Papers

We propose a novel framework for deriving semi-discrete discontinuous-Galerkin (DG) methods using operator semigroups for scalar conservation laws, then apply it to construct a class of high-order OFDG-type schemes [13] satisfying infinitely many local entropy inequalities with general E-fluxes on non-uniform meshes. Such schemes are further generalized to systems of conservation laws in any number of space dimensions by using entropy stable numerical fluxes in the sense of [1]. Finally, we prove optimal error estimates for smooth solutions to nonlinear scalar conservation laws, and prove strong convergence for discontinuous solutions to strictly convex conservation laws via compensated compactness.

As quantum computing continues to scale, quantum measurement and control (QMC) are increasingly constrained by calibration workflow complexity and by requirements for low-latency execution, robust exception handling, and traceable workflow governance. Existing frameworks for QMC are specialized and task-specific, while language-model-based agents for QMC suffer from excessive latency and cannot satisfy the strict timing and control-density demands of large-scale quantum systems. Here we propose QMClaw, a general, workflow-oriented framework for QMC built, featuring a local-first, tool-governed, robust architecture. At its core is a RuleEngine-centered control layer that processes structured context, performs rule-based state transitions, and generates execution plans for typical calibration workflows. Language models are used only for natural-language interaction, high-level task understanding, and exception support, keeping the critical fast path efficient. We implement a single qubit tune-up workflow as a demonstration and validation using real quantum device dataset. We also prove that the framework achieves quantitatively acceptable levels in terms of resource cost, LLM calling times and decision latency, enabling its practical deployment in large-scale quantum qubit measurement and control scenarios. This work presents a general workflow-oriented framework for QMC and provides evidence that rule-centered architectures are a promising design choice for scalable quantum-system calibration.

The LZ experiment has extended its nuclear-recoil search to 270 keV and reports a single nuclear-recoil-like event, LZ230616, at $\sim250$ keV, in a region with negligible expected background. We show that exothermic inelastic dark matter, in which the ambient dark state down-scatters and releases its mass splitting $|\delta|$ as recoil energy, can naturally produce a recoil peak at this energy while remaining consistent with the null result at lower energies. Our simple fit leaves the mass unconstrained, because a heavy candidate can hide its peak above the LZ region-of-interest. However, we show that the empty high-energy sideband, which LZ uses for background validation, disfavors broadly peaked spectra. For an exothermic explanation, the sharper peaks produced by lighter dark matter with larger mass splittings are therefore preferred. Realizing this scenario requires cosmologically stable states and a leptophobic mediator. Normalizing to the one observed event, we predict $\simeq4.5$ signal events in LZ's projected 1000 live-day exposure, and show that existing XENONnT and PandaX-4T data could already test the interpretation in an extended analysis window.

The overdamped approximation is widely used to describe Brownian motion in complex environments, but its validity becomes nontrivial when the friction coefficient itself fluctuates in time. We investigate this problem by comparing underdamped and overdamped Langevin dynamics subject to the same fluctuating friction and satisfying the fluctuation–dissipation relation at a common temperature. We show that environmental averaging and inertial elimination generally lead to different long-time transport when environmental fluctuations are fast compared with velocity relaxation. For rapidly fluctuating friction, the underdamped dynamics is governed by the arithmetic mean friction and yields $D_{\rm eff}^{\rm under}=k_{\rm B}T/\langle\gamma\rangle$, whereas the overdamped dynamics gives $D_{\rm eff}^{\rm over}=k_{\rm B}T\langle\gamma^{-1}\rangle$. For a two-state Markov friction, we derive the finite-time effective diffusion coefficient exactly and identify the full crossover between these two regimes, controlled by the competition between velocity relaxation and environmental switching. We further establish the fast-fluctuation result for general stationary friction processes and verify it for a continuous log-Ornstein–Uhlenbeck environment, for which the characteristic crossover time can also be determined independently. Our results reveal a noncommutativity between environmental averaging and inertial elimination, establish a timescale-dependent criterion for the validity of overdamped dynamics in temporally heterogeneous environments, and show that rapid environmental fluctuations can enhance, rather than suppress, the consequences of inertia.

Dynamic polarization controllers are key devices with broad applications in many fields. However, most on-chip polarization controllers still rely on traditional blind-search methods, whereas analytical optical-computing approaches remain insufficiently explored, particularly with respect to calibration and endless polarization control. With the accurate relative phase of Mach-Zehnder interferometer (MZI) being fully controllable on an integrated photonics chip, we present an analytical polarization control (APC) method using four phase shifters and optical computing, eliminating the need for the traditional inefficient blind-search procedure. The basic structures and operations of APC are clarified. The proposed calibration method and endless control method enable continuous APC while compensating for phase differences within the MZI structures. We simulate the influence of the endless control unit on polarization control and quantify the effect of the fourth phase difference on the output extinction ratio. With the fourth phase shifter, the phase difference encountered during Stokes vector measurement can be effectively compensated, and rotations around all three axes on the Poincaré sphere can be realized. These results establish a practical APC architecture based on optical computing for photonics chips. The proposed APC methods, combined with a FPGA-based hardware acceleration, will enable high speed on-chip polarization controllers.

We study how finite-$N$ invariant theory organizes the non-perturbative structure of matrix models. For a model of four traceless Hermitian $2\times 2$ matrices, the Hironaka decomposition realizes the gauge-invariant configuration space as an eight-sheeted branched cover of the space of primary invariants. We show that ramification points of this cover naturally generate additional saddle points when the action depends only on the primaries. For an explicit rank-two saddle, we compute its action, one-loop normalization and Picard–Lefschetz connection to the perturbative vacuum. The same saddle controls the leading Borel singularity and large-order growth of perturbation theory, while its first fluctuation correction reproduces the first subleading large-order correction with no fitted parameters. Our results provide a concrete link between finite-$N$ invariant geometry and resurgence in matrix models.

Photonic-crystal (PC) slabs composed of subwavelength silicon pillars erected on a thin silicon backing layer, with heights of only one or half lattice constant, are simulated for optical biosensing by numerical solution of Maxwell's equations. Localized optical cavity modes that form waveguides in the direction of biofluid flow, with quality factors surpassing \(10^4\), are embedded within the 2D photonic band gap of the 3D structure. Remarkable sensitivity to analyte binding is achieved using fragmented thin silicon pillars in regions of maximum localized optical-field intensity. Exceptional quality factors are realized through destructive wave interference of vertical radiation loss. This provides a rare combination of high sensitivity and low limit of detection in a device with minimal time requirement for analyte binding. The sensitivity to analyte binding is a frequency shift of nearly \(0.004\,[2\pi c/a]\) per analyte-thickness increment \(0.1a\). The sensitivity to background biofluid change is about \(4800\) nm per refractive index unit (RIU) for a specific lattice constant \(a = 5\,\mu\mathrm{m}\) using light of wavelength \(16.5\,\mu\mathrm{m}\).

We report on the utilization of a low-damage e-beam NiO$_x$ deposition process to realize field-plated heterojunction diodes (FP-HJDs) on (010) $\beta$-Ga$_2$O$_3$ films with high critical breakdown field strengths beyond 4 MV/cm and power figure of merits (PFOM) of >1 GW/cm$^2$. Diodes were fabricated on a 2.67 $\times$ 10$^{16}$ cm$^{-3}$ intentionally doped 6.2 $\mu$m thick epitaxial layer grown by metalorganic chemical vapor deposition (MOCVD) on a conductive Sn-doped $\beta$-Ga$_2$O$_3$ (010) substrate using TMGa, O$_2$, Ar carrier gas, and SiH$_4$ as the silicon dopant source. The mesa etched FP-HJD devices utilized a thin 7 nm e-beam NiO$_x$ interlayer before the sputtered NiO$_x$ layers to eliminate the effects of sputter-induced ion damage on the (010) epilayers. Current-Voltage measurements resulted in a forward current density of 700 A/cm$^2$ at 4 V, HJD ideality factor of 1.29, a V$_{bi}$ of 2 V, rectification ratio of 10$^{11}$, and a differential specific on resistance (R$_{on,sp}$) value of 2.36 m$\Omega$ $\times$ cm$^2$. Breakdown of the (010) FP-HJDs was 1.64 kV, leading to a parallel plane electric field at breakdown (E$_{||,max}$) of 4.02 MV/cm and a PFOM of 1.14 GW/cm$^2$, which is a state-of-the-art result for diodes on MOCVD-grown (010) drift layers.

Selecting an effective encoding quantum circuit is a key challenge in quantum kernel methods because different feature maps can lead to different performance. Conventional methods require constructing and evaluating every circuit for each new dataset, making it computationally expensive. We present Qmes, an open-source Python package that automatically recommends circuits through meta-learning. Qmes characterizes a dataset using classical complexity measures and queries a pre-trained model to recommend circuits without quantum evaluation at inference time. The package provides modular components for meta-feature extraction, quantum-kernel evaluation, recommender training, model selection, and user-defined circuit extension. We validate Qmes on 105 classification and 86 regression benchmark datasets. Qmes reduces the mean recommendation regret by 2.2x and 4.2x for classification and regression, respectively, compared to a non-adaptive baseline, with statistical significance confirmed via a paired Wilcoxon signed-rank test ($p < 10^{-4}$). Qmes thus enables efficient and practical encoding-circuit selection for quantum kernel methods.

Sterile neutrinos are well-motivated dark matter candidates, but their conventional production through active-sterile mixing is tightly constrained by X-ray searches and structure-formation observations. We propose a distinct production mechanism operating entirely within a sterile sector: two sterile neutrinos, $N_1$ and $N_2$, coupled to a singlet scalar $\phi$, with $N_1$ the dark matter candidate and $N_2$ held in equilibrium through frequent scattering induced by its scalar interaction. Thermal self-energies induced by the $N_2$ and $\phi$ backgrounds generate both a temperature-dependent mass splitting and an off-diagonal mixing between $N_1$ and $N_2$. As the Universe cools, the in-medium levels can undergo a level crossing, leading to resonantly enhanced conversion of the thermal $N_2$ population into $N_1$. We formulate the conversion using a density-matrix kinetic equation that consistently incorporates coherent $N_1$-$N_2$ conversion, collisional decoherence, and thermal repopulation of $N_2$. For a narrow resonance, the integrated conversion probability admits a simple analytic form that coincides with the Landau-Zener result, despite the underlying collisionally damped dynamics. In the weak-conversion regime relevant for freeze-in, this correspondence provides a robust analytic description of the resonant production. We derive the resulting dark matter abundance and identify the conditions for cosmological stability of $N_1$ and for resonant conversion to dominate over direct scattering and decay production. The resulting relic abundance scales as $Y_1\propto g_{12}^2 g_{22}M_{\rm Pl}/m_1$, making the dark matter energy density approximately independent of $m_1$. This mechanism provides a new route to sterile-neutrino dark matter that does not require appreciable active-sterile mixing.

Electrical generation of orbital angular momentum provides a promising route to current-induced torques, yet effective control of orbital Rashba textures still remains challenging, particularly because the role of the interfacial crystal field remains largely unexplored. Here, we report experimental evidence for a crystal-field-mediated interfacial anisotropic orbital Rashba effect (AORE) in epitaxial Ru/ferromagnet heterostructures. Total orbital torque was disentangled into an isotropic bulk contribution and an in-plane anisotropic interfacial contribution. The latter was strongly suppressed by degrading the crystallinity of either constituent and by inserting a Cu spacer, highlighting the essential roles of coherent interfacial orbital hybridization and direct Ru/ferromagnet contact. These results identify interfacial crystal-field coherency as a key ingredient in manipulating orbital Rashba textures and establish a route toward engineering the symmetry and directionality of orbital torques.

As global warming intensifies, the frequency and intensity of extremely high temperatures are expected to increase. This will impact the production of photovoltaics (PVs), which are increasingly adopted as an effective alternative to replace fossil fuel-based energy sources and reduce CO2 emissions. Furthermore, extremely high temperature days account for a considerable proportion of days with high PV power potential (PVpot). Therefore, this study investigates changes in PVpot on future extremely high temperature days over East Asia, a region with high greenhouse gas emissions and vulnerability to extreme climatic events. The East Asia-averaged PVpot for extremely high temperature days was estimated to decrease across all scenarios and future periods. The East Asia-averaged PVpot for extremely high temperature days was predicted to decrease more substantially toward the late 21st century, with a larger magnitude of decrease expected under the high-carbon emissions scenario compared to the low-carbon emissions scenario. By the mid-and late 21st century, PVpot for extremely high temperature days was projected to decrease in PV hotspot areas, particularly in the regions of northern China and southern Mongolia, by up to -7.2 %. The signs of PVpot projections vary across sub-regions under summer mean conditions, while on extremely high temperature days, PVpot is consistently expected to decrease in all regions. This suggests that extremely high temperatures further intensify the decrease in PVpot. Moreover, under extremely high-temperature conditions, near-surface air temperature has been identified as the primary driver of projected decreases in PVpot among the climate variables considered; its influence is expected to intensify over time, thereby accelerating PVpot decreases under the high-carbon emissions scenario.

We revisit the light tetraquark states with quantum numbers $J^{PC}=1^{++}$ using QCD sum rules, focusing on a complete set of derivative-free diquark-antidiquark interpolating currents. By calculating the operator product expansion up to dimension-eight condensates, we extract the ground-state mass of the hidden-strange $us\bar{u}\bar{s}$ tetraquark from both Laplace sum rules (LSR) and finite-energy sum rules (FESR). Our combined analysis yields $M_{us\bar{u}\bar{s}} = 1.45\pm0.11$~GeV, which agrees well with the mass of the $a_1(1420)$ resonance and supports its tetraquark interpretation. Furthermore, we perform Gaussian sum rule (GSR) analyses to probe radial excitations, adopting a two-resonance narrow-width model. The GSR fit reveals a heavier state with mass $m_2 = 1.86\pm0.12$~GeV and a relative coupling $r = 0.15\pm0.03$ for the lighter state, indicating that the $a_1(1930)$ is a promising candidate for a compact $1^{++}$ tetraquark. We also discuss the dominant decay modes of these tetraquark candidates, emphasizing hidden-strange channels such as $K^*K$ and $f_0(980)\pi$, which can be tested in future experiments.

We investigate the interplay between geometric dilution and non-Hermitian disorder in the two-dimensional quantum site-percolation model. Non-Hermiticity is introduced through random imaginary on-site potentials, representing spatially uncorrelated gain and loss, while the hopping amplitudes remain reciprocal. By combining complex level-spacing statistics, participation entropy, and multifractal analysis, we characterize the localization properties of the eigenstates as functions of the disorder and the non-Hermiticity strength. Our finite-size scaling results show that non-Hermitian disorder shifts the quantum percolation threshold ($p_q$) toward larger occupation probabilities. Consequently, the fully delocalized phase is progressively suppressed and disappears at sufficiently strong disorder. This suppression is not a simple consequence of adding on-site disorder of a given strength, but is specifically enhanced by its imaginary character, as an equally strong real (Hermitian) on-site potential produces a weaker shift of $p_q$. Nevertheless, the intermediate region between the classical ($p_c$) and quantum percolation thresholds presents a genuine multifractal critical phase, while the localization-length exponent $\nu$ remains the same, relative to its Hermitian value. Altogether, our results demonstrate that random gain and loss enhance the multifractal regime while preserving the universality class of the quantum percolation transition.

Recently synthesized carbon nanoribbons (CNRs) were investigated for hydrogen (H2) storage using first-principles density functional theory calculations. Pristine CNRs exhibited weak H2 adsorption; therefore, the host structure was modified by substituting carbon atoms at the C-H edges with 12 nitrogen atoms, followed by Mn and Y doping to enhance H2 binding. A maximum of five metal atoms could be accommodated on the 12N-CNRs. Electronic structure analysis revealed strong orbital hybridization between the metal atoms and the CNRs, while binding energy calculations confirmed the structural stability of the doped systems. Bader charge analysis further quantified the charge transfer between the metal atoms and the host structure. The average H2 adsorption energies were calculated to be -0.40 eV/H2 for the Mn-doped system and -0.25 eV/H2 for the Y-doped system, which are within the desirable range for reversible hydrogen storage. The maximum theoretical gravimetric storage capacities at 0 K reached 7.48 wt% for the Mn-doped system and 6.55 wt% for the Y-doped system. Under practical conditions of 30 atm and 298.15 K, the storage capacity of the Y-doped system decreased to 6.04 wt%, whereas the Mn-doped system maintained its full capacity of 7.48 wt%. Thermodynamic analysis indicated that H2 adsorption is favored at low temperatures and high pressures, while desorption becomes feasible at elevated temperatures and lower pressures. These results demonstrate that Mn- and Y-doped CNRs satisfy key U.S. Department of Energy requirements for reversible H2 storage and show promise as potential hydrogen storage materials under near-ambient conditions.

Open-closed-open triality relates two distinct open string descriptions through a common closed string theory. In this paper, we develop an open-closed-open triality for protected half-BPS three-point functions in four-dimensional $\mathcal{N}=4$ super Yang-Mills theory. Starting from determinant insertions representing giant gravitons, we formulate a V-type open-string Gaussian three-matrix model and, through a color-flavor transformation, derive an F-type open-string model of three bifundamental matrices forming a triangular quiver. Its closed quiver walks include oriented cubic cycles, a feature absent from the bipartite two-point case. We test the correspondence by deriving exact finite-$N$ single-giant polynomials, recovering the known F-type large-$N$ saddles, and proving the equivalence of the V- and F-type character expansions via an explicit bijection of their combinatorial data. At the closed string corner, connected three-matrix contractions determine three-colored integer Strebel surfaces. We argue that the corresponding target-space construction is naturally described by a barycentrically subdivided Belyi map or a colored Hurwitz constellation.

We derive the scalar propagator in a thermal medium under global rotation without restricting the spacetime points to a common comoving trajectory. The resulting propagator retains an explicit dependence on the radial coordinates, reflecting the lack of translational invariance in the transverse plane, and therefore cannot in general be formulated solely in momentum space. We show that the usual free Feynman propagator is exactly recovered in the nonrotating limit, providing a first consistency check of the formulation. As a nontrivial test, we apply the propagator to the interacting $\lambda\phi^4$ theory at finite temperature and rotation. The one-loop scalar self-energy obtained within the Matsubara formalism correctly separates into vacuum and medium contributions and reproduces the standard finite-temperature result when $\Omega\to0$. We subsequently construct the effective potential including screening effects through ring resummation and, for $\Omega/T\ll1$, evaluate the rotational corrections up to $\mathcal{O}(\Omega^4)$. Within this model, the resulting effective potential exhibits the expected thermal restoration of the spontaneously broken $\mathbb{Z}_2$ symmetry, while global rotation favors symmetry restoration and enhances this effect as the transverse size of the system increases. These results provide complementary consistency checks of the rotating scalar propagator and highlight the need to retain its explicit position-space structure in more general perturbative calculations.

Elastic turbulence (ET) in straight geometries has been extensively studied in idealised configurations such as periodic shear and planar channel flow, yet experiments are typically restricted to confined systems like ducts and pipes. While chaotic elastic fluctuations are observed in ducts, their onset in pipes is debated due to geometric constraints. Here we report sustained chaotic dynamics in both geometries and show they correspond to the same ET state identified in idealised setups. Our results establish ET as a geometry-independent attractor and point to a distinct transition mechanism in pipes.

In this work, we systematically investigate the baryon-baryon interactions in singly bottomed dibaryon systems within the chiral quark model and search for possible bound states. By exploring the baryon-baryon interaction, we find that low-isospin channels tend to generate deeper attractive interactions and are prone to form bound states. We also find that decuplet-decuplet systems tend to show stronger attraction and support a larger number of bound states, whereas octet-octet systems generally exhibit weaker attraction and fewer bound solutions. The binding behavior of octet-decuplet systems generall lies between these two cases. Several bound states are obtained, which are $\Delta\Sigma_b^*$ with $IJ=\frac{1}{2}0$, $\frac{1}{2}1$, $\frac{1}{2}2$, $\frac{1}{2}3$, and $\frac{3}{2}3$, the $\Delta\Sigma_b$ with $IJ=\frac{1}{2}1$, $\frac{1}{2}2$, $\frac{3}{2}1$, and $\frac{3}{2}2$, the $N\Sigma_b^*$ with $IJ=\frac{1}{2}2$, the $\Sigma\Sigma_b$ with $IJ=00$, $01$, and $11$, the $\Sigma\Sigma_b^*$ with $IJ=01$ and $02$, the $\Sigma^*\Sigma_b$ with $IJ=01$ and $02$, and the $\Sigma^*\Sigma_b^*$ with $IJ=00$, $01$, $02$, $03$, and $13$. Further investigations of the corresponding scattering processes are still required to determine whether these bound-state candidates can be identified. These states deserve further experimental investigation.

Working through next-to-next-to-leading order (NNLO) accuracy in pionless effective field theory, we compute the isovector magnetic-dipole contribution to the scalar deuteron magnetic polarizability. The polarizability follows from detailed balance and a dispersion integral with the two magnetic current counter-terms fixed by the thermal $np\to d\gamma$ rate. The conventional $\rho$ and $Z$ expansion schemes differ by $12.3\%$ at next-to-leading order but agree to $0.165\%$ at NNLO, resulting an apparent scheme dependence and supplying an independent convergence diagnostic. We obtain $\beta_{M0}^{(M1_v)}=0.0789\pm0.0010~\mathrm{fm}^{3}$, a $1.3\%$ uncertainty, compared with $4.9\%$ previously.

Compact representations of rarefied flows must retain nonequilibrium transport information while identifying their range of validity. We investigate a common localized-Gaussian strategy for discrete-velocity-method (DVM) states in monatomic normal shocks and lid-driven cavities. The strategy is specialized to the available kinetic state: a positive phase-space mixture represents shock distributions and regenerates their moment hierarchy by quadrature, whereas a shared-support physical-space map represents 20 cavity fields. Localized support, continuous evaluation, transport fidelity, and coefficient-count accounting therefore provide the common structure across the two benchmarks. For separately fitted Mach-3 and Mach-5 shocks, the method gives sub-percent errors in conserved quantities and approximately 1–2% errors in transport and higher-order moments. At the same 4608-coefficient budget, the tested multilinear grids produce 89–98% errors in these nonequilibrium quantities. For both cavity cases, the Gaussian map also outperforms matched bilinear and singular-value-decomposition baselines, reducing maximum errors by factors of approximately 7–24. In the Mach-conditioned tests, a correspondence-preserving local basis reduces the withheld Mach-6 distribution error from $42.86\pm5.40\%$ to $11.45\pm0.94\%$ at fixed storage, while its transport errors remain 30–40%; a normalized-coordinate guard rejects Mach 12 outside the training range. Independent grid studies confirm that these trends are not dominated by DVM discretization error. The results establish localized Gaussian representations as storage-efficient transport-fidelity maps for fitted kinetic states and provide quantitative acceptance criteria for parametric use.

This work presents a density functional theory (DFT) investigation of a two-dimensional (2D) C5N monolayer functionalized with Li, Na, and K for hydrogen storage. Pristine C5N exhibits weak H2 adsorption, while alkali-metal functionalization significantly enhances its storage capability. The C5N monolayer can stably accommodate up to six metal dopants, with binding energies stronger than the corresponding cohesive energies, indicating resistance to metal aggregation. Ab initio molecular dynamics simulations further confirm the thermal stability of the functionalized systems at 300 K. Charge transfer from the metal dopants to C5N enhances polarization and strengthens H2 adsorption. Each dopant can adsorb up to eight H2 molecules, yielding a maximum of 48 H2 molecules per unit cell and gravimetric storage capacities of 9.42, 8.61, and 7.93 wt% for Li-, Na-, and K-functionalized C5N, respectively. The average H2 adsorption energies of -0.16 to -0.17 eV/H2 indicate moderate interactions suitable for reversible storage. Thermodynamic analysis further demonstrates favourable H2 adsorption/desorption under practical operating conditions, while desorption-temperature, recovery-time, and volumetric analyses support the potential reversibility and storage performance of these systems. Overall, alkali-metal-functionalized C5N emerges as a promising 2D material for efficient and reversible H2 storage.

Van der Waals magnets have received blooming interest in material science and spintronics for the advantages of low magnetization, flexible stacking, strong tunability, and dangling-bond-free interfaces. However, there has been no report of room-temperature magnetic-field-free spin logic device based on a van der Waals magnet. Here, we demonstrate a room-temperature, field-free, low-power, scalable spin-orbit torque in-memory computing logic device utilizing a van der Waals magnet Fe3GaTe2 bit with strong perpendicular magnetic anisotropy and a Pt channel with strong spin Hall effect, high electrical conductivity, and electric asymmetries. Current pulse width-dependent switching measurement reveals a low intrinsic critical magnetic-field-free switching current of 1.8e7 A cm-2, a high thermal stability factor of 50, and the potential of an ultralow write power of 1.5 fJ per bit at 1 ns pulse width for a typical industrial-level device dimensions (40 times lower than the industrially optimized W/FeCoB device). These results suggest a great potential of van der Waals magnets in dense, ultralow-power, scalable in-memory computing technologies.

Future space telescopes searching for extraterrestrial life require methods to detect environments that can potentially support life. Liquid water is considered essential for life as we know it and its presence is therefore an important observable when characterizing potentially Earth-like exoplanets. Remotely inferring the presence of surface liquid water on a world from spatially unresolved observations is an outstanding challenge where the detection of ocean glint could provide supporting evidence. This study assesses the feasibility of detecting ocean glint from Earth-like exoplanets using simulated data from NASA's Habitable World Observatory (HWO). We conducted retrievals on these simulated observations using a model that included a glint contribution and performed model selection against retrievals that did not include glint. We find that over a range of spectral signal-to-noise ratios from 5 to 25, a phase angle of at least 120 deg is necessary for glint detection. Our results offer the opportunity to shape mission development by providing constraints on key telescope observing requirements.

Spin logic is of great interest for the development of high-performance, non-Von Neumann artificial intelligence chips. Of particular advantage is the programmable spin-orbit torque logic that can achieve the complete set of the 16 Boolean logic operations within a single device in an initialization-free, low-power, and scalable manner, which is, however, a challenge despite remarkable efforts over more than two decades. Here, utilizing chirally asymmetric switching, we demonstrate an initialization-free, low-power, programmable spin-orbit torque logic device that is capable of the complete set of 16 Boolean logic operations within a single device with only three inputs and ultralow power of < 1 fJ/bit. We also propose the first initialization-free, all-electrical spin-based cascading computing devices, including a half adder, a three-level full adder, a two-level full adder, and a Transfer/NOT selector. These compact and scalable computing devices are enabled by the chirally asymmetric spin-orbit torque switching of a Ta/FeCoB bilayer with a significant perpendicular Dzyaloshinskii-Moriya interaction field. These results pave an intriguing way for the development of next-generation high-performance large-scale in-memory computing chips based on chirally asymmetric spin-orbit torque switching.

We develop analytical criteria for surface electromagnetic waves at interfaces between hyperbolic materials and topological insulators. The analysis identifies propagation conditions, field penetration depths, and spectral band gaps. In the lossless model, the band edge is governed primarily by dielectric contrast, while the bulk topological coupling produces only a small shift and a weak correction to the dispersion. For structures combining hexagonal boron nitride with bismuth selenide, a thin topological insulator film on a dielectric substrate with low permittivity can substantially broaden the accessible propagation window. We also analyze a dissipative titanium and silicon hyperbolic effective medium interfaced with bismuth selenide. To make the complex branch structure visible, this lossy calculation uses an intentionally enhanced interface response and is therefore illustrative rather than a quantitative prediction for a conventional topological insulator. In the lossy case, a root of the dispersion relation represents a physical guided mode only when the fields decay away from the interface, attenuate consistently along the propagation direction, have finite penetration depths, and exhibit a consistent energy flow profile. Apparent gaps and jumps can occur when the complex quantities controlling transverse decay approach square root branch cuts. These results provide design guidelines for controlling dispersion, confinement, band gaps, and propagation loss in mid-infrared photonic structures.

One-dimensional carbon allotropes combining sp and sp2 hybridizations provide a versatile platform for atomically precise quantum wires with tunable electronic, vibrational, and mechanical responses. Recent on-surface synthesis has realized the $\gamma$-graphdiyne molecular wire on Au(100) in two interconvertible phases sharing an identical aromatic backbone but distinct linkage chemistry: an organometallic intermediate with C-Au-C bridges and a fully covalent product with diacetylenic linkages. While experimental techniques characterize the on-surface periodicity and C$\equiv$C Raman signatures, the intrinsic properties of the free-standing wires remain inaccessible. Here, we address this gap using hybrid-functional first-principles calculations. The covalent phase is a semiconductor with a direct band gap of 2.02 eV, a polyynic bond-length alternation of 0.117 Å, and a chain periodicity reproducing experiment within -0.5%. Conversely, the organometallic phase exhibits partial cumulenization and 1D metallic behavior, with spin channels crossing the Fermi level. Both isolated polymers demonstrate dynamic stability with Young's moduli of 995 nN and 861 nN, respectively, where the C-Au-C bridge acts as a soft link absorbing 9.2% of axial deformation at +6% macroscopic strain. Species-resolved vibrational analysis identifies an effective-conjugation-coordinate band at 1408 cm$^{-1}$ for the covalent phase and Au-projected modes below 400 cm$^{-1}$ for the intermediate, offering diagnostic fingerprints for phase discrimination during thermal or chemical conversion.

The laboratory-frame anti-Jaynes–Cummings (AJC) interaction retains a residual detuning $2f\lambda$ that is absent from the rotating-frame model. We map two proposed remedies—a Kerr shift $\chi(\hat a^\dagger\hat a)^2$ and collective Dicke coupling of $N$ two-level emitters—for a squeezed vacuum on that ladder ($r=1$, $\langle n\rangle=\sinh^2 r\simeq 1.38$). All quoted contrasts are the amplitude of the first turning point of the atomic ground-state population, which coincides with the two-level formula $\mathcal{C}=1/[1+(2f+\chi)^2]$ at $r=0$ to $10^{-9}$. Three results follow. (i)~A single Kerr strength never restores unit contrast at $r=1$; the $r=0$ $n$-dependent shift $\chi(2n+1)$ cannot cancel $2f\lambda$ on every occupied Fock component. (ii)~The exact $r=1$ contrast at $\chi=0$ is not reproduced by an incoherent sum $\sum_n P_n(r)\,\mathcal{C}_n$ built from the $r=0$ two-level formula; pointwise deviations are several tenths. (iii)~Collective coupling raises the contrast systematically. At $f=5$ one finds $\mathcal{C}=0.140$ ($N=1$) and $\mathcal{C}=0.575$ ($N=8$), above the unsqueezed value $8/[8+(2f)^2]=0.074$. The $N=16$ point at this $f$ remains truncation-limited and is not quoted to three digits. The same $N\sim(2f)^2$ estimate for $\mathcal{C}=1/2$ places trapped-ion values $f\sim 10^{2}$–$10^{3}$ outside the present construction. The relevant platform is ultrastrong circuit QED with $f\sim 1$–$10$. The calculation is a numerical control landscape, not a new solvable limit.

An alternative, streamlined methodology is presented for deriving the isotropic Cartesian tensor bases under the special orthogonal group $\text{SO}(3)$. By shifting the traditional interpretation of the isotropy condition to analyze it as an algebraic system of equations for the rotation matrices themselves rather than the tensor components, lower-rank bases can be explicitly established in just a few lines without requiring finite coordinate rotations or complicated contractions of infinitesimal generators. Furthermore, a transparent combinatorial interpretation is provided for the number of tensors in the general higher-rank spanning sets. Finally, the Gram-matrix method is advocated as an efficient computational sieve to resolve the subsequent linear dependence.

The transmission of shock waves generated by underwater electrical foil explosions across solid materials with varying acoustic impedances and thicknesses is investigated. Copper foils with thicknesses of 10 and 18 $\mu$m are exploded on planar substrates of aluminum, copper, and 3D-printed PLA with thicknesses up to 5 mm using a multi-gigawatt pulsed-power electrical discharge. The resulting shocks are visualized in water using high-speed shadowgraphy at 5 million frames per second, while high-resolution fiber optic hydrophone measurements provide direct quantitative measurements of shock strength after transmission through the impedance-mismatched materials. One-dimensional magnetohydrodynamic simulations are used to reproduce the foil explosion dynamics and provide insight into the thermodynamic, acoustic, and electrical properties of the foil during the explosion. The results show that shock transmission is governed not only by the impedance mismatch at the solid–water interface but also by the finite thickness and dynamic response of the supporting material. These findings provide a quantitative framework for understanding and controlling shock transmission in underwater electrical foil explosions and establish the feasibility and limitations of using solid substrates as structural supports in complex shock-generating geometries.