Papers

Young quadruple systems provide a particularly simple setting in which the connection between successive levels of fragmentation can be studied. Motivated by the recurring symmetric configurations observed in a small number of young systems, we propose a theoretical framework in which such configurations arise naturally during rapid collapse. Rotational fragmentation followed by secondary fragmentation can produce two comparable-mass components of a wide pair, each of which further fragments into an unequal-mass close pair. The combination of tidal forces and accretion-driven shear can then establish a preferred phase relation, with the lower-mass component located on the inner, preceding side of the higher-mass component in each close pair. During subsequent capture, this phase relation can shift, placing the lower-mass component on the inner, trailing side. Asymmetric partitioning of a coherent, rapidly accreting flow can also tilt the spin axes of the fragments, providing a possible origin for spin misalignments without requiring an initially incoherent large-scale flow. The proposed mechanism therefore provides a possible physical origin for the characteristic phase relations in young quadruple configurations and for stochastic spin orientations within star clusters.

Although quantum error correction is widely believed to be necessary for impactful applications of quantum computers, the design of quantum error correction codes is largely done by hand, without respect to problem or hardware constraints. In this work, we present a highly general and flexible framework for the computational design of both physics-inspired and hardware-aware quantum codes. To do so, we formulate code design as a Boolean satisfiability (SAT) problem and show how to incorporate all required error correction criteria. We prove that code design is NP-complete, ruling out any efficient algorithm for designing codes in general. Nonetheless, we show that state-of-the-art SAT solvers are able to effectively find solutions for many practical problems. Notably, we are able to design physics-inspired codes with up to 100 physical qubits in minutes, and we design new hardware-aware codes for biased noise which have a lower logical error rate than state-of-the-art surface codes.

We present a detailed observational analysis of BLG723.31.34651, the fourth reported eclipsing member of the class of Roche lobe-filling hot subdwarfs, using time series spectroscopy and multi-band photometric observations from the Goodman High Throughput Spectrograph on the 4.1-m SOAR telescope. Our light curves show periodic photometric variability at $P=64~{\rm min}$ from the tidally-deformed hot subdwarf donor and deep eclipses of the donor by an opaque accretion disc. We report two light curve model solutions that agree with each other to within $2\sigma$, both suggesting that BLG723.31.34651 contains a typical hot subdwarf donor, a white dwarf accretor, and an irradiated opaque accretion disc. Our spectroscopic analysis identifies statistically significant phase-dependent variations in the effective temperature and surface gravity coinciding with the phase-dependent variations seen in our observed light curves. We attribute these variations to a combination of intrinsic variations in local atmospheric parameters due to tidal deformation of the donor and unmodeled spectroscopic flux contributions from an accretion disc.

Interpretability is critical for machine learning models deployed in scientific space missions such as ESA's Ariel, where ground truth is unavailable during operations and physical plausibility must be assessed. While most explainable AI methods focus on feature attribution, this work investigates training data attribution through influence functions and introduces three key contributions for operational spectroscopy pipelines. First, influence is reformulated in terms of prediction rather than loss, enabling label-free deployment. Second, by leveraging the closed-form ridge solution of an Extreme Learning Machine, infinitesimal prediction influence is efficiently computed. Third, an influence-based conservative error proxy is derived by propagating training residuals through the influence sensitivities. Evaluated against simulated spectra, the proposed proxy correlates strongly with scale and shape-based spectral errors. Furthermore, influence functions enable the identification of the most influential samples and the approximation of the most harmful ones. Together, these results suggest that this approach can serve as an operational framework for scientific machine learning.

We prove a three-term asymptotic formula for the eigenvalues of the fractional Laplacian on the bounded interval $(-1,1)$. This improves the eigenvalue asymptotics of Kulczycki–Kwaśnicki–Małecki–Stós and Kwaśnicki, and confirms the conjectural $O_\alpha(n^{-2})$ remainder suggested by the numerical simulations of Kaleta–Kwaśnicki–Małecki. Moreover, we prove that the normalized eigenfunctions are bounded uniformly in the eigenvalue index $n$ and the fractional order $\alpha$. This settles the conjecture proposed by Kwaśnicki through numerical experiments. Furthermore, we prove that the $n$-th eigenfunction has exactly $n-1$ zeros in the interval $(-1,1)$ and every zero is simple, and hence there are exactly $n$ nodal domains. A key ingredient in the proof is an explicit representation of the eigenfunction.

This work presents a new two-dimensional quantifier plane that combines normalized permutation entropy and normalized permutation mutual information, both derived from Shannon's information theory and normalized consistently through the embedding dimension of the Bandt and Pompe method. Each point on the plane simultaneously characterizes the intrinsic uncertainty of a variable and the amount of information it shares with another. We further show that a third quantity, equivalent to the conditional entropy of one variable given the other, introduces a notion of informational independence and, when both projections of a variable pair are considered jointly, reveals directionality between them. We analyze regular, chaotic, and stochastic dynamics to illustrate the relevance of the informational plane and show how these regimes evolve as a function of a coupling factor.

Equilibrium steady states are fully characterized by the Boltzmann distribution, which depends only on the energy and the temperature. In contrast, nonequilibrium steady states, which describe a wide range of physical and biological phenomena, are generically much more complex, and their stationary distributions can depend on a zoo of kinetic parameters. A central challenge of nonequilibrium statistical mechanics is the identification of universal relations that hold for nonequilibrium steady states despite this complexity. We show here that a form of the Cramer-Rao inequality applies to arbitrary nonequilibrium steady-state distributions and contains no explicit dependence on kinetic parameters. A main original feature in our observation is that this inequality becomes a well-known fluctuation-response relation in equilibrium. The inequality involves three well-defined quantities: the fluctuations of the energy, the response given by the derivative of the average energy with respect to the inverse temperature, and the Fisher information with respect to the inverse temperature. We illustrate this inequality using three representative models: an active particle in a harmonic potential, a simple scheme for kinetic proofreading, and a one-dimensional model for heat conduction between two baths.

AC nanocalorimetry was used to measure the reversing heat capacity Cp of low energy indomethacin glasses as they isothermally transform into the supercooled liquid. As the film thickness increases from 75 to 600 nm, the transformation time increases by more than an order of magnitude, consistent with a surface-initiated transformation mechanism. Eventually, the transformation time becomes constant for films between 1.4 and 30 microns indicating a distinct bulk transformation pathway. The observation of size-dependent transformation kinetics for glass samples approaching 1 micron is unprecedented. We interpret the crossover in thickness dependence at 1 micron to signify the average distance between transformation initiation sites in the bulk low energy glass.

Light spectator fields provide a compelling inflationary origin for scalar dark matter, but their primordial fluctuations often generate excessive isocurvature perturbations on large scales. We develop a novel, exactly solvable filtering mechanism based on a tower of $\delta-$function contributions to the spectator mass, which we call kicks, whose dense limit converges to a smooth Coulomb-like profile. The filter produces a isocurvature spectrum during inflation that is strongly suppressed on large scales, rises with momenta as $k^3$ in the infrared, and, after a rapid turnover, smoothly approaches a constant plateau at small scales. This construction is motivated by a discrete translational invariance, admits an EFT regime in which radiative corrections can be systematically controlled, and can find a concrete realization in terms of an inflationary massive-clock model. We embed the filter in a minimal dark-matter scenario in which a spectator condensate oscillates about the minimum of a quadratic potential and behaves as pressureless matter. In this framework, the spectator dark-matter mass is directly related to the turnover scale of the inflationary isocurvature spectrum. We determine the resulting dark-matter abundance and analyze the relevant isocurvature and backreaction constraints. The most restrictive realization, in which the spectator condensate is generated during inflation, favors a relatively low inflationary scale.

In multi-fluid, matter-type gravity, the Bianchi identity constrains the divergence of the total effective stress tensor but does not, by itself, determine the currents assigned to its constituent sectors. Those currents are selected only after the off-shell matter action and equations, or an additional phenomenological closure, have been specified. We formulate this distinction and examine a spatially flat two-fluid background inspired by scale-independent EMSG. The case study combines an algebraic perfect-fluid prescription with a vanishing contracted-Hessian contribution, together with separate conservation of the total conventional and modification sectors. Because neither assumption is derived here from a concrete off-shell fluid action, the resulting system is an effective background closure rather than a microscopic EMSG model. For unequal EoS and every $\alpha\ne0$, the closure yields a Barrow-Clifton system whose transfer coefficients depend on $(w_1,w_2)$ but not on $\alpha$. Hence the nonzero-$\alpha$ family is singular: its $\alpha\to0$ limit does not recover the uncoupled GR conservation laws. We solve the two density eigenmodes and derive the associated modified Liénard equation for $H$. We also prove that the discriminant governing rank loss of the density-reconstruction map is strictly positive for every finite $w_1\ne w_2$. Thus each genuinely quadratic case has two distinct real rank-degenerate couplings. Exact vacuum and stiff-fluid families illustrate modal cancellation. When today's conventional densities are positive, the intervals on which both remain positive generally terminate at finite endpoints in the parameter ranges analyzed explicitly. These results provide a consistency diagnostic for separating action-level predictions from closure artifacts in multi-fluid, matter-type gravity; they do not establish an observationally viable EMSG model.

We report for the first time that, within the saturation framework, exclusive vector meson production at small $x$ is sensitive to the shell structure of the target nucleus. Self-consistent nuclear densities from occupied single-particle orbitals in the quark-meson coupling (QMC) model modify the coherent $|t|$-differential cross section, enhancing secondary diffractive lobes in light nuclei and displacing the higher-order minima in intermediate-mass nuclei, whereas for heavy targets the shifts are weaker. Because the small $J/\psi$ dipole is insensitive to saturation, these features make coherent $J/\psi$ production a clean probe of nuclear shell structure, most favorably for intermediate-mass nuclei such as calcium isotopes. For the larger $\phi$ dipole, shell structure must be included in the nuclear initial state before saturation effects can be isolated in differential observables at the Electron Ion Collider. Our results establish exclusive vector meson production as a probe of the mean-field nuclear structure at small $x$ and provide a baseline for isolating residual many-body correlations.

In situ AC nanocalorimetry was used to measure the reversing heat capacity of vapor-deposited glasses of decahydronaphthalene (decalin). Glasses with low heat capacity and high kinetic stability, as compared to the corresponding liquid-cooled glass, were prepared from cis-decalin and from several cis/trans-decalin mixtures. This is the first report of highly stable glass formation for molecular mixtures. The 50/50 cis/trans-decalin mixture is the highest fragility material reported to produce an ultrastable glass. The 50/50 mixture exhibited high kinetic stability, with an ~500 nm film deposited at 116 K (0.86 Tg,) displaying a transformation time equivalent to 104.4 times the structural relaxation time of the supercooled liquid at the annealing temperature. Cis-decalin and the decalin mixture formed stable glasses that had heat capacities as much as 4.5% lower than the liquid-cooled glass.

We study an extended Hubbard model on Lieb lattice at electron filling 2 and 4, and demonstrate that the interactions lead to the simultaneous emergence of altermagnetic order and a topological gap. Using unrestricted Hartree-Fock theory, we evaluate both the altermagnetic and topological order parameters and show that they co-exist with an associated quantum spin Hall effect in a large region of the phase diagram, which we further support using exact diagonalization. Moreover, we demonstrate that inversion-symmetry breaking terms can also mediate second-order topological phases with associated corner modes.

Polyphase filter banks (PFBs) are widely used to channelize digitized time-domain data in real time. However, applications such as radio astronomy often require higher spectral resolution than real-time systems can provide. We introduce a circulant inverse-PFB formalism and present a new, scalable, fast Fourier transform (FFT)-based algorithm for inverting critically sampled PFBs. This formalism explicitly identifies the origin of quantization noise amplification and enables two complementary mitigation strategies: (1) a fast, practical Wiener filter and (2) a rigorous maximum-likelihood reconstruction with time-domain priors. We evaluate both approaches using simulated 4-bit quantized PFB data. For autospectra, Wiener filtering confines reconstruction errors to less than 10% of the channel width, with a peak error below 10%. The maximum-likelihood approach further reduces reconstruction errors as additional time-domain prior information is incorporated, with priors spanning 10% of the time-domain samples reducing worst-case errors to below 2%. This framework enables high-resolution spectral analysis of archival PFB data, facilitating applications including long-baseline interferometry, pulsar and fast radio burst searches, and ultra-narrow-band physics experiments.

In this work, we comprehensively study the total and differential decay widths of the radiative Dalitz decays $H \to l^+l^-\gamma$ up to QCD next-to-leading order (NLO) accuracy within the framework of NRQCD factorization. Our calculation includes the decays of $S$-wave states ($\eta_c, \eta_b$) and the $P$-wave triplets ($\chi_{cJ}, \chi_{bJ}$ for $J=0,1,2$) to both electron ($l=e$) and muon ($l=\mu$) final states. To match realistic experimental detection thresholds, systematic kinematic cuts are implemented on the final-state photon energy. Our analysis of the lepton-pair invariant mass distribution shows distinct singular behaviors across the multiplets originating from the lepton-pair threshold region, which is regularized by the lepton mass, and the soft-photon region, respectively. For the $S$-wave states, there is only one peak near the lepton-pair threshold region, while for the $J=0$ and $J=2$ $P$-wave states, the peaks show up in both regions. However, for the $J=1$ $P$-wave states, the peak only appears in the soft-photon region. Such features provide a rich venue to probe the $\gamma^{\ast}\to l^{+}l^{-}$ form factor in heavy quarkonium decay. Integrating over the bounded phase spaces reveals a distinct hierarchy among the $\chi_{QJ}$ states in the sensitivity of our theoretical predictions to the soft-photon energy cuts, ordered as $\chi_{Q1} >\chi_{Q2}>\chi_{Q0}$. In the $\chi_{cJ}\to l^{+}l^{-}\gamma$ cases, as the energy cut increases from 100 $\mathrm{MeV}$, to 500 $\mathrm{MeV}$ the theoretical predictions at QCD NLO are reduced by $6\%(\chi_{c0})$,$66\%(\chi_{c1})$, and $21\%(\chi_{c2})$ for $l=e$, and by $17\%(\chi_{c0})$,$66\%(\chi_{c1})$, and $39\%(\chi_{c2})$ for $l=\mu$. Comparing our predictions with the upcoming high-precision experimental tests at BESIII will definitely deepen our understanding of the predictive power of perturbative calculations.

Ta2NiSe5 is a quasi-one-dimensional material that exhibits a structural and electronic phase transition from a low-temperature monoclinic (semiconductor) to a high-temperature orthorhombic (semimetal) phase at approximately TC = 326 K. Here, we used variable-temperature scanning tunneling microscopy and spectroscopy to resolve the phase transition spatially, identifying the distinct spectroscopic signatures of the monoclinic and orthorhombic phases in pristine regions and near isolated point-defects and step edges. Although the phase transition of Ta2NiSe5 is generally regarded as second-order, it has previously been described as exhibiting martensitic-like characteristics. This implies that the transformation may proceed via spatial phase coexistence and domain boundaries rather than through a continuous evolution. Our surface-sensitive measurements confirm this scenario, retrieving the coexistence and evolution of monoclinic and orthorhombic domains in real space. Upon heating through TC, we find that the two phases coexist as spatially segregated regions over extended timescales, separated by well-defined boundaries that evolve via localized nucleation and growth, rather than a spatially uniform transformation. In pristine regions, the orthorhombic phase nucleates anisotropically, perpendicular to the Ta-Ni-Ta chains, whereas point-defects and step edges act as local nucleation centers that promote the transition and suppress this intrinsic anisotropy. These results provide direct real-space visualization of how surface-specific structural and electronic variations, together with local disorder, modify the martensitic-like phase transition in Ta2NiSe5.

We performed constant strain rate deformation and stress relaxation on a poly(methyl methacrylate) glass at Tg - 19 K, utilizing three strain rates and initiating the stress relaxation over a large range of strain values. Following previous workers, we interpret the initial rate of decay of the stress during the relaxation experiment as a purely mechanical measure of mobility for the system. In our experiments, the mechanical mobility obtained in this manner changes by less than a factor of 3 prior to yield. During these mechanical experiments, we also performed an optical measurement of segmental mobility based upon the reorientation of a molecular probe; we observe that the probe mobility increases up to a factor of 100 prior to yield. In the post-yield regime, in contrast, the mobilities determined mechanically and by probe reorientation are quite similar and show a similar dependence upon the strain rate. Dynamic heterogeneity is found to initially decrease during constant strain rate deformation and then remain constant in the post-yield regime. These combined observations of mechanical mobility, probe mobility, and dynamic heterogeneity present a challenge for theoretical modeling of polymer glass deformation.

Quantum sensors can achieve precision unattainable by classical sensors. However, dissipation coming from interaction with the environment can greatly degrade the performance of quantum sensors. Therefore, it is crucial to attempt harnessing dissipation to our advantage and investigate the sensing performance of driven-dissipative systems to gain practical quantum advantages. In this paper, we study a system of two-level systems driven coherently at a detuned frequency, and importantly, connected to a chiral waveguide that serves both as an interaction mediator and a bath. We show analytically that the steady state of such a system shows enhanced sensitivity to estimate weak detuning strength while the probe preparation time only grows linearly with system size. Therefore, the enhanced sensitivity is sustained even when the preparation time is incorporated. We further establish measurement protocols to achieve such sensitivity that are experimentally implementable. The chirality of the waveguide helps us to control both precision and range of enhanced sensitivity.

Resistive switching (RS) in Nb-doped SrTiO$_3$ (Nb:STO) based memristive devices has attracted sustained interest in information processing and novel computing because of its forming-free operation, large on/off ratio, and gradual conductance modulation. Metal/Nb:STO Schottky junctions have emerged as a prototypical system for understanding RS mechanisms. Despite more than two decades of research, the physical origin of RS remains controversial, with proposed mechanisms including charge trapping and detrapping, oxygen vacancy migration, tunneling, interfacial redox reactions, and conductive filament formation. In this review, we examine these seemingly competing mechanisms and show that many experimental observations can be understood within a unified framework centered on the formation and evolution of an extrinsic interfacial layer at the metal/Nb:STO interface. We discuss how interface quality and defect-mediated processes, including proton incorporation, oxygen vacancy dynamics, and tunneling, govern Schottky barrier modulation and RS behavior. We further summarize how fabrication conditions, measurement protocols, and aging influence the interface formation and switching characteristics. This review establishes an integrated picture of M/Nb:STO heterojunctions and provides design principles for reliable oxide memristive devices through interface and defect engineering in M/Nb:STO and M/oxide/Nb:STO systems.

In this paper, we first analyze the light-cone distribution amplitudes of the pseudoscalar Glueball and point out that the two-gluon and quark-antiquark pair contributions naturally mix at the quantum loop level. Based on the $\eta-\eta'-G-\eta_c$ tetra-mixing scheme and existing experimental results, we analyze the branching ratio of $J/\psi \to P+\gamma$ with pseudoscalar meson $P$ and extract the mixing parameters of the tetra-mixing scheme. We then successfully predict the branching ratio of $\psi(2S) \to P+\gamma$, which is found to be in good agreement with experimental results. We also find that the branching ratios of $J/\psi \to X(2370)+\gamma$ and $\psi(2S) \to X(2370)+\gamma$ are highly sensitive to the Glueball-charmonium mixing angle: the destructive mixing interference in the branching ratio of $J/\psi \to X(2370)+\gamma$ occurs at $\phi_{gc}\approx0.01$, whereas that in $\psi(2S) \to X(2370)+\gamma$ occurs at $\phi_{gc}\approx 0.11$. Moreover, the $J/\psi \to X(2370)+\gamma$ branching ratio exhibits constructive mixing interference when the mixing angle is larger than $\phi_{gc}\approx 0.02$. Finally, we also study the electroproduction cross sections of pseudoscalar mesons. After excluding the resonance contributions, the theoretical calculations agree with the experimental measurements in order of magnitude, and we also present theoretical predictions for the electroproduction cross section of the $X(2370)$. These theoretical results can be readily tested by current BESIII and Belle-II experiments, and further experimental measurements will reveal the intrinsic nature of the $X(2370)$.

The Kuramoto model provides a paradigmatic framework for studying synchronization of interacting oscillators, and has been generalized to arbitrary dimensions to describe swarms, flocks and multi-dimensional opinion dynamics. Yet, existing formulations neglect inertia, a key mechanism known to enhance information propagation and collective responsiveness. Here, we introduce and analyze an inertial Kuramoto model in arbitrary dimensions. We show that inertia fundamentally alters the nature of the synchronization transition, inducing a crossover from continuous to discontinuous behavior, with the onset of hysteresis depending explicitly on both inertia and dimensionality parity. Our analytical theory is supported by extensive numerical simulations. These results establish inertia as a crucial ingredient of high-dimensional collective dynamics and reveal a novel universal structure in synchronization phenomena.

The Kepler detection pipeline, as well as the transit method, has a bias towards shorter periods, leaving a dearth of detections at longer orbital periods. This relative lack of detections has left an incomplete picture of the architectures of exoplanet systems within the long-period regime. We have built a single transit detection pipeline, utilizing a classification convolutional neural network and the onboard spacecraft diagnostics of the Kepler spacecraft, to detect long-period planets. We apply our pipeline to all currently known planetary systems in the Kepler field hosting at least one planet with an orbital period longer than 6 days. We manually vet all new signals from our pipeline, and identify four new planetary candidates, all of which are in systems where the inner planets exhibit transit timing variations (TTVs). Two of these candidates, Kepler 1752.02 and Kepler 199.03, cause two transit events that are consistent with periods of $777.78^{+0.01}_{-0.02}$ and $505.495^{+0.004}_{-0.004}$ days, and radii of $3.55^{+0.15}_{-0.15}$ and $2.74^{+0.05}_{-0.05}$ $R_{\oplus}$, respectively. Our remaining two candidates, Kepler 1897.02 and Kepler 1811.02, are single transit candidates with radii $4.81^{+0.20}_{-0.19}$ and $3.25^{+0.28}_{-0.30}$ $R_{\oplus}$, respectively. The shortest orbital periods for these candidates, consistent with the Kepler dataset (gaps and coverage), are 342 days for Kepler 1897.02 and 544 days for Kepler 1811.02. The new planetary candidates, on their own, are incapable of reproducing the observed TTV signals in the inner system. Although difficult to schedule, follow-up observations are needed to further constrain the new candidates and potentially discover the planets causing the perturbations.

Excitation-energy transfer underpins the conversion of light into usable energy in photosynthetic organisms and serves as a paradigm for evolutionary optimized transport in open quantum systems. Although this process is often described as incoherent thermally assisted hopping, such descriptions become inadequate when electronic coupling, vibronic interactions and environmental fluctuations occur on comparable energy scales. Determining how the environment controls transport therefore remains a fundamental challenge. Here, we use temperature-dependent 2DES to investigate energy transfer in the photosynthetic antenna protein allophycocyanin over the range 10 - 296 K. The dominant $\beta \rightarrow \alpha$ transfer step exhibits a pronounced non-monotonic temperature dependence: the transfer time decreases from 400 fs at 10 K to 200 fs near 30- 40 K before increasing again to 400 fs at 296 K. In contrast, the homogeneous optical dephasing time decreases monotonically across the same temperature range. To interpret these observations, we model APC as a vibronically coupled excitonic dimer interacting with a structured environment and solve the dynamics using hierarchical equations of motion. Conventional fixed-bath models, including Drude-Lorentz and explicit intermolecular-mode spectral densities, fail to reproduce the observed turnover. Quantitative agreement is obtained only when the low-frequency sector of the environmental spectral density is allowed to anharmonically evolve strongly with temperature, while the high-frequency bath remains essentially unchanged. More broadly, these findings demonstrate that transport efficiency is controlled not simply by the magnitude of environmental fluctuations, but by the distribution of environmental spectral weight across frequency space, providing new experimental constraints on theories of molecular transport in complex quantum environments.

We consider the Sherrington–Kirkpatrick model with inverse temperature $\beta>0$ and deterministic external field $h>0$. Let $q$ be the replica-symmetric fixed point: $q=\mathbb E{\rm tanh}^2 (h+\beta\sqrt q\,Z)$, where $Z$ is a standard normal. We prove that, uniformly on compact subsets of the strict de Almeida–Thouless region: $\beta^2\mathbb E{\rm sech}^4(h+\beta\sqrt{q} Z) <1,$ the overlap satisfies the concentration: $$ \mathbb E\langle (R_{12}-q)^2\rangle=O(N^{-1}). $$ As a consequence, we obtain an $O(N^{-1})$ replica-symmetric free-energy correction and identify the finite-volume replicon susceptibility. Our proof is self-contained and does not use the identification of the limiting free energy with the Parisi variational formula. Moreover, we prove the central limit theorem for the overlap in this region. The present paper provides an alternative proof of the replica-symmetric free energy formula in the de Almeida–Thouless region, which was recently established by Lopatto [arXiv:2604.11921]. An advantage of our approach is that it establishes an explicit quantitative bound and yields the replica-symmetric free energy formula as a consequence. The main result supersedes the corresponding result in our recent preprint arXiv:2607.23427, extending the replica-symmetric bounds to the strict de Almeida-Thouless region. However, we keep the previous preprint, since its argument is different and substantially simpler than the one given here.

The prospect of using altermagnets as switchable sources of perpendicularly polarized spin currents has intensified the search for candidate materials, yet metallic d-wave systems with sizable spin-splitter responses remain scarce. Here, we identify an empirical magnetic motif that supports metallic d-wave altermagnetism in the TiNiSi structural family: ferromagnetically ordered zigzag chains with antiferromagnetic interchain coupling in a relatively low-symmetry crystal environment. The TiNiSi structure type combines this motif with broad chemical flexibility and competing magnetic ground states. By combining first-principles screening of thermodynamic stability and magnetic ground states across 280 ternary systems, we identify 16 metallic d-wave altermagnets. This set recovers four experimentally known members—WFeB, NbMnP, TaMnP, and NbMnAs—and yields 12 new predictions, of which ScMnP, TaMnAs, ScMnAs, MoMnAs, MoMnSi, and WMnSi are the most promising. Noncollinear calculations indicate that the collinear altermagnetic configuration is the ground state across them. Each of the six leading new candidates has a nonzero spin-splitter angle and a finite anomalous Hall conductivity. Notably, ScMnP and TaMnAs exhibit strong spin-splitter responses despite modest altermagnetic band splitting. These results establish TiNiSi-type metallic d-wave altermagnets as a chemically versatile platform for efficient charge-to-spin conversion and provide an empirical magnetic-motif-guided route to identifying further candidates.

We study radiative double-charmonium production, $e^+e^-\to HH\gamma$ with $H=J/\psi$ and $\eta_c$, at $\sqrt{s}=10.58~{\rm GeV}$, including a possible tensor contribution from the fully charmed state $X(6900)$. The nonresonant amplitudes are calculated within the color-singlet non-relativistic QCD framework, while the $J^{PC}=2^{++}$ resonance is combined coherently with the continuum. We find that continuum–resonance interference significantly modifies the invariant-mass distributions near $M_{HH}\simeq M_X$. The $J/\psi J/\psi\gamma$ channel exhibits a pronounced phase-dependent resonant structure, with a near-resonance cross section of $0.038$–$0.111~{\rm fb}$. In contrast, the $\eta_c\eta_c\gamma$ channel is continuum dominated and shows only a localized interference effect with an extremely suppressed production rate, rendering its experimental observation extremely challenging. These channel-dependent features arise from the different effective decay structures and demonstrate the importance of an amplitude-level treatment of the $X(6900)$ contribution.

Based on a many-body formulation, we derive an electron-phonon coupling including excitonic effects that preserves thermodynamic detailed balance between electronic and phononic scattering processes. We start from the microscopic electron-nucleus Hamiltonian, expand around the Born-Oppenheimer equilibrium geometry, and construct an effective action for the electronic and phononic propagators. From the same effective action, we derive both electronic and phononic self-energies in terms of a nonlocal vertex $\mathcal G^{\textrm{s}}$ including excitonic effects, which generalizes the usual local interaction vertex $g^{\textrm{s}}$. When electrons and phonons are well-defined quasiparticles in the screened-exchange approximation and $\mathcal G^{\textrm{s}}$ is taken in its static limit, both self-energies reduce to Fermi-golden-rule expressions containing the same $\mathcal G^{\textrm{s}}$, thereby ensuring detailed balance. As an application, we compute electronic and phononic linewidths in graphene and illustrate this common-vertex construction. We analyze the competition between the reduced scattering phase space induced by the screened-exchange band structure and the enhancement of the electron-phonon vertex due to excitonic effects, finding that the vertex enhancement can compensate for and overcome the phase-space reduction in both electronic and phononic linewidths.

The usefulness of entanglement as a resource in quantum technologies increases for larger systems, that is, if more particles or higher-dimensional quantum systems are considered. Yet, the interplay between dimensionality and multiparticle entanglement is not well understood. Only for two-particle systems an unambiguous and coherent notion of entanglement dimensionality, based on the Schmidt decomposition, is known. We introduce a concept to characterize the entanglement dimensionality of multiparticle states based on decompositions of pure states into superpositions of states without genuine multiparticle entanglement. We provide constructive methods to characterize the resulting partition rank for pure and mixed states. This allows the identification of novel maximally correlated states as well as a discrete classification of quantum states under stochastic local operations and classical communication. From a mathematical perspective, our approach can be formulated in terms of the slice rank and partition rank of tensors and our results allow to characterize these by connecting them to a generalized injective tensor norm.

Equilibrium free-energy differences can be measured from nonequilibrium work fluctuations using fluctuation theorems, such as the Jarzynski equality and the Crooks fluctuation theorem. However, these approaches become statistically inefficient in high-dissipation regimes because their convergence requires trajectories with negative entropy production, events that occur exponentially rarely. Here, we demonstrate that repeated measurements of trajectory fluctuations are sufficient to determine entropy production without relying on such rare events, or to determine a lower bound on it when only partial measurements are available. This information then yields exact estimates of free-energy differences, or rigorous bounds. We validate this approach, named EquiNET, with numerical simulations, including one of biomolecular folding and unfolding, showing that it recovers accurate free-energy estimates even in regimes where conventional approaches fail.

Efficient, deterministic, and high-fidelity preparation of large Fock states is essential for scaling bosonic quantum technologies and exploring quantum phenomena at large excitation energies. We introduce a deterministic one-parameter (D1p) protocol that maps Fock-state preparation in an infinite-dimensional Hilbert space onto two-dimensional amplitude amplification. Starting from a coherent state with $|\alpha|\simeq\sqrt{n}$, the initial target-state population scales as $n^{-1/2}$, yielding an iteration count and circuit depth of $\mathcal{O}(n^{1/4})$. Phase matching guarantees unit fidelity in the ideal model; remarkably, preparing $|{10^6}\rangle$ requires only 39 iterations. The protocol uses only displacements and number-selective phase operations, requires no numerical optimization, and further extends to state transfer, general superpositions, finite-dimensional systems, and multipartite entangled states. In the large-amplitude regime, its multi-target form prepares $L$-legged cat states with an iteration count determined only by $L$; cats with up to ten legs require only two iterations, independent of the coherent-state amplitude. This framework provides a broadly applicable route to highly excited bosonic states on platforms supporting these elementary controls.