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arXiv · 1912.08169

$O(N)$ Models with Boundary Interactions and their Long Range Generalizations

Simone Giombi·Himanshu Khanchandani
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Abstract

We study the critical properties of scalar field theories in $d+1$ dimensions with $O(N)$ invariant interactions localized on a $d$-dimensional boundary. By a combination of large $N$ and epsilon expansions, we provide evidence for the existence of non-trivial $O(N)$ BCFTs in $1<d<4$. Due to having free fields in the bulk, these models possess bulk higher-spin currents which are conserved up to terms localized on the boundary. We suggest that this should lead to a set of protected spinning operators on the boundary, and give evidence that their anomalous dimensions vanish. We also discuss the closely related long-range $O(N)$ models in $d$ dimensions, and in particular study a weakly coupled description of the $d=1$ long range $O(N)$ model near the upper critical value of the long range parameter, which is given in terms of a non-local non-linear sigma model. By combining the known perturbative descriptions, we provide some estimates of critical exponents in $d=1$.

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Simone Giombi, Himanshu Khanchandani. 2019-12-17. $O(N)$ Models with Boundary Interactions and their Long Range Generalizations. https://doi.org/10.1007/jhep08(2020)010

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