Papers

Semi-Lagrangian (SL) schemes advect a distribution function along characteristics and remap it to a fixed grid. They are unconditionally stable without a global solve, and with discontinuous Galerkin (DG) integration the transfer along a magnetic field line conserves mass exactly. This paper presents the parallel and GPU design of a 3X+2V SLDG drift-kinetic tokamak solver on unstructured, flux-surface-aligned poloidal planes of shaped cross section, extruded toroidally. Transport follows magnetic field lines across the planes, and each velocity channel advances a fixed distance per step, proportional to its parallel speed, so the halo depth a channel needs grows with its speed. Velocity-dependent ragged halos exploit this, sending each channel only its own upwind depth. The 4D decomposition includes the toroidal angle, the 2D poloidal plane and the magnetic moment, and leaves the parallel velocity whole: no stage transports across the magnetic moment, while a parallel-velocity partition would put a halo inside the acceleration stage. On NVIDIA A100s the design strong-scales over the magnetic-moment axis from one to 12 four-GPU nodes, and a weak series of three points refining all five phase-space dimensions together, 16x in total per series point, holds a weak-scaling efficiency of 75% on 16 GPUs and 57% on 256, from a one-GPU base case. The pointwise interpolations within the poloidal plane do not conserve mass, and the full step's mass drift stays below 2.1x10^-5 at every series point. The design was implemented with an AI code assistant under a machine-checked regression discipline, in which every change is held to one of four exactness classes, from bit-identical to a physics rate within a stated tolerance.

Spin-dependent forces enable independent control over the effective frequencies of bosonic motional modes and their coupling strengths to spins in trapped-ion spin-boson quantum simulators. We show that the relative signs of these effective frequencies provide an important programmable resource for engineering distinct multimode dynamics. Focusing on a two-mode quantum Rabi model, changing the frequencies of the two modes from the same sign to opposite signs reorganizes the resonance structure of the spin-mediated bosonic interaction, converting the dominant resonant process from excitation exchange to correlated pair creation. In the dispersive regime, the resulting effective interaction realizes a two-mode parametric amplifier with stable oscillatory, critical, and exponentially amplifying regimes separated by a spin-dependent instability threshold. Across these regimes, the dynamics generate collective-quadrature squeezing and bipartite motional entanglement. Preparing the spin in a coherent superposition further allows different spin components to experience distinct stability regimes, generating tripartite spin-boson entanglement, while spin postselection can coherently combine the conditional bosonic branches to generate non-Gaussian entangled bosonic states. Finally, we outline an implementation using parameters within reach of current trapped-ion platforms.

Frustrated Ising models of social networks mix ferromagnetic (agreement-seeking) and antiferromagnetic (antagonistic) couplings, and the antagonistic bonds are almost always placed independently at a fixed rate, yielding a +/-J spin glass. Real signed networks (Epinions, Slashdot, Wikipedia) instead show an excess of balanced triads, and perfectly balanced placement is gauge-equivalent to an unfrustrated ferromagnet. We compare three sign-placement conditions on a frustrated random-field Ising model of a polarised population, sharing an identical graph, field assignment, and edge-weight magnitudes: an independent baseline; a balance-structured condition whose camp membership coincides with each voter's field sign; and the same condition with camp labels randomly permuted, so triadic balance is identical by construction while the camp-field correlation is removed. On a confound-controlled Kolmogorov-Smirnov test of the sampled energy-gap distribution (simulated annealing), the aligned condition differs from the baseline at every density tested (p = 7.3e-8), while the permuted condition shows no significant difference (paired mean difference 0.003, 95% CI [-0.041, 0.046]). Field-camp alignment, not triadic balance alone, drives the effect. The qualitative direction follows from a known mapping; the contribution is a quantitative, confound-controlled measurement of the effect's size away from that limit, robust to parallel-tempering sampling, system sizes up to N = 300, and structural noise calibrated to real networks, while triadic balance alone produces no detectable effect at N = 90 and at most a small one at N = 180-300 (paired change in KS distance about 0.04, 95% CI upper bound below 0.09).

The newly measured correlation between the neutrino and X-ray luminosities of Seyfert galaxies has yielded the first neutrino-based measurement of the Hubble constant. Building on this result, we forecast the reach of a global neutrino-telescope network by 2030, utilizing full-sky IceCube exposures combined with KM3NeT-ARCA and Baikal-GVD. We find that this 2030 configuration sharpens the neutrino-measured Hubble constant from today's $H_0 = 66^{+44}_{-37}$ to $H_0 =66^{+15}_{-13}$ km s$^{-1}$ Mpc$^{-1}$. Additionally, we project that the disk-corona slope of the neutrino X-ray luminosity relation ($L_\nu\propto L_X^\beta$) will reach $\beta=0.72\pm0.04$, enabling a $\geq \!5\sigma$ exclusion of the calorimetric value $\beta=1$. Finally, we show that, if a high-redshift population of neutrino sources, such as JWST's "little red dots," is identified and obeys the same luminosity relation, we can obtain a new independent measurement of the matter density $\Omega_m$ and the dark energy equation-of-state parameter $w$.

We formulate a theory of spin-polarized tunneling between a nanowire tip of a topological Kondo insulator SmB$_6$ and the bi-collinear antiferromagnet Fe$_{1+x}$Te in which the tunneling conductance which measures magnetic contrast changes sign when the bias is reversed. First we show that no time-reversal-symmetric tip, however strong its spin-momentum locking is, can produce experimentally observed magnetic contrast, which implies that time reversal must be broken at the tip surface. Within a mean-field treatment of the surface theory of SmB$_6$ we find that the interaction between conduction $d$- and $f$-electrons drives a surface phase transition near $T_c\approx10$ K in which the time-reversal-odd component of the Kondo hybridization amplitude condenses in the same symmetry channel as an out-of-plane surface magnetization, gapping out the Dirac surface states. Below the transition the spin-resolved spectral function of each gapped surface Dirac cone is odd in energy about its node. For a charge-neutral apex the Fermi level lies between the surface $\overline{\Gamma}$ and $\overline{X}$ Dirac nodes, so the spin-polarized conductance, which is determined by this function at the bias energy, reverses its sign close to zero bias. This sign change is thus a spectroscopic signature of time-reversal symmetry breaking on the surface of SmB$_6$.

Most systems trained by equilibrium propagation or coupled learning are in the same class as multi-layer perceptrons: while they may be universal function approximators, they struggle to learn associative tasks which are easy for transformers. Equilibrium propagation relies on a bidirectional flow of information through the physical system between input and output. The reverse flow is broken by more complex nonlinear systems, such as those performing multiplication which is needed to express dot-product attention. Here we explicitly restore this bidirectional flow by introducing extra circuit elements for this purpose into a double or dyadic circuit. We then use these ideas to construct an attention mechanism exploiting the exponential current law of sub-threshold MOSFET devices. We show that in simulations this circuit can be trained to perform a simple in-context learning task, despite using realistic reverse components which transmit only an approximate gradient. For this training to succeed we need cross-entropy loss (not mean squared error). We generate nudges appropriate for this loss using a novel floating circuit element, based on the same MOSFET sub-circuit used for softmax. We train the resistors in this circuit using the Lion optimiser, which can be implemented using one capacitor per parameter to store local memory of past gradient estimates.

Ultralight dark photons (DPs) are well-motivated dark matter candidates. A promising yet underexplored mechanism for their relic abundance is parametric resonance in the Abelian-Higgs model that generates the DP mass. We advance previous analytical studies through dedicated 3D lattice simulations that capture important nonlinear effects, including backreaction and relic partitioning between the dark Higgs and DPs. We further predict the associated stochastic gravitational-wave (GW) signal, which can be within reach of a broad range of detectors, opening a new avenue to probe ultralight DP dark matter.

In the Eliashberg theory of superconductivity, Coulomb interactions oppose the phonon-mediated attraction and suppress the superconducting critical temperature $T_{\mathrm{c}}$. However, most first-principles predictions continue to treat this repulsion with an empirical Coulomb pseudopotential $\mu^*_{\text{ME}}$ in the range 0.1-0.15. Here we present first-principles calculations of the Coulomb parameter $\mu$ and pseudopotential $\mu^*_{\text{ME}}$ in superconducting hydrides across a range of pressures. The screened Coulomb interaction is evaluated at the random phase approximation level with the Mantel code. We demonstrate that several hydride systems, including H$_3$S, YSbH$_6$ and Mg$_2$IrH$_6$, have strong Coulomb repulsions driven by a large density of states at the Fermi energy, $N_{\mathrm{F}}$. For Mg$_2$IrH$_6$ we obtain $\mu=0.62$ and $\mu^*_{\text{ME}}\approx0.39$, leading to a 40 K suppression in $T_{\mathrm{c}}$ relative to a standard $\mu^*_{\text{ME}}=0.16$. Our obtained $\mu^*_{\text{ME}}$ is far above the conventional range and, accounting for the energy dependence of the density of states, resolves the factor-of-two discrepancy between $T_{\mathrm{c}}$ estimates of previous studies. Across all systems and pressures studied, we find that $\mu$ closely tracks $N_{\mathrm{F}}$, suggesting that commonly used $\mu^*_{\text{ME}}$ values lead to overestimated $T_{\mathrm{c}}$ in materials where the density of states at the Fermi energy is large.

The ranks of accreting planets and brown dwarfs are growing. To help interpret their spectra, we study how accretion affects a planet's atmosphere. The atmosphere is irradiated from above by whatever nonthermal radiation from the accretion shock does not directly escape into space. This accretional heating drives a temperature inversion. Even relatively slow accretion, corresponding to mass doubling times longer than system ages, can raise temperatures by many hundreds of Kelvin at ambient pressures of order millibars. The heated atmosphere radiates an optical/infrared excess. For environments that are not too dusty, the excess concentrates in molecular lines that trace the heated layer. Thus an accretionally heated atmosphere may be distinguished by its muted absorption bands. Irradiation from the accretion shock also changes the chemical composition of the atmosphere, further altering spectra. Atmospheric retrievals promise to map out the deposition of accretional energy, helping to decide between ”hot” and ”cold” start modes of planet formation.

We argue that no material can be made completely transparent to light as long as it has a nontrivial index of refraction. The quantum decay of photons into phonons is an ineliminable source of attenuation. This survives even once all other excitations have been gapped away, impurities have been removed, and the temperature has been set to zero. Restricting for simplicity to the case of a superfluid, we determine via effective field theory methods the corresponding low-frequency contribution to the imaginary part of the index of refraction. This scales as $\omega^4$ and induces a nonanalyticity of the real part for $\omega \rightarrow 0$. We also extend our result to large coherent electromagnetic fields, such as those of a laser, showing that the effect can receive strong nonlinear enhancements. Our result is a genuine quantum lower bound to the transparency of a medium.

Universal horizons trap even arbitrarily fast signals, providing a test of black-hole thermodynamics in theories with a preferred time direction. In Einstein–aether theory, this direction is defined by a dynamical field, the aether, that can remain non-aligned relative to stationary time at infinity. In particular, for asymptotically anti-de Sitter black holes, it was so far impossible to recover a first law of black-hole mechanics when such asymptotic tilt of the aether is present. Here, we resolve this issue for an exact family of static, spherically symmetric solutions. Using the covariant phase-space formalism, we identify the asymptotic tilt and the decaying part of the aether field as a boundary source and its conjugate response. Allowing both to vary independently obstructs the definition of an energy that generates time translations. Fixing either quantity, or imposing a relation between them, restores such an energy, while externally varying the boundary data introduces work into the first law. The energies obtained by fixing the source or its response are related by a Legendre transformation. At the universal horizon, heat includes both the metric area contribution and an irreducible aether energy flux. The resulting balance separates work at infinity from horizon heat and explains why the physical temperature cannot generally be inferred from the coefficient of an area variation in the black-hole mass.

By studying the interplay of geometric frustration with Aharonov-Bohm fluxes in three dimensions, we unveil a rich playground exhibiting topological semimetallic ground states with orbital magnetic dipole, quadrupole and ferrotoroidic orders, akin to spin patterns in classical spin ices - a class of phenomena which we dub frustrated topological orbital magnetism. We demonstrate that the ground-state toroidizations underpinned by non-Abelian topological nodal lines induce measurable current-induced Hall phenomena. We further find that distinct 2-in-2-out and 3-in-1-out frustrated orbital current patterns can be associated with topological Weyl node charges, and corresponding anisotropic linear and nonlinear Hall effects. We propose signatures for experimental validation of distinct frustrated topological orbital magnetic orders in candidate materials.

The integration of low-loss dielectrics into superconducting circuits is of importance to the functionality of quantum computers and sensors. In this work, we fabricate and measure niobium resonators atop few-layer, epitaxial hexagonal boron nitride (hBN) grown by Molecular Beam Epitaxy on a sapphire substrate and compare against a control counterpart without hBN. We conduct radiofrequency measurements which probe the responses to power, temperature, and temporal fluctuations of two-level systems. The resonators integrating hBN maintain low dielectric loss with a low-power internal loss tangent on the order of $10^{-6}$, and demonstrate hBN can be added to the conventional superconducting qubit stack with minimal degradation of the quality factor. This research represents a first step towards a materials-driven strategy to eliminate phonon-mediated correlated errors in solid-state quantum systems, which leverages the thermal properties of 2D materials to prevent athermal phonons excited in the device substrate from transmitting across the superconductor-substrate interface. The same technique applied to quantum sensors would maximize phonon collection by blocking phonons from entering passive metal films.

Quantum geometry underlies a wide range of correlated phenomena in electronic systems, yet accessing the geometry of individual bands remains experimentally challenging. Advances in quantum simulators, such as ultracold atoms in optical lattices, have enabled local state preparation and site-resolved measurements, offering direct access to quantum dynamics beyond conventional transport probes. These developments naturally raise the question of whether band-resolved quantum geometry can be extracted from local occupation readouts. Here, we propose an on-site quench protocol to probe the flat-band quantum geometry via local occupation measurements in an atomic lattice. Our scheme dynamically isolates the flat-band sector by coupling a one-dimensional flat-band lattice to a two-dimensional flat-band bath. The bath selectively removes dispersive excitations, while compact localized states remain trapped due to their overlap with the flat-band modes of the bath. We show that the late-time occupation pattern directly encodes the integrated overlaps between flat-band states separated by the wavevector of the initial density pattern, thereby enabling access to integrated quantum distances between the states separated by the commensurate momenta $\delta k = 2 \pi s/r$, $s,r \in \mathbb Z$ and to the integrated flat-band quantum metric. Our results thereby establish a direct connection between quantum geometry and the long-time memory of an initial spatial pattern in flat-band systems.

Gauged Linear Sigma Models (GLSMs) have long been a key tool in understanding Calabi-Yau compactifications of string theory. While descriptions of complete intersections of polynomial defining equations have long been understood in this context, a full treatment of non-polynomial complex structure deformations has been absent from the literature. Likewise, the somewhat more exotic generalized complete intersection Calabi-Yau construction has resisted a GLSM description. In this paper we resolve both of these omissions using completely standard GLSMs with polynomial superpotentials. The non-polynomial structure seen in the geometric constructions only arises in the associated GLSM upon restriction to the vacuum space of the theory. This feature enables the construction to avoid singularities in field space that could have arisen if non-polynomial structure were incorporated directly into the GLSM superpotential.

We report the detection of a previously unknown object with a single emission line within the Hubble Ultra Deep Field, using a new JWST NIRSpec technique called Multi-Object Coronagraphy for Slitless Spectroscopy (MOCSS) with the G140M/F100LP observing mode. The MOCSS technique involves opening almost all the shutters on the NIRSpec microshutter array, while simultaneously closing the shutters that lie on top of known low redshift objects, facilitating a wide field slitless spectroscopic search without contamination from bright objects. This observational technique has enabled the detection of a strong emission line in four different dither positions and in two position angles, and thus cannot be artificial. This line is detected at 1.60 $\rm \mu m$ with a line flux of $[2.5\pm 0.3]\times10^{-18} \rm erg\ s^{-1} cm^{-2}$ and a FWHM of $13.2\pm2.0$Å, and does not correspond to any known source with some of the deepest HST and JWST imaging in existence. Based upon the absence of imaging detection, we place a lower limit on the observed frame equivalent width (EW) of 7620Å on this object, which strongly limits the number of possible lines that this line can be. Given the wavelength, an EW limit that is near the ceiling of expectation, and the lack of other lines in the bandpass, this line cannot be easily explained by [OII] at $z=3.29$, [OIII] at $z=2.20$, H$\alpha$ at $z=1.44$, and Ly$\alpha$ at $z=12.16$. We discuss possible AGN and transient phenomena that could explain the finding.

Primordial overdensities at small scales can be significantly larger than those observed at large scales. As a result, they can collapse much earlier, at redshifts $z \sim 100$. In these collapsed halos, stars and black holes can form, where they can then contribute to an early reionization of the universe. If this epoch is temporary, the free electrons will recombine yielding a low level of ionization leading into cosmic dawn. This contributes to the optical depth of the universe, and adds more weakly to low-$\ell$ polarization signals of ionization compared to later sources. We study the effects of a redshift-localized source of reionization $\Delta \tau_{burst}$ in the context of a broad suite of cosmological data to constrain this scenario, finding a preference of approximately $\sim 2-2.5\sigma$ for a new contribution. Regardless of Planck reprocessing used (PR3 - SRoll2+plik or PR4 - LoLLiPoP+CamSpec/HiLLiPoP), the results are consistent, favoring a new contribution $\Delta \tau_{burst} \sim 0.012$ ($0.001 < \Delta \tau_{burst} < 0.022$ at 95%) and a similar total optical depth $\tau \sim 0.073$. The precise era of reionization is somewhat discrepant depending on the higher-$\ell$ reprocessing used, with HiLLiPoP favoring $z\sim 45$, CamSpec $z\sim 100$ and plik $z\sim 165$. If such a source is present at $40\lesssim z\lesssim150$, LiteBIRD should be able to detect it, while Simons Observatory should also constrain it.

A periodically driven quantum many-body system is believed to approach a locally infinite-temperature-like state as dictated by the ergodicity hypothesis, when all the couplings/parameters are of the same order. When the drive is stronger than a threshold value, a large class of systems is shown to break this mandate, exhibiting Dynamical Freezing (DF): ergodicity is broken due to the emergence of local operators with permanent memory of their initial values (PRX 11, 021008, 2021). However, an exception to DF has recently been noted in a particular setting (PRX 16, 011041, 2026). Here we identify the condition for ergodicity-breaking in a system under strong drive, and show how to stabilize DF by exact, local engineering. We further show that the Floquet Hamiltonian $H_{eff} = (i/T)\ln{[U(T)]}$ is non-local when ordered by spin-flips, in a non-DF system, while it turns quasi-local under our simple, local DF engineering that keeps the Hamiltonian $H(t)$ still non-integrable at each $t$. This perplexing non-universality is absent in equilibrium, where non-integrability is believed to imply ergodicity and thermalization universally. Our work paves a way to engineering novel ergodicity-broken interacting Floquet phases of matter in various quantum platforms, and also endows DF-assisted quantum error mitigation and state stabilization techniques (see Nature 653, 1027 (2026)) with unprecedented versatility and flexibility.

The OSV conjecture relates the helicity supertrace of black holes in $4d$ $\mathcal{N}=2$ supergravity obtained through a Calabi–Yau compactification of Type IIA string theory to the modulus squared of the topological string partition function evaluated at the attractor point in moduli space for a given set of magnetic black hole charges and electric chemical potentials. We find Euclidean black hole saddles that compute this index to all orders in the 4d supergravity derivative expansion and calculate their action using equivariant localization. The gravitational on-shell action localizes entirely to the north and south poles of each black hole, with the two contributions determined by the holomorphic and anti-holomorphic topological string free energies, respectively, evaluated at the attractor values of the moduli. For single-center black hole saddles, this provides a proof of the OSV conjecture to all orders in the topological string coupling. The same localization formula also applies to all saddles that contribute to the helicity supertrace, such as multi-center black holes, which leads to a non-perturbative refinement of the conjecture.

We report the first Monte Carlo simulation of quantum field theory on Euclidean de Sitter space, $S^4$. Rather than discretizing space, we use a spectral lattice based on spherical harmonics, keeping all symmetries exact at finite cutoff. For a massless $\lambda\phi^4$ theory, the zero-mode distribution reproduces the Starobinsky-Yokoyama equilibrium at weak coupling, and deviations closely follow the one-loop renormalization of $\lambda$. At strong bare coupling, the renormalized quartic coupling saturates near the ceiling of the one-loop renormalization-group flow. This saturation is the de Sitter counterpart of the triviality mechanism that bounds the Higgs mass in flat space. Our results confirm nonperturbatively that the infrared divergences of light scalars in de Sitter are correctly resummed by the stochastic formalism. More broadly, this work opens up de Sitter space to lattice Monte Carlo methods.

Applications of quantum devices and simulators require an accurate understanding of their dynamics as well as the effects of environmental noise. While some sources of noise can be modeled as Markovian dissipation, coupling to resonators or vibrational modes often produces non-Markovian dynamics as well, making it difficult to characterize the system, particularly for interacting many-body systems. Here, we identify a broad class of exactly solvable many-body quantum systems with both non-Markovian dynamics and Markovian dissipation. We consider a prototypical model of spins coupled to lossy bosonic modes that mediate Ising-type interactions. We exclude a transverse field but allow local spin dissipation that need not commute with the interactions, including dephasing, relaxation, pumping, and even processes that generate coherences. Using an exact stochastic representation, we decouple the many-body dynamics into the evolution of individual spins, yielding exact spin observables and correlations without adiabatically eliminating the bosons. In the Markovian limit, our solutions describe Ising models with correlated dephasing and nonreciprocal interactions. An example of spin squeezing shows that both the achievable squeezing and its optimal preparation time depend strongly on the interplay between non-Markovian dynamics and Markovian dissipation.

We investigate the dynamics of charged test particles around a Letelier black hole, i.e. a black hole surrounded by a cloud of strings (CoS), in Kalb-Ramond (KR) gravity, immersed in an external, asymptotically uniform magnetic field aligned with the symmetry axis. The geometry depends on the CoS parameter and on the Lorentz-violating KR parameter only through a single combination of the two, so that the two effects can compensate each other and the Schwarzschild metric is recovered when both parameters are equal. Because the spacetime is not Ricci flat, the Wald potential is not a solution of the Maxwell equations; we show that the regular source-free magnetic test field is given in closed form by a Gauss hypergeometric function of the radial coordinate, which reduces to the Wald solution in the Schwarzschild limit. Using this exact field we derive the equations of motion, the effective potential, the circular orbits, the innermost stable circular orbit (ISCO), representative escaping, captured and curled trajectories, and the orbital, radial and vertical epicyclic frequencies in closed form; all frequency expressions are cross-checked against direct numerical integration of the full equations of motion. Within the relativistic precession model, we perform a Markov chain Monte Carlo (MCMC) analysis of the twin-peak high-frequency quasi-periodic oscillations (QPOs) of GRO J1655-40, XTE J1550-564 and GRS 1915+105 for four nested models, complemented by nested sampling to compute Bayesian evidences and to weight the two (Larmor and anti-Larmor) magnetic modes of the posterior. The Schwarzschild model is excluded for GRO J1655-40 and XTE J1550-564, with a difference in the Akaike information criterion of about 110.

Machine learning is shown not to increase Eve's successful bit-guessing probability in the binary-classifier-based wire-resistance attack on the Kirchhoff Law-Johnson Noise (KLJN) key exchange when the resistor gap is narrow. Using time-domain simulations of a non-ideal KLJN loop with $R_L = 9$ k$\Omega$, $R_H = 10$ k$\Omega$ and wire resistances from 0 to 3200 $\Omega$, we generate 3000 secure bits per wire resistance and evaluate the mean-square noise voltages at both ends over 100-sample bit exchange periods (BEPs). This probability $p$ is evaluated for the sign rule, the nearest-line rule, logistic regression, support vector machine (SVM), $k$-nearest neighbors, random forest and gradient boosting. The sign rule gives $p = 0.711$ at 50 $\Omega$ and 0.682 at 3200 $\Omega$. The nearest-line rule, logistic regression and SVM stay close to it and the other classifiers perform worse. For Gaussian noise, the likelihood ratio between the HL and LH cases depends only on the difference of the two mean-square voltages, so the sign rule is Bayes-optimal. The resulting $p_{\max}$ reproduces the measured values and predicts that about 900 to 1200 samples per bit are needed for $p = 0.95$. This difference carries about 0.19 bit per secure bit, 1.5 times the hard-decision value.

We compare three definitions of $\Xi_c$–$\Xi_c'$ mixing within a constituent-quark model: a spin-component probability angle, a common-source overlap angle, and an SU(3)-breaking mass-operator angle. The probability angle is $3.11^\circ$, while the two operator-based definitions give $2.48$–$2.58^\circ$; a second parameter set gives $2.38$–$2.49^\circ$. The operator-based angles are closer to the lattice determinations $1.2(1)^\circ$ and $0.810(50)(200)^\circ$, but remain larger. We then couple conventional $qsQ$ states to virtual $qsQg$ configurations, where $q=u,d$ and $Q=c,b$. An orbital-$S$-wave chromomagnetic transition containing both $j_{Qg}=1/2$ and $3/2$ raises the source and mass-operator charm angles to $2.67$–$3.16^\circ$ when normalized to reference short-range mass shifts. The hybrid probability stays below $1.7\%$, and the corresponding bottom angles are $0.42$–$0.48^\circ$. Eliminating the hybrid sector gives a rank-one mass correction precisely when all weighted transitions select the same retained-state combination. The mode-resolved calculation separates the flavor-breaking response that changes the mixing angle from the response that generates a second transition direction. The accompanying effective-current relation connects this mass analysis to radiative and semileptonic amplitudes through their current matrix elements.

Machine-learned conformer generators are scored on GEOM-DRUGS by proximity to a reference ensemble that standard benchmark metrics implicitly treat as ground truth. We test whether that finite set is complete on the GFN2-xTB surface used to construct it. Across five public generators, settled, low-energy structures remain outside the $0.75$\,Å reference radius after removing reflections, incorrect stereochemistry, and post-relaxation connectivity changes ($2.3$–$7.0\%$ of submitted conformers, depending on architecture). In a targeted DFT audit, $107$ of $113$ chemically screened novel/reference pairs remain outside that radius after full $\omega$B97X-D3BJ re-optimization. A threshold-free complementary test needs no radius and no energy window at all: on $15.0\%$ $[8.0, 22.0]$ of molecules some generator has already found a chemically intact structure lying below the entire released ensemble. A complementary CREST search reproduces the minimum released in $65$ of $69$ molecules, and in $11$ of them it reaches more than $0.5$\,kcal/mol below the complete released ensemble. Augmenting the references with conformers proposed by held-out architectures raises absolute coverage-precision for every generator tested, by $1.48$–$2.99$ points. Together, these results show that GEOM-DRUGS precision is sensitive not only to generator quality but also to incomplete reference support.

Large language models (LLMs) are increasingly used in molecular discovery and structure elucidation, where decisions depend on physical observations. Existing evaluations primarily focus on end-to-end molecular reconstruction, where correct predictions do not necessarily indicate reliance on the supplied properties. We introduce MolP2SBench, a benchmark for molecular property-to-structure (P2S) reasoning in LLMs. Each task presents a masked molecular scaffold with given properties and asks the model to select the missing structure from plausible candidates. We shuffle or replace properties to test reliance on correct property-structure pairing and responsiveness to counterfactual property changes. A channel-wise leaderboard uses Property-Grounded Recovery (PGR), giving equal weight to source and counterfactual recovery. Evaluating seven models, we find that LLMs can use physical properties for structure prediction, but performance varies substantially across property types. Higher accuracy with a property does not necessarily imply greater responsiveness to it: a model may benefit more from $^1$H NMR than from $^{13}$C NMR, yet be less likely to change its prediction when the $^1$H data is replaced. LLM performance also need not reflect the relative difficulty of these properties for human chemists. Although UV-Vis spectra provide less direct structural information than NMR spectra, Astra achieves higher accuracy with UV-Vis data than with NMR peaks. MolP2SBench supports studying how LLMs extract and use physical-property information, revealing patterns that may differ from conventional chemical intuition and providing a foundation for more reliably property-grounded models for molecular and quantum-chemical inference. Code and dataset: https://github.com/DUAL-Xiao/MolP2SBench.

Variability is a crucial probe of active galactic nuclei (AGN) disks, but the impact of the structure and internal physics of the disk on this variability is poorly understood. We perform 3D multi-frequency radiation magnetohydrodynamic simulations of the $1300-5940~\rm{\AA}$ emitting region of an AGN disk. This turbulent disk simulation happens to stochastically have different disk thickness above and below the midplane. Light curves emitted from the thin top of the disk are broadly consistent with traditional variability models, where the X-ray irradiation emitted from the corona is the main driver of variability in UV-optical light curves. Conversely, the UV-optical light curves emitted from the thicker bottom of the disk are not strongly correlated with the X-ray light curve and have disk continuum reverberation mapping lags that are $3-5\times$ longer than the light travel time. While these features are inconsistent with traditional variability models, they are in good agreement with numerous recent observations. Our simulations allow us to interpret these recent observations with a new model for AGN disks, where the thicker disk leads to greater X-ray absorption, less X-ray reprocessing at larger disk radii, and a stronger signal from intrinsic variability driven by fluctuations in the AGN disk. In our simulations, we can measure the inflow timescale of these fluctuations as a long lag between light curves emitted from different disk radii. Understanding how disk structure impacts AGN variability and reverberation mapping can allow us to predict the thickness of AGN disks using UV-optical AGN light curves.

For $\Delta\ge2$ and $q\ge11\Delta/6$, we prove that the antiferromagnetic $q$-state Potts partition function on finite simple graphs of maximum degree at most $\Delta$ has no Fisher zeros in a graph-uniform complex neighbourhood of $[0,1]$. For $q>11\Delta/6$, the proof establishes coupling independence throughout $[0,1]$ using a soft version of Vigoda's flip dynamics. Our main tool is a separator-shell transfer theorem for the Potts model on induced-subgraph closed classes of graphs of maximum degree at most $\Delta$, with $q\ge\Delta+1$. It yields a graph-uniform zero-free neighbourhood of $[0,1]$ from Hamming coupling independence at $0$ and a uniform coupling-independence bound on each interval $[\delta,1]$, $\delta\in(0,1]$. We also obtain zero-free Lee-Yang polydiscs around the uniform field for vertex- and edge-colour fields. For Boolean Holant problems on bounded-degree graphs whose signatures come from a fixed finite family of log-concave symmetric signatures $f$ with $f(0)>0$, such as $b$-matchings, we obtain graph-uniform zero-free polytubes around every bounded box of nonnegative activities; their union is an open zero-free neighbourhood of the nonnegative orthant. An appendix summarizes further coupling-independence inputs and the zero-free regions they yield.

We study entanglement distillation under operations that remain completely positive under partial-transpose conjugation, a.k.a. PPT channels, in the standard quantum Shannon theory regime of asymptotically vanishing but non-zero error. Our main results are: (a) a regularised formula for the PPT distillable entanglement in terms of a measured-relative-entropy-like quantity; and (b) two different single-letter converses, one based on operator quadratic forms and the other on Hirschman's strengthening of the Hadamard three-line theorem. As an immediate application of (b), we show that the PPT distillable entanglement can be strictly smaller than the regularised Rains bound, thereby resolving an open problem in the theory of entanglement manipulation [Regula et al., NJP 21:103017, 2019]. A gap appears already for $3\times 3$ Werner states: at antisymmetric weight $25/26$, a certified upper bound of $0.62107$ ebits lies below the (regularised) Rains bound, which equals $\frac{25}{26} \log_2 5 - \log_2 3 \approx 0.64766$ ebits. On a different note, (a) implies a faithful lower bound on the PPT distillable entanglement in terms of the entanglement negativity, which provides a quantitative counterpart to the qualitatively known fact that any NPT state is PPT distillable [Eggeling et al., PRL 87:257902, 2001].

Just over 1% of the known radio pulsar population resides in the Large and Small Magellanic Clouds (MCs), the satellite galaxies that are 50-62 kpc distant from the Milky Way. These pulsars are important for constraining the peak of the pulsar luminosity function, and may give insights into neutron star populations formed from stars of different metallicities than the Milky Way. Using search techniques that have proven highly effective at discovering a large number of pulsars in archival data by folding candidates near the noise floor at high harmonic folds, we reprocessed the original Parkes Multibeam MC surveys and discovered six pulsars. Five of these pulsars are located in the Large Magellanic Cloud (LMC), including one with a spin period of 3.8s, making it the slowest pulsar known in the MCs. The remaining pulsar was detected toward the Small Magellanic Cloud (SMC), and is associated with the Milky Way foreground. Four of the newly discovered pulsars exhibit scintillation, with one showing clear nulling and others showing possible nulling behavior. These discoveries bring the total number of radio pulsars known in the LMC to 49. A luminosity function and duty cycle analysis of all current MC pulsars shows that they are consistent with Galactic canonical pulsars. Population synthesis simulations suggest that deeper surveys would reveal many more pulsars in the MCs, including up to handful of millisecond pulsars, based on the adopted upper limits for their parent populations. Finally, this reprocessing demonstrates the continued importance of reanalyzing archival data, both to improve the completeness of pulsar surveys and detect scientifically valuable objects.