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arXiv · 2506.09142

Critical scaling for spectral functions

Konrad Kockler·Jan M. Pawlowski·Jonas Wessely
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Abstract

We study real-time scalar $\phi^4$-theory in 2+1 dimensions near criticality. Specifically, we compute the single-particle spectral function and that of the $s$-channel four-point function in and outside the scaling regime. The computation is done with the spectral functional Callan-Symanzik equation, which exhibits manifest Lorentz invariance and preserves causality. We extract the scaling exponent $\eta$ from the spectral function and compare our result with that from a Euclidean fixed point analysis.

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Konrad Kockler, Jan M. Pawlowski, Jonas Wessely. 2025-06-10. Critical scaling for spectral functions. https://arxiv.org/abs/2506.09142

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