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Massive Update on Strings Theory in Wikipedia
S3D writes "There is a massive update on Strings Theory in Wikipedia :
AdS/CFT
, Andrew Strominger
, Cumrun Vafa, Ashoke Sen, Juan Maldacena,
Mirror symmetry,
String field theory,
Holonomy,
Heterotic string,
Closed string
, Open string,
F-theory,
Background independence,
Higgs mechanism,
Conifold,
Tachyon_condensation,
Einsteinian_manifold,
Second superstring_revolution
Now you can easyly tell Open string from Closed string
at last."
why there is a wiki entry if its only a theory... sheesh, flat earth is a theory
All of science is "only a theory". (Yes, to Americans who still believe what they learned at school - no, theories don't "promote to Law" at some point. They stay theories regardless of what they're named). That's what science deals with.
Now superstring theory is a bit different, since as far as I know they haven't actually had any predictions yet that can be tested, they aren't really "connected to reality". In a way they're now a really complex collection of math that has yet to become a theory.
But of course, regardless of all that, there's a huge body of knowledge, terms, specialist language etc that needs to be explained to people who want to know what they mean. And that's what encyclopedias are for, you know. Just that they explain what "open string" means in superstring theory doesn't mean they're saying "this here is the only truth". They're not making any statement about the likely success of this theory at all They just explain the sort of ideas it deals with.
Sheesh.
I believe posters are recognized by their sig. So I made one.
Wikipedia is getting new knowledge all the time. If you really want to find out what's new, just visit here. I don't understand why new Wikipedia entries are meaningful stories for slashdot.
For every problem, there is at least one solution that is simple, neat, and wrong.
Most of the links are to stubs, this really isn't a massive update. Wake me when someone who knows what he's talking about adds some real (useful/readable) information on these theories.
This sig is intentionally left blank
Well, positing that tachyons are "really there" probably ought to get you labelled as somewhat misinformed. But as the wikipedia entry explains, there are (mathematical) situations where you end up with fields with imaginary mass (tachyons). You invoke symmetry breaking, fix a gauge, and your previously imaginary masses suddenly become real. No more tachyons - the tachyon field has "condensed" into a real-valued field.
As far as I know, anyone who talks about tachyons as physical particles which we might use to construct warp drives or build a better mousetrap, is venturing into crackpot domain. The word does have a useful meaning in particle theory, which is indicated by the last paragraph of the entry. I'll give it a go, but this may not be helpful - it's unfortunately rather technical and abstract. Imagine you're trying to see how some particle (field) behaves. You can sum up a lot of the field's properties by a potential energy function. This can be a crazy function with lots of peaks and valleys in it, and what it tells you is how much energy it costs for the field to be in a given state. Usually, the field chooses to sit in the minimum energy state possible - the "ground state", the deepest of the valleys. If you "kick" the field with some kind of interaction, it will go into oscillations rolling around the bottom of the valley. These excitations are what we call particles. (Sorry, I said it was technical and abstract). A tachyon occurs when you made a mistake of sorts in your work - you picked the ground state to be at a peak rather than a valley. So the field value is such that you are perched atop one of these peaks. It turns out this would seem to correspond to a bizzare particle called a tachyon - a particle for which the square of its mass is negative (since the potential function is curving down instead of up). This isn't a real particle, though - if you "kick" the field when it's in that state, it won't oscillate normally to give particle states - it will roll off the peak and into a valley. This often happens when you spontaneously break a symmetry of your theory. Imagine your potential function looked like the letter "W". You might choose your ground state to be the one with left/right symmetry, but then you'd be on the peak of the W - you'd eventually roll off to the left or right and break the symmetry. The take-home message is that the tachyon state isn't a real particle, it's an unstable situation that is an indication that you picked the wrong ground state. I think that in the early days of particle physics people didn't understand this kind of thing so well and thought tachyon particles might actually exist. Sorry if I can't figure out how to make that much clearer.
This could be solved with one entry:
Closed String: Contiguously allocated memory ending with 0x00 ('\0', 0, 0b00000000, etc)
Open String: Contigously allocated memory without a terminator (see also Closed String, Buffer Overflow)
-Adam