Papers

The James Webb Space Telescope (JWST) has revealed compact, red, overmassive accreting black holes - the so-called “Little Red Dots” (LRDs) - in chemically near-pristine hosts at $z\simeq5 - 9$, straining standard heavy-seed models. We show that a population of strongly clustered primordial black holes (PBH) with a broad mass function predicted by a QCD-epoch thermal history naturally realizes the configuration that assembles LRD-scale seeds: an intermediate-mass PBH nucleus $M_{\rm BH}\sim10^3$-$10^5\,M_\odot$ surrounded, within a few parsecs, by a swarm of light ($m\sim30\,M_\odot$) PBHs embedded in dense baryonic gas. Gas dynamical friction keeps the loss cone full and lets the core contract, so the swarm sinks and is swallowed on $t_{\rm seed}\sim10$-50 Myr, well inside the cosmic time at $z\sim10$-$15$. Because a heavy nucleus is present ab initio, the captures occur at extreme mass ratio $q\sim10^{-4}$-$10^{-2}$: the remnant is retained against gravitational recoil, and each capture reaches the innermost stable orbit under gravitational-wave (GW) emission, radiating $\simeq0.06\,m c^2$ so that the assembly efficiency is $\zeta\simeq0.06$ independent of $M_{\rm BH}$. The superposed swarm inspirals form a stochastic background $\Omega_{\rm GW} h^2\sim10^{-13}$-$10^{-11}$ with a $\Omega_{\rm GW}\propto f^{2/3}$ shape truncated below the gas-decoupling frequency and topped by a ringdown “comb” at $f_{\rm ring}(M_{\rm BH})\simeq13$ mHz for $10^5\,M_\odot$ and $\simeq1.3$ Hz for $10^3\,M_\odot$ nuclei at $z_f\simeq12$. The few comparable-mass nucleus-nucleus coalescences are instead individually resolvable LISA/deci-Hz sources. Detection, and discrimination of these signatures from a directly formed PBH seed of the same mass, would identify the LRDs as PBH-nucleus seeded black holes.

Context. The dependence of Type Ia supernova (SN Ia) standardised luminosity on host galaxy properties is a major source of uncertainty in cosmology. As next-generation surveys like LSST and HLTDS reduce statistical uncertainties, cosmological precision will be limited by astrophysical systematics. However, the empirical mass step, an indirect global proxy, may obscure the physical link to the progenitor environment. Aims. We test whether local luminosity-weighted age (LWA), used as a statistical proxy for the age of the stellar population associated with SN Ia progenitors, is more closely related to the physical driver of standardised-luminosity variations than host galaxy mass. Methods. Using SDSS-MaNGA Pipe3D, we extracted local LWA within a 1 kpc aperture for 56 SNe Ia and performed a joint likelihood analysis of local age and mass effects on Hubble residuals. Results. SNe Ia in younger environments are significantly fainter than those in older ones, with a step amplitude of 0.163 mag (5.2 sigma) after standardisation. Global and local mass steps are initially observed (0.071 mag, 2.0 sigma and 0.087 mag, 2.4 sigma), but both become insignificant when age and mass are fitted simultaneously: the global mass step decreases to 0.028 mag (0.9 sigma), while the age step remains robust at 0.156 mag (4.9 sigma). Similarly, the local mass step becomes insignificant (0.012 mag, 0.3 sigma), whereas the age step persists at 0.157 mag (4.4 sigma). The weighted Hubble residual decreases from 0.1550 to 0.1376 mag after introducing the local LWA step. Conclusions. The mass step is substantially reduced when local LWA is included. The inferred dark energy equation of state parameter (w) could be affected by local LWA, highlighting the importance of environmental effects for next-generation SN Ia cosmology.

We present a quantum mechanical model of dual parallel Mach Zehnder electro-optic modulators (DPMZMs), derived using the quantum scattering formalism [1,2]. We obtain the complete, unrestricted transformation of single-photon and coherent input states through the DPMZM architecture, including independent radiofrequency drive conditions on each internal modulator, and recover the symmetric push pull operating point as an exact special case. We numerically evaluate the resulting frequency comb structure, quantify the device sensitivity to bias error, modulation-index imbalance, and RF noise, and use the model to design a DP-MZM-based frequency-bin qubit source, reporting its fidelity as a function of these impairments.

Large language model (LLM) agents are increasingly expected to play a central role in AI-driven scientific discovery. Equipped with broad knowledge, flexible reasoning, and tool use, they have the potential to autonomously explore and solve scientific problems by repeatedly proposing hypotheses, testing them, and revising their beliefs in the light of the evidence. In current agents, however, these hypotheses, tests, and belief updates are buried in unstructured logs, and no mechanism lets the agent or the human researcher audit that process. Here we propose the Hypothesis Evolution Protocol (HEP), an agent harness that provides hypothesis generation, evaluation, and evolution as explicit, auditable operations. On materials-science research tasks, a HEP-equipped agent operates the hypothesis–test–evidence–belief cycle that planning-style agents lack, generalizes across research questions, and exploits the protocol more fully as the base LLM becomes more capable. These results mark a step toward auditable AI scientists, whose scientific reasoning can be inspected, verified, and built upon.

The interplay between band topology and strong correlations is central to modern condensed matter physics, but exact solutions are rare. Here, we present an exactly solvable model on the Kagome lattice by combining a Kane-Mele-type spin-orbit coupling with the Hatsugai-Kohmoto interaction. At 1/3 filling, we uncover a continuous topological quantum phase transition driven by electron interaction. A weakly correlated $\mathbb{Z}_2$ topological insulator gives way to a strongly correlated insulator that, while $\mathbb{Z}_2$-trivial, hosts a nontrivial spin Chern number $C_s=2$. The transition exhibits critical scaling consistent with the universality class of two-dimensional Dirac fermions. At half-filling, the same model yields a non-Fermi-liquid to Mott-insulator transition, demonstrating that correlation-driven topological and Mott transitions can be unified within a single solvable framework. Our results establish the Kagome Hatsugai-Kohmoto model as a valuable benchmark for interacting topological systems.

We show that the dispersionless version of the modified DKP hierarchy originally defined as the limit of relations for the tau-function of the Hirota-Miwa type has an equivalent reformulation as the Yang-Baxter equation for Baxter's $R$-matrix of Boltzmann weights for the 8-vertex model.

Microwave kinetic inductance detectors (MKIDs) are generally read out with microwave readout tones of high enough amplitude to adequately suppress the noise contribution of the first-stage amplifier. At high readout power, the detector's resonant frequency is altered as a result of the dependence of the kinetic inductance on the internally circulating microwave current. With the tone placed below the resonant frequency, the nonlinear frequency shift results in a positive feedback effect that can significantly enhance the responsivity of the detector, to both optical and microwave power. We report a factor of 10 enhancement in optical response by tuning the readout power and frequency to close to the resonator's bifurcation point. A corresponding decrease in the bandwidth of the resonator is observed under these conditions. We show that the strength of the feedback effect can be easily selected by adjusting the excitation, and provide a map of possible operational states to do so. Operation of MKIDs in this mode could be used to improve sensitivity when non-intrinsic noise sources are significant.

In this paper, we review the Zamolodchikov-like recursion relations for torus one-point conformal blocks in both Liouville and $A_2$ Toda theories. Starting from these relations, we derive the corresponding recursion relations in the light asymptotic limit. In Liouville theory, the light-limit recursion reproduces the known expression for the one-point light conformal block in terms of the Gauss hypergeometric function. For $A_2$ Toda theory, our recursion relation provides a new, efficient method for explicit calculations, and we have verified that it is in full agreement with previously known results in the literature. Last but not least, we present closed-form expressions for the coefficients of the insertion-point expansion for both the generic and light $A_2$ Toda one-point blocks.

The Widom line, initially identified as a crossover line between liquid-like and gas-like behavior in water and supercritical fluids, separates these two types of behavior. Here, we show that an analogous line arises in spin models on scale-free networks as a consequence of degree heterogeneity, which we analyze using the annealed network approximation. For the Ashkin–Teller and Invisible Potts models, the Widom line exists within a finite range of the degree exponent. It separates two distinct ordered regimes$-$distributed spin alignment and hub-dominant alignment$-$while also giving rise to a supercritical-like state where the two alignments become indistinguishable. These results demonstrate that degree heterogeneity alone can generate mesoscopic crossovers beyond conventional phase-transition theory, opening new directions for understanding and controlling collective dynamics in complex networks.

Synchronization is ubiquitous across natural and synthetic systems, yet most prior studies focus on the inertia-free Kuramoto model and do so at the macroscopic level. In this study, we instead investigate the inertial Kuramoto model and analyze the kinetics of individual synchronized clusters that emerge in the underdamped dynamics, driven by the interactions among multiple synchronized clusters with different frequencies. Specifically, we explore two forms of intrinsic frequency distribution – unimodal Gaussian and multimodal uniform – and show that they give rise to qualitatively different synchronized clusters: a hierarchical organization for the Gaussian distribution and a homogeneous organization for the uniform distribution. This contrast leads to qualitatively different behaviors of the order parameter: for the Gaussian distribution, it increases smoothly with increasing coupling strength, while for the uniform distribution, it grows through a series of discrete jumps that trace out the size of the Devil's staircase (DS). By resolving the kinetics at the cluster level, we further find that the route to synchronization also depends on the distribution type: with a Gaussian distribution, a single dominant cluster forms and gradually entrains the remaining oscillators, whereas with a uniform distribution, synchronization proceeds via successive cluster mergers initiated from peripheral seeds associated with the high-frequency periphery. Taken together, these findings provide a new perspective on collective synchronization dynamics in inertial complex systems.

Quantum identity authentication (QIA) has emerged as a crucial technology for secure communication systems, particularly in the burgeoning era of quantum communications. This paper proposes a novel QIA protocol based on non-classical characteristics of squeezed light fields. By exploiting quantum noise reduction properties of quadrature squeezed coherent states, the protocol fundamentally thwarts eavesdropping attempts by Heisenberg-limited uncertainty constraints. The fidelity parameter for decoy states is utilized to detect spoofing attacks, and the dynamic key update mechanism fundamentally eliminates vulnerabilities caused by key reuse. Security information ratio analysis shows that the protocol is able to resist Gaussian-cloner attacks and detect eavesdropping. Moreover, the security threshold can be further enhanced with higher squeezing, allowing tunable protection levels adaptable to different threat scenarios. Compared with binary-squeezed protocols, our proposed four-direction (quaternary-dimensional) squeezing halves the eavesdropper's guessing probability and enlarges the fidelity gap by 29% tightening the discrimination threshold without relying on extra hardware, thus facilitating practical implementation.

Yielding, plasticity, and necking are central to the mechanical performance of materials, yet a concise unified physical picture of how these nonlinear responses arise remains lacking. We develop a minimal theory for glassy polymers based on a classical volume-dependent relaxation time following the Doolittle equation, and derive the constitutive relation using the Onsager variational principle. Surprisingly, this simple theory explains yielding, plasticity, and neck initiation under constant strain rate loading via a shear unfreezing mechanism: as the sample is stretched, volume-increasing activated molecular mobility drives shear deformation from an initially frozen state to an unfrozen state. The theory yields an analytical expression for the yielding stress as a function of strain rate and temperature. It also predicts a phase diagram for necking initiation in the same parameter space, providing a mechanism beyond the classical Considère criterion. Our results establish a unified framework for nonlinear tensile behavior in glassy materials.

The $^{8}$Li$(n,\gamma)^{9}$Li reaction is considered significant for the synthesis of nuclei beyond the $A=8$ stability gap in inhomogeneous big-bang nucleosynthesis models, as well as in $r$-process nucleosynthesis scenarios. However, direct measurement of this reaction is precluded by the short half-life of $^{8}$Li and the absence of a neutron target. Consequently, existing reaction rate estimates based on indirect experimental methods and theoretical calculations differ by orders of magnitude. In the present work, the $^{8}$Li(n,$\gamma$)$^{9}$Li neutron-capture cross section and the corresponding thermonuclear reaction rate are evaluated within a phenomenological $R$-matrix framework, including both non-resonant direct capture (DC) and resonant capture through the $5/2^{-}$ state at $E_{x} = 4.30$~MeV. The uncertainties associated with the $R$-matrix input parameters are propagated using Monte Carlo sampling, while the sensitivity to the channel radius is treated as an $R$-matrix model uncertainty. The effective total uncertainties in the calculated cross sections and reaction rates are obtained by adding these two uncertainty contributions in quadrature. We obtain a total capture rate of $983.9^{+410.9}_{-261.5}~\mathrm{cm^{3}\,mol^{-1}\,s^{-1}}$ at $T = 1$~GK, with DC dominating at low temperatures ($T=0.01-0.4$~GK) and the $5/2^{-}$ resonance at higher temperatures ($T=0.5-5$~GK). The present results are consistent with the upper limit of Kobayashi et al.~\cite{Kobayashi2003}, which previous theoretical predictions exceed by factors of 3-50.

The top quark, having the largest Yukawa coupling to the Higgs sector, provides a unique window into electroweak symmetry breaking and possible new physics beyond the Standard Model. Searches for rare top-quark processes are thus powerful probes of new physics. In this work, we investigate the flavor-changing neutral-current (FCNC) top-quark decays $t\to cH$ and $t\to cS$, where $S$ denotes a light scalar, at the Compact Linear Collider (CLIC) with a center-of-mass energy of $\sqrt{s}=1.5~\mathrm{TeV}$. Our analysis focuses on a kinematic regime distinct from most previous studies, in which the top quarks are typically highly boosted. To enhance signal discrimination in the boosted regime, we construct multi-channel jet images and employ a convolutional neural network (CNN) classifier to capture jet-substructure patterns relevant to the FCNC signals. Assuming an integrated luminosity of $4~\mathrm{ab}^{-1}$, we obtain the expected $95\%$ C.L. upper limit $\mathrm{BR}(t\to cH)\times \mathrm{BR}(H\to b\bar b)<5.27\times10^{-5}$. For the exotic scalar singlet, expected $95\%$ C.L. upper limits between $3.25\times10^{-5}$ and $5.26\times10^{-5}$ are obtained for $\mathrm{BR}(t\to cS)\times \mathrm{BR}(S\to b\bar b)$, for scalar masses between $30$ and $80~\mathrm{GeV}$.

High Performance Computing (HPC) centers are expanding to integrate quantum resources, enabling hybrid quantum-classical workflows for complex optimization. Integrating quantum processing units (QPUs) into workload managers poses an orchestration challenge: a remote QPU introduces a second queue - a "two-queue problem" - alongside the scheduler's own. We present Fluence, a Kubernetes scheduler plugin backed by the Fluxion graph-based scheduler, enabling gang-scheduled placement for quantum-classical workloads and custom resources. First, under contention, Fluence's atomic gang placement eliminates the node-time a default scheduler wastes on partially placed gangs. Second, a synchronization primitive gates consumers behind a single producer's shared quantum task, cutting worker idle time roughly 1.2-12x under short queues and orders of magnitude under long ones. Third, policy-aware backend selection cuts mean per-run cost roughly 72x and time-to-result from hours to under two minutes. Together, these results show that quantum-awareness can be added to a cloud-native scheduler without modifying user containers.

Astronomical CCD images are often affected by bleeding from bright sources, producing column-aligned streaks that degrade source detection and photometry. We present a pixel-level masking algorithm for bleeding in Korea Microlensing Telescope Network (KMTNet) images, in which these streaks extend along detector columns away from the readout register. The algorithm identifies bleed-generating pixels using a conservative bleeding threshold and a bleeding index that quantifies excess signal along the expected bleeding direction. The extent of each bleed trail is then determined by termination criteria based on a background-relative detection threshold and a continuity condition. To optimize these termination parameters, we generate multiple candidate masks and evaluate them with an F-beta-like score that favors high purity while preserving recovery of sources whose photometry is biased by bleeding. Using the final mask, we apply interpolation-based cleaning and assess the performance in terms of completeness and photometric accuracy in a crowded KMTNet field, using Gaia DR3 as a reference. The source completeness improves from 94.08% to 98.61%, primarily by enabling proper aperture placement that was previously hindered by bleeding. For selected bleeding-affected sources, the root-mean-square photometric offset decreases from 0.623 mag to 0.068 mag. These results demonstrate that the algorithm provides a practical framework for mitigating bleeding artifacts in KMTNet images. We further examine the stability of the algorithm across different observing conditions and discuss limitations of the current masking and cleaning procedure.

The Quantum Approximate Optimization Algorithm (QAOA) is a promising framework for combinatorial optimization, but constrained problems are commonly handled using energetic penalty terms that require calibration and allow infeasible configurations to remain dynamically accessible. We develop a constraint-preserving QAOA framework for personnel rostering in which hard scheduling constraints are embedded directly into the mixer Hamiltonian. Using a binary rostering model with daily coverage and no-consecutive-duty constraints, we formulate the dynamics from a transition-graph perspective and introduce a guarded-XY mixer that confines the evolution to the fully feasible scheduling manifold. We further distinguish feasibility preservation from feasible-transition design and propose a tight-pattern extension that introduces collective feasible exchanges in saturated workload segments where local guarded exchanges alone are insufficient. Exact statevector simulations demonstrate that, compared with Penalty-X and Coverage-XY formulations under both expectation-value and Conditional Value-at-Risk optimization, the proposed approach eliminates hard-constraint penalty calibration, guarantees feasible evolution by construction, and consistently yields higher-quality output distributions with stronger concentration on optimal feasible schedules. To the best of our knowledge, this is the first constraint-preserving QAOA formulation for personnel rostering, and the transition-graph framework is readily applicable to a broad class of constrained quantum optimization problems.

Zero-mode waveguides (ZMWs) enable single-molecule fluorescence detection at micromolar concentrations by confining light to nanoscale volumes, overcoming the diffraction limit of confocal microscopy. However, their widespread adoption is hindered by high fabrication costs and limited throughput of traditional methods like focused ion beam or electron-beam lithography. Here, we introduce a scalable cost-effective approach using sequential nanoimprint lithography (NIL) combined with hydrofluoric acid etching to fabricate ZMW arrays with tunable diameters from a single initial master. In our sequential nanoimprint approach, each stamped NIL output serves as a master for the next nanoimprint generation. By leveraging the shrinkage of sol-gel nanopatterns during annealing, we achieve a cumulative diameter reduction from 230 nm to 115 nm over four successive imprints, all based on the same initial master. The resulting ZMWs exhibit detection volumes reduced by up to 1000-fold and fluorescence enhancement exceeding 16x, achieving performance comparable to state-of-the-art focused ion beam-fabricated devices. Eliminating the need for multiple master structures significantly expands the scalability of nanoimprint lithography approaches. By lowering the nanofabrication barriers and making ZMW arrays more accessible, the sequential NIL method paves the way towards broader adoption of nanophotonic devices in single-molecule biophysics, biosensing, and surface patterning applications.

We study the quantum properties of two- and three-dimensional spin textures – $k\pi$-skyrmions and hopfion rings – within the cluster mean-field approximation (CMFA). By combining the CMFA with a symmetrization procedure, we achieve two key advances: the accurate computation of quantum fluctuations in large spin textures and reliable access to metastable states. These challenges are generally insurmountable using standard methods, which are severely limited by the curse of dimensionality and typically restricted to ground-state properties. Exploiting the cylindrical symmetry of the studied magnetic configurations, we construct one-dimensional chain-like clusters that can be efficiently simulated using the density matrix renormalization group method, while inter-cluster interactions are treated at the mean-field level. The resulting spatial profiles of quantum features such as the local variation of the magnetization length in hopfion rings reveal limitations of the classical micromagnetic model and indicate the necessity of its extension. We demonstrate that the recently proposed regularized micromagnetic equation provides a suitable framework for this purpose.

We investigate majoron dark matter in a minimal setup, where the Standard Model is extended by three right-handed neutrinos and a complex scalar field. The theory is defined by an exact discrete gauge symmetry, $Z_N\subset U(1)_{B-L}$, while the global $U(1)_{B-L}$ symmetry emerges only as an accidental symmetry at low energies. For nontrivial choices of the discrete symmetry $Z_N$, such as $Z_5$, $Z_7$, $Z_{11}$, and $Z_{13}$, Planck-suppressed operators explicitly break this accidental symmetry and generate a small majoron mass, making the resulting pseudo-Nambu–Goldstone boson a well-motivated dark matter candidate. We study its production via the misalignment mechanism after inflation, considering both radiation-dominated and early matter-dominated cosmological histories, and confront the viable parameter space with isocurvature bounds, cosmological constraints, and indirect dark matter searches. We find that the $Z_5$ model is excluded by limits on the dominant dark matter decay into neutrinos, whereas the other models remain viable. In particular, the $Z_7$ scenario predicts a majoron mass in the $1$–$10\,{\rm MeV}$ range and can be sensitively probed by future MeV gamma-ray observations, especially with COSI, through the 511$\,$keV line from the majoron decay into an electron–positron pair and the monochromatic gamma-ray line from its decay into two photons.

We derive a low-energy $\mathbf{k}\cdot\mathbf{p}$ effective Hamiltonian for monolayer osmium carbide (OsC) and ruthenium carbide (RuC) in a planar hexagonal configuration. First-principles calculations indicate that both monolayers are dynamically stable and exhibit features of a two-dimensional quantum spin Hall (QSH) phase, characterized by a nontrivial $\mathbb{Z}_2$ topological invariant. Using symmetry analysis at the $\Gamma$ point, we construct a multiband $\mathbf{k}\cdot\mathbf{p}$ Hamiltonian including spin-orbit coupling and reduce it to a four-band low-energy model through Löwdin partitioning. The effective Hamiltonian has a block-diagonal form, with two blocks related by time-reversal symmetry, analogous to the Bernevig–Hughes–Zhang (BHZ) model. In contrast to the standard BHZ form, the symmetry-allowed off-diagonal coupling contains quadratic momentum-dependent terms, which modify the low-energy dispersion near the $\Gamma$ point. The fitted parameters reproduce the ab initio band structures in the low-energy region, yielding a compact model for analyzing the electronic and topological properties of monolayer OsC and RuC.

The Drell-Yan process is a key precision benchmark at the Large Hadron Collider and a sensitive probe of SM and SMEFT effects. Fully exploiting future LHC data requires percent-level SM predictions, motivating precise EW and mixed QCDxEW corrections. In this proceeding we report of the progress towards the calculation of mixed QCDxEW corrections to charged-current Drell-Yan with leptonic decay at high transverse masses, performed within the Nested Soft-Collinear Subtraction framework. After presenting a validation at NLO, we show results for the NNLO real corrections and compare their impact in the neutral-current and newly developed charged-current channels. These contributions are essential to match the current and future precision of LHC measurements, especially in regions where electroweak effects are enhanced by Sudakov logarithms.

We investigate the influence of medium effects on strange quark matter and their consequences for the structural properties of compact stars. In this study, the bag constant, in the MIT bag model equation of state, is reformulated as a function of the chemical potential of quark. Imposing the Bodmer-Witten stability criterion, the parameter space is constrained by evaluating the energy per baryon. The Tolman-Oppenheimer-Volkoff equations are then solved to obtain the maximum mass-radius configurations. Our analysis shows that an increase in chemical potential leads to a reduction in the effective value of bag constant, resulting in a stiffer equation of state and correspondingly higher value of maximum stellar mass. Furthermore, we examine the chemical potential dependence of the tidal Love number and tidal deformability along with their corresponding finite surface density corrections. The results demonstrate that, for the chosen set of parameters, the constraint from the GW170817 event, namely $\Lambda < 800$, is consistently satisfied. In this paper, we have tried to establish how chemical potential $(\mu)$ affects the maximum mass and tidal deformability of strange stars.

Neutron stars, due to their extremely high matter density and strong magnetic field, provide the best environment for exploring new physics beyond the Standard Model of particle physics. In this work, we study the effect of pre-existing dark matter component and an internal magnetic field on the structural properties of neutron stars. We employed relativistic mean field theory based equations of state and used a single fluid approach for solving the Tolman-Oppenheimer-Volkoff (TOV) equation to compute properties like mass-radius, tidal deformability, compactness, and non-radial oscillation frequencies. We consider the following two scenarios for equation of state (EoS): (1) density-independent couplings along with non-linear interactions of mesons, and (2) density-dependent couplings, with only considering linear interactions for mesons. These mesons mediate the interactions between nucleonic constituents of a neutron star. In the dark matter sector we consider a massive fermionic dark matter which interacts with the nucleons through a Higgs portal interaction. We explore parameter regions for Fermi momentum of dark matter in the range $k_F = 0.01$ GeV - $0.06$ GeV, and two different values of the mass of fermionic dark matter, $M_\chi = 200$ GeV and $300$ GeV. We consider two values of the central magnetic field, $B_c = 7\times10^{17}$ Gauss, $9 \times 10^{17}$ Gauss, for a magnetized neutron star. Finally, we compare the theoretical predictions with the observed mass-radius and tidal deformability data of pulsars obtained from gravitational wave observations.

Continuous quantum feedback uses time-resolved measurement records to steer monitored systems toward pure states. Yet how the information available to a controller determines the ultimate purification speed remains unresolved. We establish this relation for a qubit under fixed-spectrum Hermitian monitoring with detector loss, obtaining the exact long-time impurity-moment spectrum optimized over causal basis controls at each horizon. Rare records with nearly canceled evidence then make all moments from half order upward decay at the Bhattacharyya information rate between two quantum nondemolition record laws. Aligned quantum nondemolition monitoring preserves that binary distinguishability and attains the limit, while complete detection restores an order-dependent branch. The mechanism extends to higher dimensions, where an attainable rank-two ceiling lies above the full-rank qutrit upper bound over a finite moment interval, establishing retained record distinguishability as a purification resource.

We quantify the information content of the configuration-space two-, three-, and connected four-point correlation functions of Quijote dark-matter haloes at $z=0$ and fixed number density. We build Fisher forecasts for $\{\Omega_m, \Omega_b, h, n_s, \sigma_8, M_\nu\}$ in real and redshift space from ${\sim}38{,}000$ GPU-accelerated $N$-point measurements. Treating the statistics as a ladder, $\mathrm{2PCF} \rightarrow +\mathrm{3PCF} \rightarrow +\zeta^{(4)}_{\mathrm{conn}}$, we report the information gained at each rung. The 3PCF supplies most of the accessible higher-order information: it tightens every parameter, most strongly $\sigma_8$ and $M_\nu$, whose degeneracy it partially breaks, by factors of $1.6$–$6.3$ over the redshift-space $\{\xi_0,\xi_2\}$ baseline with per-parameter gains consistent with those of the Fourier-space halo bispectrum on the same simulations. The 3PCF gains persist under conservative, modelling-motivated scale cuts: restricted to the tree-level-validated regime with minimum triangle side $\ge40\,h^{-1}{\rm Mpc}$, it still improves $M_\nu$ by $3.9\times$. The connected 4PCF adds a further $\sim1.2$–$1.5\times$, an increment insensitive to whether the quadrupole is included in the baseline but traceable to small-scale configurations with sides $\lesssim30\,h^{-1}{\rm Mpc}$. This rung-to-rung increment is stable against derivative-sample noise and compression regularization, whereas the absolute constraints remain limited by the finite simulation ensembles and are reported as preliminary. The configuration-space ladder thus offers an independent and complementary route to the higher-order information probed by the Fourier-space poly-spectra.

Data scarcity and class imbalance are persistent challenges in machine learning that degrade model generalization and introduce predictive bias. We present a hybrid quantum-classical framework for synthetic data generation using a Quantum Circuit Born Machine (QCBM) to address these limitations. The proposed approach exploits quantum mechanical properties – superposition and entanglement – within a parameterized variational quantum circuit to model complex probability distributions that are difficult for classical generative methods to capture. Experiments are conducted on two tabular benchmark datasets: the Iris dataset and the Telco Customer Churn dataset. Preprocessing includes normalization and PCA-based dimensionality reduction to enable efficient basis encoding for quantum circuits. The QCBM is trained by minimizing Kullback-Leibler (KL) divergence between real and generated data distributions using a gradient-based parameter-shift optimization rule. Augmenting training data with QCBM-generated synthetic samples at 40-50% of the minority class improves F1-score by approximately 5-15% and minority-class recall by 10-25%. Cross-domain evaluations (Train on Synthetic, Test on Real; and Train on Real, Test on Synthetic) reveal a performance gap of only 3-10%, indicating strong distributional fidelity. Comparative analysis against classical oversampling methods – SMOTE, Borderline-SMOTE, KMeansSMOTE, and SVM-SMOTE – shows that QCBM achieves competitive classification performance and produces lower Maximum Mean Discrepancy (MMD) on the Telco dataset, suggesting superior structural similarity in certain imbalanced settings. These findings establish QCBM as a viable complementary tool for data augmentation, particularly for low-dimensional structured tabular data with class imbalance.

The enhanced X-ray Timing and Polarimetry (eXTP) mission will combine spectral, timing, and polarimetric techniques to study accreting black holes, measure their masses and spins, and test Einstein's theory of General Relativity in the strong-field regime. In this contribution, I review the capabilities of eXTP to advance our current understanding of black hole physics and astrophysics.

Non-Gaussian noise transients ("glitches") in gravitational-wave observatories degrade our ability to accurately perform astrophysical inference. We present the analysis pipeline bilby_glitch, which allows for simultaneous Bayesian inference of gravitational-wave signals and glitches. Our framework is modular and built on top of the popular bilby framework, facilitating future extensions with additional glitch and signal models. We integrate transdimensional bilby into our framework and discuss three glitch models: a physically-motivated slow scattering model, and flexible sine-Gaussian and chirplet models. Using a combination of simulated and real data, we demonstrate that bilby_glitch produces reliable results. We then reanalyse two gravitational-wave events - GW191109 and GW200129 - which show signs of interesting black-hole spins, but which may also be affected by data-quality issues. Our results for GW191109 are consistent with previous analysis. For GW200129, we recover results consistent with [Payne $\textit{et al.}$, Phys. Rev. D $\textbf{106}$, 104017 (2022) ], where the evidence of spin-precession is much weaker when using the waveform approximant NRSur7dq4 in combination with wavelet-based glitch modeling. Furthermore, we show the evidence of spin precession of this event is dependent on the interplay between the waveform approximant and glitch model, since in contrast to NRSur7dq4 we find that inference with the waveform approximant IMRPhenomXPHM shows strong evidence of spin-precession when used in combination with wavelet-based glitch modeling.

The progenitor channels of fast radio bursts (FRBs) remain debated, with a central question being whether their cosmic rate traces star formation promptly or instead follows it with the long time-delay characteristic of compact-binary mergers. We perform a forward-modeling, hierarchical Bayesian analysis of the CHIME/FRB population, jointly fitting the catalog sample, baseband fluences, and localized host redshifts, while self-consistently incorporating the survey selection function through the injection framework. Across a range of delay-time models, the reconstructed FRB rate robustly peaks at the same redshift as the cosmic star-formation history, with a mean delay of only $0.1-0.3$ Gyr that remains consistent with a prompt, zero-delay origin at the $2\sigma$ level. For dominant FRB population, this finding rules out the multi-Gyr delays reported previously and interpreted as the evidence for compact binary merger origin, and instead points toward progenitor systems linked to young stellar remnants, most notably magnetars formed in core-collapse supernovae.