We use the embedding formalism to construct conformal fields in $\textit{D}$ dimensions, by restricting Lorentz-invariant ensembles of homogeneous neural networks in ($\textit{D}$ + 2) dimensions to the projective null cone. Conformal correlators may be computed using the parameter space description of the neural network. Exact four-point correlators are computed in a number of examples, and we perform a 4D conformal block decomposition that elucidates the spectrum. In a non-unitary example the decomposition precisely matches OPE coefficients for the self-correlator, but not for the mixed correlator. In others, the analysis is facilitated by recent approaches to Feynman integrals. Generalized free CFTs are constructed using the infinite-width Gaussian process limit of the neural network, enabling a realization of the free boson. The extension to deep networks constructs conformal fields at each subsequent layer, with recursion relations relating their conformal dimensions and four-point functions. Numerical approaches are discussed.

United States

James Halverson

Joydeep Naskar

China

Jiahua Tian

Conformal fields from neural networks

<p>Dark matter particles with a mass around 1 eV can decay into near-infrared photons. Utilizing available public blank sky observations from the NIRSpec IFU on the James Webb Space Telescope (JWST), we search for a narrow emission line due to decaying dark matter and derive leading constraints in the mass range 0.8–3 eV on the decay rate to photons, and more specifically, on the axion-photon coupling for the case of axionlike particles. We exclude <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo>&lt;</mo><mn>3.5</mn><mo>×</mo><msup><mn>10</mn><mn>26</mn></msup><mtext> </mtext><mtext> </mtext><mi mathvariant="normal">s</mi></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>DM</mi></mrow></msub><mo>≃</mo><mn>0.8</mn><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></math> and, in the case of axions, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>a</mi><mi>γ</mi><mi>γ</mi></mrow></msub><mo>&gt;</mo><mn>1.3</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>m</mi></mrow><mrow><mi>a</mi></mrow></msub><mo>≃</mo><mn>2.2</mn><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></math>. Our results do not rely on dedicated observations, rather we use blank sky observations intended for sky subtraction, and thus our reach may be automatically strengthened as JWST continues to observe.</p>

Ryan Janish

Elena Pinetti

Hunting Dark Matter Lines in the Infrared Background with the James Webb Space Telescope

We study electric-magnetic duality in compactifications of M-theory on twisted connected sum (TCS) G 2 manifolds via duality with F-theory. Specifically, we study the physics of the D3-branes in F-theory compactified on a Calabi-Yau fourfold Y, dual to a compactification of M-theory on a TCS G 2 manifold X.   <math> <mi>N</mi> </math>  $$ \mathcal{N} $$  = 2 supersymmetry is restored in an appropriate geometric limit. In that limit, we demonstrate that the dual of D3-branes probing seven-branes corresponds to the shrinking of certain surfaces and curves, yielding light particles that may carry both electric and magnetic charges. We provide evidence that the Minahan-Nemeschansky theories with E  n  flavor symmetry may be realized in this way. The SL(2, ℤ) monodromy of the 3/7-brane system is dual to a Fourier-Mukai transform of the dual IIA/M-theory geometry in this limit, and we extrapolate this monodromy action to the global compactification. Away from the limit, the theory is broken to   <math> <mi>N</mi> </math>  $$ \mathcal{N} $$  = 1 supersymmetry by a D-term.

Benjamin Sung

Italy

Electric-magnetic duality in a class of G 2-compactifications of M-theory

In this paper we study the 6d localized charged matter spectrum of F-theory directly on a singular elliptic Calabi-Yau 3-fold, i.e. without smoothing via resolution or deformation of the entire fibration. Given only the base surface, discriminant locus, and the SL(2, ℤ) local system, we propose a general prescription for determining the charged matter spectrum localized at intersections of seven-branes, using the technology of string junctions. More precisely, at each codimension-2 collision of seven-branes, we determine the local seven-brane content and compute the number of massless string junctions modulo the action of the SL(2, ℤ) monodromy. We find agreement with the predicted results from 6d anomaly cancellation in all cases considered. Examples include a generic Weierstrass model with arbitrary Kodaira fiber intersecting an I 1, as well as cases with jointly charged matter localized at intersections of non-abelian seven-branes.

Antonella Grassi

Cody Long

Julius Shaneson

6D anomaly-free matter spectrum in F-theory on singular spaces

Gauge coupling unification misleads infrared observers if new gauge bosons do not simultaneously come into the spectrum. Though easy to engineer in gauge theory, the situation in string theory is nuanced due to moduli dependence. We study the possibility of faking gauge coupling unification in the context of 4D F-theory compactifications. Specifically, we formulate a sufficient condition that we call a strong calibration, under which seven-brane gauge couplings on homologically distinct divisors become equal at codimension one in Kähler moduli space. We prove that a strong calibration is preserved under appropriate topological transitions and that a pair of nonintersecting divisors each admitting a contraction can always be strongly calibrated. Within the tree ensemble [J. Halverson et al., Phys. Rev. D 96, 126006 (2017)], we find that <math><mrow><mo>≈</mo><mn>77.12</mn><mo>%</mo></mrow></math> of pairs of intersecting toric divisors can be strongly calibrated and <math><mo>≈</mo><mn>3.22</mn><mo>%</mo></math> can never be calibrated. Physically, this means that gauge coupling unification can be faked in most cases that we study, but in others it can not, which is surprising from a gauge theoretic perspective.

Faking gauge coupling unification in string theory

Dark Yang-Mills sectors, which are ubiquitous in the string landscape, may be reheated above their critical temperature and subsequently go through a confining first-order phase transition that produces stochastic gravitational waves in the early universe. Taking into account constraints from lattice and from Yang-Mills (center and Weyl) symmetries, we use a phenomenological model to construct an effective potential of the semi quark-gluon plasma phase, from which we compute the gravitational wave signal produced during confinement for numerous gauge groups. The signal is maximized when the dark sector dominates the energy density of the universe at the time of the phase transition. In that case, we find that it is within reach of the next-to-next generation of experiments (BBO, DECIGO) for a range of dark confinement scales near the weak scale.

Anindita Maiti

Brent Nelson

Gustavo Salinas

Gravitational waves from dark Yang-Mills sectors

We argue that the following three statements cannot all be true: (i) our vacuum is a type IIB/F-theory vacuum at moderate to large <math><msup><mi>h</mi><mrow><mn>1</mn><mo>,</mo><mn>1</mn></mrow></msup></math>; (ii) the <math><msup><mi>α</mi><mo>′</mo></msup></math> expansion is controlled via the supergravity approximation, à la the Kachru-Kallosh-Linde-Trivedi and Large Volume scenarios; and (iii) there are no additional gauged sectors from 7-branes. Since nearly all known globally consistent F-theory models with the exact chiral spectrum of the Standard Model and gauge coupling unification occur at moderate <math><msup><mi>h</mi><mrow><mn>1</mn><mo>,</mo><mn>1</mn></mrow></msup></math>, this finding calls for new moduli stabilization scenarios or/and a rich 7-brane dark sector.

Slovenia

Mirjam Cvetič

CERN

Ling Lin

Constraints on standard model constructions in F-theory

Diophantine equations are in general undecidable, yet appear readily in string theory. We demonstrate that numerous classes of Diophantine equations arising in string theory are decidable and propose that decidability may propagate through networks of string vacua due to additional structure in the theory. Diophantine equations arising in index computations relevant for D3-instanton corrections to the superpotential exhibit propagation of decidability, with new and existing solutions propagating through networks of geometries related by topological transitions. In the geometries we consider, most divisor classes appear in at least one solution, significantly improving prospects for Kähler moduli stabilization across large ensembles of string compactifications.

Michael Plesser

United Kingdom

Fabian Ruehle

Kähler moduli stabilization and the propagation of decidability

Axionlike particle (ALP)–photon couplings are modeled in large ensembles of string vacua and random matrix theories. In all cases, the effective coupling increases polynomially in the number of ALPs, of which hundreds or thousands are expected in the string ensembles, many of which are ultralight. The expected value of the couplings <math><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi><mi>γ</mi></mrow></msub><mo>≃</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>10</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> provide viable targets for future x-ray telescopes and axion helioscopes, and in some cases are already in tension with existing data.

Towards string theory expectations for photon couplings to axionlike particles

We propose deep reinforcement learning as a model-free method for exploring the landscape of string vacua. As a concrete application, we utilize an artificial intelligence agent known as an asynchronous advantage actor-critic to explore type IIA compactifications with intersecting D6-branes. As different string background configurations are explored by changing D6-brane configurations, the agent receives rewards and punishments related to string consistency conditions and proximity to Standard Model vacua. These are in turn utilized to update the agent’s policy and value neural networks to improve its behavior. By reinforcement learning, the agent’s performance in both tasks is significantly improved, and for some tasks it finds a factor of   <math> <mi>O</mi> <mfenced> <mn>200</mn> </mfenced> </math>  $$ \mathcal{O}(200) $$  more solutions than a random walker. In one case, we demonstrate that the agent learns a human-derived strategy for finding consistent string models. In another case, where no human-derived strategy exists, the agent learns a genuinely new strategy that achieves the same goal twice as efficiently per unit time. Our results demonstrate that the agent learns to solve various string theory consistency conditions simultaneously, which are phrased in terms of non-linear, coupled Diophantine equations.