arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1408.0199hep-thmath-phmath.MP
收藏

量子场论中的量子谱维数

Quantum spectral dimension in quantum field theory

Gianluca Calcagni, Leonardo Modesto, Giuseppe Nardelli

摘要:

在量子场论(QFT)中,当系统在给定的分辨率下被探测时,我们将时空的谱维重新解释为有效自能跃迁振幅的标度。这幅图有四个主要优点:(a)它免除了通常的解释(在协变方法中不令人满意),其中,代替跃迁振幅,在抽象扩散时间内求解非相对论扩散方程的概率密度;(b)它解决了经典和量子引力中高阶和非局域色散关系已知的负概率问题;(c)它澄清了量子光谱维的概念,而不是经典的概念。然后,我们考虑一类对数色散关系与量子粒子,并表明,频谱尺寸$d_s$的时空,这些量子探针可以偏离其经典值,等于拓扑维数$D$。特别地,在存在较高动量功率的情况下,它随着尺度而变化,从红外(IR)中的$D$下降到紫外(UV)中的值$d_s^{\rm UV}\leq D$。我们把这个一般结果应用于Stelle可重整引力理论,得到了对任意维数$D$的普适值$d_s^{\rm UV}=2$.

英文摘要:

We reinterpret the spectral dimension of spacetimes as the scaling of an effective self-energy transition amplitude in quantum field theory (QFT), when the system is probed at a given resolution. This picture has four main advantages: (a) it dispenses with the usual interpretation (unsatisfactory in covariant approaches) where, instead of a transition amplitude, one has a probability density solving a nonrelativistic diffusion equation in an abstract diffusion time; (b) it solves the problem of negative probabilities known for higher-order and nonlocal dispersion relations in classical and quantum gravity; (c) it clarifies the concept of quantum spectral dimension as opposed to the classical one. We then consider a class of logarithmic dispersion relations associated with quantum particles and show that the spectral dimension $d_s$ of spacetime as felt by these quantum probes can deviate from its classical value, equal to the topological dimension $D$. In particular, in the presence of higher momentum powers it changes with the scale, dropping from $D$ in the infrared (IR) to a value $d_s^{\rm UV}\leq D$ in the ultraviolet (UV). We apply this general result to Stelle theory of renormalizable gravity, which attains the universal value $d_s^{\rm UV}=2$ for any dimension $D$.

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。

↑