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1. Real-time dynamics of the Schwinger model as an open quantum system with Neural Density Operators

   https://doi.org/10.1007/JHEP06(2024)211  

   Lin, Joshua; Luo, Di; Yao, Xiaojun; Shanahan, Phiala E (June 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> Ab-initio simulations of multiple heavy quarks propagating in a Quark-Gluon Plasma are computationally difficult to perform due to the large dimension of the space of density matrices. This work develops machine learning algorithms to overcome this difficulty by approximating exact quantum states with neural network parametrisations, specifically Neural Density Operators. As a proof of principle demonstration in a QCD-like theory, the approach is applied to solve the Lindblad master equation in the 1 + 1d lattice Schwinger Model as an open quantum system. Neural Density Operators enable the study of in-medium dynamics on large lattice volumes, where multiple-string interactions and their effects on string-breaking and recombination phenomena can be studied. Thermal properties of the system at equilibrium can also be probed with these methods by variationally constructing the steady state of the Lindblad master equation. Scaling of this approach with system size is studied, and numerical demonstrations on up to 32 spatial lattice sites and with up to 3 interacting strings are performed. 

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2. The EFT of large spin mesons

   https://doi.org/10.1007/JHEP04(2025)049  

   Cuomo, Gabriel; Dubovsky, Sergei; Hernández-Chifflet, Guzmán; Monin, Alexander; Zare, Shahrzad (April 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> We use effective string theory to study mesons with large spinJin largeN_cQCD as rotating open strings. In the first part of this work, we formulate a consistent effective field theory (EFT) for open spinning strings with light quarks. Our EFT provides a consistent treatment of the endpoints’ singularities that arise in the massless limit. We obtain results, in a systematic 1/Jexpansion, for the spectrum of the leading and daughter Regge trajectories. Interestingly, we find that the redshift factor associated with the quarks’ acceleration implies that the applicability regime of the EFT is narrower compared to that of static flux tubes. In the second part of this work, we discuss several extensions of phenomenological interests, including mesons with heavy quarks, the quarks’ spin and the daughter Regge trajectories associated with the worldsheet axion, a massive string mode identified in lattice simulations of 4dflux tubes. We compare our predictions with 4dQCD spectroscopy data, and suggest potentialstringyinterpretations of the observed mesons. We finally comment on the relation between the EFT spectrum and the Axionic String Ansatz, a recently proposed characterization of the spectrum of Yang-Mills glueballs. 

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3. JAXVacua — a framework for sampling string vacua

   https://doi.org/10.1007/JHEP12(2023)146  

   Dubey, A; Krippendorf, S; Schachner, A (December 2023, Journal of High Energy Physics)

   A<sc>bstract</sc> Moduli stabilisation in string compactifications with many light scalars remains a major blind-spot in the string landscape. In these regimes, analytic methods cease to work for generic choices of UV parameters which is why numerical techniques have to be exploited. In this paper, we implement algorithms based on JAX, heavily utilising automatic differentiation, just-in-time compilation and parallelisation features, to efficiently construct string vacua. This implementation provides a golden opportunity to efficiently analyse large unexplored regions of the string landscape. As a first example, we apply our techniques to the search of Type IIB flux vacua in Calabi-Yau orientifold compactifications. We argue that our methods only scale mildly with the Hodge numbers making exhaustive studies of low energy effective field theories with$$ \mathcal{O} $$ $O$(100) scalar fields feasible. Using small computing resources, we are able to construct$$ \mathcal{O} $$ $O$(10⁶) flux vacua per geometry withh^1,2≥ 2, vastly out-performing previous systematic searches. In particular, we showcase the efficiency of our methods by presenting generic vacua with fluxes below the tadpole constraint set by the orientifold with up toh^1,2= 25 complex structure moduli. 

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4. Automated and accurate segmentation of leaf venation networks via deep learning

   https://doi.org/10.1111/nph.16923  

   Xu, Hao; Blonder, Benjamin; Jodra, Miguel; Malhi, Yadvinder; Fricker, Mark (October 2020, New Phytologist)

   Summary Leaf vein network geometry can predict levels of resource transport, defence and mechanical support that operate at different spatial scales. However, it is challenging to quantify network architecture across scales due to the difficulties both in segmenting networks from images and in extracting multiscale statistics from subsequent network graph representations.Here we developed deep learning algorithms using convolutional neural networks (CNNs) to automatically segment leaf vein networks. Thirty‐eight CNNs were trained on subsets of manually defined ground‐truth regions from >700 leaves representing 50 southeast Asian plant families. Ensembles of six independently trained CNNs were used to segment networks from larger leaf regions (c. 100 mm²). Segmented networks were analysed using hierarchical loop decomposition to extract a range of statistics describing scale transitions in vein and areole geometry.The CNN approach gave a precision‐recall harmonic mean of 94.5% ± 6%, outperforming other current network extraction methods, and accurately described the widths, angles and connectivity of veins. Multiscale statistics then enabled the identification of previously undescribed variation in network architecture across species.We provide aLeafVeinCNNsoftware package to enable multiscale quantification of leaf vein networks, facilitating the comparison across species and the exploration of the functional significance of different leaf vein architectures. 

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5. Scattering from (p, q)-strings in AdS5 × S5

   https://doi.org/10.1007/JHEP03(2025)181  

   Pufu, Silviu S; Rodriguez, Victor A; Wang, Yifan (March 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> Motivated by understanding the scattering of gravitons and their superpartners from extended (p,q)-strings in type IIB string theory via AdS/CFT, we study an integrated two-point function of stress tensor multiplet operators in the presence of a half-BPS line defect in$$ \mathcal{N} $$ $N$= 4 SU(N) super-Yang-Mills theory. We determine this integrated correlator at the five lowest non-trivial orders in$$ 1/\sqrt{N} $$ $1/\sqrt{N}$at fixed Yang-Mills coupling andθangle. Our calculations are performed explicitly when the line defect is a Wilson line, in which case we find a finite number of perturbative contributions at each order in$$ 1/\sqrt{N} $$ $1/\sqrt{N}$, as well as instanton contributions. Using SL(2,ℤ) transformations, our results can also be applied to Wilson-’t Hooft line defects dual to extended (p,q)-strings in the bulk. We analyze features of these integrated correlators in the weak coupling expansion by comparing with open-closed amplitudes of type IIB string theory on AdS₅× S⁵, as well as in its flat space limit. We predict new higher-derivative interaction vertices on the D1-brane and, more generally, on (p,q)-strings. 

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