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arXiv · 1904.05751

Bubble-resummation and critical-point methods for $\beta$-functions at large $N$

Tommi Alanne·Simone Blasi·Nicola Andrea Dondi
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Abstract

We investigate the connection between the bubble-resummation and critical-point methods for computing the $\beta$-functions in the limit of large number of flavours, $N$, and show that these can provide complementary information. While the methods are equivalent for single-coupling theories, for multi-coupling case the standard critical exponents are only sensitive to a combination of the independent pieces entering the $\beta$-functions, so that additional input or direct computation are needed to decipher this missing information. In particular, we evaluate the $\beta$-function for the quartic coupling in the Gross-Neveu-Yukawa model, thereby completing the full system at $\mathcal{O}(1/N)$. The corresponding critical exponents would imply a shrinking radius of convergence when $\mathcal{O}(1/N^2)$ terms are included, but our present result shows that the new singularity is actually present already at $\mathcal{O}(1/N)$, when the full system of $\beta$-functions is known.

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Tommi Alanne, Simone Blasi, Nicola Andrea Dondi. 2019-04-11. Bubble-resummation and critical-point methods for $\beta$-functions at large $N$. https://doi.org/10.1140/epjc%2Fs10052-019-7190-9

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