arXiv subjects

Michelangelo Tartaglia

Publications and source records attributed to Michelangelo Tartaglia.

4 recordsLinked to original sources

arXiv2026

Non-abelian asymmetric orbifolds with vanishing one-loop vacuum energy

We present a partial classification of four-dimensional, non-supersymmetric Type II toroidal orbifolds with non-abelian point groups of rotations, and vanishing vacuum energy at one loop in string perturbation theory. The classification is complete within a class of such orbifolds with the restriction that the point group only acts on a $T^5$ inside the full internal $T^6$. By studying their decompactification limits along the leftover $S^1$, we see that the 17 solutions we find can alternatively be obtained as Scherk--Schwarz compactifications of some parent asymmetric orbifold. Along the way, to ensure the absence of anomalies, we compute bordism groups $Ω_3^{Spin(BG)}$ for a variety of non-abelian crystallographic groups $G$.

hep-th↗

arXiv2026

Asymmetric orbifolds with vanishing one-loop vacuum energy

We present a systematic study of non-supersymmetric type II toroidal asymmetric orbifolds with vanishing vacuum energy at one-loop in string perturbation theory. These are engineered through the conservation of a supercharge-like operator in each individual sector in the orbifold sum, despite the overall explicit breaking of spacetime SUSY. We provide a full classification of such orbifolds with finite Abelian point-group, which can only admit $\mathbb{Z}_k \times \mathbb{Z}_k$ point group with $k=2,3,4$. We present detailed constructions, alongside other examples with non-Abelian point group. For some of these models, it is possible that this cancellation persists at higher loops.

hep-th↗

arXiv2025

(Quadratically) Refined Discrete Anomaly Cancellation

In this work we study the cancellation of non-perturbative anomalies of gravitational theories with gauge group $\mathbb{Z}_k$ in six dimensions. These subtle anomalies require a classification of deformation classes of manifolds with discrete gauge bundles known as bordism groups. The consistency of the theory demands a cancellation of the fermion anomalies, which can be done by the transformation properties of 2-form fields in the theory. Since the 2-forms in six dimensions are themselves chiral, their formulation needs subtle topological information encoded in a so-called quadratic refinement. A matching between the fermionic anomalies and the defining properties of the quadratic refinement, lead to strong consistency constraints on the charged fermion spectrum. We explicitly determine these consistency conditions for the case of a single chiral 2-form and various discrete gauge groups. Since we provide a model-independent formulation, these restrictions hold universally for theories of this type.

hep-th↗

arXiv2024

Exotic supergravities and the Swampland

In six dimensions, there is an exotic $\mathcal{N}=(4,0)$ supermultiplet that contains only fields of spin $\leq 2$, but no graviton, and that on a circle reduces to 5D $\mathcal{N}=4$ supergravity. It has been proposed that, if suitable interactions exist, the $(4,0)$ theory might provide a consistent alternative UV completion for $\mathcal{N}=4$ 5D supergravity, realizing a supersymmetric version of asymptotic safety. In this note we argue that any Lorentz-invariant $(4,0)$ theory (interacting or not) carries an exact global symmetry when compactified on $S^1$, and is therefore incompatible with the Swampland no global symmetries conjecture. Another example of exotic supergravity, the 6D $(3,1)$ theory, does not have this problem. We study the general case and find that the only exotic spin-2 field that reduces to Einsteinian gravity and has no global symmetries when compactified on a high-dimensional torus is that of the $(3,1)$ theory. All other possibilities either yield several gravitons or have global symmetries.

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