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arXiv 1012.1739gr-qc
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圈量子引力的洛伦兹协变性

Lorentz covariance of loop quantum gravity

Carlo Rovelli, Simone Speziale

摘要:

圈引力的运动学可以给出一个明显的洛伦兹协变公式:传统的SU(2)-自旋网络希尔伯特空间可以映射到SL(2,C)函数的空间K,其中洛伦兹协变是明显的。K可以用Livine、Alexandrov和Dupuis研究的“投影”自旋网络的某个子集来描述。它是由SL(2,C)函数构成的,完全由它们对SU(2)的限制决定。它们在SU(2)标积中是平方可积的,但在SL(2,C)标积中不是。因此,SU(2)-自旋网络态可以用洛伦兹协变SL(2,C)函数表示,因为双分量光子可以用洛伦兹协变古普塔-布莱克斯形式主义描述。正如沃尔夫冈·维兰德(Wolfgang Wieland)在一篇相关论文中所指出的,这种明显的洛伦兹协变公式也可以直接从正则量子化中获得。我们证明了圈量子引力的自旋泡沫动力学在体元中是局部SL(2,C)不变的,并且在边界上产生精确的K态。这阐明了SL(2,C)spinfoam形式如何在边界上产生SU(2)理论。这些结构定义了一个整洁的洛伦兹协变形式主义的圈引力。

英文摘要:

The kinematics of loop gravity can be given a manifestly Lorentz-covariant formulation: the conventional SU(2)-spin-network Hilbert space can be mapped to a space K of SL(2,C) functions, where Lorentz covariance is manifest. K can be described in terms of a certain subset of the "projected" spin networks studied by Livine, Alexandrov and Dupuis. It is formed by SL(2,C) functions completely determined by their restriction on SU(2). These are square-integrable in the SU(2) scalar product, but not in the SL(2,C) one. Thus, SU(2)-spin-network states can be represented by Lorentz-covariant SL(2,C) functions, as two-component photons can be described in the Lorentz-covariant Gupta-Bleuler formalism. As shown by Wolfgang Wieland in a related paper, this manifestly Lorentz-covariant formulation can also be directly obtained from canonical quantization. We show that the spinfoam dynamics of loop quantum gravity is locally SL(2,C)-invariant in the bulk, and yields states that are preciseley in K on the boundary. This clarifies how the SL(2,C) spinfoam formalism yields an SU(2) theory on the boundary. These structures define a tidy Lorentz-covariant formalism for loop gravity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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