Papers

Observations indicate that supermassive black holes (SMBHs) in high-redshift galaxies formed on timescales far shorter than classical growth models allow. One hypothesis suggests intermediate-mass black hole (IMBH) seeds as an efficient growth channel. Using N-body simulations, we demonstrate that in dense stellar-mass black hole (BH) clusters ($\ge 5\times10^9 M_{\odot}/{\rm pc}^3$), runaway gravitational-wave binary BH (BBH) mergers can produce a $\sim 10^3 M_\odot$ IMBH within 10 Myr from the formation of the BH subsystem. This scenario is simple and avoids large uncertainties regarding stellar mergers and evolution in the IMBH formation via very massive stars channel. We find that the runaway GW-merger mechanism relies on hard BBH formation through a chain of exchanged soft BBHs with accumulated hardening, which is far more efficient than three-body scattering. We analyze how IMBH formation depends on cluster density, total mass, initial mass function, and stellar halo potential. We find that due to cluster expansion, the systems forming IMBHs have densities consistent with present-day nuclear star clusters, such as those in the Milky Way and M33. Furthermore, we show that IMBH spin remains low due to repeated mergers, and we estimate the rate of GW190521 and GW231123-like events within the first 100 Myr to be $2.27-247.52$ and $3.23-63.63 $ per Gyr per cluster.

The K-$\Gamma$ valence-band splitting $\Delta_{K\Gamma}$ that governs hole transport in few-layer WSe$_2$ is not a fixed material constant. It is tuned by interlayer stacking, strain, pressure, and the dielectric and displacement-field environment. Its computed value also depends on the level of electronic-structure theory. Bilayer WSe$_2$ therefore realizes a tunable multivalley landscape rather than a single operating point. We combine first-principles inputs with an analytical two-valley device model for gate-all-around (GAA) field-effect transistors, and obtain three results. (i) The minimum subthreshold swing stays near the thermionic limit of $60$~mV~dec$^{-1}$ independently of layer number, because well below threshold the quantum capacitance remains far below the oxide capacitance. (ii) The effective mobility is set by the K-to-$\Gamma$ occupation ratio: valley redistribution is strong when $\Delta_{K\Gamma}$ is of order $k_BT$ and fades toward single-valley $K$ transport as the splitting grows. (iii) In this small-splitting regime, biaxial strain tunes the effective mobility - and hence the on-current - through the valley population while the subthreshold swing stays at the thermionic limit, decoupling mobility control from electrostatic switching in a way distinct from scattering-based strategies. A symmetric GAA gate controls carrier density at essentially fixed splitting, and because an out-of-plane field increases $\Delta_{K\Gamma}$, its midplane-symmetric potential avoids driving the channel out of the small-splitting regime. The design principle has two facets: small $\Delta_{K\Gamma}$ - set by layer number, stacking, strain, and dielectric engineering - maximizes the valley tunability of $\mu_\mathrm{eff}$, whereas larger $\Delta_{K\Gamma}$, for example through compressive strain, suppresses the heavy $\Gamma$ valley and maximizes the on-state mobility.

We present a microscopic analysis of the nuclear matrix element (NME) of the two-neutrino double-$\beta$ ($2\nu\beta\beta$) decay for open-shell heavy deformed nuclei, taking into account the fact that nuclear level density increases rapidly with excitation energy as well as the contribution of two-body current (2BC). Taking $^{76}$Ge $\rightarrow$ $^{76}$Se decay as an example, we found that due to the rapid increase of the level density of the intermediate nucleus $^{76}$As with excitation energy $E_n$, the single-$\beta$ Gamow-Teller (GT) matrix elements become highly fragmented with very small magnitude, and exhibit seemingly random sign patterns at high $E_n$ region. This leads to an effective cancellation at high $E_n$ region in calculating the $2\nu\beta\beta$ NME which then turns out to converge at $E_n \lesssim 5$ MeV, indicating that the contribution of high-lying states of the intermediate nucleus to $2\nu\beta\beta$ NME is negligible. Besides, the 2BC in the transition operator is found to contribute $\sim 10\%$ quenching to the $2\nu\beta\beta$-decay NME of $^{76}$Ge.

Multiparameter quantum estimation has emerged as a central task in quantum metrology. In this work, we investigate multiparameter quantum estimation in a hybrid exciton–optomechanical (EOM) system. The system consists of a semiconductor quantum well embedded inside a driven optomechanical microcavity, where the excitonic, optical, and mechanical modes interact coherently through exciton–photon and radiation-pressure couplings. Using the Gaussian-state formalism, we derive the covariance matrix of the steady-state quantum fluctuations and employ both the symmetric logarithmic derivative (SLD) and right logarithmic derivative (RLD) approaches to evaluate the quantum Fisher information matrix associated with the simultaneous estimation of the exciton–photon coupling strength $g$ and the excitonic decay rate $k_x$. We analyze the corresponding quantum Cramér–Rao bounds and determine the most informative precision limit governing the attainable estimation accuracy. The influence of several experimentally relevant parameters, including temperature, driving power, optomechanical coupling strength, and dissipation rates, is investigated in detail. Our results show that strong hybrid interactions and low-temperature regimes significantly enhance the estimation precision, whereas thermal fluctuations and dissipation processes deteriorate the metrological performance. Furthermore, we compare the ultimate quantum limits with experimentally feasible Gaussian measurement strategies based on homodyne and heterodyne detection. We show that heterodyne detection provides better estimation performance than homodyne schemes and can approach the optimal quantum precision limit in suitable parameter regimes.

Diffusion Monte Carlo (DMC) and Monte Carlo for particle transport with importance sampling both involve simulations of weighted walkers that undergo birth and death processes (splitting and Russian Roulette). The established implementations of these methods are quite different: Particle simulation Monte Carlo employs a stack to handle the splitting history whereas in traditional DMC one follows a swarm of walkers. The particle simulation Monte Carlo approach involves a depth first traversal of the visited configurations whereas the traditional DMC approach may be seen as a breadth first traversal. In the present work the implementation of a depth first, stack based approach to DMC is described and a complete code is presented. The depth first approach, called DMCD here, can be more memory efficient than the breadth first approach, both for total memory and for use of a memory hierarchy and of co-processors. The implementation appears very natural for population control and for descendant weighting and it unifies algorithmic treatment of the eigenvalue problem (DMC) with the linear equation problem (particle transport). A concern with DMCD that is not present in the breadth first approach, and that is successfully addressed here, is the need to maintain a pool of starters for use when a new walker is required and the stack is empty. The DMCD approach appears to have the potential to become the preferred implementation for many DMC applications.

Birefringence in test mass substrates is an emerging limitation for current and future laser-interferometric gravitational-wave detectors, particularly as detectors move toward higher circulating power, cryogenic operation, and crystalline optical materials. Spatially varying birefringence alters both the polarization state and spatial mode content of the intracavity field, reducing interference contrast and coupling into length and alignment control signals. Accurate modeling of these effects is complicated by the fact that most frequency-domain simulation tools employ scalar modal propagation and lack native support for polarization and two-dimensional substrate maps. In this work, we present a practical and general method for simulating inhomogeneous birefringence without modifying existing simulation frameworks. The approach represents the two polarization components as independent scalar fields and introduces their coupling through an equivalent triple-Mach-Zehnder construction that reproduces the Jones matrix of a birefringent medium. We demonstrate the method using realistic birefringence maps of the KAGRA sapphire input test masses. The technique is compatible with any frequency-domain interferometer model and enables efficient birefringence studies for next-generation gravitational-wave detectors.

The Doppler backscattering (DBS) diagnostic measures flows and electron density fluctuations. Recent work indicates that DBS can also infer the magnetic pitch angle (Yeoh et al., NF 2026). We present the preliminary design of a DBS for the Pegasus-III Experiment. This DBS will serve two objectives. First, it will advance diagnostic science, by supporting understanding of the DBS instrumentation functions, using DBS to constrain the magnetic equilibrium, and data-driven inference of plasma properties from DBS signals. Secondly, it will support Pegasus-IIIs research directions, such as solenoid-free plasma initiation and O-X-B mode conversion for heating and current drive, since density fluctuations affect mode conversion efficiency and pitch angle measurements can be used to locate the mode conversion window. This ex-vacuum DBS system uses a single channel, tuneable Ka-band source, a corrugated horn antenna, and a homodyne I/Q receiver with baseband digitization. For greater flexibility, which is especially important for pitch angle measurements, the quasioptical elements include a rotatable spinner for O- and X-mode selection and a mirror with 2D steering. Using the Scotty beam-tracing code, for a range of poloidal launch angles $8^\circ$ to $18^\circ$ and a corresponding toroidal launch angle between $0^\circ$ to $3^\circ$ for maximal backscattered DBS power, we find that the DBS system is capable of measuring ion-scale density fluctuations $1\leq k_{\perp,c} \leq8 \text{ cm}^{-1}$ at a range of normalized radial coordinates from the outer core ($\rho \sim 0.65$) to just beyond the last-closed flux surface (LCFS), where $\rho=0$ corresponds to the magnetic axis and $\rho=1$ the LCFS. The system is also designed with additional toroidal steering capability, $-4^\circ$ to $8^\circ$, to resolve the toroidal response needed for magnetic pitch angle measurements.

Using the form factors of the transtions $B\to T$ with $T$ refering to a tensor meson, such as $a_2(1320), f_2(1270),K^*_2(1430), D_2^*(2460)$ and $D^*_{2s}(2573)$, within the covariant light-front quark model (CLFQM), we provide a detailed investigation of the corresponding semi-leptonic decays $B\to T\ell\nu_\ell$ with $\ell=e,\nu,\tau$. All the branching ratios of these decays are larger than $10^{-5}$, in which the maximum value can reach up to $10^{-3}$, indicating promising prospects for experimental observation. Furthermore, we also calculate the longitudinal polarization fractions $f_L$ and forward-backward asymmetries $A_{FB}$ for these considered decays. All the decays $B\to T \ell\nu_{\ell}$ are dominated by the longitudinal polarization, where the polarization fractions can reach up to $\sim70\%$ for the decays $B\to T \ell^{\prime}\nu_{\ell^\prime}$ with $\ell^\prime=e, \mu$, those of the decays $B\to T \tau\nu_{\tau}$ are a little smaller. The $A_{FB}$ values of the decays $B\to T \ell^{\prime}\nu_{\ell^\prime}$ and $B\to T \tau\nu_{\tau}$ have opposite signs.

We report the first identification of molecular clumps directly associated with the re-brightening regions of the large-scale X-ray jets of SS 433, based on $^{12}$CO ($J$ = 1–0) observations with the Nobeyama 45-m Radio Telescope. Multiple clumps are detected toward the eastern and western jet heads, showing clear spatial correlation with the X-ray emission. The X-ray emission peaks immediately downstream of the molecular clumps, while the hardness ratio is enhanced at their surfaces, indicating that the observed structures cannot be explained by absorption effects. These results provide direct evidence for shock–cloud interactions between the jets and the surrounding interstellar medium. We suggest that turbulence generated at the jet–cloud interface amplifies magnetic fields, producing the observed non-thermal X-ray emission. Our findings highlight the importance of jet–ISM interactions in shaping the X-ray properties of microquasar jets.

Theoretical quantum dynamics calculations scale deeply with system size, rendering classical calculations intractable for complex systems. While quantum computing offers a natural solution, its application to nuclear quantum dynamics remains scarce. Here, we present a quantum algorithm to study photodissociation dynamics on quantum computers, benchmarked on the NOCl molecule. The wavefunction is propagated via a split-operator method, utilizing the Quantum Fourier Transform and unitary transformation matrix to switch representations. To impose outgoing boundary conditions on a truncated grid, we use a non-unitary absorbing potential propagator, implemented through a dilation scheme. The photodissociation cross section is calculated from the auto-correlation function, which is extracted using the Hadamard test. Our quantum computing results agree well with benchmarks under ideal conditions, and we further demonstrate that the algorithm is robust to noise and statistical sampling errors, indicating the promising application of noisy devices to quantum dynamics studies.

We show that generic Maxwell fields can be represented within the matter-space framework by introducing two independent matter-space flows. In the one-flow formulation the electromagnetic field strength is the pull-back of a two-form on a three-dimensional matter space and therefore satisfies $F\wedge F=0$, so that a single flow captures only a degenerate, helicity-carrying sector. The minimal completion is obtained by writing $$F=G^{(1)}+G^{(2)},$$ where each sector field $G^{(I)}$ is the pull-back of a matter-space two-form from an independent flow. Each sector is individually degenerate, $G^{(I)}\wedge G^{(I)}=0$, while the full field satisfies $F\wedge F=2G^{(1)}\wedge G^{(2)}$; the invariant excluded by the one-flow theory is thus recovered as an inter-flow quantity. We interpret this structure in terms of mutual helicity: the total helicity decomposes into two self-helicity contributions and a mutual term whose exterior derivative is $F\wedge F$. Hence a configuration with vanishing mutual helicity lies in the degenerate sector, whereas a nondegenerate Maxwell field necessarily carries a nontrivial mutual helicity. A variational principle for the total field recovers the sourced Maxwell equation, the two matter-space variations combining into the full equation whenever the sector kernels intersect trivially. Generic electromagnetism is thereby reconstructed as the minimal coupled completion of two individually degenerate matter-space sectors.

Chemical substitution offers an effective route to tune magnetic ordering and magnetocaloric performance in rare-earth oxides for cryogenic refrigeration. Here we investigate the structural evo lution, magnetic properties, and magnetocaloric effect of polycrystalline zircon-type Gd1-xErxVO4 (x=0, 0.1, 0.25, 0.5, and 0.75). Powder X-ray diffraction confirms that all samples crystallize in the tetragonal zircon structure without detectable impurity phases. Substitution of Gd3+ by the smaller Er3+ ion produces a systematic lattice contraction and modifies the magnetic behavior of the rare-earth sublattice. In particular, the magnetic ordering temperature is suppressed from 3.65(2) K in GdVO4 to 2.76(2) K in Gd0.9Er0.1VO4 , accompanied by a weakening of the spin-flop-like field-induced anomaly observed in the parent compound. A low Er concentration correspondingly improves the low-temperature magnetocaloric performance, with Gd0.9Er0.1VO4 exhibiting a max imum magnetic entropy change of 45.1 J kg-1 K-1 for mu_0 Delta H=7T. These results demonstrate that weak Er substitution effectively tunes the competition among exchange interactions, dipolar coupling, and magnetic anisotropy, optimizing the balance between magnetic ordering and available spin entropy in zircon-type rare-earth vanadates, which is crucial for developing efficient cryogenic refrigeration materials.

The local electronic states of muon (Mu) as an isotope of hydrogen (H) in high-quality single-crystalline ceria (CeO$_2$) are investigated using muon spin rotation/relaxation ($\mu\text{SR}$) and first-principles density functional theory (DFT) calculations. Upon positive muon implantation, both paramagnetic (Mu$^0$) and diamagnetic (Mu$^*$) states are observed below $\approx$10 K. Magnetic field dependence of the Mu$^0$ signals combined with DFT results provides evidence for the formation of a polaron state, consisting of Mu bonded to a ligand oxygen and a $4f$ electron localized on a nearby Ce site. The crystal-orientation dependence of the Mu$^0$ signal suggests strong anisotropy of the $4f$ electron due to the spin-orbit coupling with lifted degeneracy. Furthermore, the Mu$^0$ state exhibits transition to the Mu$^*$ state that corresponds to another Mu$^0$ state (exhibiting a diamagnetic response due to fast spin/charge fluctuations) at temperatures above $\approx$10 K, before disappearing above $\approx$30 K. These findings suggest rapid diffusive motion of the $4f$ electrons and/or Mu (as well as H) at higher temperatures.

In Scalar-Tensor-Vector Gravity (STVG, also known as MOG), a massive vector field $\phi_\mu$ generates a repulsive fifth force that endows rotating black holes with a gravitational charge $Q \propto \sqrt{\alpha}\,M$, modifying the near-horizon geometry through a single deformation parameter $\alpha$. We investigate how this vector-field coupling imprints itself on the thermal continuum emission of geometrically thin, optically thick accretion disks in the Kerr-MOG black hole. By re-deriving the innermost stable circular orbit (ISCO), the Novikov-Thorne radiative flux, the relativistic energy shift, and the null geodesic structure for the Kerr-MOG spacetime, we compute fully relativistic disk spectra across a broad range of spins, inclinations, and fifth-force strengths using a dedicated xspec spectral model (kmspec). We find that the fifth-force charge pushes the ISCO outward, lowers the peak disk temperature, and systematically softens the thermal continuum relative to its Kerr black hole counterpart at the same spin, with the deviation amplified at high observer inclinations. The resulting spectral modification closely mimics a reduction of spin in the pure Kerr black hole framework, indicating that independent spin measurements from, e.g., iron-line reflection spectroscopy are indispensable for disentangling the vector-field contribution. All results recover the standard Kerr black hole predictions when $\alpha = 0$, and the model is validated against independent analytic and numerical benchmarks to machine precision. Application to a 69.6~ks XMM-Newton observation of LMC~X-1 yields $\alpha < 0.044$ at 90% confidence, consistent with the Kerr metric and general relativity.

Gaussian quantum channels constitute a pivotal physical framework for characterizing the dynamics of Gaussian quantum states. Extensive scholarly attention has been devoted to the estimation of parameters associated with Gaussian channels. However, while previous research has predominantly focused on parameter estimation within inertial frames, the noninertial scenario, particularly in the context of the Unruh effect, remains largely unexplored. In this paper, we analyze the impact of the Unruh effect on the estimation precision of Gaussian channel parameters, with a specific focus on thermal attenuator and thermal amplifier channels. Our findings reveal that the Unruh effect significantly degrades the precision of single-parameter estimation for Gaussian channel parameters when employing both the input coherent state and squeezed vacuum state. For the two-parameter estimation, we further demonstrate that the quantum Cramér-Rao bound serves as an asymptotically achievable precision limit. Consistent with the single-parameter case, the Unruh effect exerts a detrimental impact on the precision of two-parameter estimation. Notably, heterodyne measurement is near-optimal for both single- and two-parameter estimation in the limit of high acceleration or large thermal mean numbers. These results provide crucial theoretical insights and practical guidance for advancing quantum parameter estimation in a relativistic context.

For the 1D generalized Coulomb problems–a family that includes the quantizations of the 1D generalized Kepler problems of Ma-Meng-Xiao \cite{MMX2025}–we construct two explicit unitary intertwiners $\hat\iota_{\pm}$, the quantum analogs of the classical symmetry regularization maps $\iota_{\pm}$ of \cite{MMX2025}, that unitarily identify each $H_{\kappa}$-energy-definite portion of the Hilbert space $L^{2}(\mathbb{R}_{>0},\mathrm{d}q)$ with a unitary lowest-weight representation of $\widetilde{\mathrm{SL}}(2,\mathbb{R})$.

Future space-borne gravitational-wave (GW) detectors, such as LISA and DECIGO, are expected to detect a large number of GW events, a fraction of which may be strongly lensed by intervening galaxies or galaxy clusters. In this work, we develop a comprehensive framework to simulate strongly lensed GWs in the context of space-borne detectors. Based on realistic astrophysical models for both the source population and the lens distribution, we construct mock catalogs of lensed GW events, referred to as GW-LMC-Space. Our results show that, for a four-year LISA observation, the expected number of lensed events ranges from $0$ to $131$, depending on the adopted formation model of massive black hole binaries (MBHBs). The corresponding lensing probability for MBHBs can reach up to $\sim 0.3\%$. For DECIGO, we find that the number of lensed events in a one-year observation is expected to lie in the range of $0$–$44$, with a lensing probability of $\sim 0.15\%$ for stellar-mass binary black holes (BBHs), binary neutron stars (BNSs), and neutron star–black hole binaries (NSBHs). We further show that the overlap of lensed signals is a common feature in space-borne detectors, which can significantly affect both the signal-to-noise ratio (SNR) estimation and event identification. These results highlight the importance of accounting for signal overlap in the analysis of strongly lensed GW events in future space-borne GW observations.

We construct an exact rotating vacuum of the NS–NS sector, equivalently a Double Field Theory vacuum. The construction applies compact $\mathbf{SO}(2)$ S-duality to a rotating Einstein–scalar seed. The solution has four independent parameters $\{\mathfrak{m},j,\mathfrak{q},\zeta\}$. To our knowledge, this is the first explicit rotating solution of the pure NS–NS vacuum equations with all three NS–NS fields $\{g,B,\phi\}$ determined analytically, independent dilaton and $H$-flux charges, and no Maxwell sector. The static limit is obtained by taking the rotation parameter $j\to 0$. In this limit the geometry is not the spherical Burgess–Myers–Quevedo solution. Instead, it is an axial Zipoy–Voorhees branch carrying $H$-flux, so an oblate deformation remains after rotation is switched off. This geometric memory is absent in pure general relativity and in Einstein–Maxwell–dilaton–axion. The two static branches nevertheless share the same $\ell=0$ parametrized post-Newtonian data $\{MG,\beta_{\mathrm{PPN}},\gamma_{\mathrm{PPN}},h\}$. They give two inequivalent NS–NS geometries at identical monopole charges, with the degeneracy lifted at $\ell=2$. At the Kerr horizon locus the outer shell is generically singular in curvature. Above the threshold $|\mathfrak{q}|>\sqrt{\mathfrak{m}^{2}-j^{2}}$, polar geodesics are repelled outward and the rotation axis becomes regular in curvature at the shell. On that axis the inverse metric $g^{\mu\nu}$ stays finite while the lower-index Riemannian metric components diverge, whereas off the axis the inverse metric itself diverges. This axis-local degeneracy may offer a setting for non-Riemannian geometry in Double Field Theory, where $g_{\mu\nu}$ is not fundamental and the $\mathbf{O}(D,D)$ variables $\{d,\mathcal{H}_{AB}\}$ remain well defined.

This paper proposes a design-for-test (DFT) methodology and architecture for testing and validation of silicon photonic integrated circuits. We describe the design of silicon photonic circuits and components that comprise the proposed DFT architecture. The designs are extensively simulated and validated as test-access and fault-detection circuitry. We demonstrate how the DFT approach can be deployed on photonic integrated circuits and how they can be tested for correct operation, in terms of signal power and phase. The application is demonstrated on two distinct types of designs – an optical neural network comprising optical devices in a feed-forward topology, and on an optical logic circuit with feedback loops.

We develop an agent-based, stock-ow-consistent model of an economy undergoing automation, built to ask which scal instrument reaches the durable surplus that articial intelligence creates. The model separates two channels: a competitive return on reproducible robotic capital, and a mobile, foreign-held intellectual-property rent earned by AI. Production is an endogenous nested-CES technology; wealth concentration is microfounded through heterogeneous, persistent returns to wealth; and taxation and capital mobility are modelled as behavioural responses. The central result is that the durable surplus is the foreign-held AI rent, a cross-border licence fee that corporate, robot, and compute or token taxes largely miss and that only a source-based levy (a digital-services-style tax or a withholding) reaches. The appropriate policy depends decisively on whether a country owns the automation or imports it: for a host that owns the rent the problem is domestic inequality, reached by progressive and wealth taxes; for a rent-importing host the problem is base erosion and a gradual transfer of capital ownership abroad, which a residence-based wealth tax cannot reach. We report conditional orderings, stress-tested with global (Sobol) sensitivity and a formal stability analysis, rather than point forecasts.

Conventionally, existing vehicle platooning approaches are designed for connected vehicles, typically including connected autonomous vehicles and connected human-driven vehicles. Non-connected vehicles, such as non-connected autonomous or human-driven vehicles, are not incorporated. As a result, these platooning approaches may not properly reflect real-world mixed traffic conditions at the current stage. To address this limitation, this study proposes a hybrid platooning pattern that conditionally permits non-connected vehicles to join platoons, thereby enhancing platooning diversity and flexibility. However, it was found that the unregulated integration of non-connected vehicles can trigger rapid platoon expansion, significantly amplifying the risk of disturbance propagation in traffic flow. This, in turn, exacerbates the inherent conflict between traffic throughput and stability. To mitigate these challenges, this paper further develops a hybrid platooning control strategy based on deep reinforcement learning (DRL). This strategy integrates vehicle dynamics, platoon topology, and traffic flow states through a multi-level state representation network, enabling a dynamic trade-off between traffic capacity and stability. Numerical simulations demonstrate that the proposed strategy effectively suppresses velocity disturbance propagation by dynamically optimizing platoon structures, thereby significantly enhancing the stability and safety of mixed traffic while reducing fuel consumption and emissions.

The analysis of non stationary signals in complex physical systems often relies on Time Frequency distributions. Among these, the Pseudo Wigner Ville Distribution (PWVD) stands out for its superior resolution but is mathematically challenging due to its inherent quadratic nonlinearity. This nonlinearity generates complex interference artifacts and cross terms in the phase space, potentially obscuring the physical features of the signal, particularly for nonlinear chirps. In this work, we establish a mathematically grounded framework for the PWVD for general windowed nonlinear chirps. By leveraging the theory of oscillatory integrals with coalescing stationary points, we derive a uniform asymptotic expansion that bridges the gap between heuristic signal processing and semiclassical geometric approaches (Berry's chord construction). The resulting closed form representation, expressed in terms of symmetric incomplete Airy functions, provides a unified description of the nonlinear transform's behavior, regularizing the transition across the instantaneous frequency caustics. While the framework is general, we show its power on two illustrative examples: the high precision nonlinear chirps of coalescing binaries in gravitational-wave astronomy and radar nonlinear chirps for pulse compression applications. The analytical results successfully predict the structure of interference patterns and quantify the systematic bias in peak based frequency estimation. Therefore, this study establishes a systematic bridge between nonlinear mathematical analysis and precision experimental physics, validating the PWVD as a robust tool for detailed source characterization in high signal to noise regimes.

Quantum entanglement is a central resource of quantum information science, yet its correlations are ordinarily treated as properties of the quantum state rather than as the outcome of an underlying physical process. Here we explore the hypothesis that these correlations are mediated dynamically by a field propagating locally at finite velocity through an extension of ordinary spacetime. The model embeds physical $(3,1)$-dimensional spacetime in a warped five-dimensional geometry containing an additional timelike coordinate. Within the adopted geometric ansatz, the form of the extended spacetime metric is determined by the five-dimensional vacuum Einstein equations. A massless field propagating through the resulting five-dimensional bulk can mediate correlations whose projection onto observable four-dimensional spacetime connects arbitrarily distant locations at equal laboratory time, while preserving operational no-signaling. Coupling this field to a Bohm–Bub-inspired collapse scheme provides a possible dynamical realization of entanglement correlations and, under a stated statistical consistency condition, reproduces Born statistics. The framework leads to a concrete experimental test. Two nominally independent Bell pairs are predicted to develop a weak, distance-dependent contextual correlation between particles belonging to different pairs, as a consequence of bulk-field mediation. This cross-pair correlation is absent in standard quantum mechanics for independently prepared systems and is predicted to decrease as the inverse square of their separation. It could therefore be tested by varying the distance between two simultaneous Bell experiments using existing photonic technology. Observation of such a signal would support a dynamical spacetime account of quantum entanglement and could have implications for quantum networks employing multiple independent entangled resources.

The notion of fidelity for quantum states is a measure of how much two states overlap. In the matrix formalism of quantum mechanics, states are represented by density operators, i.e., positive semi-definite matrices with trace equal to 1 in a complex Euclidean space $M_n(\mathbb{C})$. Felipe-Sosa and Felipe (2022) introduced the notion of quantum states on certain Krein spaces with indefinite metric induced by a fundamental symmetry $J$, calling these $J$-states. We define an analogous notion of measurement for $J$-states to the regular quantum theory and use it to show that a notion of fidelity holds in the Krein setting. We also show that an analogous result to the Fuchs-Caves measurement holds in this setting. Following the developments of Bag, Rohilla, and Trivedi (2024), we then extend this definition of fidelity to $U$-quantum states on $S$-spaces. We demonstrate that the analogous geometric motivation holds in the Krein and $S$-space setting, as holds for quantum fidelity and geometric means of operators.

The Vera C. Rubin Observatory began commissioning its camera, LSSTCam, in April 2025, with the Legacy Survey of Space and Time (LSST) scheduled to start in 2026. A primary science goal is constraining Dark Energy through weak gravitational lensing of the large-scale structure (cosmic shear). After a full year of data from LSST, these measurements are expected to reach precision comparable to recent Dark Energy Spectroscopic Instrument (DESI), providing an independent test of hints that Dark Energy may evolve over time. However, cosmic shear requires exquisite control of instrumental systematics. This proceeding presents an overview of the Rubin Observatory commissioning – the successes achieved and the systematic issues we are working to resolve.

We present a patch-level scoring architecture for unsupervised gravitational-wave glitch detection that mitigates the signal dilution limitation identified in Cirfeta (2026b). The CLS token of frozen DINOv2 (ViT-S/14) performs global average pooling over 37x37=1369 patches, systematically suppressing signals occupying less than 5% of the spectrogram grid. We replace the global CLS similarity metric with a top-$k$ order statistic over individual patch token similarities against a Vector-Quantized reference index ($K=64$ centroids per class, 19 Gravity Spy O3b morphologies, 1216 total centroids). Applied to strain-domain injections in LIGO O4a L1 data (session 20260524), we demonstrate a statistically significant distributional separation ($\text{KS}=0.963$ at optimal $k=68$) for spatially extended morphologies (SpiralBurst), while confirming the patch-size temporal resolution limit for ultra-short transients (AsymBlip). A topological saliency map constructed from spatial patch similarity against a background matrix (78 null segments) correctly localizes glitch signatures for Scattered_Light and injected SpiralBurst. The Max/Mean ratio analysis demonstrates that patch-level saliency functions as a topological visualizer rather than a binary detector, consistent with the non-isotropic geometry of DINOv2 embedding space on GW spectrograms.

We present a simple universal computational algorithm for computing compositional phase diagrams of rocks and their melts at given temperature and pressure. It makes use of the mathematical concept of the convex hull of a set of points in the space spanned by the composition and the Gibbs free energy. All the complexities of determining the stability or separation of phases, the localization and orientation of tie lines, as well as the determination of characteristic points, curves and surfaces such as the solidus, liquidus, solvus, and the eutectic/peritectic points etc, are taken care of by the algorithm that computes the convex hull, supplemented with an algorithm to physically classify the resulting simplices. For the convex hull computation, the publicly available Qhull package can be used, which is available in SciPy. This makes this method accessible and intuitive for a broad set of scientific and educational applications. Although the method is not practical for systems of a large number of components, it is remarkably stable and efficient for systems of up to four. We present our implementation of the method as a publicly available Python package.

The absolute number of negative muons contained in a beam is essential for many experiments at accelerator facilities, but determining this number in pulsed beams has been difficult, particularly at high intensities. A method utilizing the yield of the $\beta$ delayed $\gamma$ rays from the residual nuclei following the muon nuclear capture reaction has recently been demonstrated for determining the muon number in the pulsed muon beam. In particular, the in-beam activation method employs isotopes with short lifetimes, enabling the beam intensity to be monitored during beam irradiation. However, the applicability of this method was limited because the required production branching ratio (BR) data were available only for a limited number of isotopes, restricting its use to specific experimental conditions. To broaden the applicability of this method, we searched for new candidate isotopes that are suitable for beam intensity measurement using the in-beam activation method and assessed their feasibility to a wide range of experiments. Based on the strength of the production BR, the muon capture probability, the practical detection efficiency of the detector, and the rarity of the target material in the surrounding structures, the reactions $^\mathrm{nat}$Ag ($\mu^-, \nu_\mu x$) $^{107m}$Pd and $^\mathrm{nat}$Pd ($\mu^-, \nu_\mu x$) $^{107m, 105m}$Rh are identified as a useful references for determining the number of muons in pulsed beams using the in-beam activation method.

Infrared divergences in QED cancel in inclusive observables through the Bloch–Nordsieck and KLN mechanisms. However, this cancellation removes only the unphysical infrared regulator. The detector resolution scale $\omega_{\max}$, which specifies the maximum energy of unresolved soft photons, remains in the observable cross section. We emphasize that this surviving scale has a natural interpretation as a coarse-graining scale in the reduced density matrix of the hard sector. Soft photons below $\omega_{\max}$ are not observed and are effectively traced over. The corresponding soft-sector overlap therefore becomes resolution dependent, $D_{ij}=D_{ij}(\omega_{\max})$. Observable infrared memory is consequently defined not only by the asymptotic soft sector itself, but also by the resolution scale separating observed and unobserved infrared degrees of freedom. This provides a bridge between the traditional infrared-safe cross-section formulation and the modern interpretation of soft photons as carriers of infrared memory and quantum information.

Public elevation data can support landscape research, environmental interpretation, planning, education, and public engagement, but their practical reuse is often limited by fragmented delivery and specialist processing requirements. This paper presents RO-LiDAR GeoQuickView, an independent, voluntary, and non-commercial Web-GIS initiative for exploring and reusing publicly accessible elevation data in Romania. The platform integrates LiDAR-derived digital terrain models (DTMs) and complementary elevation models of different resolutions, publishes standardized hillshade visualizations for immediate browser access, supports participatory landscape documentation, and provides a spatial index for direct raster retrieval. Its most detailed currently integrated component is the 0.5 m LAKI III Zone A DTM coverage for Caras-Severin, Gorj, Mehedinti, and Dolj counties. LAKI III Zone B, comprising Suceava, Neamt, Bacau, and Vrancea counties, is the next scheduled high-resolution extension. It will be integrated after the public products become available and pass through the same harmonization and quality-control workflow. The platform also incorporates LAKI II and additional public altimetric sources through a source-aware processing workflow that accommodates different acquisition units, including one-kilometre cells and larger raster blocks. The paper documents the data architecture, harmonization steps, quality-control procedures, access modes, application range, and limitations. The platform is conceived as an accessibility layer over public data infrastructures: it supports rapid discovery and preliminary interpretation, but it does not replace official products, specialist modelling, expert review, or field verification.