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arXiv 1604.02745hep-thhep-lat
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格点量子引力与渐近安全性

Lattice Quantum Gravity and Asymptotic Safety

J. Laiho, S. Bassler, D. Coumbe, D. Du, J. T. Neelakanta

摘要:

本文研究了由欧氏动力学三角剖分(EDT)定义的量子引力的非微扰形式,试图与温伯格的渐近安全方案建立联系。我们发现,微调是必要的,以恢复半经典的行为。这样的微调通常与打破目标对称性的晶格调节器,在这种情况下,我们认为,目标对称性是一般的坐标不变性的理论。在引入和微调一个非平凡的本地测量项,我们发现没有障碍,采取连续极限,我们发现的证据表明,四维,半经典几何恢复在长距离尺度的连续极限。我们还发现在短距离尺度下的谱维数与3/2一致,这个值可以解决黑洞的渐近安全性和全息熵标度之间的矛盾。我们认为,在连续统理论的相关耦合的数量是一个,一旦对称性破缺的晶格调节器占。这样的理论是最大的预测,没有可调参数。普朗克单位的宇宙学常数是唯一相关的参数,用来设定晶格尺度。普朗克单位的宇宙学常数在紫外线下为1阶,在红外线下经历重整化群,直到很小的值。如果这些发现在进一步的研究中成立,晶格可能提供一个广义相对论的可重整化量子场论的非微扰定义,没有可调参数,宇宙学常数在红外线中自然很小。

英文摘要:

We study the nonperturbative formulation of quantum gravity defined via Euclidean dynamical triangulations (EDT) in an attempt to make contact with Weinberg's asymptotic safety scenario. We find that a fine-tuning is necessary in order to recover semiclassical behavior. Such a fine-tuning is generally associated with the breaking of a target symmetry by the lattice regulator; in this case we argue that the target symmetry is the general coordinate invariance of the theory. After introducing and fine-tuning a nontrivial local measure term, we find no barrier to taking a continuum limit, and we find evidence that four-dimensional, semiclassical geometries are recovered at long distance scales in the continuum limit. We also find that the spectral dimension at short distance scales is consistent with 3/2, a value that could resolve the tension between asymptotic safety and the holographic entropy scaling of black holes. We argue that the number of relevant couplings in the continuum theory is one, once symmetry breaking by the lattice regulator is accounted for. Such a theory is maximally predictive, with no adjustable parameters. The cosmological constant in Planck units is the only relevant parameter, which serves to set the lattice scale. The cosmological constant in Planck units is of order 1 in the ultraviolet and undergoes renormalization group running to small values in the infrared. If these findings hold up under further scrutiny, the lattice may provide a nonperturbative definition of a renormalizable quantum field theory of general relativity with no adjustable parameters and a cosmological constant that is naturally small in the infrared.

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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