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arXiv 2405.04501math.PRmath-phmath.MP
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通过高斯自由场研究球形模型与自旋$O(N)$模型的大$N$极限

The Spherical model and the large-$N$ limit of the Spin $O(N)$ model via the Gaussian free field

Juhan Aru, Aleksandra Korzhenkova

AI总结:

本研究通过高斯自由场(GFF)关联Berlin-Kac球形模型与大$N$极限下的自旋$O(N)$模型,证明了二者在不同温区的场分布形式,指出虽单格点自由能一致,但低温区零模存在差异。

摘要:

我们重新探讨了Berlin-Kac球形模型与自旋$O(N)$模型在$N \to \infty$极限下的关联,并阐释了二者如何通过离散高斯自由场(GFF)建立联系。\n 利用概率极限定理与测度集中性,我们证明了d维环面上球形模型的无穷体积极限在高温区为有质量GFF,在临界温度下为标准GFF,在低温区为标准GFF加上一个Rademacher随机常数。临界温度下的证明方法为全新成果,依赖于对环面上零平均格林函数的精细分析。\n 我们在自旋维数与环面尺寸的双重极限下研究自旋$O(N)$模型。先令$N \to \infty$,再令环面尺寸趋于无穷,我们证明不同自旋坐标成为独立同分布(i.i.d.)场,其分布在高温区为有质量GFF,临界温度下为标准GFF,低温区为标准GFF加上一个高斯随机常数。\n 特别地,尽管两个模型的单格点极限自由能在所有温度下均一致,但它们的有限维分布在低温区的零模方面仍存在差异。

英文摘要:

We revisit the relation between the spherical model of Berlin-Kac and the spin $O(N)$ model in the limit $N \to \infty$, and explain how they are connected via the discrete Gaussian free field (GFF). Using probabilistic limit theorems and concentration of measure, we prove that the infinite-volume limit of the spherical model on a $d$-dimensional torus is a massive GFF in the high-temperature regime, a standard GFF at the critical temperature, and a standard GFF plus a Rademacher random constant in the low-temperature regime. The proof at the critical temperature appears to be new and relies on a fine analysis of the zero-average Green's function on the torus. We study the spin $O(N)$ model in the double limit of spin dimensionality and torus size. Sending $N \to \infty$ first, and then the torus size to infinity, we show that the different spin coordinates become i.i.d. fields, distributed as a massive GFF in the high-temperature regime, a standard GFF at the critical temperature, and a standard GFF plus a Gaussian random constant in the low-temperature regime. In particular, although the limiting free energies per site of the two models agree at all temperatures, their finite-dimensional laws still differ in terms of their zero modes in the low-temperature regime.

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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