Papers

We study nonlinear scalarization of Schwarzschild black-holes for a phantom scalar coupled to the Gauss–Bonnet invariant. Three polynomial couplings satisfying $\zeta''(0)=0$ are introduced to investigate its nonlinear coupling dependence. Since the phantom factor $\epsilon$ disappears in the probe scalar equation, its nonlinear evolution is the same as in the canonical scalar theory. We construct nodeless probe solutions and fully backreacted two branches of lower and primary. At equal mass and equal temperature, respectively, the lower branches have higher Wald entropy and lower Helmholtz free energy than primary branch, but their heat capacities are negative. This implies that lower branch favors than primary branch. Finally, we show that there is no nonlinerly stable scalar phase for a phantom kinetic theory.

Position verification, introduced by Chandran et al. (SIAM J. Computing 2014), allows verifiers to test a prover's claimed position by an interactive protocol. Classical position verification is impossible. Even for Quantum Position Verification (QPV), there always exists an LOCC (Local Operations and Classical Communication) attack if the adversary can hold an exponentially large amount of preshared entanglement. Somewhat surprisingly, we show that we can circumvent this barrier in the idealized continuous-time model, where time is represented by a real-valued parameter and challenge messages can be sent at a time sampled uniformly from a real interval. In this model, we give a BB84-based protocol that remains secure against any finite coalition of LOCC adversaries with arbitrary finite (possibly exponential) quantum storage and entanglement. Our construction can also be instantiated in the discrete-time model. Even though the previous impossibility results apply, we are able to obtain an information-theoretic QPV protocol in which the honest parties' total resources (communication and storage) can be significantly smaller than the adversarial resource bound. In fact, we can achieve any desired polynomial gap between honest parties and adversarial resources. To our knowledge, all previous protocols in the literature required resources of the honest parties to be at least as large as the adversarial entanglement. Interestingly, the resource gap between the honest and adversarial party resources in our protocol depends on how precisely time can be measured. As the precision of the best-known clock improves with further research, the resource gap in our protocol keeps increasing. In particular, the adversarial resource bound keeps increasing while the honest parties' resources remain largely the same. We call this the "I sleep, you work" paradigm.

In mean-field theory, the ground state of a two-component Bose-Einstein condensate (BEC) in a uniform system is either uniformly mixed or totally separated. Beyond-mean-field effects introduce an additional phase, the mixed-bubble state, in which the two components remain mixed within one of the separated domains. Here we show that a mixed-bubble state can emerge in a binary mixture of spin-1 ${}^{7}{\rm{Li}}$ and ${}^{23}{\rm{Na}}$ BECs even within the mean-field framework. We further demonstrate the existence of a metastable uniformly-mixed state, which undergoes a transition to the mixed-bubble state triggered by a local perturbation.

Random circuit sampling is a leading approach to demonstrating quantum computational advantage, but benchmarking noisy implementations through linear cross-entropy requires costly calculations of ideal output probabilities. We propose a metrological benchmark based on the response to controlled perturbations, characterized by quantum Fisher information (QFI). A relation between QFI and out-of-time-order correlators enables protocols with local or global control. For Haar-random circuits, the average QFI approaches its maximal value in the local protocol and grows linearly with the number of qubits under collective control. In contrast, Clifford circuits yield zero QFI despite extensive operator spreading, showing that the response probes dynamical properties beyond spreading alone. A butterfly protocol further uses system size to enhance sensitivity, yielding a mean inverse sensitivity proportional to the number of qubits with single-qubit readout. Its fluctuations distinguish the Haar and Clifford ensembles despite their identical mean responses. For noisy implementations, we derive an exact relation between the noisy and ideal QFI within a global white-noise model, providing a quantitative reference for the degradation of the benchmark. These protocols enable metrological benchmarking of noisy random quantum circuits without computing ideal output probabilities.

The discovery of the binary neutron star merger GW170817 and its electromagnetic counterparts marked the beginning of the era of multimessenger gravitational-wave astronomy. In contrast, binary black hole (BBH) mergers, which constitute the majority of gravitational-wave sources detected to date, are generally expected to be electromagnetically dark. However, if BBH mergers occur within the dense gaseous environments of active galactic nucleus (AGN) accretion disks, interactions between the merging black holes and surrounding gas may produce electromagnetic emission across multiple wavelengths. AGN disks may therefore provide a natural multimessenger laboratory for studying BBH mergers and their astrophysical environments. A key question is whether such a scenario is supported by current observations and whether the associated electromagnetic signatures are sufficiently distinctive and detectable. In this review, we summarize the current theoretical and observational status of BBH mergers in AGN accretion disks, focusing on the evidence for their occurrence, the physical mechanisms and expected signatures of electromagnetic emission, and searches for candidate counterparts. We also discuss the major challenges in identifying and confirming these associations and the prospects for future multimessenger observations with current and forthcoming multiwavelength facilities.

The Future Circular Collider (FCC), in its leptonic configuration has been chosen by CERN as main proposition for the next high-energy collider. This project aims to achieve luminosities one to two orders of magnitude higher than ever. Feasibility studies have led to the definition of tolerances on magnet imperfections and correction strategies. This is crucial for ensuring the performance of one of the main elements of the acceleration chain, the High Energy Booster (HEB) ring. The efficiency and overall performance of these strategies greatly influence new magnet specifications and tolerances, affecting main optic functions. Horizontal and vertical orbit corrections use horizontal and vertical kickers, respectively. Skew quadrupoles address vertical dispersion and transverse coupling. Normal quadrupoles correct the horizontal and vertical phase advances. This study simulates the distribution of these four corrector types to minimize the equilibrium emittance at the extraction energy of 45.6 GeV. The calculated strengths of these correctors and the associated misalignments are presented. The study also discusses the limitations and drawbacks of the proposed correction strategy.

In fixed-source Monte Carlo particle-transport problems, obtaining an acceptable variance on the sought response is of paramount importance. Currently, the only rigorous tool to analyze the variance of such games is the framework of the moment equations, which is unfortunately unwieldy to use in practice. In this paper, we establish a formula that enables expressing the variance of a Monte Carlo simulation as a sum of 'variance contributions' collected throughout the underlying particletransport process. This formula applies to both direct and adjoint games, and provides a new tool to pinpoint the variance-inducing mechanisms in Monte Carlo simulations, understand common variance-reduction techniques, and even conceive new ones. We showcase the use of the variance-decomposition formula on several applications. In particular, we revisit zero-variance schemes and analyze existing variance-reduction techniques, underlining their strengths and weaknesses. A few relevant numerical examples substantiate our theoretical findings.

Primordial magnetic fields (PMFs) are anticipated to be a cosmological candidate for generating a stochastic gravitational wave background (SGWB) through their anisotropic stress. In particular, if parity violation is present in the production of PMFs, it can induce a helical component in the PMFs, leading to circular polarization in the isotropic SGWB. In this study, we phenomenologically consider parity-violating inflationary magnetogenesis and compute the intensity and circular polarization of the SGWB for several assumed power spectra of helical PMFs. Using the planned sensitivity of the LISA-TAIJI network, we calculate the signal-to-noise ratio (SNR) and perform a Fisher forecast to assess the feasibility of constraining the parameters of helical PMFs. We conclude that it is possible to estimate the helical-to-non-helical power ratio~$r_H$ with $\mathrm{SNR}^{V}>2$ if the PMF strength is $\mathcal{B} \gtrsim 10~\mathrm{nG}$ ($50~\mathrm{nG}$) in the case of the delta-function-type (scale-invariant-type) PMF spectrum. Our results offer a useful criterion that indicates the future observational limit on helical PMFs at the small scale $k_\mathrm{LISA} \approx 10^{12}~\mathrm{Mpc}^{-1}$.

Experiments often detect only selected transitions, leaving the underlying state dynamics and dissipation hidden. We show that waiting-time distributions between directed visible events can reconstruct the boundary dynamics without observing the reverse of every detected transition. Under a simple source-target closure condition, they determine visible rates and the hidden excursions connecting observed states, yielding a rigorous lower bound on total entropy production that improves the standard waiting-time estimate when reverse events are available. Remarkably, observing only a spanning directed cycle is sufficient to identify the full Markov generator, even when all reverse cycle edges and other microscopic transitions remain unseen.

We present examples of classical time crystals (in a parabolic potential for the position) that admit simple exact analytic solutions. The kinetic energy in these crystals is piecewise parabolic as a function of speed and is minimised at nonzero values of the speed. The solutions are periodic, while the speed acquires definite periodic discontinuities. The solutions are stable along the branches where the action is lower. We also examine the classical time crystal with quartic kinetic energy. We show how the quartic kinetic energy can be emulated by a piecewise parabolic one, leading to accurate and transparent solutions.

We propose an Improved version of the Lagrangian Finite Time Lyapunov Exponents(IFTLE) framework as a new quantifier for Comprehensive Synchronization analysis of multilayer networks undergo adaptive coupling scheme in order to incorporate the effects of deformation in synchrony due to the dynamic variations in the coupling strengths of intra-layer and inter-layer links. Theoretical formulation of the IFTLE along with its numerical validation has been provided using a three layer network of Chaotic Rössler oscillators. The numerical illustration clearly shows the efficacy of the proposed method revealing the need for comprehensive synchrony deformation analysis in adaptive coupling scenarios. Also we have stated a few properties of IFTLE useful for the quantification purpose.

Charged particle track reconstruction at the High-Luminosity Large Hadron Collider is challenged by dense hit environments and combinatorial ambiguities. Existing graph-based and Transformer approaches commonly rely on static geometric neighbourhoods, which cannot adapt as track-level representations evolve. We propose the Evolving-Geometry Transformer (EGT), a graph Transformer that reconstructs the hit-connectivity graph at successive encoder layers and incorporates relative hit coordinates as learnable attention biases. Across five simulation benchmarks spanning linear, helical, and reduced TrackML events with up to 200–500 simultaneous trajectories, EGT achieves the highest FitAccuracy on three of five settings under the shared benchmark protocol, reaching 79.6% on the most complex setting and exceeding the strongest baseline by 1.6 percentage points. Replacing the evolving topology with a static graph reduces the perfect-track rate from 81% to 29%, while removing the geometric bias reduces it to 73%. Under synthetic background injection equal to the number of signal hits, FitAccuracy decreases by 3.4 percentage points. The neural-network forward pass requires 31~ms per event on an NVIDIA A100 GPU. These results indicate that iterative refinement of hit associations improves complete-track recovery when local geometry alone is insufficient to determine trajectory membership.

We study self-interacting dark matter composed of heavy baryons in a confining dark $SU(N)$ gauge theory with a single heavy vector-like quark, $m_Q \gg \Lambda_d$. In this regime, the dark baryons are compact Coulombic bound states whose long-distance interactions can be described by a multipole expansion. We derive the leading baryon-baryon interaction by adapting the quarkonium operator-product-expansion formalism to heavy baryons. The resulting force contains non-retarded London dispersion, retarded Casimir-Polder, and Yukawa contributions from dark glueball exchange. We find that the self-interaction phenomenology depends strongly on the number of colors. For $N=2,3$, the attractive interaction is too weak to overcome the short-distance Pauli repulsion, and no phenomenologically relevant velocity dependence is obtained within our minimal set-up. For sufficiently large $N$, the attractive interaction remains competitive with the repulsive core and can generate strong velocity dependent cross sections. Taking $SU(10)$ as a representative finite-$N$ realization, we find regions compatible with self-interaction requirements inferred from dwarf galaxies and clusters, while allowing much larger cross sections at low velocities relevant for gravothermal evolution. These regions correspond to GeV-scale dark baryons and a confinement scale close to that of QCD, which naturally motivate an asymmetric dark matter origin.

Radchenko and Wheeler (RW) recently proved a finite pentagon relation for real quadratic special values of the modular quantum dilogarithm and used it to establish the rank-$1$ twisted convolution identity conjectured by the current authors. RW gave an explicit argument in the principal case and remarked that their proof holds for all rank-$1$ admissible tuples. We extend their proof to all rank-$r$ admissible tuples and provide an explicit dictionary between the modular quantum dilogarithm and the Shintani-Faddeev modular cocycle conventions in the respective papers. Thus, we establish that, if $d,r$ are positive integers such that $r<\frac{d-1}{2}$ and $\frac{d^2-1}{r(d-r)} \in \mathbb{Z}$, then there exist ghost $r$-SICs: i.e., configurations of $d^2$ rank-$r$ subspaces in $\mathbb{C}^d$ that satisfy a non-Hermitian equichordal condition. Under the Stark conjecture, these configurations are Galois conjugate to Hermitian equichordal configurations called $r$-SICs (or rank-$r$ SIC-POVMs).

Plate tectonics is described in two registers: a discrete one, in which rigid plates tile the sphere and meet at trivalent junctions, and a continuous one, in which Bercovici and Wessel (1994) replace hard plate outlines by smooth shape functions of finite boundary half-width $\delta^*$. We prove that the two registers are connected by a limit theorem. Generalizing the shape functions to a signed-geodesic-distance construction, we show that they converge almost everywhere, exponentially in $1/\delta^*$, to the plate indicator functions; that the sharp plate mosaic is a finite regular trivalent CW decomposition of the sphere under an explicit structural hypothesis; and that a component-counted weighted Euler characteristic $\chi_w^{\delta^*}(\tau)$, built from the super-level sets of the shape functions, equals $V-E+F=2$ for all $\delta^*$ below an explicit threshold $\delta_0(\tau)$, with its face, edge and vertex terms converging separately to the numbers of plates, boundary arcs and triple junctions. The theorem is proved unconditionally on the signed-distance offset cover under positive-reach, separation and bounded-sector hypotheses, and transferred to the normalized partition-of-unity field for thresholds $\tau<1/3$ by a comparison lemma whose junction-ball step, a planar single-crossing property, is certified numerically. The residual $|\chi_w-2|$ defines a topological diffuseness index for diffuse plate boundaries. For the present-day PB2002 network the hypotheses are measured to be non-vacuous, with $\delta_0(0.15)\approx2.8$ km. The theorem is the mathematical foundation of the topological audit of plate reconstructions presented in a companion paper (Kim, 2026, submitted to Geoscience Frontiers).

We investigate whether a spherically symmetric black hole can have a complete inner end at finite, nonzero areal radius while satisfying the standard energy conditions sufficiently far outside its horizon. Retaining two independent metric functions, we treat both null-type and spacelike-type asymptotic throats and derive a necessary and sufficient integral criterion for causal geodesic completeness. Under boundedness and finite-limit assumptions on the independent curvature components, null-type ends have limiting curvature fixed by the throat radius, whereas spacelike-type ends admit an additional nonnegative curvature parameter. We obtain criteria for bounded curvature in timelike and null parallel-propagated frames. Complete spacelike-type examples can have bounded scalar invariants and bounded timelike-frame curvature but unbounded null-frame curvature at infinite affine parameter. We also prove that the radial null energy condition must fail arbitrarily close to every complete inner end in the stated class. Nevertheless, explicit real-analytic constructions with either type of throat satisfy the null, weak, dominant, and strong energy conditions throughout a sufficiently distant exterior region. Smooth constructions can become exactly Schwarzschild beyond a finite radius. These results establish the compatibility of complete asymptotic throats with exterior energy conditions while distinguishing completeness from different levels of curvature regularity.

Fiber orientation and compartmental microstructure are central to the characterization of white matter tissue in diffusion MRI, yet existing methods either resolve fiber orientations without quantifying microstructure, or quantify microstructure while assuming a fixed number of compartments and a single fiber direction. Nonparametric approaches that recover both require tensor-valued diffusion encoding and computationally expensive Monte-Carlo inversion of an ill-posed inverse Laplace transform. We propose to reframe this problem as an object detection-like task, adopting the Detection Transformer (DETR) architecture to jointly predict mean diffusivity (MD), fractional anisotropy (FA), main fiber direction, and signal fraction for a variable number of compartments per voxel from standard multi-shell diffusion MRI with linear encoding. Hungarian matching during training resolves permutation invariance across compartments. We introduce mean Average Precision as a reproducible benchmark metric. Evaluated on synthetic test data with up to five compartments per voxel, our model achieves $R^2=0.95$ for MD, $R^2=0.88$ for FA, and a median angular error of 4.2{\deg}, with performance scaling naturally with compartmental signal fraction.

Gausslet orbitals on a cubic lattice, introduced in [Steven R. White, J. Chem. Phys. 147, 244102 (2017)], represent a localized, smooth, and systematically refineable basis set featuring a "diagonal" approximability of the electron repulsion integral tensor. The present work develops efficient algorithms for evaluating overlap integrals required for electronic-structure simulations using these Gausslets, specifically the kinetic, nuclear, and electron repulsion integrals (both with and without the diagonal approximation). Computational efficiency improvements rest on the exploitation of translation, permutation, and octahedral symmetries, a reordering and precomputation of nested sums, as well as an early truncation of small coefficients. Our algorithms reduce the number of electron repulsion integrals on a $5 \times 5 \times 5$ grid from $125^4 = 244140625$ to $138187$ due to symmetries, and achieve a wall-clock runtime for evaluating the remaining integrals with a truncation tolerance of $10^{-5}$ in under 1 second on a laptop computer. We apply the developed methodology to compute the ground state of the hydrogen atom and molecule as a demonstration.

We report the temperature and pressure tunability of an unusual structural transformation associated with a two-step metal-insulator-metal (MIM) transition in the kagome lattice compound PrIr$_3$B$_2$ using synchrotron X-ray powder diffraction. At ambient conditions of temperature and pressure, the monoclinic ($C2/m$) and the hexagonal ($P6/mmm$) phases coexist as twinned structure in the crystal. As the temperature (pressure) is decreased (increased), PrIr$_3$B$_2$ converts fully to monoclinic structure at $T =$ 280 K (at ambient pressure) and $P =$ 1.2 GPa (at room temperature). Temperature dependence of the monoclinic structure at ambient pressure presents complex evolution of lattice parameters with weak but clearly discernable anomalies at \SI{\sim 250} {\K} and \SI{\sim 110} {\K}, which are correlated with the second MIM transition and the linear to nonlinear temperature-dependent resistivity crossover, respectively. These anomalies are likely due to some charge order state causing a partially gapped Fermi surface. The magnetic phase diagram of PrIr$_3$B$_2$ is also investigated from anisotropic measurements. At 10 K, a superzone gap opens near the antiferromagnetic transition, which does not close even in the polarized state. From the tunability of the crystal structure and magnetic and electronic ground state, promising electronic orders are indicated in this kagome metallic magnet.

This paper investigates electron transport properties across N/AM interface or N/AM/N heterojunction. Based on Hamiltonians in the three regions, general wave functions are proposed and combined linear equations are constructed. Reflection and transmission coefficients as well as spin polarizatioin of the altermagnet heterostructure are obtained. When electron incident from normal metal to altermagnet, it is scattered and split into + branch and _ branch transmitting into altermagnet zone with separate refractive angles. Total internal reflection might happen to + branch. Critical angle of total reflection is determined by incident conditions and properties of AM material. In the heterostructure case, spin-up and spin-down electrons transmitted with same propagation directions but different transmission probabilities. Transmission and polarization periodically change with length of the junction. Exchange field and spin-splitting strength have pronounced effect on spin-polarized transmittance while the effect of spin-orbit coupling is quite small. Optimized system can be found by tuning parameters of the AM material. This study will lay the theoretical groundwork for experimental research on spin-selective outputs and spintronic devices.

Fingerprint recognition is a widely deployed biometric, but supervised training requires large labeled enrollment sets. Self-supervised learning (SSL) removes this requirement, and hybrid quantum-classical models have been proposed to enrich the learned representations. Prior quantum SSL studies consider a single contrastive objective, so it is unclear whether reported benefits depend on the objective or can be attributed to the quantum circuit. We insert the QuFeX quantum feature-extraction module into three SSL frameworks, the contrastive SimCLR and MoCo v2 and the non-contrastive BYOL, and compare each hybrid with its classical counterpart at matched representation width (8 features, equal to 8 qubits) on the SOCOFing fingerprint dataset, with a CIFAR-10 control, using k-nearest-neighbor identification on encoder features. In single-run experiments the hybrid scores clearly higher for both contrastive objectives, whereas for BYOL a multi-seed analysis shows no reliable difference, suggesting that any benefit depends on the SSL objective. A hardware-efficient circuit (QNet) does not show the same gain. We examine whether the gains can be attributed to the quantum circuit, considering circuit architecture, trainable parameter count, nonlinearity, and the classical simulability of 8-qubit circuits.

Nonlinear partial differential equations (PDEs) underpin computational fluid dynamics, yet resolving nonlinear transport on fine grids remains computationally demanding. Quantum linear-evolution algorithms offer a possible route to large-scale simulation but cannot directly propagate nonlinear coupling. Here we develop a Frozen–Oseen quantum homotopy method (FOQHAM) framework that links transport-aware auxiliary-operator selection to the size of the resulting linear representation. We freeze the full Fréchet derivative at a prescribed flow profile, retaining transport and profile-gradient coupling and close each prescribed finite-order homotopy hierarchy as a fixed affine linear system by product lifting. We formulate its propagation through Linear Combinations of Hamiltonian Simulations (LCHS), without outer homotopy iterations or profile updates. For spatially semidiscrete equations, we establish local approximation bounds and exact closure of the finite-order hierarchy. Classical tests on Burgers, Korteweg–de Vries, Zakharov–Kuznetsov, and one- and two-dimensional isothermal compressible Navier–Stokes equations provide numerical evidence of accurate non-iterative approximations in the tested regimes. The framework thus connects nonlinear PDE approximation to quantum linear evolution and offers a conditional path toward quantum acceleration.

In this paper, we establish Edgeworth expansions of extreme eigenvalue distributions for two types random unitary ensembles at the spectral edges and reveal certain universal structures for the correction terms. More precisely, we show the correlation kernels for the Gaussian-type unitary ensembles and Laguerre-type unitary ensembles admit full expansions at the soft edge and the hard edge, respectively. The coefficients of the correction terms are given by finite sums of Airy function or the Bessel functions of the first kind and their derivatives with polynomial coefficients. By lifting the kernel expansion to the associated Fredholm determinant, we further obtain full expansions for the largest eigenvalue distribu- tion of the Gaussian-type unitary ensembles and the smallest eigenvalue distribution of the Laguerre-type unitary ensembles. In addition, the first correction term therein involves the derivatives of the leading term.

FeTe has long been regarded as a nonsuperconducting antiferromagnetic metal with trivial band topology, but recent advances in stoichiometry control have begun to challenge this picture. Here we use higher-order epitaxy on zinc-blende MnTe to stabilize near-stoichiometric FeTe with strongly suppressed interstitial Fe and a superconducting transition onset near 13 K. Angle-resolved photoemission spectroscopy reveals markedly enhanced quasiparticle coherence, well-defined Fe-derived hole bands, and a nearly two-dimensional Dirac-cone-like state near the Fermi level. First-principles calculations identify an inversion between odd- and even-parity bands, yielding nontrivial $Z_2$ topology and a Dirac surface state consistent with experiment. These results elucidate the intrinsic electronic structure of stoichiometric superconducting FeTe and provide evidence for nontrivial band topology, positioning FeTe/MnTe as a promising platform for exploring topological superconductivity.

We show that heavy dark baryons in a confining $SU(N)$ sector with a moderately large number of colors, $N\sim10$–$100$, can generate self-interactions spanning the full range of astrophysical velocities. Their chromo-electric polarizability induces van der Waals interactions that yield $\sigma/m_{\rm DM}\sim30$-$100~\mathrm{cm^2/g}$ at dwarf-galaxy velocities, decrease to the values required by galaxy clusters, and rise to $100$-$1000~\mathrm{cm^2/g}$ at velocities of a few $\mathrm{km/s}$, as suggested by the second perturber of JVAS B1938+666. Remarkably, for a given ratio $m_Q/\Lambda_d$, these observations can be used to infer the value of $N$. The resulting self-interaction phenomenology favors GeV-scale dark baryons, independently of the relic-abundance requirement. At these masses, a dark baryon asymmetry comparable to the visible one can account for the observed dark-matter abundance.

When driven by a large enough electric field or current, the insulating state of vanadium dioxide ($VO_2$) typically collapses abruptly into the metallic state (the insulator-metal transition, IMT) following a brief incubation delay. These incubation delays, typically lasting microseconds or less, have been analyzed predominantly through macroscopic electro-thermal modeling, providing little statistical insight into the transition dynamics. Here, we investigate the electrically driven IMT in a two-dimensional $VO_2$ lattice and demonstrate that the material behaves as a complex, interdependent network despite being a single structural entity. Because metallic domains dissipate significantly more Joule heat than insulating regions, each switching event raises the Joule heating of the network, resulting in network dependency and triggering a cascading chain reaction. Combining time-resolved resistance measurements with a Joule-coupled resistor-network model and interdependent-network theory, we observe an abrupt (first-order) transition preceded by an anomalously long incubation plateau lasting thousands of seconds. During this metastable plateau, an effective branching factor of the switching activity approaches unity at criticality, and the plateau lifetime diverges with exponent $\zeta=1/2$; the order parameter scales with exponent $\beta=1/2$. These signatures coincide with those predicted for interdependent networks, indicating that dissipative Joule coupling alone can drive mixed-order catastrophic cascades in a single-network correlated-oxide system.

We report the possible detection of a Dark Galaxy Candidate (DGC; AGC 322753), via the cross-matching of the Arecibo Legacy Fast ALFA (ALFALFA) and the FAST All Sky HI (FASHI) HI blind surveys. It is detected by both surveys at the same recessional velocity, with a comparable HI mass of $2\times10^{9}$ M$_\odot$, and with similar HI spectral features. The ALFALFA and FASHI spectra show a double-peaked profile, compatible with a disc-like ordered rotation, and an HI linewidth at 50 per cent of the peak ($W_{50}$) of $\sim$85 km s$^{-1}$. The common intersection of the two beams allows the source position to be constrained with much greater precision than in either survey individually. Being detected by both radio telescopes, a Radio Frequency Interference (RFI) origin is excluded. No evidence of an optical counterpart was found down to $\sim$27.5 mag arcsec$^{-2}$ in the DESI Legacy Imaging Surveys, which leads to a stellar mass limit of $M_\star \lesssim 5\times10^{7}$ M$_\odot$. Given this stellar mass limit, AGC 322753 has $M_{\rm HI}/M_\star \gtrsim 40$. The HI mass is higher than expected for totally starless haloes; this could imply that AGC 322753 is not completely 'dark' but could host a luminous counterpart below the current optical detection limit.

We characterize bound entanglement in bipartite qutrit systems by combining the Positive Partial Transpose (PPT) criterion with a structural, non-completely positive map. Focusing on a comprehensive three-parameter bipartite qutrit family $\rho_{a,b,c}$, we present an exact analytical and geometric partitioning of the physical state space simplex. We derive the closed-form quadratic boundary governing the leaf-like PPT region $(a^2+ab+b^2-b \leq 0)$ over the domain $0 < a \leq \frac{1}{3}$, and identify the exact linear threshold $(a > c)$ that characterizes the PPT bound entangled sub-region. This family strictly generalizes the well-known Horodecki bound entangled states, which appear as a single slice of the three-dimensional leaf. Applying the structural map to this decomposition, we show that it certifies bound entanglement throughout the entire threshold region, accounting for $14.76\%$ of the total PPT leaf area.

Consider two orthonormal bases of a bipartite Hilbert space such that states in one basis are weakly entangled and states in the other are strongly entangled. We establish a quantitative version of the following uncertainty principle: every state that is localized in one basis must be delocalized in the other. More specifically, we lower bound the sum of the Shannon entropies of any state's coefficient distributions in the two bases by the difference between the entanglement Rényi entropies of their basis states. The result follows from new lower and upper bounds on the entanglement of superpositions that may be of independent interest. As an application, our result limits the power of weakly-entangled states in representing ground states of Hamiltonians with strongly-entangled energy eigenstates. We illustrate this application numerically for the Sachdev-Ye-Kitaev model.

Faulty syndrome measurements can corrupt an otherwise correct quantum-error correction step. Bivariate bicycle (BB) codes contain dependent stabilizer checks, so every valid syndrome obeys additional parity constraints, or metachecks. We study how far this built-in redundancy can identify measurement faults and when the remaining ambiguity is unavoidable, while separately checking the code's logical structure. A logical decomposition is used as a preliminary safety check: it identifies a $k/2$-dimensional annihilator subspace and a $k/2$-dimensional colon quotient, and the minimum-weight logical need not be visible from the annihilator side alone. On the measurement side, translation symmetry partitions syndrome locations into classes that carry identical metacheck information. This gives an exact characterization of the leading single-fault ambiguity, a bound on how many fault locations can be distinguished, and a family-level repair limit when the encoded dimension stays bounded while the block length grows. Under a static-data assumption, the same calculation gives the minimum number of checks that must be remeasured to remove every single-fault ambiguity. Exact finite-code calculations illustrate both regimes: all single measurement faults are distinguishable in a 72-qubit BB code, whereas the 144-qubit Gross code merges its 72 syndrome locations into 36 indistinguishable pairs. In a 108-qubit example, one logical component first appears at weight 12 while the other contains a weight-10 logical. Sustained phenomenological experiments show that joint data–measurement decoding is more robust than a separated repair stage on the more ambiguous codes. The resulting tests apply to general two-block BB codes, including non-coprime periods and repeated-root cases.