Papers

In this work, an aSi and cSi heterojunction solar cell with an intrinsic layer is simulated using AFORS-HET software. The study focuses on the role of the electronic density of states DOS of the amorphous emitter, p type aSiH, in governing the performance of the HIT cell and the electronic transfer across the heterointerface. It is found that the DOS of the p type aSiH emitter can cause an unfavorable recombination and trapping effect, which becomes more severe and difficult to avoid when the bulk dangling-bond density in the a-Si emitter approaches or exceeds the doping concentration. An increase in deep trap density beyond a critical value causes a drop in the built in voltage and shifts the depletion layer into p type aSi. This situation leads to a sharp decline in HIT cell performance, namely the open circuit voltage and the fill factor, and to the appearance of an S shaped IV characteristic. The simulation results suggest that the emitter activation energy needs to be optimized to achieve high efficiency. Under optimal conditions, holes accumulate near the heterojunction interface, leading to the formation of an inversion layer. This paper presents a physical mechanism for recombination processes within the emitter and concludes with the optimized parameters required to achieve a HIT cell efficiency comparable to Sanyo record of 23 percent on a thin silicon wafer.

The Petz recovery map provides a near optimal decoder for approximate quantum error correction, but its inverse square-root normalization complicates circuit implementation. We use the polar structure of the Petz recovery isometry to implement recovery through a single quantum singular value transformation (QSVT). We give explicit block-encoding circuits and an extended recovery isometry that yields approximate Petz recovery without postselection. We bound the diamond distance between the approximate and ideal Petz encoding-recovery channels in terms of a spectrum-weighted loss, which provides a channel specific objective for optimizing the QSVT angles. Uniform polynomial approximation yields an asymptotic error bound that decays exponentially with the number of QSVT iterations, at a rate controlled by the smallest nonzero scaled singular value. Applications to Haar-random encoding and the Hayden-Preskill protocol illustrate the tradeoff between circuit depth and recovery accuracy and place existing scrambling decoders within a common Petz recovery framework.

The muon anomalous magnetic moment, $a_\mu = (g-2)_\mu/2$, shows a sizeable discrepancy between Standard Model (SM) predictions and direct measurements, hinting at either New Physics or limitations in modeling low-energy strong interactions. As the uncertainty in the SM predictions currently exceeds the experimental uncertainty by a substantial margin, further improvements in theoretical precision are essential to clarify the origin of this discrepancy. The SM theoretical uncertainty is dominated by hadronic processes. The hadronic light-by-light (HLbL) scattering contribution relies on highly accurate data for hadron production via two-photon fusion. Operating at $\sqrt{s}=3.773\,\text{GeV}$ with over $20\,\text{fb}^{-1}$ of integrated luminosity, the BESIII experiment is ideally suited to probe these processes at small momentum transfers. By precisely measuring channels like $e^+e^-\to e^+ e^-\pi^0$ and $e^+e^-\to e^+ e^-\pi^0\pi^0$, BESIII provides the critical experimental input necessary to sharpen the SM prediction and clarify the true nature of the $a_\mu$ anomaly.

No: neither through the bosenovae of gravitational atoms formed around stars and compact objects, nor through those of boson stars formed in the galactic dark-matter halo. We assume that all the dark matter consists of ultralight bosons with attractive self-interactions, which can be captured in the gravitational potential of astrophysical objects or condense into self-gravitating configurations. When these systems collapse in a bosenova, part of their mass is turned into relativistic radiation that escapes the galaxy. We bound the mass that a single object can eject and sum it over realistic models of the Milky Way and of other types of galaxies. For gravitational atoms, with realistic stellar populations and stellar evolution, the stars of the Milky Way deplete at most $\epsilon^{\rm GA}_\star\simeq3\times10^{-9}$ of its halo, and the pump is equally negligible in other galaxies. The central black hole, Sgr A$^*$, could reach $\epsilon^{\rm GA}\sim10^{-3}$, but only for a boson mass disfavoured by ultrafaint dwarf galaxies and beyond the validity of the perturbative treatment, where only a geometric bound on the dark matter flux is available. For boson stars feeding on the rest of the halo, these would radiate at most $\sim3\times10^{-5}$ of the Milky-Way halo and $0.1\%$ of a DF2-like one.

We model selected 6.7 GHz methanol flare profiles in G358.93-0.03 using the one-dimensional Maxwell-Bloch framework. The 2019 non-periodic flare, associated with an accretion burst, produced complex single-dish light curves characterized by sharp rises, multiple peaks, secondary structure, and extended decays. For six representative velocity channels, we model each light curve as a sum of scaled intensity responses from effective emitting systems driven by phenomenological pump pulses of fixed width but with component-dependent background rates, amplitudes, and arrival times. The inferred initial inverted column densities correspond to characteristic superradiance timescales $T_{R,0} \simeq 0.3$-$1.4~{\rm d}$, which are shorter than the adopted dephasing and relaxation timescales, $T_2 = 6.9~{\rm d}$ and $T_1 = 144.4~{\rm d}$. The fitted components therefore lie in the fast-transient superradiance regime. Existent VLBI observations motivate the possibility that a single-dish velocity channel blends emission from multiple unresolved flaring regions, although these observations are not used as direct fitting constraints. Although the decomposition is not unique, it provides a physically motivated description of the complex flare morphology within a unified Maxwell-Bloch framework.

How galaxies stop forming stars is a complex and central problem in astrophysics. Numerous physical mechanisms have been proposed, yet a simple, unified framework connecting these mechanisms remains lacking. Here, we derive a step-function quenching response from the fundamental principle of gas mass conservation, governed by the competition between gas-supply and gas-depletion timescales. This response also enables the gas-supply timescale to be inferred from the observed quenched fraction. Applying this method to approximately 350,000 galaxies, we find a characteristic gas-supply timescale of ~1 Gyr, reveal distinct inside-out and outside-in quenching signatures associated with supermassive black holes and dark matter halos, respectively, and identify galaxies with intermediate stellar surface mass densities as occupying a critical state for quenching and rejuvenation. Our work establishes a unified physical framework in which a simple step-function response captures how diverse physical processes regulate galaxy quenching and the resumption of star formation through their effects on the competition between gas-supply and gas-depletion timescales.

We extend Hintz's separation of variables for radiative gravitational and electromagnetic perturbations from Kerr-Newman to Kerr-Newman-de Sitter black holes. On subextremal backgrounds with nonzero rotation and charge, an explicit algebraic matrix transformation yields coupled two-component radial and angular ordinary differential systems linked by a common separation constant. The transformation is independent of the frequency and azimuthal number and applies to both signs of spin weight. For real frequencies, we establish a complete angular mode decomposition. We also translate regularity at the future black hole outer and cosmological horizons into ingoing and outgoing boundary conditions, respectively, for the separated radial systems. These results show that exact separation of the coupled radiative equations extends beyond asymptotically flat Kerr-Newman spacetime.

Widely used methods for identifying crystal structure in atomistic simulations are limited in practice to a handful of simple structures, leaving many important crystalline systems without automated classification techniques. Voronoi topology analysis offers a route to classifying arbitrary crystalline and defect environments, but realizing this potential first requires enumerating the Voronoi cell topologies that can arise under thermal perturbation of a structure of interest. We present an algorithm that deterministically enumerates all Voronoi cell topologies arising from generic infinitesimal perturbations of an arbitrary crystal structure, producing structural classifiers that extend automated identification to general crystalline systems. We demonstrate the approach on several structures of general interest.

A subset of active galactic nuclei (AGN) manifests as compact radio sources with peaked radio spectra, commonly referred to as peaked-spectrum (PS) sources. Generally, PS sources are interpreted as young radio jets, but the early evolution of the jet is rarely observed and not fully understood. Here, we present VT J182357-234511 (VT J1823-2345), a radio transient in the Very Large Array Sky Survey (VLASS) that resembles a PS source. Notable properties of VT J1823-2345 include: (i) brightening by a factor of 3 between 1996 and 2021 at 1.4 GHz, (ii) peaked spectra with high frequency peaks at $\nu_{\mathrm{p,obs}}\gtrsim6\,\mathrm{GHz}$, (iii) a peaked 3 GHz light curve that has been fading since 2023, (iv) a resolved Gaussian (major-axis) size of 0.4 mas in 2024, and (v) a linear polarization fraction $p_{\mathrm{L}}\simeq0.73\%$ at 8.8 GHz with an extreme Faraday rotation measure $\mathrm{RM_{\mathrm{obs}}} \sim +12,000\,\mathrm{rad}\,\mathrm{m}^{-2}$. On the sky, VT J1823-2345 coincides with a supernova remnant and an F-type star, but no background galaxy is seen. Based on the multi-wavelength properties, we disfavor Galactic transients, explosive extragalactic transients, and blazar variability as plausible explanations. We argue that VT J1823-2345 is consistent with a "short-lived" parsec-scale PS source with a decades-old jet that does not grow into a large-scale radio galaxy. From comparing the full VLASS light curves, we speculate that VT J1823-2345 is similar to many VLASS nuclear transients reported in the literature, which may represent an emerging class of transient radio jets, perhaps related to episodic AGN activity or jetted tidal disruption events.

We study large-k symmetric and antisymmetric Wilson loops in N=4 super-Yang-Mills theory. We represent their generating functions as Fredholm determinants built from the Hermite kernel weighted by a symbol function that encodes the representation. Using the integrable structure of the kernel, we systematically apply the Tracy-Widom approach to derive a closed system of integro-differential equations. The equations are then solved order by order in 1/N by a WKB ansatz, while keeping the symbol function general. We find a closed-form expression for the leading and subleading order contributions to the generating functions. Finally, specializing to the two representations, we perform the large-k saddle-point analysis and find the subleading contribution to the Wilson loop. Our results confirm the previously observed discrepancies with the dual D-brane description of giant Wilson loops.

Replica Symmetry Breaking (RSB) theory for spin glasses, which is exact in infinite dimensions, provides detailed predictions for the behavior of these systems. One of these predictions is that vanishing magnetic fields induce chaotic behavior. Here, vanishing has a precise meaning: we refer to an externally applied magnetic field with intensity scaling as $1/\sqrt{N}$, where $N$ is the number of spins in the system. RSB predicts that this chaotic behavior depends only on the probability density function of the overlap, $P(q)$, as computed at zero field. We proceed to test the RSB prediction in the 3D Edwards-Anderson model, by first computing the $P(q)$ numerically in the absence of a magnetic field. We then use this function as input to analytically compute the statistics of the states in the regime of a vanishing magnetic field, using a representation based on the Bolthausen-Sznitman coalescent process (which is exact for the mean-field Sherrington-Kirkpatrick model). This mixed numerical-analytical approach allows us to determine the prediction of RSB for the overlap distribution function measured in the presence of a small vanishing field, as well as the increase in chaoticity as the field strength grows. The above RSB predictions are quantitatively compared with the outcome of numerical simulations of the three-dimensional Edwards-Anderson in the presence of a small vanishing field, finding very good agreement. This agreement provides strong support for the idea that three-dimensional spin glass at zero magnetic field and low temperature is well described by RSB theory.

Anharmonic intensities reveal vibrational coupling that band positions alone cannot determine. We derive explicit second-order infrared transition moments in curvilinear normal coordinates, including kinetic metric derivatives and transport through variational resonance polyads. The vibrational perturbation-to-second-order-then-diagonalization (VP2TD) treatment covers fundamentals, overtones, three-quantum transitions, and hot bands. A general computational platform combines Extended Symmetry-Adapted Local Coordinates (ESALCs), using Cartesian (ESALC-C) or internal (ESALC-I) primitives, with interchangeable quantum-chemical programs and parallel finite differences. Independent oscillator matrices verify the intensity equations; a molecular water check reproduces second-order amplitudes within $8.4\times10^{-8}$ atomic units. Comparisons with established tools reproduce a formaldehyde Fermi polyad within 0.163 cm$^{-1}$ and 0.061 km mol$^{-1}$ and water Raman activities within $10^{-7}$ Angstrom$^6$. For 29 matched formaldehyde rotational line pairs, the predicted hot-to-fundamental intensity ratio, using the measured lower-state energy, is consistent with the nuclear-spin-corrected median: the differences are 3.9% (ESALC-I) and 3.8% (ESALC-C), compared with a 15% uncertainty estimate for individual measured line intensities. Common analytic reference derivatives ensure identical harmonic observables, while internal coordinates reduce and localize intermode anharmonic couplings. Rotation-vibration constants extend the same tensor treatment. An integrated adiabatic discrete-variable representation treats large-amplitude motions, and finite-level partition functions provide anharmonic thermochemistry.

Trapped-ion devices are being investigated for transportable applications, including the transfer of exotic charged particles between laboratories and the development of portable quantum technologies. To date, ion transport has been demonstrated only in magnetic (Penning) traps, whereas radiofrequency (Paul) traps are the predominant platform in quantum science. Here, we report the first transport of a few thousand ions confined in a linear Paul trap over distances of several kilometers, with transport durations of 15 and 45 min. These results establish a foundation for mobile trapped-ion quantum devices capable of operating while in motion and may enable the transport of exotic ions in Paul traps between experimental facilities.

We study quantum spectrum and eigenstate property estimation using multiple initial states and generalized Hadamard tests. Building on the QFAMES (quantum filtering and analysis of multiplicities in eigenvalue spectra) framework, we introduce a new method that samples evolution times independently for each initial-state pair. Under the stated assumptions, when statistical error determines the sampling cost, the total Hamiltonian simulation cost required for fixed-accuracy eigenvalue and observable estimation is independent of the number of initial states, up to logarithmic factors. This improves scalability when many initial states are needed to explore the target eigenspaces. The method also reduces the cost of multiplicity recovery and retains Heisenberg-limited scaling for eigenvalue estimation. Numerical experiments support the predicted statistical error scalings.

Stochastic physical computers use random transitions between states to process inputs. We quantify their ability to solve distinct tasks as the control parameters of a device vary. For Markov jump devices, we bound the number of classification tasks attainable at a prescribed output margin, with each task defined as a binary labeling of fixed inputs. Combining geometric packing with fluctuation-response inequalities, we bound this number in terms of the control range and dimension, rate sensitivities, output fluctuations, and entropy production. For state and net-current observables, when controls change kinetics without changing thermodynamic forces and energies, the number of tasks is shaped by entropy production and output fluctuations. If the product of their maximum values over the allowed control settings and inputs is too small, the device can perform at most one task. An exactly solvable two-state switch illustrates how sufficient driving and observation time enable barrier tuning to select copying or inversion.

Recent LHAASO observations indicate that microquasars and massive star clusters contribute to Galactic cosmic rays, and likely also to the pre-knee spectral hardening. Their markedly different astrophysical environments, compared with supernova remnants (SNRs), may imprint distinct cosmic-ray abundances. We investigate the spectra and composition of new-source cosmic rays under two abundance scenarios: Case-1, the SNR-like composition with enhanced heavy nuclei, and Case-2, the surface abundances of microquasar companion stars. We constrain injection spectral indices using LHAASO proton, helium, and all-particle spectra, and use their <lnA> data for model discrimination. Under the assumption of a unified heavy-element injection spectrum, Case-2 fits the <lnA> data significantly better than Case-1, but at the cost of large, physically unmotivated differences between heavy-element and He injection indices. This suggests the need to either relax the unified heavy-element injection-index assumption or explore alternative abundance patterns. We predict that if the new-source composition follows Case-1, the individual elemental spectral indices before the knee should remain nearly consistent; if it follows Case-2, the Mg, Si, and Fe spectra will be significantly softer than those of He, C, and O. Future element-resolved energy-spectrum measurements by HERD and LHAASO will provide a decisive test of this discriminating feature.

The probability of interstellar contact depends not only on the abundance of technological civilizations but also on their spatial connectivity. Treating civilizations as nodes linked whenever their separation is smaller than the distance a signal travels within a communicative lifetime, we determine the radial structure of Galactic civilization networks. An exponential stellar disc replaces the uniform disc of earlier work, and the fraction of stars hosting civilizations may vary with radius as a Galactic Habitable Zone (GHZ). The isolation, contact and network transitions are frontiers several kiloparsecs wide, not boundaries: the contact frontier is set entirely by the disc scale length, and the network frontier, broadened by gradient percolation, stays near 1.5 scale lengths. The two frontiers overlap over a band containing the Sun, where both transitions proceed at once. Within this factorized GHZ model, the radius of peak civilization density depends only logarithmically on the strength of supernova sterilization, and the wide range of published peak radii, from the Galactic centre to 12 kpc, is reproduced primarily by varying that one parameter. Under the present normalization, the location of the zone has only a modest effect on the local contact probability, whereas the modelled Galactic connectivity is minimized when the civilization-density peak lies near the solar Galactocentric radius, where current determinations place the peak.

Lab-scale membrane distillation (MD) modules are commonly used for membrane characterization and developing empirical heat-transfer correlations. Entrance-induced flow structures can introduce geometry-specific effects into measured temperature polarization (TP) and heat transfer. However, the dependence of these effects on module geometry and flow condition remains unclear. We performed three-dimensional computational fluid dynamics (CFD) simulations of direct contact membrane distillation (DCMD) over inlet Reynolds numbers of $\Re_{\mathrm{in}}=10$-$1000$, focusing on side-chamber length and main-channel height. We discovered that counter-rotating streamwise vortices formed near the main-channel entrance across all geometries, but their downstream persistence increased with $\Re_{\mathrm{in}}$. At lower $\Re_{\mathrm{in}}$, the vortices mostly decayed before mid-channel, while at higher $\Re_{\mathrm{in}}$ they persisted farther downstream and produced pronounced spatial variations in TP. Increasing side-chamber length reduced the secondary-flow kinetic energy entering the main channel, and generally strengthened TP, whereas increasing main-channel height reduced the bulk velocity and streamwise kinetic energy, resulting in a thicker thermal boundary layer and stronger TP. For most geometries, the deviation from the straight-channel baseline changed from stronger TP at lower $\Re_{\mathrm{in}}$ to weaker TP at higher $\Re_{\mathrm{in}}$. Entrance effects therefore vary in both magnitude and direction with operating condition and cannot be represented by a constant correction across the Reynolds-number range.

We prove a new extension principle for the spherically symmetric Einstein–Maxwell–charged scalar field system. Rather than imposing conditions for mass ratio $2m/r$ as in Christodoulou's small-mass-ratio criterion or as in An–Chen–Singh's proof [1] with $2m/r<3/8$, here we work through a proposal by An-Tan [2] with finite Doppler exponent (blueshift). By conducting two successive blow-up analyses, followed by a stationary comparison and a rigidity argument, we establish the uniform boundness of $\alpha'$ with $\alpha'=\partial_v\alpha/\partial_vr$ and $\alpha=\partial_v(r\phi)/\partial_vr$. This provides the desired extension principle in An-Tan [2] and completes the picture of weak cosmic censorship developed therein. As we were about to release our preprint, Cicortas communicated to us that together with his collaborators, they concomitantly used a different approach to obtain the corresponding extension principle with finite blueshift (Doppler exponent) for the uncharged Einstein-scalar field system. Hence, we decided to put the current paper as an appendix to An-Tan [2], thereby completing the proof of the weak cosmic censorship for the Einstein-Maxwell-charged scalar field system. At the same time, we are working with Cicortas and his collaborators to write a new preprint containing both approaches for the Einstein-scalar field system.

We present a new quantitative, scale-critical $C^1$ extension principle for the spherically symmetric Einstein–scalar field system. We derive estimates for solutions in the causal past of a possibly singular endpoint $\mathcal{O}$ of the center. Assume that there is no trapped surface in this region and assume that the Doppler exponent (blue shift) along each incoming null cone is uniformly bounded. We then prove that the solution can extend regularly across $\mathcal{O}$ provided the mass ratio $\mu=2m/r$ satisfies $\sup\mu<\frac38$. This improves the small-mass-ratio condition in Christodoulou's extension principle by an explicit threshold of order one. Our proof has three new ingredients. First, we derive several new uniform scale-critical pointwise estimates for the scalar field and its derivatives. Second, we obtain refined estimates in an exterior self-similar domain within the triangular causal past region. Third, we establish a family of higher-order Morawetz-type identities and identify the ranges of $\mu$, with which there are coercive spacetime estimates. The unweighted identity yields the threshold $\mu\leq\frac14$, while employing extra self-similar weight raises the threshold to $\mu<\frac38$ and provides a weighted control, which implies that the solution's BV norm along an outgoing null cone is small, so that Christodoulou's theory of bounded variation solutions gives the extension.

Line intensity mapping (LIM) provides a unique window into the high-redshift universe, but the separation of signals from overlapping emission lines and bright continuum foregrounds remains a central analysis challenge. At millimeter wavelengths in particular, [CII], [CI] and numerous CO transitions overlap with comparable brightness, leading to significant spectral confusion. This work presents a joint likelihood framework that incorporates multi-tracer cross-correlations both between distinct LIM tracers and with external galaxy surveys. By jointly fitting all auto- and cross-spectra between the LIM and galaxy data, this approach combines the spatial and spectral information in each dataset to break degeneracies between overlapping lines and recover individual bias-weighted line intensities at fixed cosmology, even at redshifts where no direct cross-correlation is available. We validate this framework on realistic mocks of an extended SPT-SLIM-like survey spanning 125-175 GHz over 100 deg$^2$, combined with an LSST Y1-like photometric galaxy catalog, and recover CO(2-1) through CO(6-5) and [CI](1-0) over $0.3\lesssim z\lesssim4$ in the presence of bright continuum foregrounds. We demonstrate that adding the photometric galaxy data tightens line constraints by a factor of $\sim$3-4 where the galaxies overlap the lines in redshift, and by $\sim$20-50% at higher redshifts beyond the galaxy coverage, where the gain comes indirectly from constraining the low-redshift interlopers. These results highlight external tracer overlap as a primary consideration when optimizing the frequency coverage and footprint of near-future LIM experiments.

We establish topological recursion for the spin enumeration of hypermaps, or, in the dual language, spin dessins d'enfants. This problem has remarkable features distinguishing it from other applications of topological recursion to enumerative combinatorics. First, the spectral curve is elliptic rather than rational, as in most cases studied before. Second, it contains degenerate ramification points, and one has to apply a version of degenerate topological recursion. Finally, the meromorphic correlator differentials have "moving" poles on the antidiagonals between pairs of distinct arguments, and one has to adjust the loop equations to this kind of degeneracy as well. The computations involve concepts of different kinds, such as BKP integrability, Gaussian integrals, the x-y swap, and symplectic duality.

We present a stochastic calculus approach for modeling generalized parton distribution functions using information provided from lattice QCD calculations of Mellin moments, without assuming a functional form. Reconstructing the underlying dependence on the partonic momentum fraction from a limited number of moments constitutes an intrinsically non-unique inverse problem. Our goal is to provide a model agnostic way to determine GPDs subject to integral constraints. Thus, we derive and show usage of a controlled Langevin approach based on stochastic calculus and Brownian motion. The method combines a variational formulation, based on minimizing a Dirichlet action subject to the imposed constraints, with stochastic dynamics that generates an ensemble of admissible functions. The resulting ensemble provides a preferred reconstruction and characterizes the variability associated with incomplete integral information within the chosen stochastic model. The framework can accommodate general integral kernels and prescribed function values, offering a flexible approach to reconstructing functions from indirect constraints. Beyond its application to GPD phenomenology, the method provides a general strategy for investigating inverse problems in which integral observables are known but the underlying functional dependence remains undetermined. The approach may have more general applications beyond the scope of studying 3D hadron structure, and it is particularly useful in situations where we know definite integrals of functions with kernels, but do not know the underlying function.

Extracting the London penetration depth, $\lambda(T)$, from the measured magnetic susceptibility, $\chi(T)$, of a superconducting platelet in a perpendicular magnetic field requires knowing the function $\chi(\lambda)$ computed for the actual sample geometry. Thin films are increasingly important in quantum computing and superconducting electronics, most of which operate at ultra-low excitation fields in the vortex-free regime. Understanding their electromagnetic response in the Meissner–London (finite-$\lambda$, no vortices) state is therefore essential for extracting intrinsic properties such as the London penetration depth and superfluid phase stiffness. While numerous prior works have addressed different aspects of this problem, here we focus on providing an analytical semi-empirical representation of $\chi(\lambda)$ based on the 2D sheet-current model and establishing the limits of its applicability using two independent full 3D numerical solutions: finite-element modeling and a volume-current integral equation. As a result, we provide $\chi(\lambda)$ for a disc of radius $a$ and thickness $d$ in closed form, valid for all $\lambda$ and for aspect ratios $\delta\equiv d/(2a)\le0.05$, and accurate to $0.1\%$. The two-dimensional sheet description with Pearl length $\Lambda=2\lambda^2/d$ is adequate for $\delta \lesssim10^{-4}$ and $\lambda \gtrsim 4d$. Thicker films require the full closed form, which includes the three-dimensional corrections. Using the same numerical analysis, we provide an empirical formula that maps rectangular samples—the geometry most commonly used in experiments—onto a disc with an “effective radius” for subsequent calculation of $\chi(\lambda)$, and formulate a complete calibration protocol for whole-sample susceptibility measurements.

We show that graphene nanoflakes realize a previously unexplored form of orbitronics in which orbital currents emerge in the absence of intrinsic angular momentum of the constituent atoms. Starting with a hexagonal graphene nanoflake, we demonstrate the presence of energy-degenerate eigenstates with opposite non-zero expectation values of the angular momentum. Placing electrodes in an appropriate configuration on the flake couples the reservoirs more strongly to one of the two opposite-angular-momentum states, yielding a chiral current that carries a net orbital angular momentum. The resulting circulating orbital currents generate magnetic fringe fields that are experimentally accessible with spin centers or superconducting quantum interference magnetometers, providing avenues for their experimental realization. Finally, our work establishes a new platform for exploring and studying orbitronics in zero-dimensional systems.

We present the first analytic computation of the time-domain multipoles of the gravitational waveform from hyperbolic black-hole scattering at leading order in the post-Minkowskian expansion, to all orders in velocity. We perform the partial-wave projection as a cut loop integral, which enables the use of dimensional regularization and associated integration techniques. As opposed to the frequency domain, the time-domain multipoles are logarithmic and do not contain Bessel-like functions. Our results pave the way for the incorporation of post-Minkowskian fluxes in waveform models for binary mergers.

We obtain a systematic understanding of the time-domain gravitational waveform of hyperbolic black-hole scattering at first order in the self-force expansion and all orders in the post-Newtonian/post-Minkowskian (PN/PM) expansion. The continuous frequency spectrum of unbound orbits makes the inverse Fourier transform to the time domain diverge order by order; we introduce a dimensional-regularization-inspired prescription that cures this uniformly. We show that the full waveform then follows, at any PM and PN order, from a single family of integrals, generated by the Lauricella function $F_D^{(3)}$, which we calculate using strategies familiar from the study of Feynman integrals. As a proof of principle, we use this understanding to compute the quadrupolar 1SF waveform through relative 10PM-20PN, that is to order ${\cal O}(G^{10} v^{42})$, the full 1SF waveform to 10PM-10PN, as well as the asymptotic fluxes and the dissipative scattering angle at the corresponding accuracy.

In small collision systems strange hadrons are suppressed, and the suppression grows with the number of strange quarks. Exact strangeness conservation in a finite volume accounts for this, but when it is imposed on hadrons it leaves the $\phi$ meson unsuppressed, contrary to observation. We impose the conservation law on the strange quarks in a causally connected cluster, before hadronization, and count separately the combinations of a strange quark with the antiquark created together with it. A pair created from the vacuum cannot form a $\phi$, a pair created from a gluon can only if it loses its color. With one function of multiplicity, the mean number of strange quarks per cluster, the model describes kaons, $\phi$, $\Xi$ and $\Omega$ in pp and p–Pb collisions at the LHC; the data require that about half of the same-pair combinations are excluded from the $\phi$, and reject both an unsuppressed $\phi$ and a $\phi$ built only from different pairs at about five standard deviations. The same-pair combinations are those that carry the spin correlation observed in $\Lambda\bar\Lambda$ production, whose dilution is thereby tied to the $\phi$ suppression and is predicted to decrease with multiplicity

QCD calculations that use multihadron fragmentation functions usually involve multiple invariant mass scales simultaneously, with only one being the hard scale associated with an overall hard process. The other scales are associated with relative internal motion intrinsic to the fragmenting parton and the multihadron system. Nonperturbative contributions to this later type of dependence attract interest for their association with intrinsic partonic structures, but care is needed in disentangling the truly nonperturbative effects from perturbative behavior and relating the former to universal nonperturbative matrix elements. To this end, we show how to evolve collinear multihadron fragmentation functions in a way that accounts for the simultaneous presence of these extra scales. The general multihadron fragmentation functions evolve in the same way as ordinary single hadron fragmentation functions, with the dependence on the extra scales separated out. We use this to unify treatments of perturbative and nonperturbative effects in multihadron systems in a way that optimizes for interpretations focused on partonic structure.

The lower-symmetry $Am2m$ structure was recently proposed as the intrinsic ambient-pressure phase of La$_3$Ni$_2$O$_7$ based on synchrotron x-ray diffraction, whereas earlier studies investigated its properties assuming the commonly accepted $Amam$ structure. Here, we reexamine the crystal structure in La$_3$Ni$_2$O$_7$ and the spin configuration of spin-density-wave (SDW) state via $^{139}$La nuclear quadrupole resonance (NQR). The observation of two distinct La(2) sites in the NQR spectra is naturally accounted for by the $Am2m$ structure without any special assumptions, whereas it cannot be reconciled within the $Amam$ framework. Within the $Am2m$ framework, we reanalyze the spin configuration of the SDW phase and identify it as a large-tiny spin-stripe structure, arising naturally from two inequivalent Ni sites with large and tiny magnetic moments. These results establish the itinerant nature of the SDW order at ambient pressure in La$_3$Ni$_2$O$_7$, providing a basis for understanding its relationship to the emergence of high-$T_c$ superconductivity under high pressure.