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lionelbrits

Website: http://www.physics.thetangentbundle.net/wiki/Main_Page

Elective surgery to increase height

June 17, 2008 12:54pm

@ #2: "Saw a segment", eh? Geesh!

HOWTO divide a freezer-bag into individual servings before freezing

April 15, 2008 7:50am

#6: Ditch the squares and simply divide it into narrow rows. This should be fine for ground meat. Although I'd feel pretty funny defrosting such a meat popsicle.

Truth about teleportation

February 15, 2008 4:49pm

@ Tom (27)

The argument you make is a bit nitpicky and doesn't address discernability. If you want, consider two scenarios:

a) you give me an electron, and I let it hitch a ride on a spaceship to the moon, where it is left behind.
b) you give me an electron, and I use quantum entanglement to transfer its state to an electron that I put on the moon a couple of days prior.

A careful tally will show that no electrons were created or destroyed in the process. Of course you can argue in other ways how the two scenarios differ, but that is missing the point. In either case, "your electron" ends up on the moon, in all ways that are real.

One runs into people who deny teleportation is possible because, they say, if something didn't physically travel from A to B then it can't end up at B. This is a bit like arguing that people can't fly because human flight is impossible.

To those who complain that the term "quantum teleportation" is misleading, I would like to state that the term isn't some sensationalist jargon to grab headlines. It is an accurate, technical term that describes exactly that. I'm sorry but the world just isn't made out of "particles" with "states" attached to them. It is a convenient metaphor to teach to undergraduate quantum mechanics students until they can wrap their head around quantum mechanics as a whole, but it isn't a complete, or even accurate description of nature.

To those I haven't put to sleep yet, I'd like to state that the fact that fundamental particles are indistinguishable is something you can test. If you hold that they are "different" particles that just look the same, and you try to predict things like entropy, you get entirely the wrong answer.

These aren't just technical distinctions. The world just isn't the way it appears at first sight.


Truth about teleportation

February 15, 2008 3:37pm

@ Charlie Lesoine, and others

You said: "Yes, but no matter what, they are still two different electrons". I have to emphasize that this thinking is not correct, according to modern understanding of quantum field theory (of nature, in general).

At best you can say that the system has two electrons, and the system is in some quantum state Psi. You can't talk about electron A and electron B. You can only talk about "the electron that is over here" and "the electron that is over there".

The idea of "particles" (and even waves) is an unfortunate accident of human interpretation. Nature is governed by the fascinating rules of quantum mechanics and particles are just a limited, crude description of something altogether more complex.

Cheers.

Truth about teleportation

February 15, 2008 12:23pm

As someone with some training in the subject, I would like to add that fundamental particles of the same type are indistinguishable, which is a technical term meaning that swapping two particles has no effect on the system. I would like to add that this isn't just a technical distinction but that it actually has non-intuitive observable consequences.

So if we were able to duplicate the state of say, an electron, by putting another electron which is on the moon into that state (and necessarily scrambling the first in the process), then to say that what we did is somehow different from physically moving the electron from A to B is not a scientific or otherwise sane viewpoint. (There are fairly solid mathematical proofs based on very well established physical laws which back this up, but which this margin is too small to contain =).

Imagine plucking waves on a guitar string. "Matter" is no more than one of those notes, it isn't the string itself. So if I record the note and play it on a different string somewhere else, then to say I didn't move it is a bit metaphysical.

Cheers

Lazyweb: Bitmap to Vector?

January 25, 2008 8:13am

There's a adobe illustrator version over here: http://vektordb.lafkon.net/index.php?id=132
Sadly I can't open AI files so I can't say if it is any good. (found on wikipedia)

Computer mouse remade in stainless steel

January 13, 2008 8:54am

* cue terminator themesong *

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