Papers

Cosmological first-order phase transitions (FOPTs) in the early Universe are an exciting prediction of many beyond the Standard Model scenarios. Owing to the stochastic nature of bubble nucleation, some causal patches may remain trapped in the false vacuum long after the surrounding regions have completed the transition and started to redshift. Under suitable conditions, these delayed patches can become sufficiently overdense to collapse into primordial black holes (PBHs). One therefore expects characteristic parameters, such as the PBH mass and PBH formation time to be sensitive to the underlying phase-transition dynamics. Here, we adopt a model-independent framework with a fixed mean bubble separation scale ($R_*$) to directly compare the impact of exponential and Gaussian nucleation profiles on PBH formation. We further incorporate the effects of friction on the bubble walls arising from interactions with the surrounding plasma. We find that friction significantly modifies the bubble dynamics, leading to significant changes in the PBH mass and formation time for both nucleation histories. Moreover, the stochastic gravitational-wave spectrum generated by the FOPT can provide a complementary probe of the underlying dynamics, allowing the effects of friction on the bubble wall evolution to be distinguished from the frictionless case.

We incorporate the $\Delta(1232)$ resonance into pion-induced QED radiative corrections to neutron decay and inverse beta decay (IBD). Within the framework of heavy-baryon chiral perturbation theory with explicit $\Delta$ degrees of freedom, we compute additional contributions and study their impact on IBD cross sections and on the renormalization of the nucleon isovector vector and axial-vector charges. $\Delta$ resonance does not renormalize the vector charge. For the axial-vector charge, including the $\Delta$ resonance improves convergence and reduces the QED radiative correction to the experiment-over-lattice-QCD ratio $g_A/\left(g^\mathrm{QCD}_A g_V\right)$. $\Delta$ resonance increases the pion-induced QED radiative corrections to IBD by a factor $1.2$-$1.3$.

We analyze pattern formation from a homogeneous steady state in a one-component nonlocal adhesion model with population pressure and degenerate mobility. First, using linear stability analysis, we derive the instability threshold and a selection rule for the fastest-growing mode, and elucidate the mechanism by which the selected wavenumber shifts toward lower wavenumbers as the mean density increases. We then perform a weakly nonlinear analysis near the critical adhesion strength and derive an explicit expression for the Landau coefficient in the Stuart–Landau equation. This expression shows that the critical bifurcation is classified as supercritical or subcritical according to the mean density, the nonlinear exponent, and the second-harmonic response ratio of the kernel. Furthermore, we show that a large nonlinear exponent promotes a transition to subcriticality and confirm, through numerical bifurcation analysis and time-dependent simulations, a bifurcation structure with a fold point and the formation of mesa patterns. Finally, through the energy limit as \(m\to\infty\), we relate the observed mesa profiles to a capacity-constrained limiting structure.

Developing physical neural network (PNN) hardwares is important to next generation artificial intelligence systems. Phononic devices-using heat current to encode and process information-is one of the solutions to neuromorphic computing. In this work, we back map an artificial neural network (ANN) into a PNN simulation model using polymer networked nanoparticles (PNNPs). Our atomistic simulation results demonstrate that the polymer linked nanoparticle networks can potentially realize information processing using heat current. Using high-throughput molecular dynamics (MD) simulations and the trust region Bayesian optimization (TuRBO) methods, we tune the plasticity of polymer linkers and the temperatures of nanoparticles to optimize the performance of the PNNP machines, which is similar to tune the weights and bias in ANNs. After 5 rounds of high-throughput MD simulations, we show that the PNNP machines have improved in performance. We also use a testing data set to verify the heat flow outputs from the top 5 PNNP machines in each round.

Spintronics and orbitronics rely on current-induced accumulations of magnetic dipoles: spin and orbital angular momentum. However, electronic orbitals inherently carry multipoles beyond the dipole, with the rank-2 orbital quadrupole as the leading term. Here we use polarization-resolved Kerr microscopy to observe current-induced orbital-quadrupole accumulation at the surfaces of Ti and Pt, metals with markedly different spin–orbit-coupling strengths. By separating the symmetric and antisymmetric components of the off-diagonal optical conductivity, we isolate the time-reversal-even quadrupolar response from the conventional time-reversal-odd magnetic-dipolar one, and find that the quadrupolar optical response exceeds the dipolar one in both metals. First-principles analysis of the measured responses indicates that the quadrupole accumulations are of the same order of magnitude in the two metals despite their widely different spin–orbit-coupling strengths, consistent with a previously unidentified channel of charge-to-orbital conversion that does not require spin–orbit coupling. Our findings establish that current-induced orbital polarization is fundamentally multipolar, expanding current-induced phenomena from the dipolar to the multipolar regime and opening a route to electrical control of orbital-ordered phases.

We report the serendipitous discovery of a large, low-surface-brightness radio bubble in 944 MHz continuum data from the ASKAP Evolutionary Map of the Universe (EMU) survey. The structure, centred on the elliptical galaxy LEDA 217397 at a redshift of $z=0.040$, spans $\sim$8.4 arcmin, corresponding to a projected diameter of $\sim$399 kpc, and consists of two partly overlapping shells both with radii of $\sim$114 kpc. The integrated flux density of the bubble is $56.8\pm2.9$ mJy at 944 MHz, implying a rest-frame 1.4 GHz luminosity of $\sim$ $1.4\times10^{23}$ W Hz$^{-1}$. Combining the EMU measurement with MWA GLEAM-X data at 88–185 MHz, we derive a steep integrated spectral index of $\alpha=-1.04\pm0.04$, and a two-frequency spectral-index map suggesting a possible exterior flattening. Spectral Energy Distribution (SED) fitting indicates a massive ($\log M_{\ast}/M\odot = 10.97\pm0.09$), quiescent (SFR=$0.025\pm0.083\,M\odot$ yr$^{-1}$) early-type host with no mid-infrared AGN signature and no overdense environment. We compare the bubble with odd radio circles (ORCs) and large radio shells, and discuss three scenarios for its origin: a starburst-driven wind, a merger-driven shock, and AGN jet-inflated bubbles. The starburst wind is disfavoured on energetic grounds ($\gtrsim$$10^{59}$ erg required versus $\sim$$10^{8}$ yr electron lifetimes), and neither a halo-scale merger shock nor a spherical nuclear blast wave can explain the unusually regular, double-shell geometry; a bipolar nuclear outburst – a relic AGN jet episode, possibly triggered by a supermassive-black-hole merger – provides the most natural explanation, with later shocks possibly re-energising the plasma. Deeper broad-band radio, polarimetric, spectroscopic and X-ray observations are needed to confirm its nature.

We investigate the electronic properties of a two-dimensional topological insulator patterned with an array of circular holes. The band structures of the topological insulator superlattices are calculated using the Bernevig-Hughes-Zhang model, discretized with the finite element method. The band topology is studied using the Fukui-Hatsugai-Suzuki method, exploiting the fact that topological charge is conserved when a band gap closes and reopens. We find that when the holes are close to each other and the edge states overlap significantly, the material loses its topological character and becomes a trivial insulator. The results show that patterning topological insulators changes their properties, and this can be achieved with a feature size compatible with current lithographic techniques. This shows the potential to incorporate patterned topological insulators in future electronics.

Dual-comb spectroscopy (DCS) enables high-speed, high-resolution spectroscopy by down-converting optical spectra to the radio-frequency (RF) domain through the interference of two mutually detuned frequency combs. Accurately resolving narrow molecular absorption features requires closely spaced comb lines generated by large laser cavities with long round-trip times, thereby hindering the miniaturization of high-resolution spectrometers. Here, we circumvent this limitation by demonstrating a swept-source dual-comb spectrometer using two unidirectional racetrack semiconductor lasers integrated on the same chip. The traveling-wave frequency combs are generated by strong RF injection at the laser cavity round-trip frequency of 14.3~GHz—otherwise known as quantum walk combs—and are continuously tuned in frequency by varying the laser drive currents. This enables continuous spectral sampling over a 32~cm$^{-1}$ range centered near 8~\textmu m, with an effective sampling interval of approximately 80~MHz. The outputs of both combs are coupled into the same monolithically integrated light coupler, providing automatic collinear alignment before the combined beam interrogates the sample. We benchmark the spectrometer against an external-cavity tunable laser and validate its performance using HITRAN simulations for 1.25% nitrous oxide. Finally, the unidirectional comb architecture suppresses the detrimental effects of optical feedback, yielding comparable residuals even under deliberately introduced strong feedback. More broadly, the benefits of miniaturization extend beyond reduced footprint: chip-scale integration enables new forms of electrical and optical control that can fundamentally change how dual-comb spectrometers are operated.

We propose a novel, highly efficient method for isolating the isomeric state $^{26\text{m}}\text{Al}$ from an overwhelming ground-state $^{26\text{g}}\text{Al}$ background (isomeric ratio $\sim 20:1$) using optical pumping through a 2.0 m flight zone in collinear laser spectroscopy (CLS). To investigate the underlying optical pumping (OP) dynamics, we developed a comprehensive rate equation framework. While the transition pathways can be intuitively conceptualized via a primary 7-manifold scheme, our numerical simulation solves the full 47-level rate equations by explicitly accounting for all degenerate Zeeman sublevels ($m_F$) to rigorously incorporate polarization selection rules and Clebsch-Gordan coefficients. When the continuous acceleration voltage matches the resonance conditions of the $^{26\text{g}}\text{Al}$ hyperfine transitions, the ground-state atoms undergo a 100% efficient transition into uncoupled dark states within the 2.0 m flight zone. Consequently, background fluorescence from the ground state is completely suppressed in the detection chamber, whereas $^{26\text{m}}\text{Al}$ atoms utilize a closed cycling structure to survive the flight zone, yielding a high-intensity, background-free resonance peak.

Fault-tolerant architectures implement non-Clifford T gates through magic-state distillation, so the T-count of a synthesized circuit dominates its physical cost. The Solovay-Kitaev algorithm approximates any single-qubit unitary from a finite gate set with a sequence length that grows only polylogarithmically in the inverse target error, but it optimizes for numerical convergence rather than circuit economy, and its output carries structural redundancy that a gate-level compiler cannot see. We report a measurement of what diagrammatic post-processing recovers from that redundancy. Twelve hundred random single-qubit targets, spanning the three Pauli rotation families and the general gate U(theta, phi, lambda), are synthesized over Clifford+T at three recursion depths, translated into graph-like ZX-diagrams, simplified by automated rewriting, and extracted back to circuits. Post-processing removes 26.6-30.1% of the total gate count and 18.5-22.2% of the T-count. The absolute saving grows with recursion depth, from about 60 to about 1600 gates, while the fractional saving does not: it rises slightly from the shallowest setting and is then flat across a twenty-five-fold change in circuit length, and by the deepest setting the four target families are no longer distinguishable from one another. Because the rewrite rules preserve the implemented linear map, the approximation error is unchanged. The compile-time cost of the rewriting layer, by contrast, grows sharply with depth and comes to dominate the synthesis itself.

A nuclear excitation mechanism, nuclear excitation by radiative electron-ion recombination (NERER), is put forward theoretically here. NERER is a third-order process that proceeds via a virtual electronic state: an electron recombines into an atomic vacancy of an ion with the simultaneous emission of a real photon and excitation of the nucleus. The photon emission compensates the energy mismatch between the free-bound electronic transition and the nuclear transition energies, thus there is no resonant condition imposed to the incident electron. We develop here the theoretical framework for NERER, and investigate the case of the $8.4$ eV isomeric excitation of $^{229}$Th for the production of the nuclear clock isomer $^{229m}$Th. Our results show that, with the coupling to the inner atomic shells for highly-charged ions, the NERER cross section can exceed the one of the known lower-order process of nuclear excitation by inelastic electron scattering by more than one order of magnitude. Our findings offer a new pathway for nuclear excitation and efficient isomer production, and support further investigations for high-order effects in the interplay between the atomic and nuclear systems.

Gate synthesis and circuit optimization are usually studied separately, and evidence on their interaction is contradictory: ZX-calculus rewriting removes a stable fraction of Solovay-Kitaev circuits, yet almost nothing from number-theoretically synthesized circuits. We show both behaviours follow from a single bound. For any optimizer that preserves the implemented element exactly–including all sound ZX rewriting with extraction–the achievable T-count is bounded below by the denominator exponent of the synthesized ring element. This exactness barrier is computable per instance and separates exact post-processing from approximation-aware resynthesis by a certified factor reaching 101x at recursion depth five. The two behaviours are then the barrier operating at different distances from the floor. For Solovay-Kitaev circuits we prove that the local ZX simplification layer (spider fusion and identity removal) computes exactly the free-product normal form of Z_2 * Z_8, giving exact per-instance compression and, under a calibrated ergodicity hypothesis, a depth-independent limit law confirmed on two independently constructed nets. For number-theoretically synthesized circuits the floor is already saturated: on single-qubit words automated ZX simplification attains it exactly, via a closed-form formula for minimal T-count in terms of phase linkage through the Z-axis normalizer. At two qubits and beyond the same valuation yields unconditional rigidity certificates, which on the quantum-Shannon-decomposition plus gridsynth pipeline certify 99.4-99.9% of the synthesized T-count as incompressible, with rigidity strengthening as accuracy tightens. This explains, and predicts the size of, the near-null optimization recently reported for that pipeline.

Microwave electric-field measurements with Rydberg atoms require accurate Rydberg-transition electric-dipole matrix elements. We calculate these matrix elements for Rb and Cs using a Dirac-Fock plus core-polarization method, which core-valence exchange is treated explicitly and core-valence correlation is represented by a cutoff core-polarization potential. A smooth cutoff-radius model fitted to quantum-defect energies reproduces the target energies with MHz-level residuals for states up to $n=90$. Comparisons with model-potential matrix elements and internal length-velocity consistency show that the $s$-$p$ transitions are generally the most robust, whereas the $p$-$d$ and $d$-$f$ transitions show stronger atom- and branch-dependent sensitivity to short-range modeling. The largest relative differences arise from radial-integral cancellation, where short-range phase changes are amplified by the small final matrix element. These results provide a practical reliability assessment for Rydberg-transition electric-dipole matrix elements used in field-sensing applications.

Developing oxide absorbers with broadband high-temperature electromagnetic absorption performance has long been desirable in the electromagnetic absorption field, yet their absorption performance has remained unsatisfactory. Here, through an extreme mixing strategy, we successfully develop an ultrabroad effective absorption bandwidth (EAB) of 9.3 GHz in high-entropy perovskites up to 600 degree celsius, surpassing the previously reported oxide absorbers. Specifically, we achieve the extreme mixing in high-entropy perovskites by the successful incorporation of up to 13 cation elements, with 8 and 5 cations occupying the A- and B-sites, respectively, using a laser-driven controllable synthesis technique. Such extreme mixing maximally promotes the formation of atomic-scale interfaces to markedly amplify atomic-level interfacial polarization loss for the effective dissipation of electromagnetic wave energy, thereby giving rise to a remarkably broad EAB of 9.3 GHz in high-entropy perovskites up to 600 degree celsius. Owing to the profoundly increased electrical conductivity that causes impedance mismatch at elevated temperatures, however, their EAB deteriorates to 4.6 GHz at 700 degree celsius. This work establishes a new extreme mixing design paradigm for enabling high-entropy oxide absorbers with unprecedented high-temperature EM absorption performance.

We investigate the Joule-Thomson expansion of a non-commutative Schwarzschild-AdS black hole, whose space-time geometry is described by the Lie-algebraic $\kappa$-deformed space-time, and show that the $\kappa$-deformation parameter induces Joule-Thomson expansion in an uncharged-AdS black hole. We find the ratio of minimum inversion temperature to critical temperature $T_i^{(min)}/T_c \simeq 0.493$, is independent of the deformation parameter, and is in close agreement with the value for Reissner-Nordstrom black hole. Furthermore, we show the existence of a minimum black hole mass (depending on the $\kappa$-deformation parameter) below which the Joule-Thomson expansion vanishes.

The low-energy dynamics of antiferromagnetic spin waves map onto a massive Klein-Gordon scalar field, providing a solid-state platform for analogue-horizon physics. We show that an inhomogeneous spin current generates an effective magnon flow capable of forming black- and white-hole horizons. Horizon-pair cavities exhibit resonant transport and superradiant-like amplification mediated by magnon-antimagnon mixing. Our central result is that a periodic arrangement of submagnonic and supermagnonic regions forms a non-reciprocal magnonic crystal in which entering the supermagnonic regime makes negative-norm propagating channels available and enables the bulk gap to close and reopen. This drives a topological transition characterized by a change in the Zak phase and the emergence of a hybrid magnon-antimagnon edge state. These results establish a direct connection between analogue-horizon physics and topological magnonics, providing an electrically tunable route for controlling magnonic band topology.

The Solar wind is a continuous flow of charged particles emanating from the solar surface and governed by complex, interacting magnetohydrodynamic processes. Accurate specification of inner-boundary conditions is essential for heliospheric modeling and solar-wind prediction. In many practical applications, only a subset of interacting multi-field variables is directly available, but for a comprehensive view of solar wind prediction and downstream magnetohydrodynamic simulations, a more complete boundary state is required. In this work, we study the problem of learning the multi-field multi-scale solar magnetohydrodynamic state at 30 solar radii ($R_\odot$) using operator learning. Specifically, given the radial velocity and radial magnetic field, we aim to reconstruct the non-radial velocity and magnetic field components, radial and non-radial current density, thermodynamic density, and pressure components. This mapping is highly nonlinear, spatially coupled, and multi-scale, making it a challenging task for data-driven scientific machine learning. To address this problem, we employ a Local Neural Operator (LocalNO) that learns mappings between input and output function spaces while retaining locality and resolution-awareness. Unlike conventional regression models and autoencoder models, neural operators are better suited for learning structured field-to-field transformations arising from physical systems. The resulting predictions along with inputs are intended to serve as boundary condition variables for future inner-heliospheric modeling pipelines.

Recent observations have revealed gas-rich debris disks around intermediate-mass stars at ages of tens of Myr. The origin of this gas remains unclear: it may be primordial, retained from the protoplanetary phase, or secondary, released from volatile-rich solids. Secondary-origin models reproduce CO emission but often overpredict neutral carbon. Recent observations and disk-evolution models suggest that primordial gas may survive longer than previously assumed, motivating thermochemical tests of the primordial-remnant scenario. We test the previously unexplored possibility that primordial-origin disks satisfy the observational constraints on gas-rich debris disks. Specifically, we determine under what conditions a disk around a $2\,M_{\odot}$ star reproduces substantial CO, low CI/CO ratios, and weak HCO+ emission consistent with current non-detections. We post-processed 20-40 Myr structures from 1D disk-evolution models with Cloudy, varying irradiation geometry, dust-to-gas mass ratio (DTG), and cosmic-ray ionisation rate. In the dust-poor models (DTG $=10^{-4}$), CO remains optically thick around $R\sim100$~au. The models yield low disk-integrated CI/CO mass ratios. Our model produces CO radial intensities of the observed order of magnitude, but its CI-emitting region is more extended than observed. The standard CR model overproduces HCO+, whereas the weak CR model brings its predicted luminosity within current observational limits. These results demonstrate that a primordial origin remains chemically viable for CO-rich debris disks. The main remaining tension is the excessive radial extent of the CI emission, although it may reflect our simplified modelling. Further testing of the primordial-origin scenario will require multidimensional, self-consistent modelling, spatially resolved CI observations, and deeper searches for HCO+.

A recent experimental study reports the spontaneous formation of a three-dimensional woven ferroelectric domain fabric in bulk KTN:Li during sufficiently slow cooling through the ferroelectric transition. The present work develops a nondimensional phase-field framework to examine a physically plausible route by which such a state can emerge. A large-area two-dimensional model first resolves the cooling-rate-dependent formation of a frustrated crossing precursor by combining first-order ferroelectric thermodynamics, electrostatic and elastic interactions, compositional modulation, and effective charge screening. Slow cooling produces a persistent population of charge-associated crossings, whereas the corresponding fast-cooling pathway does not. A three-dimensional extension then incorporates cubic gradient anisotropy, flexoelectric coupling, and strain-gradient regularization to examine whether the planar precursor can develop a genuine woven topology. Within the explored nondimensional parameter regime, slow cooling produces a directly resolved geometrical separation and exchange of depth ordering between the intersecting wall families, whereas the corresponding fast-cooling pathway does not. This distinction is reproduced across independent realisations and remains robust to timestep refinement and changes in computational domain size. The simulations suggest that slow cooling provides a kinetic window for topological selection and that global charge relaxation can coexist with strong local charge concentration at surviving crossings. The model is not calibrated to material-specific KTN:Li coefficients and does not reproduce the experimentally observed low-temperature disappearance of the woven state.

S251112cm is a nearby ($93 \pm 27$~Mpc) compact-binary merger candidate with a high inferred probability that at least one component is below $1\,M_\odot$. This event provides a rare test case for electromagnetic follow-up of a theoretically predicted but unconfirmed sub-solar-mass merger candidate. Motivated by scenarios predicting NIR-bright emission over weeks to months, we carried out a deep, galaxy-targeted UKIRT $J$-band campaign over approximately two months, prioritizing host candidates by a ranking that combines the three-dimensional localization probability with WISE W1 luminosity as a stellar-mass proxy. Of $\sim9000$ candidate hosts, we monitored 59, corresponding to 7.7% of the cumulative weighted host prior. Difference imaging reveals no convincing transient down to typical depths of $J\sim22$–23~mag (AB). At this distance, both a Type~Ic-BL supernova template and an AT\,2017gfo-like KN template—including time-shifted variants up to $\Delta t \sim 60$~days—would have remained above our median depth for multiple epochs within the monitored hosts. Comparison with a canonical KN model grid, summarized through conditional weighted consistent-fraction maps, shows that bright configurations with high dynamical and wind-ejecta masses are strongly disfavored, while less luminous configurations remain largely permissible. While these constraints are host-limited and do not constitute an event-wide exclusion, this campaign provides the first empirical case study of long-baseline, deep NIR follow-up for a sub-solar-mass merger GW class and demonstrates a host-weighted framework applicable to future galaxy-targeted campaigns.

We present phase-connected timing and polarization measurements for two long-period FAST-CRAFTS pulsars, PSRs J0000+6252 and J2131+3642, and extend single-pulse emission-state analysis to a five-source sample including PSRs J1903+1407, J1502+4653, and J2112+4058. FAST L-band timing baselines span 414 to 511 days; the two pulsars have spin periods of 1.11 to 1.55 s, period derivatives of $(3.99$ to $4.06)\times10^{-15}~{\rm s~s^{-1}}$, characteristic ages of 4.34 to 6.16 Myr, surface magnetic fields of $(2.15$ to $2.52)\times10^{12}$ G, and spin-down luminosities of $(4.21\times10^{31}$ to $1.16\times10^{32})~{\rm erg~s^{-1}}$. Their rotation measures are $70.2\pm26.7$ and $-44.6\pm7.6~{\rm rad~m^{-2}}$, with linear polarization fractions of 17.6% to 27.2%. PSR J2131+3642 shows a short monotonic PA segment permitting a formal rotating-vector-model fit, though limited longitude coverage leaves the geometric parameters poorly constrained; PSR J0000+6252 has too few PA points for such a fit. Gaussian mixture modeling (GMM) of single-pulse energy distributions identifies null, weak, and burst components in PSRs J0000+6252, J1903+1407, J1502+4653, and J2112+4058, while J2131+3642 shows only weak and burst states. We also identify bright single pulses (peak intensity $\geq10\times$ the integrated average profile): 42 in J0000+6252, four each in J1903+1407 and J2112+4058, and none in J2131+3642 or J1502+4653. These bright pulses occur within the main emission window with no evidence of periodic recurrence, consistent with sporadic enhancements of the normal radio-emission beam. For J2112+4058, we measure a scattering timescale $\tau_{\rm sc}=5.84\pm0.18$ ms at $\nu_{\rm ref}=1.25$ GHz. Together, these results highlight the diversity of magnetospheric variability among slowly rotating neutron stars.

We study spectral density estimation for the normalized adjacency matrix of an unweighted graph under local access model. Previously, Cohen-Steiner et al. [KDD 2018] proposed an algorithm for $\varepsilon$-approximate spectral density estimation in the Wasserstein-1 distance, using $2^{O(1/\varepsilon)}$ local queries to the graph. In this paper, we prove that every constant-success estimator with Wasserstein–$1$ error at most $\eps$ requires $2^{\Omega(1/\eps)}$ queries, showing that the Cohen-Steiner algorithm is optimal up to constant in the exponent. This resolves the open problem left by previous researches Jin et al. [COLT 2023] and Peng et al. [COLT 2026]. We then turn to quantum local access model. We give an $\widetilde O(\eps^{-3})$-query algorithm estimating the spectral density with Wasserstein-1 error at most $\eps$. Finally, we prove a $\widetilde\Omega(\eps^{-4/3})$ quantum lower bound when the graph is sufficiently large. As a result, quantum local access model changes the dependence on $\eps$ from exponential to polynomial.

The stability of markets hosting leveraged exchange-traded products is governed not by any single product's loop gain but by the spectral radius of a loop-gain matrix, and scalar per-product monitoring underestimates system feedback by construction. Recent work measures the self-reinforcement of a leveraged fund's daily close rebalancing through a scalar loop gain and treats cross-asset spillovers as bias. We model complexes on correlated underlyings as a coupled feedback system with matrix gain L and show that scalar monitoring has two blind spots: (i) cycle amplification, since rho(L) >= max_i l_ii for nonnegative coupling, strict under two-way coupling; and (ii) transmitted displacement, which arises already under one-way coupling and is invisible to the receiver's own gain. We give a reduced-form estimator of L requiring only prices and public fund assets – no signed order flow – via cross-asset overnight reversals, reporting its measurement-convention sensitivity explicitly. In simulation the spectral radius is recovered with RMSE 0.005 at T=250, a lead-lag confounder yields a 2% false-alarm rate, and in a calibrated blind-spot configuration the scalar monitor reports "safe" and the matrix monitor "unsafe" on 100% of paths. In the 2026 Korean single-stock LETF episode we detect transmission from the SK Hynix complex into Samsung Electronics' closing price (DiD z=-2.82; exact randomization p=0.0055 against 182 control pairs), scaling with the sender's rebalancing capital; conservatively, about 41% of Samsung's closing displacement variance is imported – invisible to its own "moderate" gain of 0.24. The same estimator returns nulls for the U.S. MSTR-Bitcoin-Coinbase complex, whose capital is comparable but whose closing venue is far deeper. Monitoring should be organized around the (complex x venue) matrix, not around products.

This review provides a comprehensive survey of weak-coupling theoretical approaches applied to understand the emergent superconductivity in the pressurized nickelate bilayer system $La_{3}Ni_{2}O_{7}$. Following the landmark discovery of its high-Tc superconductivity under pressure, this material has rapidly become a new paradigmatic platform in the field of unconventional superconductivity, joining cuprates and iron-based systems. We focus on three pivotal theoretical frameworks: the random phase approximation (RPA), the fluctuation-exchange approximation (FLEX), and the functional renormalization group (FRG). These methods are deployed to analyze the effective pairing interactions and emergent instabilities arising from the low-energy electronic structure, which is commonly modeled by a bilayer two-orbital Hubbard Hamiltonian incorporating the Ni $d_{x^2-y^2}$ and $d_{3z^2-r^2}$ orbitals.

Conventional polarization characterization techniques provide only the averaged response of ferroelectric films, limiting the investigation of domain-dependent reliability mechanisms in HfO2-based ferroelectrics. In this work, a new domain decoupling method is proposed to separately analyze ferroelectric domains with distinct switching behaviors. A three-domain model consisting of upward non-switchable domains, downward non-switchable domains, and switchable domains (Pd) is first introduced to describe heterogeneous domain populations during electrical cycling. By combining complementary switching-current measurements, the responses of different domain populations can be selectively extracted and reconstructed. The proposed method enables quantitative tracking of individual domain populations during cycling. As a demonstration, the method is further applied to analyze the time-dependent evolution of domain populations after electrical cycling. This approach provides a new route for investigating imprint, fatigue, and other reliability-related phenomena in ferroelectric devices.

We revisit the long-standing ambiguity surrounding the complex pole structure of the $\Lambda(1405)$ resonance by reframing it as a classification problem for convolutional neural networks (CNNs). By training our models to recognize subtle geometric variations on nearly degenerate lineshapes using targeted differential feature on empirical CLAS data, we establish a data-driven consensus on large inference samples. Our results show that the analytic structure characterized by two poles on the $[bt]$ sheet and additional pole on the $[bb]$ sheet globally dominates. The inference-guided pole parameter extraction reveals that the $\Lambda(1405)$ is a two-state system, characterized by a molecular state sitting below the $\bar{K}N$ threshold and a non-molecular state lying above the $\Sigma \pi$ threshold.

We propose a new way to probe elliptic small-$x$ gluon geometry in hard diffractive dijet deep inelastic scattering: a localized lepton wave packet carrying orbital angular momentum is used as a tunable transverse analyzer of the target. Unlike the conventional plane-wave setup, where the probe provides a fixed transverse projection, the OAM mode supplies additional radial and azimuthal structure while leaving the target dipole matrix element unchanged. We characterize the resulting elliptic response through $S_M=D_M-C_M$ and find finite-yield response nodes whose origin depends on the OAM channel. In the present benchmark, the $M=1$ crossing is associated mainly with a zero of the direct response, whereas the $M=3$ channel exhibits a nontrivial cancellation $D_3=C_3\neq0$. Signed transverse response densities show that this node results from a spatial cancellation rather than from a disappearance of the underlying scattering strength, and its position can be shifted by changing the beam–target offset. The specific sensitive value of $M$ depends on the analyzer profile and kinematics; the broader result is that localized OAM wave packets provide a controllable probe-side degree of freedom for small-$x$ gluon tomography.

We investigated the quantum size effect (QSE) in bimetallic Pt$_{1-x}$Pd$_x$ and Pt$_{1-x}$Ni$_x$ nanoparticles, using $^{195}$Pt nuclear magnetic resonance measurements. The temperature and size dependencies of the anomaly in the nuclear spin-lattice relaxation rate divided by temperature $1/T_1T$ in the Pt$_{1-x}$Pd$_x$ nanoparticles suggest similar electron states between Pt and Pd atoms and are well understood by the QSE. The temperature and composition variations of $1/T_1T$ and Knight shift reveal a systematic increase in the density of states and reduction of the characteristic energy scale $T^*$ with increasing Ni content, consistent with the Kubo gap $\delta_{\mathrm{Kubo}}$. In contrast to Pt$_{1-x}$Cu$_x$ nanoparticles where the QSE is suppressed, the Pt$_{1-x}$Ni$_x$ nanoparticles exhibit clear signatures of quantum energy discretization. This discrepancy highlights the essential role of $d$-electrons in the manifestation of the QSE. Furthermore, analysis of the modified Korringa parameter $K(\alpha)$ suggests enhanced ferromagnetic correlations with increasing Ni concentration, approaching a ferromagnetic quantum critical regime. These results provide experimental evidence that $d$-electron density of states plays a crucial role in the manifestation of the QSE in the nanoparticles formed by the metallic $d$-electron atoms.

We investigate the duty-cycle-dependent atomic response under full-depth intensity pulse-width modulation in Bell–Bloom optical pumping. A time-domain Bloch model explicitly resolves the pump-on/off spin dynamics, yielding piecewise analytical transient solutions and a periodic steady-state description without cycle averaging or harmonic truncation. An extended free-induction-decay method independently determines the effective dark and pump-on transverse-relaxation rates, $W_0$ and $W$. The predicted lock-in responses agree well with experimental results. We find that for each Larmor frequency $\omega_0$, the slope is maximized at a finite pump rate that increases with $\omega_0$. These results provide a practical framework for sensitivity-oriented optimization of the duty cycle and pump rate in PWM-driven atomic magnetometers.

Topological order can fractionalize the quantum numbers of the underlying particles. A paradigmatic example is the spin-1/2 states at the edges of an antiferromagnetic integer-spin chain, protected by a topological Haldane gap in the bulk and mutually coupled in short chains. Owing to their topological protection, they are natural building blocks for hybrid spin-superconductor quantum systems. Whether fractionalization survives the coupling to a superconducting condensate, however, remains an open question. Here we grow molecular Haldane chains of antiferromagnetically coupled spin-1 triangulene units on a proximitized Au(111)/Nb(110) surface and resolve a parity-dependent coupling of their spin-1/2 edge states to the superconducting condensate by scanning tunnelling spectroscopy. Odd-length chains host Yu-Shiba-Rusinov bound states inside the superconducting gap, originating from the net S=1 ground state, whereas even-length chains form an S=0 ground state decoupled from the superconductor. A two-site superconductor model reveals that this alternation arises from the sign and strength of the inter-edge interaction, a mechanism independently validated by extra-gap spin excitations in tunnelling spectra. Collective many-body spin excitation modes are also detected decoupled from the superconductor by the much larger Haldane gap. The length-tunable coupling of the edge spins to the superconductor opens a route toward molecular spin qubits based on $\pi$-conjugated carbon architectures.