sage
发表文章数: 1125
武功等级: 天山六阳掌
(第六重)
内力值: 535/535
Physics Benchmarks of String theory 4: More Appli
After all the previous advances, people are eager to apply string theory to
the real world. They encounter some practical problems. These problems
seems to be serious at that time, although less serious from what we
know now.
The first problem is that there seems to be no obvious way to
implement non-abelian gauge symmetry while we know it a least should
contain the strong and weak interactions.
The invention of the Heterotic string by David Gross, Jeff Harvey,
Emil Martinec and Ryan Rohm solved this problem in the closed string
framework. It also predicts two, and only two, possible unification
gauge group. At that moment, string theory got the FIRST most
realistic framework to apply to our world. It seems to be the correct
model (although we realize now that there are other possibilities). Heterotic string
will go down the history as the first hint that string theory might be the model of the
real world.
Superstring theory lives in 10 dimensions. In order to be the
fundamental physics theory of our world, 6 of those dimensions must
form a compact manifold.
There was a series of questions asked at that time as to which
manifold to use, also guided by physics requirements.
We observe chiral fermion at low energy. One class of compact manifold
with chiral fermions has singularities, called orbifold. The technical
problem of doing string theory on orbifold was solved by Dixon,
Harvey, Vafa, and Witten.
We do not observe supersymmetry in nature yet. From this and other
physics reasons, it is desirable to have compactifications with N=1
supersymmetry. Orbifold could break enough supersymmetry to satisfy
this condition. On the other hand, a set of so called Calabi-Yau
manifolds could also be used to achieve the same purpose. It was first
developed by Candelas, Horowitz, Strominger, and Witten.
| 发表时间：2005-09-28, 09:31:30 |
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轩轩
发表文章数: 1352
武功等级: 易筋经
(第二重)
内力值: 567/567
Re: Physics Benchmarks of String theory 4: More Appli
On the other hand, a set of so called Calabi-Yau
manifolds could also be used to achieve the same purpose. It was first
developed by Candelas, Horowitz, Strominger, and Witten.
卡丘紧化要满足多少物理要求？？？？
只听说要让它上面只有一个killing旋量，但这个是数学要求。翻译成物理是什么
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：2005-09-28, 09:46:01 |
作者资料
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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 4: More Ap
>只听说要让它上面只有一个killing旋量，但这个是数学要求。翻译成物理
>是什么
N=1 supersymmetry. There is only one copy of susy generators, that killing spinor.
| 发表时间：2005-09-28, 10:08:30 |
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