Papers

The search for life beyond the Solar System is at a turning point, transitioning from theoretical predictions to observations enabled by next-generation observatories. The Extremely Large Telescope (ELT) will host the ArmazoNes high Dispersion Echelle Spectrograph (ANDES), optimized for visible-to-near-infrared high-resolution spectroscopy. We present a simulation–detection pipeline and evaluate the detectability of CO$_2$, H$_2$O, and the biosignature gases O$_2$ and CH$_4$ in high-resolution transmission spectroscopy of transiting habitable-zone rocky planets with ANDES. Assuming cloud-free, modern Earth-like atmospheres, we model transmission spectra using noise estimates from the ANDES Exposure Time Calculator, based on the latest preliminary instrument design in seeing-limited mode. We introduce a novel Bayesian cross-correlation function (CCF) framework that incorporates molecule-specific kernels and a new autoregressive model to account for correlations in the CCF. We apply our framework to 18 known potentially habitable transiting exoplanets and estimate the number of transits required for a decisive detection ($\log_{10} B \ge 2.0$). We find that H$_2$O is the most accessible species, with potential detections in 10-19 transits for the TRAPPIST-1 planets and 30 transits for LHS 1140 b. CO$_2$, CH$_4$, and O$_2$ are more difficult to detect, requiring approximately 1.5, 3, and 4 times as many transits as H$_2$O. These estimates are lower limits that assume favorable observing conditions, perfect detrending, and the absence of systematics, yet still imply large observing campaigns. Alternative approaches, such as reflected-light high-dispersion coronagraphy of nearby nontransiting planets, may offer a promising complementary route for biosignature searches.

Observations with the JWST revealed an unexpected abundance of barred galaxies at Cosmic Noon. However, the physical properties of these early bars are almost unconstrained, as it is their impact in the structural evolution of high-z disc galaxies. In this work, we derived the stellar populations of EGS-24154, a barred spiral galaxy at $z=1.17$. First, we investigated the role of the stellar bar in the early assembly history and structural evolution of the galaxy. Second, we studied the properties of the interstellar medium to shed light on the interplay with the central supermassive black hole. We analysed medium-resolution NIRSpec/IFS data of EGS-24154 through full-spectral fitting and derived light and mass-weighted ages and metallicities. We then reconstructed the spatially-resolved SFH, derived the ionizing mechanisms of the interstellar medium analysing several emission lines, characterized the dynamics of EGS-24154, and constrained the properties of a biconical outflow launched by the AGN. EGS-24154 is a baryon-dominated, gas-rich disc galaxy, which grew more than 90% of its stellar mass when the Universe was ~2 Gyr old. We found that the stellar population of the bar started to form at $z\sim5$, compatibly to the time when the stellar disc started to assemble. We observed a star formation desert in the bar region, which is responsible for quenching star formation over several Gyr. We then interpreted that the feedback from the AGN prevented the growth of central mass concentration, allowing the stellar bar to grow in size and strength. In this first study of spatially-resolved stellar populations of a barred disc galaxy at $z>1$, we demonstrated how stellar bars are key drivers of the early structural and dynamical evolution of disc galaxies. In particular, our results call for a revision of most models of disc and bar formation in early baryon-dominated, gas-rich disc galaxies.

Final state radiation in collider processes can be interpreted as interactions with unobserved degrees of freedom and is often discussed within the context of decoherence of an entangled state. We consider the radiative decay of the $Z$ boson as a representative example and perform a detailed analytical study of the $\tau^-\tau^+\gamma$ spin state, as determined by the chiral interactions of the Standard Model, over the complete three-body phase space. We explore various quantum information observables to quantify how the $\tau^-\tau^+$ spin state changes with the photon radiation. We find some striking features, for example that the emitted photon could either lead to decoherence or monotonic enhancement of entanglement for the fermion pair.

We perform a systematic survey of the Hagedorn behaviour at infinite-distance points in the conformal manifold of four-dimensional large-$N$ $\mathcal{N}=2$ Superconformal Field Theories admitting a Lagrangian description. Many properties of these theories can be understood in terms of the Lie algebra encoding the shape of their quiver. We find that in the overall-free limit, the Hagedorn temperature is determined by the largest eigenvalue of an affine or finite Cartan adjacency matrix. This defines two types of universality classes of theories sharing the same high-energy exponential growth of states characteristic of string-like spectra. The first and largest is the affine case, corresponding to orbifold and orientifold projections of $\mathcal{N}=4$ super-Yang-Mills, and all share the same temperature. The others fall into universality classes following an ADE classification with a temperature set by the dual Coxeter number, and can be obtained by deforming the affine case. Our results apply to all large-$N$ $\mathcal{N}=2$ quivers with any classical gauge symmetry, including those with matter charged beyond bifundamental representations. We further discuss the string-theoretic construction of these theories and some of the holographic implications, as well as how our methods extend to broad families of theories with less supersymmetry. We also consider limits where only part of the theory becomes free, and find lower and upper bounds on the exponential rate predicted by the CFT Distance Conjecture. Both these bounds and the Hagedorn temperature are set by the same eigenvalue, and when the quiver has a single gauge node the lower bound is saturated, giving a natural explanation for the three universality classes recently found in the literature.

Massive astrophysical objects can source huge static configurations of a scalar field. When such an object ends up forming a black hole, for instance, via a core-collapse supernova, the scalar field loses its source abruptly; then the static configuration becomes dynamical and propagates away in a burst, a "scalar tsunami". These bursts accumulate over cosmological history, forming a relic stochastic diffuse scalar background peaked in the $1-10^3~\text{Hz}$ range. We propose this as a novel mechanism for the generation of such a background, compute its spectrum, and compare it with the sensitivity of future experiments. We show how this extends the experimental sensitivity to scalar masses $m_\phi\lesssim 10^{-13}~\text{eV}$, ten orders of magnitude larger than those accessible via individual transient events previously considered.

The signature prediction of extra-dimensional theories is the appearance of a tower of massive gravitons. In this work, we study the constraints on resonant heavy spin-2 particles at the Large Hadron Collider (LHC), with focus on the entire tower of gravitons, beyond the traditional single-resonance analysis. Since several states of the tower can lie within the same accessible mass window, the combined signal is enhanced, and the resulting constraints can be significantly stronger than those obtained from a single resonance alone. We first update the current constraints on single graviton searches stemming from diphoton and dilepton data from ATLAS and CMS, using datasets collected above $\sim 200\,{\rm GeV}$, and then consider the impact on the bounds of the full tower of states for different extra-dimensional scenarios. This allows us to extend the reach of current searches to lower mass regions than typically considered, paving the way for future analyses by experimental collaborations.

We develop a general Fokker-Planck framework describing the dynamical evolution of Keplerian binaries subjected to stochastic perturbations. The formalism provides an algorithmic way to obtain the Fokker-Planck drift and diffusion coefficients of any set of orbital variables given the statistics of the perturbations. We apply the method to three physically distinct regimes: adiabatic tidal perturbations, white-noise tidal perturbations, and impulsive encounters with a third body of arbitrary density profile. In each regime we provide explicit drift and diffusion coefficients for all six orbital elements, derive the associated evolution timescale, and obtain analytic steady-state distribution functions. Our results extend previous treatments by including the evolution of the binary's orientation, retaining the complete tensor structure of tidal correlators, treating non-pointlike perturbers, and resolving the exact geometry of impulsive encounters. The latter correction leads to a steady-state eccentricity distribution that is slightly sub-thermal. We also show how these equations can be applied directly in several astrophysical scenarios, including binaries perturbed by dark matter subhaloes, ultralight dark matter, and the interstellar medium. This work delivers both a complete mathematical framework and a practical toolkit for stochastic binary evolution, providing ready-to-evaluate equations to be applied directly to binary population data.

Massive fields exchanged during inflation source cosmological collider features in the correlators of primordial curvature fluctuations. While their structure is fixed by the symmetries of inflation, the amplitude of such signatures is a priori unknown, though bounded by physical principles such as unitarity. We assess the observational viability of the scalar cosmological collider by combining precise numerical predictions derived using CosmoFlow with observational data from Planck bispectrum reconstructions. Working in the limit of weak quadratic mixing between the Goldstone and scalar sectors (as assumed by all previous searches), we find that perturbativity restricts the collider signals to be unobservably small, except for double- and triple-exchange configurations at low masses. Larger bispectra can be generated by increasing the mixing to non-perturbative (but still unitary) values: however, this distorts the signal, damping its amplitude and shifting the collider oscillations. Furthermore, strong mixing breaks the factorization of the bispectrum into a free amplitude and a fixed shape, and complicates both theoretical predictions and observational searches. Despite the challenges, we argue that strong mixing analyses are necessary to obtain meaningful constraints on the scalar cosmological collider from current and upcoming datasets.

We construct an explicit anomaly-free completion of a gauged baryon-number symmetry. The new gauge factor is \(U(1)_{\tilde B}\): when restricted to the Standard Model fields its charge \({\tilde B}\) coincides with ordinary baryon number, whereas in the full theory it becomes an extended baryonic symmetry acting on both the Standard Model and a secluded sector. We show that anomaly cancellation alone leaves a broad class of solutions, but that requiring consistent symmetry breaking, viable decays of the exotic states, the absence of stable coloured relics, a neutral dark matter candidate protected by a \(Z_2^{\rm DM}\) parity, and improved high-scale gauge-coupling unification strongly constrains the structure of the model. These requirements necessitate enlarging the minimal secluded fermion sector by additional scalar fields and Yukawa interactions, giving rise to a light pseudoscalar that plays an important role in the dark matter phenomenology. We implement the resulting renormalisable model in SARAH and analyse its spectrum and phenomenology with SPheno, MicrOMEGAs, SModelS, and HiggsTools. We identify viable regions of parameter space containing a heavy baryonic Z', an even heavier secluded sector, a neutral dark matter candidate compatible with relic-density and direct-detection constraints, and improved gauge-coupling evolution relative to the Standard Model. In these regions, the relic abundance is determined either by co-annihilation with nearby secluded states or by annihilation into light pseudoscalars from the extended scalar sector.

The phase-space density of dark matter within the Milky Way is a key quantity that encodes information about the nature of the dark sector. The local phase-space density is also required to properly interpret the results of dark matter direct detection experiments. However, there are at present few observational constraints. In this paper, we show that a simple coordinate transformation reveals a near-universal DM phase-space distribution function among three independent suites of cosmological simulations of Milky Way-mass galaxies. We provide evidence for this with plots of kinematic features as well as machine learning-based classifiers that are sensitive to all of the correlations in the full multivariate phase space. Deviations from universality are found only at extremes of galactic radius and/or velocity, and in one simulation that has a prominent accreted dark disc. We further show that the parameters for the coordinate transformation can be inferred from metal poor stars ($\log_{10}[{\rm Fe}/{\rm H}]< -2$). These stars also contain signatures of the dark disk, allowing the existence of such a structure to be inferred from observation. Finally, we construct a model of this universal phase-space distribution using a normalizing flow, trained on the standardized phase-space across simulations. We will apply our method to survey data from Gaia and SDSS in a forthcoming work.

The global evolution of protoplanetary disks sets the initial conditions for planet formation. However, most models focus on individual evolutionary phases, with idealized initial conditions and oversimplified prescriptions for angular momentum transport and thermodynamics. We present a more realistic semi-two-dimensional ($1+1$D) model incorporating gravitational instability (GI), magnetohydrodynamic (MHD) winds, magneto-rotational instability (MRI), stellar irradiation, self-shadowing, and radiation transport. The radial distribution of large-scale magnetic flux drives two different pathways of disk evolution. When the vertical field is spatially uniform, a puffed-up, MRI-heated inner rim shadows the disk beyond it, sustaining a massive, gravitationally unstable region for $\sim 1$ Myr and, for several Myr, a compact ($\lesssim 10$ AU), cold ($\sim10$ K), low-turbulence ($\alpha_\mathrm{SS}\sim10^{-4}$), high-density ($\Sigma\gtrsim300\,\mathrm{g\,cm^{-2}}$), optically thick reservoir, so that the disk mass inferred from mm-continuum emission can be greatly underestimated. When the field instead scales with midplane gas pressure, it drives stronger transport in the inner disk and eventually strips the shadow, leaving an extended, flared disk whose observable mass closely traces the true mass. Our results connect GI-dominated Class~0/I disks to MHD wind-driven Class~II disks, and point to three broader conclusions: (i) disk physics is strongly inhomogeneous in space and time, so constant-$\alpha$ treatments miss essential physics; (ii) thermodynamics plays an active role, with self-shadowing simultaneously preserving GI and weakening MHD winds; and (iii) the distribution of large-scale magnetic flux is the key uncertainty, closely linked to whether the shadow is maintained. The two pathways align, respectively, with observations of compact, shadowed disks and extended, irradiated disks.

Diffraction is characterized by forward scattering and a large rapidity gap. Ordinary hard scattering also produces gapped events and presents a significant background to identification of diffractively produced events. We present a fully differential factorization of gapped hard $ep$ scattering. We find that the unpolarized azimuthally-dependent structure functions $F_{3,4}^{\rm gap}$ and the longitudinal $F_L^{\rm gap}$ vanish at leading power for hard scattering. Azimuthal dependence is thus a pure diffractive signature. This is borne out in Monte Carlo simulations.

The snowlines of major volatiles in protoplanetary disks play a pivotal role in dust evolutions and volatile delivery to nascent planetary systems. In this paper, we report the Atacama Large Millimeter/submillimeter Array Band 1 ($\approx7.5\,\mathrm{mm}$) observations of methanol (CH$_3$OH) emission lines in the disk around the FU-Ori type star V883 Ori, where accretion outburst heats the disk and the majority of ices has sublimated. We detect three CH$_3$OH emission lines at an angular resolution of $\approx0.\!\!^{\prime\prime}2$. The stacked CH$_3$OH image exhibits a centrally-peaked morphology in contrast to the previous (sub-)mm observations that show a central depression. By fitting radially-resolved line profiles, we derive the radial intensity profile of the CH$_3$OH emission where we find a steep increase at $\lesssim40\,\mathrm{au}$. The column density of CH$_3$OH reaches at least $\sim10^{19}\mathrm{-}10^{20}\,\mathrm{cm^{-2}}$ at $\sim10\,\mathrm{au}$. This provides direct evidence that a significant amount of warm gaseous methanol is present in the innermost region of the disk where its emission has been suppressed in previous (sub-)mm observations due to the optically thick dust emission. The steep increase in the intensity profile may indicate that the CH$_3$OH snowline in the midplane is located at $\sim30\mathrm{-}55\,\mathrm{au}$, or that the CH$_3$OH emission traces the temperature structure given that the emission is likely optically thick. Our results demonstrate the capability and significance of (sub-)cm observations in probing the innermost opaque region of disks, paving the way for the future observations with upcoming facilities.

I show that, in the mass range $0.1\,\text{GeV} < m_a < 6\,\text{GeV}$, the strongest current bound on axion-like particles (ALPs) coupled to photons comes from very high energy $a\gamma$ production at the LHC. In this regime, the two photons from the ALP decay are collimated and reconstructed as a single photon.

We revisit the classical expansion of the planetary Hamiltonian for small eccentricities and mutual inclinations of the orbits, presenting a derivation based entirely on vector formalism. We demonstrate that the secular part of the disturbing function, as well as any other Fourier harmonic, can be expressed in terms of scalar products of vectors lying in the system's invariant plane. Furthermore, we show how to express any such term using the angular momentum and eccentricity vectors of the orbits.

Solid-state spin-photon interfaces promise to scale quantum networks through on-chip photonic integration and multiplexed entanglement generation. To date, remote entanglement between integrated emitters has been realized only in cavity-enhanced systems, where fabrication yield and spectral matching remain major obstacles. Here we demonstrate heralded remote entanglement between diamond tin-vacancy spin qubits embedded in separate on-chip waveguides. Combining intrinsically efficient photon emission with a broadband waveguide architecture provides high device yield and obviates the need for spectral matching to cavity modes. We realize coherent optical and spin control and achieve high-visibility two-photon interference. By combining photon-mediated entanglement generation with real-time feedforward, we produce a consistent entangled state independent of the heralding pattern. These results establish waveguide-integrated tin-vacancy centers as a compelling platform for scalable quantum network nodes.

We curated 320 cubic ($Fd\bar{3}m$) spinel entries from the Materials Project-nitrides, oxides, sulfides, and selenides, including single-cation mixed-valence $A_3X_4$ compounds-and trained tree-ensemble surrogates for the formation energy, energy above the convex hull, band gap, total magnetization, and metallicity. Cations were assigned to tetrahedral-like and octahedral-like groups from CrystalNN coordination numbers rather than from element identity, and the evaluation was group-aware throughout: splits were grouped by reduced formula, every transform was fit on training folds only, and champion models were selected on cross-validated scores before the holdout was examined. Over twenty repeated grouped holdouts (single-seed refits that reuse the tuned hyperparameters, and are therefore mildly optimistic) the champions reach mean absolute errors of $0.121\pm0.030$ eV/atom for the formation energy, $0.048\pm0.013$ eV/atom for the hull distance, and $1.27\pm0.19$~\muBfu{} for the magnetization, with a metallicity accuracy of $0.85\pm0.06$. Band-gap regression does not beat a trivial baseline on the 19-member non-metal holdout under paired bootstrap testing, we report this negative result and trace it to sample scarcity and to the semi-local DFT labels. On the identical grouped split, the tabular champion is more accurate than an untuned MEGNet trained from scratch (0.087 versus 0.209 eV/atom formation-energy MAE on the primary holdout), a comparison that bounds, rather than settles, the descriptor-versus-graph question at this data scale. SHAP attribution ties the magnetization model to octahedral $d$-occupancy and the formation-energy and band-gap models to electronegativity descriptors, and grouped conformal intervals, permutation nulls, and leave-one-chemistry-out tests bound a domain of applicability that is uneven across anions and cations.

Cosmic voids are underdense regions that can provide an effective large-scale environment with a de Sitter-like gravitational behavior. Motivated by recent black-hole solutions embedded in void density profiles, we construct a symmetric thin-shell wormhole by gluing two copies of the positive-lapse region of a black hole inside a cosmic void. The surface stresses are obtained from the Darmois–Israel junction conditions, and the corresponding null, weak, dominant, and strong energy-condition combinations are written directly in terms of the void mass function and density profile. We further develop the thermodynamics of the static shell, deriving a first law that relates the shell entropy to the black-hole and cosmological-like horizon entropies. We then formulate the radial dynamics of the throat through an effective potential and study the local stability of static configurations when the exotic matter on the shell obeys either a generalized cosmic Chaplygin gas or a modified cosmic Chaplygin gas equation of state. In both models the Chaplygin parameter $B$ is fixed by the static junction condition, so that the remaining stability test is governed by the void geometry and by the equation-of-state parameters. Numerical results reveal that GCCG-supported configurations are generically unstable, whereas MCCG-supported wormholes can be stable for a sufficiently large linear term in the equation of state. The resulting framework connects the de Sitter-like structure of cosmic voids with the standard thin-shell wormhole formalism and provides a starting point for identifying stable or unstable wormhole configurations located between the black-hole and cosmological-like horizons of the void spacetime.

We study the motion of spinning test particles in Schwarzschild spacetime within the Mathisson–Papapetrou–Dixon pole–dipole approximation, imposing the Tulczyjew–Dixon spin supplementary condition. Restricting to equatorial orbits with the particle spin aligned with the orbital angular momentum, and retaining terms through linear order in the specific spin $s$, we derive the spin-corrected radial potential, circular-orbit conditions, bound periodic trajectories, epicyclic frequencies, and Lyapunov exponents of unstable circular orbits. The spin–curvature coupling shifts the circular-orbit energy and angular momentum and moves the innermost stable circular orbit to $r_{\rm ISCO}=6M-2\sqrt{2/3}\,s+\mathcal{O}(s^2)$ in the sign convention adopted here. We construct bound periodic orbits using the Levin–Perez-Giz zoom–whirl taxonomy and show how the particle spin deforms the corresponding energy–angular-momentum map. We then obtain the coordinate-time azimuthal and radial epicyclic frequencies and use them as kinematical inputs for relativistic-precession and resonance prescriptions for quasi-periodic oscillations. Finally, we relate the Lyapunov exponent of unstable circular orbits to the local separatrix structure governing near-homoclinic zoom–whirl motion. The resulting formulation provides a compact analytic connection between linear-in-spin MPD dynamics, periodic-orbit taxonomy, epicyclic-frequency shifts, and transient strong-field phenomenology in a nonrotating black-hole background. Also, we study the gravitational waveforms from the periodic orbits of a massive spinning particle around a black hole, presenting those associated with extreme mass-ratio inspirals involving a stellar-mass compact spinning object orbiting a supermassive black hole.

Hardware neurons incorporating built-in memory components are critical technologies for implementing large scale neural networks that exhibit adaptive-itinerant behavior and produce biological-inspired spiking patterns that match neuroscience known operations (1). Moreover, neurons capable of full quantum information processing through their qubit states and quantum trajectory provides capability for hybrid quantum-classical operations through the level of coherence/entanglement and non-Markovianity (2,3). These attributes further contribute to solving complex quantum mechanical problems by providing a rich and diverse group for expressing quantum neural states. Upgrading these hardware neurons now with optical spin qubits excitable with pulsed laser excitation in the near infrared and designed from negatively charged silicon vacancies in semiconductor silicon carbide (4) and Neodymium rare earth ions in the superconducting Niobium/Niobium oxide film (5) that form the memory provides access to the unique spin Hamiltonian that considers electronic and nuclear interactions. In this manuscript, we experimentally measure opto-electronic quantum-classical neurons integrated with a optical spin qubit and examine how tailored neuronal spiking sequences drive the photoluminescence oscillations and modulate the quantum spin transitions. We derive a quantum model for the system that considers the interaction between the neuron and optical qubit spin and perform calculations to project how quantum computing operations are expandable across the state space in the quantum-classical neuron and spin qubit system. For example, the resulting impact on the neuron quantum states where the strength is adjustable due to dynamical memory changes. These results are critical for realizing hardware neurons with quantum optical capabilities and inspired by the existence in biology of biophotons.

We investigate the modified thermodynamic properties of a deformed Schwarzschild black hole arising from new noncommutative corrections to the tetrad fields obtained through the Seiberg-Witten map. By deriving the corrected event horizon radius, we evaluate the corresponding thermodynamic quantities, including the Hawking temperature, entropy, heat capacity, Helmholtz free energy, and pressure. We also examine the evaporation process of the black hole within this noncommutative framework. The behavior of the heat capacity reveals a rich thermodynamic structure consisting of three distinct phases: two unstable phases with negative heat capacity, corresponding to a large black hole and a small black hole, separated by an intermediate stable phase with positive heat capacity. Our analysis also shows that the Schwarzschild black hole in noncommutative geometry possesses a finite lifetime that exceeds that of its classical counterpart, owing to the effective contribution of noncommutativity to the black hole mass. The noncommutative correction naturally introduces a fundamental length scale, {\Theta}=1,6.10^-35 m, which is of the order of the Planck length.

Spacetime torsion provides a natural extension of general relativity and may lead to black hole solutions that differ significantly from their Einsteinian counterparts. We investigate a class of Reissner-Nordström-like black holes in Poincaré gauge gravity, where the effective charge is generated entirely by spacetime torsion instead of an electromagnetic field. Within the physically relevant torsion sector, the spacetime exhibits a single-horizon structure, free from the inner horizons and extremal states characteristic of charged black holes. Using the sixth-order Wentzel-Kramers-Brillouin (WKB) approximation, Leaver's continued-fraction method, and the eikonal correspondence between quasinormal modes and unstable null geodesics, we study scalar perturbations and spin-2 test fields on the torsion-modified background. We find that increasing torsion decreases both the oscillation frequencies and damping rates, leading to longer-lived ringdown signals. We further compare the model predictions with Event Horizon Telescope observations of Sgr A* and M87*, along with representative LIGO-Virgo-KAGRA (LVK) ringdown scales, to derive constraints on the torsion parameter via a profile-$\chi^{2}$ analysis supplemented by Monte Carlo sampling. Although the resulting bounds remain consistent with the Schwarzschild limit within current observational uncertainties, our results show that spacetime torsion leaves correlated imprints on both black hole shadows and ringdown observables.

The classical Gibbs-Duhem relation applies to quasi-static processes and neglects kinetic effects, leaving a fundamental gap between Gibbs thermodynamics and Newtonian mechanics. Here, we derive a generalized Gibbs-Duhem framework that incorporates kinetic contributions, thereby establishing a unified connection between classical thermodynamics and Newtonian mechanics. Based on this framework, we propose an alternative evolution equation governing density dynamics at fluid-fluid interfaces. In appropriate limiting cases, the resulting density evolution equation naturally recovers the definition of the speed of sound, Bernoulli's law, and the van der Waals equation of state (EOS).

Hybrid quantum-classical machine learning workflows repeatedly evaluate many small parametrized circuits during training and model exploration. In this regime, framework dispatch and orchestration overhead often dominate runtime. Prior simulators accelerate execution but leave open the question of when compile-once specialization is the right choice for static variational circuits. We answer this question with VQCSim, a compile-once, PyTorch-native statevector execution path with native autograd. In a systematic MQT Bench study, VQCSim compiles all tested static circuits and provides 87.7% end-to-end semantic validation. Across a five-GPU evaluation set, VQCSim delivers pooled median speedups of 4.49x for native inference and 26.78x for native training, while retaining a 3.31x advantage under matched finite-difference training. Ablation identifies native autograd as the dominant source of acceleration (27.6x), with compile-once caching and batch vectorization contributing additional gains. The speedup trades higher GPU memory (VQCSim is memory-limited at the high end) for lower runtime. We derive a hardware-aware regime map and release vqcsim-oracle, an open-source backend selector with 91.1%-97.7% top-1 agreement (including cross-GPU transfers), enabling automatic simulator selection in QML design loops.

Next-to-the leading order of the differential cross-section of the subprocess of annihilation of quark-antiquark pair \(q\bar{q} \rightarrow g\gamma\) of prompt photon production in nonpolarized and longitudinally polarized proton-proton collisions at NICA energies has been investigated. Shown, that contribution of the next-to-leading order to the differential cross-section of annihilation of quark-antiquark pair \(q\bar{q} \rightarrow g\gamma\) is significant at the high energies of colliding protons and consist around 15% of leading order calculation. The influence of longitudinal polarization of colliding protons on the contributions of the next-to-leading order is more significant than, on the contributions of the leading order and it is significant at high energies of colliding protons. PYTHIA 8.316 + POWHEG BOX Monte Carlo (MC) event generator has been used for numerically simulation of prompt photon production in annihilation of quark-antiquark pair in NLO approximation for determination of the dependences of cross section on the sum of energies of colliding protons \(\sqrt{s}\), transverse momentum \(p_{T}\), cosine of scattering angle \(Cos(\theta)\), rapidity y of photon and \(x_{T}\). The NLO+PS simulation accurately reproduces the fundamental signatures of pQCD.

We investigate the thermodynamic and optical properties of Kerr–Bertotti–Robinson black holes, namely rotating black holes immersed in an external Bertotti–Robinson electromagnetic background. In the fixed-$a$ ensemble, we derive the horizon mass relation, the Hawking temperature, the entropy, the Helmholtz-type free energy, the heat capacity, and the extremal remnant configuration. These quantities reduce smoothly to their Kerr counterparts as $B\to0$. In the weak-field regime, the leading thermodynamic corrections arise at order $B^2$; the extremal radius is shifted at this order, whereas the remnant mass receives its first correction only at order $B^4$. We also introduce a formal AdS-like thermodynamic interpretation of the Bertotti–Robinson scale, treating the associated pressure as an effective response variable rather than a genuine cosmological pressure. Because the spacetime is not asymptotically flat, we further compute the finite-radius Komar mass and the Komar charge associated with the horizon generator. Using the Hamilton–Jacobi formalism, we derive the separated null-geodesic potentials, the impact parameters of spherical photon orbits, and the celestial coordinates of the shadow boundary for a finite-distance observer. We then characterize the photon-region boundaries, ergosphere thickness, photon–ergosphere gap, shadow area, and magnetic shadow susceptibility. Within the perturbative regime considered, the Bertotti–Robinson background decreases the averaged ergosphere thickness and shadow area, increases the photon–ergosphere gap, and produces a negative shadow susceptibility whose magnitude is enhanced by rotation.

In this paper, we discuss the experimental determination of the nonlocal characteristics of two-qubit gates. Based on the recently derived expressions for the entangling power and gate typicality of two-qubit gates, we construct two-qubit quantum circuits to measure the entangling power and gate typicality of the two-qubit gates, which are generated by the elements of the su(4) Cartan subalgebra. These elements describe the native interactions in many quantum processors. Hence, these circuits can be used to determine the nonlocal characteristics of native gates of many quantum processors. In each circuit, the native gate is applied twice. In addition, each circuit consists of at least one CNOT gate. A set of six two-qubit circuits is constructed to measure the entangling power. The number of circuits is further reduced to three by increasing the nonlocal resources (the number of CNOT gates). To measure the gate typicality, a set of three two-qubit circuits is constructed. Measurement of gate typicality requires more nonlocal resources than the measurement of entangling power.

Cold Dark Matter predicts a population of low-mass halos which are sensitive to its fundamental nature and the primordial power spectrum, yet remain undetected. Although elusive, their discovery may be possible thanks to wave-optics lensing of gravitational waves (GWs) by the superposition of many halos along the line of sight. We study the statistical properties of stochastic diffractive lensing, which imprints correlated fluctuations on the amplitude and phase of the original waveform. The stochastic distortions can be described by an orthogonal basis that captures the dominant ”tones” associated with the dark matter properties, or dark timbre, which is not degenerate with binary source parameters. LISA is most sensitive to halos of $O(10\text{--}10^4\,M_\odot)$, and because the imprint recurs in every source, stacking $\sim(50,500)$ loud binaries could confirm them at the $(2,5)\sigma$ level ($\sim0.2$ to $\gtrsim4\sigma$ for realistic merger rates and different concentration estimations). The per-event signal is only $O(10^{-3})$ in cold dark matter, demanding major advances in waveform accuracy and data analysis. Even short of that reach, stochastic diffraction places stringent bounds on models that enhance small-scale structure, such as axion miniclusters and primordial black holes.

We propose an efficient algorithm based on shadow Hamiltonian simulation to approximately simulate the real-time dynamics of observables under time-independent Hamiltonians. Shadow Hamiltonian simulation works at the level of the operator algebra generated by the observables through commutators with the Hamiltonian. Exactly encoding the quantum state in this picture is generally inefficient for interacting systems due to the exponential growth of the operator algebra. Our algorithm overcomes this bottleneck by systematically identifying the elements of the algebra most relevant to the target observables. This targeted approach is a controlled approximation that yields a highly efficient quantum state encoding that substantially reduces the size of the qubit register required to perform the time evolution using the shadow Hamiltonian. We propose two main pruning schemes, one based on a predefined operator basis and another on a constructed Krylov basis. We also present a hybrid scheme that builds a Krylov basis within a pruned algebra in the predefined basis. We benchmark our algorithm using lattice spin systems in one and two dimensions, for both one- and higher-point correlators as observables.

Open questions in collisionless plasma dissipation can be addressed using space-based observations in different astrophysical environments, with implications for both astrophysical and laboratory plasma systems. We study a low-$\beta$, highly imbalanced, sub-Alfvénic stream observed by Parker Solar Probe (PSP) to identify and distinguish between signatures of stochastic heating (SH) and resonant heating (RH) by parallel ion cyclotron waves (ICWs). Prior work studying this stream (Bowen et al., 2025) showed that the SH rate, accounting for intermittency, matched the amplitude of the local energy transfer (LET) rate while the RH rate did not. This comparison relied on a number of assumptions regarding the nature of the diffusive process, and the calculation of the LET rate. We introduce a novel technique of inverting the proton guiding center equation to empirically measure velocity-space diffusion coefficients using three-dimensional proton velocity distribution functions (VDFs), from the ion electrostatic analyzer (SPANi) on PSP. Measured diffusion coefficients are used to determine phase-space heating rates, leading to a calculation of a fully kinetic heating rate independent of assumptions made in prior work. We show that scale-dependent analytic expressions for SH via non-coherent fluctuations match the empirical measurements from PSP data, provided that we account for intermittency in the heating calculation. In contrast, the derived heating rates for SH that accounts for the effects of the helicity barrier, and heating rates for RH via $\parallel$-ICWs do not peak in the same region of velocity-space as the empirical measurements, nor reach the required magnitude. Our approach provides novel methodology to uniquely identify and constrain heating processes in collisionless plasmas, and shows evidence of a Fokker-Planck like diffusive process in the near-Sun solar wind.