CyberSec Research

Correlators of affine Kac-Moody currents evaluate to a sum over multi-color-trace contributions. We present a `single-trace current system' defined on a genus 0 Riemann surface, whose correlators evaluate to precisely the single-trace term in the evaluation of a standard affine Kac-Moody at level 1. We demonstrate that using the single-trace current system in genus 0 Berkovits-Witten twistor string correlators gives pure $\mathcal{N} = 4$ super Yang-Mills tree amplitudes, and explain how this works both at the level of the string theory correlator and from the perspective of the effective field theory. We explain how using the single-trace current system in genus 0 correlators of the ambitwistor string gives pure Yang-Mills tree amplitudes, and briefly discuss a proposal to go to higher loops.

We construct generalized symmetries in two-dimensional symmetric product orbifold CFTs $\text{Sym}^N(\mathcal{T}),$ for a generic seed CFT $\mathcal{T}$. These symmetries are more general than the universal and maximally symmetric ones previously constructed. We show that, up to one fine-tuned example when the number of copies $N$ equals four, the only symmetries that can be preserved under twisted sector marginal deformations are invertible and maximally symmetric. The results are obtained in two ways. First, using the mathematical machinery of $G$-equivariantization of fusion categories, and second, via the projector construction of topological defect lines. As an application, we classify all preserved symmetries in symmetric product orbifold CFTs with the seed CFT given by any $A$-series $\mathcal{N}=(2,2)$ minimal model. We comment on the implications of our results for holography.

This is the manual of the first version of QEDtool, an object-oriented Python package that performs numerical quantum electrodynamics calculations, with focus on full state reconstruction in the internal degrees of freedom, correlations and entanglement quantification. Our package rests on the evaluation of polarized Feynman amplitudes in the momentum-helicity basis within a relativistic framework. Users can specify both pure and mixed initial scattering states in polarization space. From the specified initial state and polarized Feynman amplitudes, QEDtool reconstructs correlations that fully characterize the quantum polarization and entanglement within the final state. These quantities can be expressed in any inertial frame by arbitrary, built-in Lorentz transformations.

We study asymptotics of the $d=4$, $\mathcal{N}=1$ superconformal index for toric quiver gauge theories. Using graph-theoretic and algebraic factorization techniques, we obtain a cycle expansion for the large-$N$ index in terms of the $R$-charge-weighted adjacency matrix. Applying saddle-point techniques at the on-shell $R$-charges, we determine the asymptotic degeneracy in the univariate specialization for $\hat{A}_{m}$, and along the main diagonal for the bivariate index for $\mathcal{N}=4$ and $\hat{A}_{3}$. In these cases we find $\ln |c_{n}| \sim \gamma n^{\frac{1}{2}}+ \beta \ln n + \alpha$ (Hardy-Ramanujan type). We also identify polynomial growth for $dP3$, $Y^{3,3}$ and $Y^{p,0}$, and give numerical evidence for $\gamma$ in further $Y^{p,p}$ examples. Finally, we generalize Murthy's giant graviton expansion via the Hubbard-Stratonovich transformation and Borodin-Okounkov formula to multi-matrix models relevant for quivers.

We develop a framework based on modern amplitude techniques to analyze emission and absorption effects in black hole physics, including Hawking radiation. We first discuss quantum field theory on a Schwarzschild background in the Boulware and Unruh vacua, and introduce the corresponding $S$-matrices. We use this information to determine on-shell absorptive amplitudes describing processes where a black hole transitions to a different mass state by absorbing or emitting quanta, to all orders in gravitational coupling. This on-shell approach allows for a universal description of black holes, with their intrinsic differences encapsulated in the discontinuities of the amplitudes, without suffering from off-shell ambiguities such as gauge freedom. Furthermore, the absorptive amplitudes serve as building blocks to describe physics beyond that of isolated black holes. As applications, we find that the Hawking thermal spectrum is well understood by three-point processes. We also consider a binary system and compute the mass shift of a black hole induced by the motion of a companion object, including quantum effects. We show that the mean value of the mass shift is classical and vacuum-independent, while its variance differs depending on the vacuum choice. Our results provide confirmation of the validity of the on-shell program in advancing our understanding of black hole physics.

We apply the method of regions to the evaluation of dual conformal integrals with small off-shellness. In contrast to conventional approach, where the separation of regions is performed via dimensional regularization which breaks the dual conformal invariance (DCI) of separate contributions, we use the regularization which is sufficiently generic combination of dimensional and analytic regularizations which preserves the DCI. Within this regularization, the contribution of each region becomes DCI. We show that our method dramatically simplifies the calculations. As a demonstration, we calculate a slightly off-shell DCI pentabox integral up to power corrections. The contributions of all 32 regions appear to be expressible in terms of $\Gamma$-functions thus giving, after removing the regularization, the final expression in terms of cross-ratios logarithms only. We have checked that our result for pentabox integral numerically agrees with the result of the recent Belitsky&Smirnov paper [arXiv:2508.14298] which has essentially more complicated form.

We investigate axion-like particles coupled to gravity through a parity-violating Chern-Simons (CS) interaction. In this framework, axion dark matter (DM) can decay into pairs of circularly polarized gravitons, producing a persistent, nearly monochromatic GW signal. We compute the expected signal at Earth assuming a Navarro-Frenk-White Galactic halo model with the corresponding velocity distribution, and compare it with the narrowband sensitivities of the LIGO O4 run and the projected reach of the Einstein Telescope. The resulting bounds on the axion-graviton coupling $\alpha$ improve upon the cosmological stability requirement for axion masses $m_\phi \lesssim 10^{-11}$ eV, excluding values up to four orders of magnitude below the stability limit. This constitutes a robust direct terrestrial constraint on the axion-gravity CS coupling. We also discuss distinctive observational signatures, such as circular polarization asymmetries, annual modulation, and potential enhancements from DM substructures, which could serve as smoking-gun evidence for parity-violating gravitational interactions.

This work aims to explore the gravitational consequences of a recently proposed black hole solution presented in the literature [Phys. Dark Univ. 50 (2025) 102061]. We initiate our analyzes by taking into account the horizon structure, focusing on both the event and Cauchy horizons. Subsequently, we examine the quasinormal modes by considering all types of perturbations -- scalar, vector, tensor, and spinorial. To strengthen these results, we also compute the time-domain for each perturbation. Next, we turn to the study of optical properties of the black hole. In particular, we investigate null geodesics, the photon sphere and its stability, as well as the corresponding black hole shadows. Following this, we analyze gravitational lensing phenomena in two regimes: the weak-field limit, utilizing the Gauss-Bonnet theorem, and the strong deflection limit, employing Tsukamoto's approach. In addition, we confront the lensing observables with Event Horizon Telescope (EHT) data for $Sgr A^{*}$ and $M87^{*}$. Finally, constraints on the parameter $\xi$ -- which is introduced by higher-order curvature-scalar gravity, thereby differing from the Schwarzschild solution -- are estimated using Solar System measurements such as the precession of Mercury's orbit, gravitational light bending, and time delay (or Shapiro effect).

We study a class of infinite-distance loci, referred to as K-points, in one-parameter complex-structure moduli spaces of type IIB string theory compactified on Calabi-Yau manifolds. We show that around K-points the effective four-dimensional supergravity exhibits certain unusual properties. The two most prominent being that the leading order dependence of the prepotential on the gauge couplings is non-perturbative and that the leading gauge kinetic terms in the action vanish when evaluated on an anti self-dual graviphoton background. These properties are shared with the conifold locus in moduli space, rather than the large complex-structure locus. The conifold locus is well-known to arise from integrating out a charged BPS state, and so the similarities suggest that the K-point also arises from integrating out a BPS state. We develop such an interpretation, finding that it corresponds to a BPS state which is extremely light, whose mass in Planck units is doubly-exponentially small in the distance to the K-point. The state behaves as if it had complex charges, or as if it couples to the self-dual and anti self-dual parts of the graviphoton differently. Assuming such an integrating-out scenario is indeed the correct physics for the K-point, we discuss the implications for our understanding of infinite distances in moduli space and for the Swampland Distance Conjecture.

This work considers how exponential corrections to the Bekenstein-Hawking entropy formula affect the thermodynamic behavior of the FLRW cosmological model. These corrections drastically change the form of the Friedman field equations inducing non-trivial phase transition behavior. For negative values of the trace parameter $\alpha$, the system presents first-order phase transitions above the critical temperature, and for positive $\alpha$, the system undergoes a reentrant phase transition. As these corrections are presumably relevant at the early Universe stage, to corroborate the presence of some potential vestige of this contribution in the current era, a study has been carried out comparing observational data and current values of the Hubble parameter.

In this work, we investigate new solutions to the decoration transformation in terms of various special functions, including the hyperbolic gamma function, the basic hypergeometric function, and the Euler gamma function. These solutions to the symmetry transformation are important to decorate Ising-like integrable lattice spin models obtained via the gauge/YBE correspondence. The integral identities represented as the solution of the decoration transformation are derived from the three-dimensional partition functions and superconformal index for the dual supersymmetric gauge theories.

Following Feynman's lectures on gravitation, we consider the theory of the gravitational (massless spin-2) field in flat spacetime and present the third- and fourth-order Lagrangian densities for the gravitational field. In particular, we present detailed calculations for the third-order Lagrangian density.

The strong gravitational pull of the neutron star leads to the accretion of dark matter (DM) inside the core of the neutron star. The accretion of DM affects the bulk properties of the neutron star. Here, we study how the accretion of WIMP (Weakly Interacting Massive Particles) dark matter particles affects the $\Delta-$admixed hyperon star's bulk properties specifically mass, radius, tidal deformability, $f-$mode frequency and moment of inertia. The inclusion of dark matter softens the EOS (equation of state) and reduces the maximum possible mass, canonical radius, canonical tidal deformability, and moment of inertia of canonical star. However, the $f-$mode frequency of the canonical star increases. We find a cubical correlation between the dark matter fermi momenta $k_f^{DM}$ and bulk properties of canonical star.

The periodic Temperley-Lieb category consists of connectivity diagrams drawn on a ring with $N$ and $N'$ nodes on the outer and inner boundary, respectively. We consider families of modules, namely sequences of modules $\mathsf{M}(N)$ over the enlarged periodic Temperley-Lieb algebra for varying values of $N$, endowed with an action $\mathsf{M}(N') \to \mathsf{M}(N)$ of the diagrams. Examples of modules that can be organised into families are those arising in the RSOS model and in the XXZ spin-$\frac12$ chain, as well as several others constructed from link states. We construct a fusion product which outputs a family of modules from any pair of families. Its definition is inspired from connectivity diagrams drawn on a disc with two holes. It is thus defined in a way to describe intermediate states in lattice correlation functions. We prove that this fusion product is a bifunctor, and that it is distributive, commutative, and associative.

Inspired by the BESIII newest observation of an axial-vector particle $X(2300)$ in the $\psi(3686)\rightarrow \phi\eta \eta'$ process (Phys. Rev. Lett. {\bf134}, 191901 (2025)), we simulate its production in $e^+e^-$ collisions at $\sqrt{s}=4.95$ GeV using the parton and hadron cascade model PACIAE 4.0. In this model, the final partonic state (FPS) and the final hadronic state (FHS) are simulated and recorded sequentially. Besides the excited strangeonium and tetraquark interpretations, we propose for the first time that the $X(2300)$ could also be a hadro-strangeonium state, in which a strangeonium and a light hadron are bound together. The excited strangeonium and tetraquark states are, respectively, produced by coalescing with $s\bar{s}$ and $ss\bar{s}\bar{s}$ in the FPS with the quantum statistical mechanics inspired dynamically constrained phase-space coalescence (DCPC) model. The hadro-strangeonium state is generated by the recombination of $\phi\eta/\phi \eta'$ in the FHS with DCPC. We then calculate the $X(2300)$'s orbital angular momentum quantum number in its rest frame and perform the spectral classification for each of the above candidates. Given its quantum numbers $J^{PC} = 1^{+-}$, the $X(2300)$ is identified as a $P$-wave $s\bar{s}$, an $S$-wave $ss\bar{s}\bar{s}$ or an $S$-wave $\phi\eta/\phi \eta'$ candidate. The production rates for the $X(2300)$ candidates with different configurations are estimated for the first time. Those for the excited strangeonium and tetraquark states are on the order of $10^{-4}$, while the hadro-strangeonium state is produced at a rate on the order of $10^{-6}$. Moreover, significant discrepancies are observed in the rapidity distributions and the transverse momentum spectra among the different configurations. These discrepancies could be served as valuable criteria for deciphering the nature of the $X(2300)$.

A magnetic quiver framework is proposed for studying maximal branches of 3d orthosymplectic Chern-Simons matter theories with $\mathcal{N} \geq 3$ supersymmetry, arising from Type IIB brane setups with O3 planes. These branches are extracted via brane moves, yielding orthosymplectic $\mathcal{N}=4$ magnetic quivers whose Coulomb branches match the moduli spaces of interest. Global gauge group data, inaccessible from brane configurations alone, are determined through supersymmetric indices, Hilbert series, and fugacity maps. The analysis is exploratory in nature and highlights several subtle features. In particular, magnetic quivers are proposed as predictions for the maximal branches in a range of examples. Along the way, dualities and structural puzzles are uncovered, reminiscent of challenges in 3d mirror symmetry with orientifolds.

Exact single-time and two-time correlations and the two-time response function are found for the order-parameter in the voter model with nearest-neighbour interactions. Their explicit dynamical scaling functions are shown to be continuous functions of the space dimension $d>0$. Their form reproduces the predictions of non-equilibrium representations of the Schr\"odinger algebra for models with dynamical exponent $\mathpzc{z}=2$ and with the dominant noise-source coming from the heat bath. Hence the ageing in the voter model is a paradigm for relaxations in non-equilibrium critical dynamics, without detailed balance, and with the upper critical dimension $d^*=2$.

Bumblebee models, a class of vector-tensor theories in which a vector field acquires a nonzero vacuum expectation value that spontaneously breaks spacetime symmetries, are ubiquitous in the literature. In this paper, we highlight several often-overlooked properties of these models by analyzing their cosmological perturbations. We show that a non-minimal coupling to gravity is essential for the stability of the setup. However, avoiding propagation of a ghost mode then requires imposing a relation between the coupling coefficients, known as the degeneracy condition, which reduces the bumblebee model to a subset of generalized Proca theories with a marginal non-minimal operator. By imposing the degeneracy condition, the vector field becomes non-dynamical at the background level, and the form of its potential is completely fixed in vacuum. We show that the vacuum expectation value of the vector field can drive a de Sitter solution, for which the effects of the non-minimal coupling are negligible at the background level but provide essential order-one corrections to the sound speed of the scalar mode, keeping the setup weakly coupled at the level of perturbations. Treating this stealth de Sitter solution as a dark energy candidate, we study its coupling to matter and find the effective gravitational coupling for the matter density contrast in the quasi-static regime. At the level of perturbations, the system behaves differently from $\Lambda$CDM, providing a potential observational signature to distinguish the two models.