Papers

Recently, the Super-Kamiokande Collaboration reported an indication of the diffuse supernova neutrino background (DSNB) with a statistical significance of $2.6\sigma$. Motivated by this possible discovery, we investigate the impact of axion cooling on the DSNB flux on the basis of long-term neutrino-radiation hydrodynamic simulations. We compare the observed flux and our models and obtain a $1\sigma$ upper limit $|g_{ap}|<1.3\times10^{-9}$ on the axion-proton coupling constant, which is comparable to the conventional limit based on the SN 1987A neutrino burst. In contrast to the SN 1987A bound, the DSNB constraint does not rely on the properties of a single observed supernova, because the DSNB represents the cumulative neutrino emission from a cosmic population of core-collapse events. More generally, this approach can be applied to other feebly interacting particles that modify protoneutron-star cooling.

The effective half-light radius $R_e$ marks an arbitrary 50-per-cent light boundary, and scaling relations involving such `effective' radii and their associated surface brightnesses, $\mu_e$, systematically (and undesirably) vary as the percentage changes. Here, the projected radius $R_5\equiv R_{-2}$, where the logarithmic slope of the surface-brightness and intensity profile equals 5 mag/dex and -2, respectively, and where the luminosity per logarithmic radial interval is maximal, is developed as an alternative. It can be measured non-parametrically or with a parametrized fit. For the Sérsic $R^{1/n}$ family, $R_5=(2n/b_n)^nR_e$, with $R_5/R_e$->e$^{1/6}\approx$1.181 as n->$\infty$. Reparameterizing the (now $b_n$-free) $R^{1/n}$ model in terms of $R_5$ and $\mu_5$ removes the non-linear $R_e$-n coupling, and because the local slope is 5 mag/dex at $R_5$, correlated measurement errors in $R_5$ and $\mu_5$ better cancel when deriving the inferred total magnitude ($\propto\mu_5-5\log R_5$). Additionally, an exact single-integral identity is provided to relate any projected light percentage to the percentage within a sphere of the same radius. The scale radius $R_5$ is shown to be connected, through a weakly n-dependent factor to the anisotropy-insensitive internal radius $r_{-3}$, yielding a refined n-dependent Wolf-type mass estimator $M_{-3}$ and spatial mass-to-light ratio $(M_{dyn}/L)_{-3}$. Specifically, $M_{-3}\approx4G^{-1}<\sigma_{los}^2>R_{-2}\approx4.72G^{-1}<\sigma_{los}^2>R_e$. Past half-light substitutions in dynamical mass estimators introduce systematic Sérsic-dependent offsets of 12-18 per~cent in enclosed mass and offsets spanning >20 per~cent in the mass-to-light ratio within $r_{-3}$. Dynamical mass estimators appropriate for (dark matter)-free stellar systems are also provided, and all relations are implemented in the companion Python package R5Tools.

We investigate infrared line signatures from radiatively decaying sterile-neutrino dark matter using publicly available JWST/NIRSpec IFU blank-sky observations. The main signal considered is the sterile-to-sterile transition $N_1\to N_2\gamma$, induced by the transition magnetic dipole coefficient $d_{NN\gamma}$, with $m_1>m_2$. In contrast to ordinary two-photon decays of axion-like or Majoron-like particles, the observed photon energy is not fixed by the full dark matter mass, but by the small mass splitting $\Delta m=m_1-m_2$. Thus, a keV-scale sterile-neutrino dark matter state can generate an eV-scale infrared photon line in the JWST band. We construct a $\chi^2$-based line-search analysis using the NIRSpec IFU $\rm F170LP$-$\rm G235M$ blank-sky data toward $\rm GN\text{-}z11$, modelling the smooth continuum with a cubic spline and including the Milky Way halo decay flux. In the absence of a significant excess, we derive projected limits on $d_{NN\gamma}$ and on the decay width $\Gamma_{N_1\to N_2\gamma}$ for $0.1~{\rm eV}\lesssim\Delta m\lesssim1~{\rm eV}$. For a sterile component saturating the dark matter abundance, the strongest sensitivity reaches $d_{NN\gamma}\lesssim7\times10^{-14}~{\rm GeV}^{-1}$ and $\Gamma_{N_1\to N_2\gamma}\lesssim10^{-25}~{\rm s}^{-1}$. We also include a minimal anomalous-Majoron benchmark, $\omega\to\gamma\gamma$, obtaining JWST sensitivity to $\lambda_{\omega\gamma\gamma}\sim10^{-11}$-$10^{-9}~{\rm GeV}^{-1}$ for $m_\omega\sim0.6$-$1~{\rm eV}$.

Magnetic droplets are highly nonlinear spin-wave solitons that can be excited in nanoscale spintronic devices with strong perpendicular magnetic anisotropy. Although extensively studied in nanocontact-based spin-torque oscillators, their stabilization in pure spin current-driven devices such as spin Hall nano-oscillators (SHNOs) has remained elusive. Here, we micromagnetically demonstrate the robust stabilization of non-propagating high-frequency droplets in CMOS-compatible W/CoFeB/MgO nanoconstriction SHNOs under oblique magnetic fields. While the constriction geometry gives rise to noncircular droplet shapes in an inhomogeneous effective field landscape, stable droplet modes exhibiting complete core magnetization reversal and pronounced hysteresis are observed. At lower current densities, droplets display breathing oscillations with periodic expansion and contraction, whereas higher drive currents lead to drift, deformation, and the emergence of sidebands around the fundamental frequency. Tuning the strength and orientation of the applied magnetic field alters the effective field landscape, allowing droplets to escape confinement and propagate over distances exceeding 2$\mu$m.

Currently, the CP-violating phase $\delta$ is the least precisely known among the neutrino mixing parameters. In the coming years, accelerator neutrino experiments such as DUNE and Hyper-K will measure $\delta$, significantly increasing the precision. Such a measurement is usually performed by comparing the oscillation probabilities in the neutrino and antineutrino sectors, thereby directly observing the CP violation. This approach, however, has some downsides: in particular, it is more challenging to obtain good statistics in the antineutrino sector, leading to increased statistical errors. In principle, however, it is possible to determine $\delta$ by looking only at the neutrino sector, studying the energy dependence of the oscillation probability. We investigate this possibility in detail; we find that, if this approach is used, the main issue would be the degeneracies with other mixing parameters, which affect the sensitivity to $\delta$. Those parameters, however, have already been measured with great precision, which will increase even more in the next few years; if those constraints are taken into account by introducing Gaussian penalty terms in the $\chi^2$, it is possible to achieve better results focusing only on the neutrino sector, rather than using the standard approach. Those degeneracies could also be broken by exploring a wider range of $L/E$: this can be achieved, for instance, by increasing the neutrino energy. In this way, the total beam intensity could also increase due to the relativistic boost (however, the conversion efficiency could decrease, affecting the total luminosity). We find that if the relativistic boost increases the number of events in the high-energy configuration, the best performance would be achieved in such a set-up; otherwise, the optimal approach would be to focus only on the neutrino mode without changing the beam energy.

This work proposes a semi-analytical theory for improving orbit design of the GARATÉA-L Brazilian lunar mission. The dynamical model incorporates the lunar gravitational potential up to degree 12 and order 3 harmonics and a third-body perturbation model accounting for the eccentricity and inclination of the Earth's orbit with respect to the Moon. Through Hori's method, short- and medium-period terms are eliminated from the Hamiltonian to derive a first-order theory in mean orbital elements. It is demonstrated that nominal frozen orbits designed under simplified circular and equatorial assumptions for the motion of the third body are not maintained in this more realistic dynamical environment, leading to significant eccentricity growth and potential collisions of the probe with the lunar surface. The inclusion of the third body's inclination and eccentricity breaks the system's axial symmetry, introducing the longitude of the ascending node into the double-averaged variational equations and rendering stationary frozen orbits practically unattainable. Consequently, the problem is addressed through a parametric study around the simplified model's frozen conditions to identify “low-drift" states where eccentricity variations are highly decreased. A new nominal orbit is proposed for GARATÉA-L. Numerical validation against high-fidelity propagation and JPL ephemeris confirms that this new configuration maintains the “low-drift" behaviour throughout the mission, ensuring orbital safety and avoiding the collision predicted by simpler models.

We compute the renormalized scalar vacuum polarization $\langle \phi^2 \rangle$ of a massive, non-minimally coupled quantum field in the Hartle–Hawking state exterior to a family of static, spherically symmetric quantum-corrected, effective and regular black holes: the Kazakov–Solodukhin quantum-deformed black hole, the two effective loop-quantum-gravity geometries of Zhang–Lewandowski–Ma–Yang, the renormalization-group improved Schwarzschild black hole of Bonanno–Reuter, and the Bardeen regular black hole. We adapt the extended point-splitting mode-sum formalism, implemented as a high-performance code, and present the exterior profile of the vacuum polarization over a grid of the quantum-deformation parameter, the field mass $\mu=mM$ and the curvature coupling $\xi$. The five geometries display qualitatively distinct horizon responses. In all five geometries the deformation imprint is governed by the sign of the background Ricci scalar through the DeWitt–Schwinger curvature term linear in $(\xi-1/6)\mathcal{R}$, and is strongly suppressed at conformal coupling. We verify this both in magnitude and in the $\xi$-dependence. In the near-extremal regime of the two geometries with inner horizons we find a sign change of the horizon polarization at light field mass – absent for Reissner–Nordström at matched temperature and removed by conformal coupling – identifying a genuinely quantum-geometric, de-Sitter-core-driven regime. Every result reduces to the Schwarzschild value in the classical limit, validating the calculation.

We implement a moving boundary condition in a 1D quantum liquid to study nonlinear wave breaking and its regularization by dispersion. Programmable optical potentials allow us to compress a weakly interacting ultra-cold Bose gas trapped on an atomchip at tunable speeds of up to three times the speed of sound and we subsequently measure the quasi-in-situ density distribution to extract the shock wave edge dynamics. We resolve both leading and trailing edge velocities and observe a shock wave width that increases linearly in time, which are distinguishing features of dispersive shock waves, consistent with asymptotic predictions using Whitham's method. Quantitative agreement is found with finite temperature non-polynomial Schrödinger equation simulations, taking into account the imaging process and the finite height of the piston potential. Our results constitute a controlled, quantitative test of dispersive shock dynamics in a 1D quantum fluid and demonstrate that the coarse-grained dispersive-shock phenomenology remains robust even as the microscopic dynamics depart from the strictly integrable 1D regime.

In this paper, we investigate the convergence of an implicit defect-correction solver for a viscous discretization based on the alpha-damping scheme for unstructured grids. We show that significantly more robust iterative convergence is achieved by evaluating the damping term at the midpoint between two adjacent cell centers (edge midpoint) rather than at the face centroid. A one-dimensional Fourier analysis reveals that the implicit solver tends to be stable when the damping term in the residual is smaller than that used to construct the Jacobian. This observation suggests that the solver can be stabilized by effectively reducing the magnitude of the damping term in the residual - an effect achieved by the edge-midpoint evaluation. Robust convergence is demonstrated numerically for two-dimensional viscous-flow problems on highly irregular mixed-element and triangular grids.

Fast Radio Bursts probe ionised baryons through their observed dispersion measures. We present \turbofrb, a semi-analytic stochastic forward model for the intergalactic dispersion-measure distribution, $P({\rm DM}_{\rm IGM}\mid z)$, that resolves the diffuse IGM, halo, and filament contributions as explicit physical channels, with the halo and filament encounter rates coupled by a latent line-of-sight environmental variable. Only four effective parameters are calibrated against hydrodynamical ray-traced IllustrisTNG benchmark. The model matches the benchmark mean DM to the percent level and yields a per-redshift Jensen-Shannon divergence of at most $5\times10^{-3}$ across $z = 0.5$-$2.5$. The per-sightline channel decomposition makes explicit what closed-form parametric descriptions cannot show: the diffuse IGM sets the body of the distribution, while halos and filaments populate the high-DM tail. Applied to representative localised FRBs, the forward likelihood quantifies host-excess events independently of their astrophysical signatures and recovers the injected $H_0$ within $1\sigma$ in a closed-loop consistency test. The \turbofrb package is available at \href{https://github.com/jefersonfortunato/turbofrb}{github.com/jefersonfortunato/turbofrb}.

Using supersonic expansion, we create a time-gated, directional beam of Xe atoms with a narrow momentum distribution and detect their collisions with a levitated nanosphere cooled to its quantum ground state. We observe individual momentum kicks below 50 keV/c with 96% confidence and distinguish directional momentum transfer from the atomic beam against the background of thermal collisions. Our experiments constitute a first step toward the exploration of distance-dependent short-range interactions between atoms and levitated systems, as well as toward the use of levitated platforms for impulsive force sensing in previously unexplored parameter regimes.

Plasmon-enhanced fluorescence (PEF) is one of the most widely investigated optical phenomena in hybrid systems of emitters and plasmonic nanoantennas, with applications ranging from biosensing to single-molecule emission microscopy. In this work, we extend finite-element modelling of PEF beyond spherically symmetric geometries using a body-of-revolution finite-element method (BOR-FEM). By exploiting exact or equivalent rotational symmetry, 3D emitter-nanoantenna systems are reduced to computationally efficient 2D formulations while retaining the essential electromagnetic interactions governing excitation and emission. We validate the framework against three previously investigated emitter-nanorod systems, including one requiring an equivalent axisymmetric geometric transformation, before applying it to an emitter-core-shell nanorod system. Specifically, we investigate the PEF of the terminal chlorophyll emitter of the major plant light-harvesting complex (LHCII), the most abundant membrane protein on Earth, interacting with a gold core-dielectric shell nanorod with one or two dielectric shells. The simulations reveal that the interplay between excitation enhancement, radiative-rate enhancement, and non-radiative Ohmic losses gives rise to four distinct shell-thickness-dependent operating regimes (quenching, enhancement, suppression, and decoupling), with recovery of the intrinsic quantum yield in the decoupling regime. The predicted enhancement factors for experimentally relevant dual-shell nanorods agree well with previously reported measurements. These results establish BOR-FEM as an efficient and versatile framework for modelling PEF in rotationally-symmetric nanoantenna geometries and in non-axisymmetric geometries that admit equivalent axisymmetric representations, providing a practical route for the rational design and optimisation of plasmon-enhanced bio-nanophotonic systems.

We develop a quantum algorithm for slow analytic Hamiltonians $\widetilde H(t)=H(t/T)$ with $\|H(s)\|\leq\alpha$ that achieves nearly additive query complexity and low gate overhead. Our main technical contribution is a periodic Gevrey extension of $H(s)$, together with Fourier component decay and truncation bounds that enable an efficient finite-dimensional simulation. Combined with Floquet embedding and optimal time-independent Hamiltonian simulation technique, this gives query complexity $\widetilde{\mathcal O}\!\left(\alpha T+\log(1/\varepsilon)\right)$ and additional gate complexity $\widetilde{\mathcal O}\!\left((\alpha T+\log(1/\varepsilon))^2\log(1/\varepsilon)\right)$, assuming coherent access to $H'(s)$ and endpoint derivatives. For slow analytic control Hamiltonians, only block encodings of the time-independent control operators are required, with the same query complexity and lower gate overhead. Our method also extends to Gevrey Hamiltonians and improves the precision dependence for simulating slow analytic semi-dissipative linear differential equations.

We present here the results of the optical light curve variability analysis of the blazars PKS 0735+178, in weeks-scale flare state, observed in three sectors with the Transiting Exoplanet Survey Satellite (TESS). The TESS observations in this study coincide with a well-known neutrino emission phase detected with four different neutrino observatories at multiple epochs in a narrow time window. We segmented the rising and decaying parts of the flare and individually analyzed their flux distribution, excess variance, variability timescale, and the power spectral density (PSD). The source displayed an elevated excess variance of ~25%, with a multi-modal flux distribution (coherent in the rising and distorted in the decaying phase). The variability timescale analysis highlights a much faster decay than the rising scale, and the PSDs depict a nominal change in the power spectral slope. We discuss a likely connection in the optical variations and the neutrino events, and briefly explain a possible physical scenario for the observed optical flux behavior in view of previously discovered radio-band results.

Singular kicked rotors have long been compared with power-law random banded matrices (PRBM) because their momentum-space Floquet matrix elements decay algebraically. However, it has remained unclear whether the deterministic correlations of the rotor become irrelevant at long distances and, consequently, under what conditions the two systems share the same infrared theory. To address this question, we derive a nonlocal supersymmetric nonlinear sigma model directly from a quantum kicked rotor with a power-law or logarithmic singularity. By carrying out the renormalization-group analysis up to two-loop order, we show that, after matching the symmetry class and coupling convention, the rotor reproduces the long-range Anderson transition of the corresponding PRBM, including its localized, critical, and extended infrared regimes.

It is well known in random matrix literature that the limiting spectral distribution of a Wigner matrix is the semi circular law while the limiting spectral distributions of other patterned matrices like Toeplitz, Hankel, symmetric circulant and reverse circulant matrices have unbounded supports. One fundamental difference between the Wigner matrices and the other matrices mentioned above is that the Wigner matrices have $O(n^2)$ independent random variables while the others have $O(n)$ independent random variables. In this paper, we show that this is not true in general. In particular, we form matrices with $O(n)$ independent random variables whose empirical spectral distributions are arbitrary close to the semi circular law.

Ferroelectrics enable large charge doping of two-dimensional overlayers, but the coexistence of switching and nonswitching charge dynamics complicate electro-optical analysis. Here, we investigate the optoelectronic response of a ferroelectric/graphene device under 365 and 530 nm illumination, disentangling effects on ferroelectric dipole alignment from extrinsic current pathways. Graphene acts as a high-gain sensor, amplifying subtle polarization dynamics into a pronounced resistance difference. By resolving switching and nonswitching channels in dark and illuminated conditions, we reveal a competition between photovoltaic charge screening and defect-assisted excitation that governs device electrostatics. Above-band gap illumination generates free carriers that induce leaky ferroelectric hysteresis and suppress the graphene resistance ratio between opposite remanent polarization states from 290% to 15% due to dynamic photovoltaic charge screening. In contrast, 530 nm illumination primarily induces charge redistribution in ferroelectrics via defect-state excitation, leading to a significantly weaker suppression of the resistance variation of graphene. These results establish practical guidelines for selecting photon energy and intensity to either preserve remanent polarization while tuning channel doping or deliberately reconfigure polarization through optical programming.

Quantum magnets provide a microscopic platform for studying confinement and gauge-constrained structures mediated by emergent gauge fields. We investigate confined spinon complexes in the columnar valence-bond-solid (VBS) phase near deconfined quantum criticality using pinned-spin defects and quantum Monte Carlo simulations. The pinned spins act as static spinon sources with controlled positions, spin projections, and VBS vorticities, enabling measurement of defect energies and direct real-space visualization of the associated VBS domain-wall strings. For matched spinon-antispinon sources, the excitation energy saturates beyond a characteristic separation as one extended dipole reorganizes into two shorter neutral dipoles, providing energetic and real-space evidence of string breaking. We further show that domain-wall connectivity is governed by lattice-scale VBS phase offsets in addition to vorticity and spin-projection neutrality. Compatible multi-pin patterns generate connected four-spinon complexes and extended domain-wall networks that retain their global connectivity under local distortions. These results establish pinned-spin defects as a controlled tool for assembling and resolving multi-spinon structures and their confining strings in a VBS phase.

Goldreich-Levin reductions are ubiquitous in cryptography: they convert an algorithm capable of guessing $\langle r, m \rangle$ (mod $2$) for a hidden string $m$ and a random challenge $r$, to one that is capable of extracting the entirety of $m$. Here, we describe a "simultaneous" Goldreich-Levin reduction for two entangled parties who are capable of guessing $\langle r, m \rangle$ given uniformly random identical challenges $r$. This allows to upgrade any unclonable encryption scheme satisfying "search" security to one satisfying the gold standard of unclonable "indistinguishability". As a corollary, we show that the simplest candidate unclonable encryption scheme from BB84 states satisfies unclonable indistinguishability. This result was discovered by GPT-5.6 Ultra after a few interactions. Our prompts included recent results on unclonable encryption by Ananth and Sahai, and Ragavan.

The anomalous Hall conductivity in magnetic Weyl semimetals scales linearly with the momentum separation between Weyl nodes, establishing a geometric paradigm for three-dimensional Hall responses. Here we discover an analogous phenomenon in the spin Hall effect: a quantized spin Hall conductivity (SHC) in nodal-ring semimetals that scales linearly with the nodal-ring radius $R$. From an ideal model with a single nodal ring, we derive analytically that the SHC inside the spin-orbit-coupled gap obeys $\sigma_{\alpha \beta}^{S, 3D}=\sigma_0^{S,2D} \cdot (\pi R/2 \pi)$, where $\sigma_0^{S,2D}=(e^2/h) \cdot (\hbar/2 e)$ is the two-dimensional quantum spin Hall conductance. Crucially, the symmetry of the spin-orbit coupling acts as an independent switch: Rashba coupling generates purely conventional SHC components, while Weyl coupling additionally activates unconventional ones, providing separate control over response magnitude and tensor symmetry. We validate this principle in yttrium nitride, where strain tunes $R$ and symmetry breaking toggles between response types. Our work establishes a new paradigm for engineering quantized geometric responses in three dimensions, opening pathways to tailored spin-orbit functionalities.

To address the challenge that elastic wave energy can only transmit through narrow path waveguides in topological metamaterials, the proposal of large area waveguides effectively breaks through this technical bottleneck. Nevertheless, elastic waves are vector waves with complex multi component transmission characteristics. Realizing the cooperative transmission of in plane and out of plane fully polarized components poses substantial challenges for elastic wave energy transmission and trapping applications. To tackle the above mentioned problems, this paper proposes a fully polarized elastic topological heterostructure based on the quantum valley Hall effect. First, symmetric unit cell structures are designed to obtain unit cells with distinct topological properties for in plane and out of plane modes, and multiple types of supercell structures are fabricated to realize the simultaneous transmission of fully polarized elastic wave energy for both in plane and out of plane components. Furthermore, a gradient valley locked structure is designed using large area waveguide states to constrain and converge the transmitted energy, and its energy harvesting performance is analyzed. The results demonstrate that the proposed structure enables coupled transmission of fully polarized elastic wave components. Moreover, the energy harvesting capability of the gradient valley locked phononic crystal plate is approximately 4.79 times that of conventional single component transmission structures, which greatly improves the efficiency and transmission stability of acoustic energy harvesting. This work provides new insights for the engineering application of topological metamaterials in the field of energy harvesting.

The aim of this paper is to provide the reader with a review and current state of the art of the fabrication of high T2 coherence diamond, optimised by the use of double electron-electron resonance (DEER) spectroscopy. Using DEER, we study the formation, transformation, and annealing of paramagnetic defects in as-grown CVD diamond and after post-processing. Electron irradiation leads to the formation of an additional S = 1/2 resonance in the DEER spectrum, which we consider to be a composite X ensemble. By tracking the concentrations of X and P1 point defects during annealing from 650C to 1200C, we find that the X ensemble initially consists of a mixture of V- spins and interstitial spins, which disappear at about 650C. Vacancies migrate during annealing, forming clusters that persist to 1000C and disappear upon annealing at 1200C, contributing to the X ensemble signal. We have developed a model of the influence of the mixed spin bath on the coherence of NV centers, which includes independent couplings with P1 centers, V-, divacancies, and interstitials. Detailed DEER studies allowed us to reveal and resolve a weak signal from two additional S = 1/2 species associated with hydrogen: NVH- and consistent with a substitutional hydrogen defect, which overlaps the vacancy spectral line. Taken together, these results show that the NV-DEER method is a powerful tool for investigating paramagnetic defects in diamond with high precision and nanoscale resolution, essential for material optimisation. The achieved high T2 coherence time is consistent with the spin bath model, and the crystals reach the quality required for advanced quantum sensing applications.

This article presents a fast, high-order Nyström solver for the two-dimensional Lippmann–Schwinger equation arising from time-harmonic scattering by penetrable, piecewise-smooth heterogeneous media. Relying on high-order evaluation of the Newtonian potential on unstructured grids adapted to interfaces of discontinuity, the methodology achieves high-order accuracy using existing fast algorithms such as the fast multipole method. As an iterative method the solver exhibits rapid convergence when coupled to a preconditioning strategy that exploits a class of structured-grid solvers—fast solution methods offering quasi-linear time and memory complexity and nearly-constant iteration counts, but long limited in accuracy. The preconditioning strategy couples the Nyström discretization—given by high-order quadrature nodes over a (curved) unstructured mesh conforming to the support of the spatially varying contrast—to a uniform Cartesian grid underlying the fast preconditioner via a pair of transfer operators. The resulting preconditioner inherits the frequency-robust behavior of its Cartesian counterpart without sacrificing the geometric flexibility and high-order accuracy of the unstructured discretization. We prove that invertibility of the proposed preconditioner holds under explicit conditions on the mesh sizes and on the Cartesian preconditioner. Numerical experiments demonstrate that the preconditioned system requires significantly fewer GMRES iterations than its unpreconditioned counterpart, with iteration counts almost independent of mesh size and wavenumber, and illustrate the method's robustness for inhomogeneities with piecewise-smooth refractive indices and jump discontinuities across interfaces.

We investigate the axial Ward identity for massive fermions under a constant magnetic field at arbitrary strength, maintaining an arbitrary spacetime configuration of a perturbative electric field. We show that a spatially modulated electric field prevents the exact cancellation between the anomaly and pseudoscalar terms, generating a local axial-charge source even in the adiabatic regime where the frequency is subthreshold to massive-fermion production. Remarkably, unlike conventional magnetic responses, this charge generation is dominated not by the contribution of the lowest Landau level, but by those of the higher Landau levels. Our findings provide a microscopic foundation for anomaly-induced transport and anomalous optical responses in gapped systems. In particular, we find that the spatially modulated chiral magnetic effect in weakly gapped Weyl semimetals that exhibits a linear suppression of the magneto-resistance by the magnetic-field strength instead of the renowned quadratic suppression.

We make progress towards the impossibility of quantum-computation, classical-communication (QCCC) key agreement by giving the first unconditional polynomial-query attacks that tolerate imperfect completeness in the following settings. First, we give a quantum attack on protocols with arbitrarily many rounds in which both parties' oracle queries and communication are classical before the final round, while local computation may be quantum throughout, and the final round may involve quantum oracle queries and one quantum message. Second, we give a classical attack on constant-round QCCC protocols in which Alice has classical oracle access and Bob may make quantum queries throughout. In both settings, the attacker is computationally unbounded and makes $poly(\lambda)$ queries to recover the key with nonnegligible probability whenever each party's total honest query bound is at most $poly(\lambda)$ and the valid agreement probability is inverse-polynomial. As consequences, we rule out query-bounded IND-CPA security for quantum public-key encryption with classical public and secret keys and classical messages of polynomially bounded length in the QROM in either of two settings: (i) key generation has classical oracle access, while encryption, decryption, and the ciphertext may be quantum; or (ii) encryption has classical oracle access and ciphertexts are classical, while key generation and decryption may have quantum oracle access. Both results assume negligible correctness error and polynomial honest query complexity. Combining the constant-round attack with the constructions of Bartusek and Khurana (CRYPTO 2025), we also rule out constant-round oblivious state preparation with polynomial honest query complexity and negligible correctness error in the QROM against computationally unbounded quantum receivers making polynomially many oracle queries.

Noisy Bell mixtures may carry entanglement, standard teleportation usefulness, projective-measurement steerability, and optimized Cavalcanti-Jones-Wiseman-Reid (CJWR) and Clauser-Horne-Shimony-Holt (CHSH) violations. If the noise already has an ability, the mixture may lose and later recover it at distinct boundary crossings as the Bell weight decreases. We characterize ability-absence intervals and definitive thresholds for mixtures of $|\Phi^+\rangle$ with arbitrary complex two-qubit $X$ noise. A closed-form singular-value flow of the Pauli correlation tensor gives the exact teleportation-useless, CJWR-satisfying, and CHSH-local intervals, while the positive partial transpose criterion gives the exact separable interval. At fixed populations and coherence magnitudes, these intervals widen as the relative phase between the $\Phi$-block coherence of the noise and the Bell coherence increases from $0$ to $\pi$. The definitive thresholds form a universal chain from entanglement through teleportation usefulness and the three-setting CJWR witness to the common two-setting CJWR witness and CHSH-nonlocal threshold. Replacing teleportation usefulness by steerability gives a second chain, although their thresholds are not mutually ordered. For arbitrary pure two-qubit noise, the steerability thresholds in both directions for projective measurements and arbitrary positive operator-valued measures equal the entanglement threshold. For arbitrary product noise, an effective $X$-state singular-value flow gives the teleportation usefulness, CJWR witness, and CHSH-nonlocal thresholds. If a local noise factor is pure, the entanglement threshold and all four steerability thresholds are zero. For generic full-rank mixed $X$ noise, finite-setting semidefinite programs give upper bounds on the unknown directional projective-measurement steerability thresholds.

The chiral-induced spin selectivity (CISS) effect is generally attributed to spin-selective transport through chiral molecules, while the role of the molecule-electrode interface remains largely unexplored. Here, we show that adsorption of chiral amino acid derived molecules on ferromagnetic Ni thin films generates a remanent chirality-dependent magneto-optical response that is localized to the molecule-Ni/NiO interface and can be reversibly switched by an external magnetic field, demonstrating its genuine magnetic character. A comprehensive series of control experiments establishes that the response originates from the interfacial region rather than from the molecular layer or the bulk ferromagnet. First-principles calculations reveal that Boc-methionine adsorption proceeds through energetically accessible sulfur- and carboxyl-bound configurations that produce distinct molecular orientations and ligand-p/Ni-d hybridization, thereby defining structurally and electronically distinct interfaces. Together, the experimental and theoretical results support the formation of chiral spinterfaces, identifying the molecule-ferromagnet interface as an active and previously overlooked component of CISS systems. These findings broaden the microscopic picture of CISS beyond the chiral molecule itself and reveals interface electronic structure as a key design parameter for spin-selective molecular devices.

Bose-Einstein condensates of photons in dye filled microcavities are known to feature many properties of the ideal bose gas at thermal equilibrium. Nevertheless, the finite photon life time renders them driven dissipative systems where losses are balanced by continuous driving by a pump laser. We show here with simulations based on a classical field model that their driven-dissipative nature causes their first order coherence to feature Kardar-Parisi-Zhang (KPZ) scaling, a phenomenon well known in the related condensates of exciton-polaritons. Remarkably, we find that the KPZ scaling even occurs in a regime with large density fluctuations. We discuss the modification of the scaling by the occupation of excited states and how to recover the universal scaling behavior by spectral filtering.

The Galactic Center is a crowded region containing powerful particle accelerators and objects producing non-thermal radiation, including the diffuse very-high-energy (VHE) gamma-ray component known as the `Ridge', whose hard spectrum suggests particle acceleration up to PeV energies. The relevant processes can be tested, and the source parameters can be constrained via Cherenkov telescope observations. Two Single-Mirror Small-Size Cherenkov Telescopes (SST-1M) are currently operated in stereoscopic mode at the Ondřejov Observatory. Their future relocation is being considered, including a site with excellent visibility of the Galactic Center. We present recent observations demonstrating SST-1M capabilities for detecting extended emission and discuss prospects for probing the Galactic Center region, including searches for a spectral cut-off above 10 TeV. We show that the large field-of-view and good VHE sensitivity make SST-1M an ideal instrument for the search for PeVatrons.

The formation of the majority of brown dwarfs (BDs) remains uncertain. They may form in molecular cloud cores in a process akin to low mass star formation, or via fragmentation in circumstellar discs. Studying the youngest, most embedded sources is crucial for distinguishing these scenarios. We investigate molecular gas morphology and kinematics around one young & embedded very low luminosity object (VeLLO), IRAM 04191+1522, utilising archival ALMA observations of 13CO, C18O, and SO. We trace gas on scales of a few 10s to 100s of au around the source to search for outflowing and/or infalling structures. The red and blueshifted 13CO (3-2) emission show distinct morphologies and kinematics. The blueshifted emission to the north-west may trace shocked material oriented differently from the previously reported approx. 0.1 pc CO outflow. Redshifted emission mainly to the south-east and south-west may trace the base of an outflow cavity. The position angle of this cavity suggests the presence of a second outflow, which supports the possible binary nature of this VeLLO. The C18O (2-1) emission is highly complex, comprising structures at different spatial scales and distances from the source. These may trace a mix of molecular outflow, outflow cavity, and disc emission. SO 65-54 reveals evidence for anticlockwise rotation around the central source, together with a northern structure of uncertain origin. We have identified a complex set of 13CO (3-2) and C18O (2-1) structures alongside evidence of a new outflow cavity at a distinct position angle from previously detected outflows. This supports the scenario that IRAM 04191+1522 is a binary system. The northern SO gas structure remains unexplained. Higher spectral resolution observations at intermediate scales are needed to characterise these substructures, their connection to larger scale structures, and to determine this system's final fate.