Recent years have seen an increasing body of work examining how quantum entanglement can be measured at high energy particle physics experiments, thereby complementing traditional table-top experiments. This raises the question of whether more concepts from quantum computation can be examined at colliders, and we here consider the property of magic, which distinguishes those quantum states which lead to a genuine computational advantage over classical states when used in algorithms. We examine top-antitop pair production at the LHC, showing that nature chooses to produce magic tops, where the amount of magic varies with the kinematics of the final state. We compare results for individual partonic channels and at proton level, showing that averaging over final states typically increases magic. This is in contrast to entanglement measures, such as the concurrence, which typically decrease. Also, while some entanglement measures (e.g., the concurrence) have a nonzero threshold for entanglement, there is no such nonzero threshold for magic. Our results create new links between the quantum information and particle physics literatures, providing practical insights for further study.

This paper presents a new set of multijet event shape variables introduced to further understand the Mueller-Navelet jet topology. This topology consists of having at least one pair of jets with a very large rapidity separation between them, treating additional jet activity inclusively. This multijet topology is expected to shed light on the radiation pattern that is expected in the high-energy limit of the strong interaction. The paper relies on a Monte Carlo event generator analysis. One set of predictions uses the bfklex event generator, which is based on Balitsky-Fadin-Kuraev-Lipatov (BFKL) perturbative quantum chromodynamics (pQCD) evolution with a resummation of large logarithms of energy at leading-logarithmic accuracy. The bfklex predictions are compared with a fixed-order next-to-leading order pQCD calculation using powheg matched to the parton shower of pythia8 ($\mathrm{NLO}+\mathrm{PS}$), which is the standard for NLO generator predictions at the LHC. We find that both approaches lead to compatible results at current LHC energies, assuming the current experimental constraints for the reconstruction of low transverse momentum jets in ATLAS and CMS. This shows the reliability of the BFKL approach at describing the behavior of the strong interaction in the preasymptotic limit of high center-of-mass energies. Differences between the $\mathrm{NLO}+\mathrm{PS}$ and the BFKL-based approaches are found when the jet multiplicity is increased or when the minimum transverse momentum of the jets is decreased.

An intriguing class of 6D supersymmetric theories are known as little strings theories, which exhibit a rich network of T-dualities. A robust feature of these theories are their Higgs branches. Focusing on the little string theories that are realized on a single curve of zero self-intersection, we utilize brane systems to derive the magnetic quivers. Using a variety of techniques (including branching rules, brane dynamics, F-theory geometry, quiver subtraction, and the decay and fission algorithm), we detail the Higgs branch Hasse diagram and determine the transverse slices for every elementary Higgs branch RG-flow. Building on these insights, we pursue two directions: first, we infer potential T-dual models by linking changes in 2-group structure constants along Higgs branch RG-flows to the RG-flow transition types encoded in the Hasse diagram. Second, we conjecture an algorithm for the non-Abelian flavor symmetry of the compactified little string theory by inspecting the magnetic quivers of all T-dual frames.

The global Schwinger formula, introduced by Cachazo and Early as a single integral over the positive tropical Grassmannian, provides a way to uncover properties of scattering amplitudes which are hard to see in their standard Feynman diagram formulation. In a recent work, Cachazo and one of the authors extended the global Schwinger formula to general ${\varphi }^p$ theories. When $p=4$, it was conjectured that the integral decomposes as a sum over cones which are in bijection with noncrossing chord diagrams, and further that these can be obtained by finding the zeroes of a piecewise linear function, $H(x)$. In this note we give a proof of this conjecture. We also present a purely combinatorial way of computing ${\varphi }^p$ amplitudes by triangulating a trivial extended version of noncrossing ($p-2$)-chord diagrams, called extended diagrams, and present a proof of the bijection between triangulated extended diagrams and Feynman diagrams when $p=4$. This is reminiscent of recent constructions using Stokes polytopes and accordiohedra. However, the ${\varphi }^p$ amplitude is now partitioned by a new collection of objects, each of which characterizes a polyhedral cone in the positive tropical Grassmannian in the form of an associahedron or of an intersection of two associahedra. Moreover, we comment on the bijection between extended diagrams and double-ordered biadjoint scalar amplitudes. We also conjecture the form of the general piecewise linear function, $H^{{\varphi }^p}(x)$, whose zeroes generate the regions in which the ${\varphi }^p$ global Schwinger formula decomposes into.

Dynamo processes are ubiquitous in astrophysical systems. In relativistic astrophysical systems, such as accretion disks around black holes or neutron stars, they may critically affect the launching of winds and jets that can power electromagnetic emission. Dynamo processes are governed by several microscopic parameters, one of them being magnetic helicity. As a conserved quantity in nonresistive plasmas, magnetic helicity is transported across the system. One important implication of helicity conservation is, that in the absence of helicity fluxes some mean-field dynamos can be quenched, potentially affecting the large-scale evolution of the magnetic field. One of the major challenges in computing magnetic helicity is the need to fix a meaningful electromagnetic gauge. We here present a fully covariant formulation of magnetic helicity transport in general-relativistic plasmas based on the concept of relative helicity by Berger and Field and Finn and Antonsen. This formulation is separately invariant under gauge-transformation of the Maxwell and Einstein equations. As an application of this new formalism we present the first analysis of magnetic helicity transport in the merger of two neutron stars. We demonstrate the presence of global helicity fluxes into the outer layers of the stellar merger remnant, which may impact subsequent large-scale dynamo amplification in these regions.

Spontaneous scalarization of black holes typically occurs through the condensation of a scalar field, with the field evolving from a $U(1)$-symmetric phase into a symmetry-breaking one with lower energy. We show that there exist symmetry-breaking phases which are themselves unstable to the formation of an additional scalar condensate, or “cloud,” which is partly accreted into the black hole. By studying the fully nonlinear dynamical evolution of the process, we find that symmetry breaking causes the accretion channels of scalar clouds to be nondegenerate, favoring a dominant channel for evolution. Additionally, the final states form a characteristic energy band due to varying amounts of radiation emitted by clouds in different channels.

New models of electrically charged objects as solutions of the Einstein-Maxwell field equations are obtained and studied in the present work. Static and rotating models are built. In both cases, the full spacetime geometries are obtained by matching two spacetime regions, an interior region containing electrified matter and an exterior electrovacuum region. In the static case, the interior region contains a spherically symmetric distribution of matter constituted by a de Sitter-type perfect fluid with electric charge, whose energy density profile is given by a Tolman-like relation. The interior solution is smoothly matched with the exterior Reissner-Nordström electrovacuum solution, thus producing different kinds of objects, such as charged regular black holes and overcharged tension stars, that we analyze in some detail. We also investigate the connection between the present static solution and the regular black holes with a de Sitter core presented in the work by Lemos and Zanchin [Regular black holes: Electrically charged solutions, Reissner-Nordström outside a de Sitter core, Phys. Rev. D 83, 124005 (2011)]. We then employ the Gürses-Gürsey metric and apply the Newman-Janis algorithm to construct a charged rotating interior geometry from the static interior solution. The resulting interior metric and the electromagnetic field are smoothly matched to the exterior Kerr-Newman electrovacuum solution, thus producing a regular interior for the exterior Kerr-Newman geometry. The transition from the interior region to the exterior region of the spacetime is smooth in the sense that no boundary shell is present. The main properties of the complete rotating solutions are analyzed in detail, showing that different kinds of rotating objects, such as charged rotating black holes and other charged rotating objects, also emerge in the rotating case.

An observer with a finite lifetime $\mathcal{T}$ perceives the Minkowski vacuum as a thermal state at temperature $T_D=2\hslash /(\pi \mathcal{T})$, as a result of being constrained to a double-coned-shaped region known as a causal diamond. In this paper, we explore the emergence of thermality in causal diamonds due to the role played by the symmetries of conformal quantum mechanics (CQM) as a ($0+1$)-dimensional conformal field theory, within the de Alfaro-Fubini-Furlan model and generalizations. In this context, the hyperbolic operator $S$ of the SO(2,1) symmetry of CQM: (i) is the generator of the time evolution of a diamond observer; (ii) its dynamical behavior leads to the predicted thermal nature; and (iii) its associated quantum instability has a Lyapunov exponent ${\lambda }_L=\pi T_D/\hslash$, which is half the upper saturation bound of the information scrambling rate. Our approach is based on a comprehensive framework of path-integral representations of the CQM generators in canonical and microcanonical forms, supplemented by semiclassical arguments. The properties of the operator $S$ are studied with emphasis on an operator duality with the corresponding elliptic operator $R$, using a representation in terms of an effective scale-invariant inverse square potential combined with inverted and ordinary harmonic oscillator potentials.

In this study, we investigate the black hole shadow of an exact black hole solution of the loop quantum gravity (LQG) theory. We discuss some of its optical characteristics after generalizing it to the rotational case, including null geodesics and black hole shadow. From these we can compare the impact of different theories on the most deeply understood properties of the black hole and get a new way to test the accuracy of the modified gravity theory.

We compare the quantum chromodynamics (QCD) axion phase-space distribution from unitarized next-to-leading order chiral perturbation theory with the one extracted from pion-scattering data. We derive a robust bound by confronting momentum-dependent Boltzmann equations against up-to-date observations of the cosmic microwave background, of the baryonic acoustic oscillations and of primordial abundances. These datasets imply $m_a\le 0.16\mathrm{eV}$ for the 95% credible interval, i.e., $\sim 30\%$ stronger bound than what previously found. We present forecasts using dedicated likelihoods for future cosmological surveys and the sphaleron rate from unquenched lattice QCD.

The exact Friedman solution to the field equations of general relativity (GR) describing a homogeneous and isotropic universe together with its linear and higher-order perturbations are the theoretical roots of the current standard model of cosmology. However, despite its global successes, this standard model currently faces a number of tensions and anomalies, which occur mostly from a mismatch between early and late cosmic time region depictions. Actually, in the era of precision cosmology, the late inhomogeneities in the densities of the Universe components can no more be neglected. Moreover, since GR is fundamentally nonlinear, any linear perturbation theory is doomed to fail at reproducing precisely its features, while higher-order perturbed Friedman-Lemaître-Robertson-Walker (FLRW) models cannot either claim the status of exact solution to Einstein’s field equations. Fortunately, other GR solutions exist which are best suited for this purpose, e.g., exact inhomogeneous solutions able to represent a matter-cosmological constant dominated universe region. Among these, the Szekeres solution, which is devoid of any symmetry, appears as a proper tool for this purpose. Moreover, since these solutions possess the FLRW model as a homogeneous limit, they can be smoothly matched to the standard representation at the inhomogeneity-homogeneity transition. In this paper, the Szekeres solution and its main interesting properties, as well as the equations needed to use this solution in a cosmological context are presented. Then the prospects for a broader use of its abilities are sketched out. In particular, the use of neural networks is proposed to allow, in the future, the fitting of the huge amount of data becoming available to constrain the arbitrary functions and the constant parameters characterizing the Szekeres model, running for representing our late Universe with an increased precision.

We use the integrated Sachs-Wolfe (ISW) effect, by now detectable at $\sim 5\sigma$ within the context of $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) cosmologies, to place strong constraints on dynamical dark energy theories. Working within an effective field theory (EFT) framework for dark energy we find that including ISW constraints from galaxy–cosmic microwave background (CMB) cross-correlations significantly strengthens existing large-scale structure constraints, yielding bounds consistent with $\mathrm{\Lambda }\mathrm{CDM}$ and approximately reducing the viable parameter space by $\sim 70\%$. This is a direct consequence of $\mathcal{O}(1)$ changes induced in these cross-correlations by otherwise viable dark energy models, which we discuss in detail. We compute constraints by adapting the $\mathrm{\Lambda }\mathrm{CDM}$ ISW likelihood from Stölzner et al. [Phys. Rev. D 97, 063506 (2018)] for dynamical dark energy models using galaxy data from 2 MASS, wide-field infrared survey explorer (WISE) $\times$ SuperCOSMOS, Sloan Digital Sky Survey Data Release 12, the catalog of photometric quasars and NRAO Very Large Array Sky Survey, CMB data from Planck 18, and baryon acoustic oscillation and redshift space distortion large-scale structure measurements from BOSS and 6dF. We show constraints both in terms of EFT-inspired ${\alpha }_i$ and phenomenological $\mu /\mathrm{\Sigma }$ parametrizations. Furthermore we discuss the approximations involved and related aspects of bias modeling in detail and highlight what these constraints imply for the underlying dark energy theories.

The Dark Energy Spectroscopic Instrument (DESI) collaboration has recently released measurements of baryon acoustic oscillation (BAO) from the first year of observations. A joint analysis of DESI BAO, cosmic microwave background (CMB), and Type Ia supernovae (SNe Ia) probes indicates a preference for time-evolving dark energy. We evaluate the robustness of this preference by replacing the DESI distance measurements at $z<0.8$ with the Sloan Digital Sky Survey (SDSS) BAO measurements in a similar redshift range. Assuming the $w_0{w}_a\mathrm{CDM}$ model, we find an evolution of the dark energy equation of state parameters consistent with $\mathrm{\Lambda }\mathrm{CDM}$. Our analysis of ${\chi }^2$ statistics across various BAO datasets shows that DESI’s preference for evolving dark energy is primarily driven by the two luminous red galaxy (LRG) samples at $z_{\mathrm{eff}}=0.51$ and $z_{\mathrm{eff}}=0.71$, with the latter having the most significant impact. Taking this preference seriously, we study a general Horndeski scalar-tensor theory, which provides a physical mechanism to safely cross the phantom divide, $w=-1$. Utilizing the effective field theory of dark energy and adopting the $w_0{w}_a\mathrm{CDM}$ background cosmological model, we derive constraints on the parameters $w_0=-0.856\pm 0.062$ and $w_a=-0.53_{-0.26}^{+0.28}$ at 68% CL from Planck CMB, Planck and Atacama Cosmology Telescope (ACT) CMB lensing, DESI BAO, and $\mathrm{Pantheon}+\text{datasets}$, showing good consistency with the standard $w_0{w}_a\mathrm{CDM}$ model. The modified gravity model gives results discrepant with $\mathrm{\Lambda }\mathrm{CDM}$ at the $2.4\sigma$ level, while for $w_0{w}_a\mathrm{CDM}$ it is at $2.5\sigma$, based on the best-fit ${\chi }^2$ values. We conclude that modified gravity offers a viable physical explanation for DESI’s preference for evolving dark energy.

Continuous gravitational wave searches with terrestrial, long-baseline interferometers are hampered by long-lived, narrow band features in the power spectral density of the detector noise, known as lines. Candidate gravitational wave signals which overlap spectrally with known lines are typically vetoed. Here we demonstrate a line subtraction method based on adaptive noise cancellation, using a recursive least squares algorithm, a common approach in electrical engineering applications such as audio and biomedical signal processing. We validate the line subtraction method by combining it with a hidden Markov model (HMM), a standard continuous wave search tool, to detect an injected continuous wave signal with an unknown and randomly wandering frequency, which overlaps with the mains power line at 60 Hz in the Laser Interferometer Gravitational Wave Observatory. The performance of the line subtraction method is tested on a injected continuous wave signal obscured by (i) synthetic noise data with both Gaussian and non-Gaussian components, and (ii) real noise data obtained from the Laser Interferometer Gravitational Wave Observatory Livingston detector. In both cases, before applying the line subtraction method the HMM does not detect the injected continuous wave signal. After applying the line subtraction method the mains power line is suppressed by 20–40 dB, and the HMM detects the underlying signal, with a time-averaged root-mean-square error in the frequency estimate of $\sim 0.05\mathrm{Hz}$. The performance of the line subtraction method with respect to the characteristics of the 60 Hz line and the control parameters of the recursive least squares algorithm is quantified in terms of receiver operating characteristic curves.

We compute the renormalization-group equations governing the evolution of dimension-8 four-fermion operators in the Standard Model effective field theory (SMEFT). We describe the calculation and present analytic results for both the full flavor structure of the SMEFT and with the assumption of minimal flavor violation. We present numerical results for the renormalization-group evolution of the coefficients, and study their impact on fits of the Large Hadron Collider (LHC) Drell-Yan data. The effects of running on the dimension-8 coefficients can reach 50% or more when evolving from 10 TeV scale down to few-GeV energies relevant for the analysis of fixed-target data. However, the impact of the dimension-8 running on the analysis of Drell-Yan data from the LHC is minimal.

We show that any nonlinear field theory giving rise to static solutions with finite energy like, e.g., topological solitons, allows us to derive an infinite number of integral identities which any such solution has to obey. These integral identities can always be understood as being generated by field transformations and their related Noether currents. We also explain why all integral identities generated by coordinate transformations become trivial for Bogomolnyi-Prasad-Sommerfield (BPS) solitons, i.e., topological solitons which saturate a topological energy bound. Finally, we consider applications of these identities to a broad class of nonlinear scalar theories, including the Skyrme model. More concretely, we find nontrivial integral identities that can be seen as model-independent relations between certain physical properties of the solitons in such theories, and we comment on the possible connection between these new relations and those already found in the context of astrophysical compact objects. We also demonstrate the usefulness of said identities to estimate the precision of the numerical calculation of soliton observables.

Here, we consider a classically scale-invariant extension of the Standard Model (SM) with two-component dark matter (DM) candidates, including a Dirac spinor and a scalar DM. We probe the parameter space of the model, constrained by relic density and direct detection, and investigate the generation of gravitational waves (GWs) produced by an electroweak first-order phase transition. The analysis demonstrates that there are points in the parameter space, leading to a detectable GW spectrum arising from the first-order phase transition, which is also consistent with the DM relic abundance and direct detection bounds. These GWs could be observed by forthcoming space-based interferometers such as the Big Bang Observer, Decihertz Interferometer Gravitational-wave Observatory, and Ultimate-Decihertz Interferometer Gravitational-wave Observatory.

We investigate the conversion of kinetic mixing dark photon dark matter into gravitational waves within the magnetic field of the Sun. Our study reveals that the WKB approximation is invalid in this scenario. We derive an analytic solution for the conversion probability with unitary evolution feature. This solution aligns in form with previous studies on photon-gravitational wave conversion. Interestingly, it is applicable in situations where the WKB approximation fails. We extend the unitary evolution solution to other conversion processes, such as axion-photon and dark photon-photon conversions. When the WKB approximation conditions are met, this solution reduces to the WKB result. We compute the characteristic strain of gravitational waves resulting from dark photon conversion in the solar magnetic field, spanning frequencies from ${10}^{-5}\mathrm{Hz}$ to ${10}^6\mathrm{Hz}$. Our findings indicate that the characteristic strain derived from the unitary evolution solution differs significantly from that of the WKB solution. The resulting strain signal is far below the sensitivity of current gravitational wave interferometers. Nevertheless, we have proposed an exotic gravitational wave source, which could be useful in nonminimal dark sector models.