sage
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Physics Benchmarks of String theory 1: Beginning
This is a start of a set of short survey on the historical development of string theory. The focus is strictly on its physics or stronly physics motivated achievments.
Strictly speaking. string theory has yet to become real physics, since we are still not sure if anything from it is relevant. However, one >20 years journey since its beginning, it did achieve several things which makes it closer to being phyiscs. I am going to focus completely on those physics related developments.
Without a cliam of completeness, I will also try to hightlight the people who gave the imporant physics contributions.
1) beginning
String theory has a lowly beginning. It was not invented for a theory
for quantum gravity (It is still not clear if it is the theory of
quantum gravity). It was not invented for mathematical beauty either.
It is invented for a pure and ugly phenomenological reason: physics of mesons.
Before the time of QCD, it is not clear what the correct theory for
strong interaction is. All kinds of crazy ideas float around. There are also a lot of strange experimental results. Among them, there was a mysterious linear relation between the spin and mass of the mesons, called Regge behaviour.
G. Veneziano guessed an amplitude for meson scattering which has this
behavior.
After a little while, L. Susskind (probably others as well), realized
that this could come from a theory of strings where the mesonic poles
are string resonances.
This is the beginning of the string theory.
| 发表时间：2005-09-21, 12:31:30 |
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轩轩
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Re: Physics Benchmarks of String theory 1: Beginning
mysterious linear relation between the spin and mass of the mesons
是共振态粒子的质量的平方和自旋的正比关系吧。实验上如何测量其自旋
引力是非局部的，量子力学也是非局部的。《相对论通俗演义》
i will love you till the null infinity.
| 发表时间：2005-09-21, 21:53:25 |
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sage
发表文章数: 1125
武功等级: 天山六阳掌
(第六重)
内力值: 535/535
Re: Physics Benchmarks of String theory 1: Beginn
是共振态粒子的质量的平方和自旋的正比关系吧。
Yes.
实验上如何测量其自旋
Spins of mesons are measured by looking at the distributions of their decay products.
| 发表时间：2005-09-22, 15:54:02 |
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