Dynamical Cobordism Conjecture: solutions for end-of-the-world branes

The three tachyon-free non-supersymmetric string theories in ten dimensions provide a handle on quantum gravity away from the supersymmetric lamppost. However, they have not been shown to be fully consistent; although local anomalies cancel due to versions of the Green-Schwarz mechanism, there could be global anomalies, not cancelled by the Green-Schwarz mechanism, that could become fatal pathologies. We compute the twisted string bordism groups that control these anomalies via the Adams spectral sequence, showing that they vanish completely in two out of three cases (Sugimoto and SO(16)2) and showing a partial vanishing also in the third (Sagnotti 0’B model). We also compute lower-dimensional bordism groups of the non-supersymmetric string theories, which are of interest to the classification of branes in these theories via the Cobordism Conjecture. We propose a worldvolume content based on anomaly inflow for the SO(16)2 NS5-brane, and discuss subtleties related to the torsion part of the Bianchi identity. As a byproduct of our techniques and analysis, we also reprove that the outer ℤ2 automorphism swapping the two E8 factors in the supersymmetric heterotic string is also non-anomalous.

Section: Discussionmentioning

confidence: 80%

Global anomalies & bordism of non-supersymmetric strings

Basile,

Debray,

Delgado

et al. 2024

“…Indeed, in the simplest case of only untwisted NS-NS tadpoles plus suitable fluxes, static and time-dependent classical solutions have been derived and their properties, stability and cosmological implications have been thoroughly studied [57][58][59][60][61][62][63][64][65][66][67][68]. Moreover, in [69,70] it was argued that these solutions might play a role in the cobordism conjecture of the Swampland program [71,72]. Following [73], it would be interesting to study the consistency of D1 branes in this four-dimensional background.…”

Section: Jhep04(2024)103mentioning

confidence: 99%

Rigid vacua with Brane Supersymmetry Breaking

Angelantonj,

Condeescu,

Dudas

et al. 2024

We construct new string vacua featuring Brane Supersymmetry Breaking, based on T4/ℤN orientifolds with O5+ planes and $$ \overline{\textrm{D}5} $$ D 5 ¯ branes. Differently from the original construction, in these vacua the cancellation of twisted R-R charges of D-branes and orientifold planes is achieved in a non-trivial way, and results in rigid configurations with few open-string moduli, which highly restrict the possible deformations of the model. The breaking of supersymmetry and, consequently, the non-vanishing untwisted and twisted NS-NS tadpoles, generates a rich potential both for the dilaton and the blown-up moduli.We also uncover the stringy origin of the J form entering the gauge kinetic functions in the low-energy effective action, and display its relation to the NS-NS tadpoles for the scalars in the tensor multiplets. As a result, the J form can be consistently identified also when supersymmetry is broken, thus solving an embarrassing puzzle related to its very existence. We also discuss the unitarity constraints for one-dimensional defects in these vacua, where the Kač-Moody algebra for D9 and $$ \overline{\textrm{D}5} $$ D 5 ¯ can be realised both in the left-moving and right-moving sectors.

“…It implies, in particular, that the asymptotic kinetic terms of the moduli emerge upon integrating out the towers of states becoming light (i.e. those towers with a characteristic mass scale below the species scale [2,134]). This reverses the logic of the Distance Conjecture, as the infinite field distance itself emerges because of the existence of a tower of states becoming massless to start with (see [16,18,133] for the original works and [46,85,[135][136][137][138][139][140] for multiple follow-ups).…”

Section: The Emergence Proposalmentioning

confidence: 99%

Stringy evidence for a universal pattern at infinite distance

Castellano,

Ruiz,

Valenzuela

2024

Infinite distance limits in the moduli space of a quantum gravity theory are characterized by having infinite towers of states becoming light, as dictated by the Distance Conjecture in the Swampland program. These towers imply a drastic breakdown in the perturbative regimes of the effective field theory at a quantum gravity cut-off scale known as the species scale. In this work, we find a universal pattern satisfied in all known infinite distance limits of string theory compactifications, which relates the variation in field space of the mass of the tower and the species scale: $$ \frac{\overrightarrow{\nabla}m}{m}\cdotp \frac{\overrightarrow{\nabla}{\Lambda}_{\textrm{sp}}}{\Lambda_{\textrm{sp}}}=\frac{1}{d-2} $$ ∇ → m m · ∇ → Λ sp Λ sp = 1 d − 2 in d spacetime dimensions. This implies a more precise definition of the Distance conjecture and sharp bounds for the exponential decay rates. We provide plethora of evidence in string theory in diverse dimensions and with different levels of supersymmetry, and identify some sufficient conditions that allow the pattern to hold from a bottom-up perspective.