Thursday, April 25, 2013

Erik Verlinde 全息原理的一个具体实现是anti-de Sitter空间上的引力体系与一个共形不变的场论对偶

全息原理的一个具体实现是anti-de Sitter空间上的引力体系与一个共形不变的场论对偶,简称AdS/CFT。这个对偶由弦论中的膜理论发展而来。一方面,在膜的附近,时空弯曲,越靠近膜时空越接近anti-de Sitter空间,另一方面,膜上的理论是共形不变的场论。AdS/CFT对偶还可以推广为其他时空中的引力体系与非共形不变的场论之间的对偶,例如,从一个共形场论出发,我们可以用该理论中的一些算子加到作用量中得到另一个场论,而anti-de Sitter空间同时变形为另一个时空。

http://link.springer.com/content/pdf/10.1007%2FJHEP04%282011%29029.pdf

Perhaps the best known example is the elasticity of a polymer. A single polymer

molecule can be modeled by joining together many monomers of xed length, where each

monomer can freely rotate around the points of attachment and direct itself in any spatial

direction. Each of these con gurations has the same energy. When the polymer molecule

is immersed into a heat bath, it likes to put itself into a randomly coiled con guration

since these are entropically favored. There are many more such con gurations when the

molecule is short compared to when it is stretched into an extended con guration. The

statistical tendency to return to a maximal entropy state translates into a macroscopic

force, in this case the elastic force.
 

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