arXiv subjects

Mathieu Boisvert

Publications and source records attributed to Mathieu Boisvert.

5 recordsLinked to original sources

arXiv2026

Observables in Schr\"odinger CFTs: How Aliens Built the Pyramids

We discuss the algebraic structure of observables in Schr\"odinger CFTs. These operators have zero mass (or particle number) and generically transform in staggered ''pyramid representations'' built from ''alien operators,'' as we explain with the doubled state-operator correspondence. We comment on implications for the space of non-relativistic CFTs, thermal physics, and generalize the exceptional symmetry conservation laws of Bekaert, Meunier, and Moroz, and Golkar and Son. We show that alien operators are analogous to double-twist operators in Lorentzian CFT, with systematic cross-channel corrections from massless particles when they exist.

hep-th↗

arXiv2026

Where is tree-level heterotic string theory?

We continue the tree-level S-matrix bootstrap program for quantum gravity, now in ten-dimensional theories with half-maximal supersymmetry. This setting includes the heterotic string and allows us to test whether the string-like structures found in the maximally supersymmetric bootstrap persist with less supersymmetry and in non-planar gauge sectors. Imposing analyticity, crossing symmetry, unitarity, and Regge boundedness, we constraint weakly coupled UV completions of supergravity and super Yang-Mills. In the gravitational sector, much of the boundary of the allowed region is explained by extremal amplitudes supported on a single linear Regge trajectory, or by convex combinations of such amplitudes. In the gluon sector, the non-planar problem reveals a tension between representation-channel positivity and the trace decomposition of the EFT data, obstructing a direct normalization by $G$ or $g_{\rm YM}$; a coupled gluon/graviton bootstrap may be necessary to directly constrain the relative strength of gauge and gravitational interactions. Overall, our results support the emergence of linear Regge trajectories as a robust feature of the tree-level quantum-gravity bootstrap.

hep-th↗

arXiv2025

Revisiting Schr\"odinger CFTs: Factorization, Massless Particles, and a Path to the Bootstrap

We revisit Schr\"odinger CFTs from a modern point of view. We introduce the ''harmonic trap geometry,'' analogous to the cylinder picture in relativistic CFTs, and demonstrate a state-operator correspondence that applies to all operators, including descendant, massless, and ''normal-ordered operators.'' A thermofield double construction plays an extremely important role. We systematically classify all physical spectra in the harmonic trap and their unitarity bounds, extending earlier results to include both massless and massive states of all spins, providing a new analytic treatment of unitarity bounds, and establishing foundations for a bootstrap. In our reformulation, previously known perturbative non-renormalization theorems follow immediately from non-perturbative factorization at fixed points and along RG flows. Massless states are described by an effective 1d CFT, as predicted by DLCQ, and violate the non-renormalization theorems. We include a self-consistent review of Schr\"odinger CFTs in our framework, making the paper accessible to anyone with a field theory background.

hep-th↗

arXiv2025

Cardy limit of the 3d superconformal index

We study the superconformal index $Z(q)$ of 3d $\mathcal{N}=2$ gauge theories in Cardy-like limits $\beta = \log \tfrac{1}{q} \to 0^+$, extending techniques recently developed in the 4d $\mathcal{N}=1$ context. For theories with vectorlike matter content we find on the first sheet ($q \to 1$) that $Z(q) \sim \beta^{-\#}$, where the exponent $\#$ is determined by a $multiscale\ decomposition$ of the BPS moduli space appearing in the localization formula for the index. On the second sheet ($q \to e^{2\pi i})$ we find $Z(q) \sim e^{\#/ \beta}$, and that the long-standing puzzle of apparent gauge-enhancing saddles is resolved (in the absence of Chern--Simons couplings) via a novel $Lorentzian\ factorization$ formula that establishes complete screening. A key insight is the use of $Poisson\ resummation$, which streamlines the asymptotic analysis, sharpens the link to Kaluza--Klein effective field theory, and provides a dual description of parts of the BPS moduli space in terms of punctured surfaces. The Lorentzian factorization formula also emerges from Poisson resummation, though applied after a contour crossing in moduli space. This, in turn, hints at a correspondence between 3d monopoles and vortices via 2d duality.

hep-th↗

arXiv2024

A story of non-conformal branes: spindles, disks, circles and black holes

We consider the $(p+2)$-dimensional gauged supergravities arising as a consistent truncation of type II on $S^{8-p}$, which are associated with the near-horizon limit of D$p$-branes, for $p=2,4,5,6$ (and NS5-branes for $p=5$). In a truncation of these theories with only abelian gauge fields and scalars, we find several classes of new solutions, with and without supersymmetry. Our ansatz for such backgrounds is inspired by the recent progress in the study of branes wrapped on orbifolds, but unlike those examples we consider "non-conformal branes", $i.e.$ no Anti de Sitter factors in the metric. Focusing on cases with non-trivial gauge fields, we can divide the solutions that we present in three categories: 1) branes wrapping Riemann surfaces, spindles and disks, 2) branes wrapped on a circle with a holonomy for the gauge field along the circle and 3) electrically charged black holes in gauged supergravity, which uplift to rotating branes in ten dimensions. We carefully analyze the conditions for supersymmetry in all these cases.

hep-th↗