be like approximating the motion of a car by summing up the motion of each individual particle inside it, and also all the particles in the road... and why not the earth and the sun and the galaxy as well? After all, this is a Universal Wave Function.

Jenny said...

I *am* Jenny Nielsen and I must admit that line was pretty funny. (I wrote that page when I was a senior in highschool.)

Flavin said...

I offer my humble thanks that you liked the joke, and my apologies that you've been quoted by the likes of Sal.