Papers

Understanding the nature of the exotic $Z_c(3900)$ and $Z_{cs}(3985)$ states, and searching for the predicted isovector partner $W_{c1}$ of the $X(3872)$, remain central challenges in exotic-hadron spectroscopy. We investigate the femtoscopic correlation functions (CFs) of the $D^{(\ast)0}D_{(s)}^{(\ast)-}$ systems. Since these charm-meson–antimeson pairs are not $G$-parity eigenstates, their CFs contain contributions from both the $C$-odd and $C$-even sectors, providing direct access to the dynamics underlying the $Z_c$, $Z_{cs}$, and the predicted isovector exotic $W_{c1}$. Within a heavy-quark-spin-symmetric coupled-channel framework, we show that the $C$-even admixture enhances the low-momentum CFs by more than $2.5\sigma$ in the vicinity of their thresholds. Free from Coulomb distortions and accessible in high-multiplicity $pp$ collisions at the LHC, these channels offer the first direct femtoscopic probe of the isovector $C$-even sector and of the elusive $W_{c1}$ state.

Interlayer twisting offers a geometric route to controlling electronic states, but whether it can simultaneously reconstruct magnetic symmetry and band topology remains unclear. Here, based on symmetry analysis and first-principles calculations, we show that commensurate twisting drives magnetic topological phase transitions in stacked bilayer CrO. In particular, it transforms an antiferromagnetic Dirac semimetal into either a $d$-wave altermagnetic bipolarized Weyl semimetal or an unconventional compensated magnetic Weyl semimetal. A key result is that the Weyl points in the $d$-wave altermagnetic phase lie at generic $k$ points in the Brillouin zone and are protected by the spin symmetry $\left\{ C_2 T||C_{2z} T\right\}$. This sharply contrasts with conventional two-dimensional Weyl semimetals, where Weyl points are typically protected by mirror or rotational symmetries and thus pinned to high-symmetry lines. We further show that commensurate twisting preserves the spin symmetry $\left\{ C_2 T||C_{2z} T\right\}$, making the Weyl phase a robust consequence of twisting rather than a fine-tuned feature of a specific angle. Our work establishes a symmetry-based route to engineering magnetic topological phases in twisted two-dimensional materials.

Turbulent transport in magnetic confinement fusion devices governs the overall plasma confinement properties and regulates the plasma-material interaction at the first wall. In the plasma boundary, turbulence is typically investigated through three-dimensional two-fluid flux-driven turbulence simulations. In this work, the GBS boundary turbulence code is extended to enable turbulence simulations in reversed field pinch configurations, encompassing the reversal surface and an arbitrary level of magnetic chaos. The differential operators implemented in the code are modified to avoid the approximations of large-aspect ratio and weak poloidal magnetic field. Three-dimensional Poisson and Ampere solvers are implemented to allow for turbulence simulations in conditions of partially or fully disrupted magnetic flux surfaces. This modified version of the GBS code is then applied to simulate turbulence in the boundary of RFX-mod reversed field pinch plasmas. Turbulent eddies across the reversal surface show properties similar to those typically found in tokamak boundary turbulence simulations. Despite the good agreement found with experimental measurements, these simulations reveal a significant limitation of the fluid-based turbulence modeling of the edge region in reversed field pinch plasmas, which arises from the intrinsically short parallel connection length. This conclusion is also supported by a linear gyrokinetic analysis that identifies trapped electron modes as the dominant microinstability in this region.

The detailed evolution of triple star systems is complicated and poorly known. Using archived optical/infrared and $\gamma$-ray data, we identified the pulsar PSR~J0435+3233 as a $\gamma$-ray pulsar in a hierarchical triple system, with a helium white dwarf (WD) as a close inner binary companion and a Sun-like star as the distant tertiary. PSR~J0435+3233 and the WD companion are in a circular orbit with a period of $P_{\rm orb1} = 8.0$~days and an eccentricity of $e=0.00016$. The tertiary is a G-type subgiant with a mass of $0.98(12) M_\odot$ at a distance of $2.1(4)$ kpc from the Earth. By simultaneously fitting the observed spin-period variations of the $\gamma$-ray emission (over 16.7 years) and radio emission (over 4.9 years) from PSR~J0435+3233, the changes in the inner orbital parameters, the Shapiro delay, Gaia astrometry, and the outer companion mass, we determined the outer elliptical orbit for the tertiary, with a period $P_{\rm orb2} = 73.5$~yrs and an eccentricity $e_2 = 0.598$. The outer orbit is either nearly perpendicular to the inner orbit with a mutual inclination of $\sim 85^\circ$, or moderately inclined by $\sim 54^\circ$. For the former geometry, the pulsar, the WD, and the tertiary star have masses of $1.16(5) M_\odot$, $0.273(8) M_\odot$, and $0.91(5) M_\odot$, respectively; for the latter geometry, the corresponding masses are $1.34(15) M_\odot$, $0.305(23) M_\odot$, and $1.13(7) M_\odot$. This is a unique triple system for detailed multi-band observations and for studying the evolutionary path and dynamic processes of a primordial triple star system. It will ultimately evolve into a system consisting of a neutron star and two white dwarfs.

The HAL QCD method has been one of the powerful tools to extract hadron-hadron interactions directly from lattice QCD simulation data. In this paper, we aim at examining the effectiveness of the HAL QCD method by deriving a formula to calculate quantities in the HAL QCD method, such as the so-called R-correlators and HAL QCD local potentials, from the hadron-hadron scattering amplitudes within effective models. In this framework, we can judge whether the HAL QCD local potential, evaluated in the present formula, reproduces the properties of the original hadron-hadron interaction or not via the scattering amplitude, which is a solution of the Lippmann–Schwinger equation with the original hadron-hadron interaction as an input. In an analysis within a simple model of elastic scattering, we show that, when the original interaction is predominantly local, the HAL QCD local potentials quantitatively reproduce phase shifts of the hadron-hadron scatterings and correctly indicate the existence/absence of the bound state with its binding energy $\sim$ MeV. Higher-order corrections in the derivative expansion of the HAL QCD nonlocal potentials can provide a better description of the binding energies of the bound states. The lattice discretization and finite-volume effects of spacetime modify the results only slightly, as long as their scale is not comparable to the interaction range. Furthermore, we consider the $\bar{K} N$ potential in a bare to $\bar{K} N$ transition amplitude, which shows singular behavior around the origin in the recent HAL QCD results of the lattice QCD simulation data, and discuss the cause of such singular behavior in the HAL QCD method through our model analysis of the $\bar{K} N$ scattering.

The weak wall-normal pressure variation in pressure-driven rarefied Poiseuille flow is a stringent test of higher-order constitutive models: it is almost invisible in the total-pressure norm, yet it is generated by anisotropic molecular stress. A tangent-form nonlinear coupled constitutive relation (NCCR) reproduces its convex topology, but the physical reason for its quantitative success remains unresolved. We ask whether the constitutive stress relation and reduced streamwise forcing are independently accurate or whether their effects compensate. A direct simulation Monte Carlo (DSMC) campaign is analysed using two-dimensional momentum budgets, a pressure-error norm based on the transverse signal, a matched-outlet-Knudsen comparison and componentwise tests of the pre-elimination NCCR balance. The non-equilibrium wall-normal stress over-supports the measured pressure defect, while streamwise transport of shear stress supplies an opposing correction. The state map, momentum budgets and forcing diagnostics show that neither outlet Knudsen nor outlet Mach number alone organises the pressure amplitude; along the fixed-ratio sequence, rarefaction is accompanied by larger changes in the constitutive diagnostics than in pressure amplitude. The DSMC-inferred stress relation departs from the fixed reduced coefficient, and even the best common scalar closes the dominant shear component far more accurately than the normal components that carry the pressure field. Correcting the coefficient alone can therefore worsen the reconstruction, whereas restoring omitted streamwise-momentum terms reduces the amplitude bias in strongly accelerated cases. The reduced law can remain accurate through stress–momentum compensation, showing that agreement of a weak non-equilibrium observable need not imply correct internal closure mechanics.

Curl forces are position-dependent, non-conservative, and non-dissipative forces that, in general, cannot be derived from an ordinary potential energy. Consequently, their equations of motion do not, in general, follow from a standard variational principle. In this paper, we present a dual variational formulation for particle dynamics under curl forces. By introducing variables dual to position and velocity and an auxiliary function, we construct a pre-dual action in which the equations of motion act as constraints. Stationarity with respect to the primal variables defines a dual-to-primal mapping, whose substitution into the pre-dual action gives an action expressed entirely in terms of the dual variables. The Euler–Lagrange equations of the dual action recover both the original equations of motion and their prescribed initial conditions. We also introduce an auxiliary dual Hamiltonian that is conserved along stationary dual trajectories, although it does not represent the physical energy. The formulation is illustrated using two nonlinear curl force fields in two and three dimensions and the classical Ziegler column. These examples demonstrate that non-conservative curl-force dynamics can admit variational descriptions even in the absence of an ordinary potential energy or a conventional Lagrangian.

We introduce a density-level pivot construction for the Chevallier-Polarski-Linder (CPL) parameterization by defining the normalized dark energy density $f_p\equiv f_{\rm DE}(a_p)$ and the equation of state $\omega_p\equiv \omega(a_p)$ at an optimized pivot scale factor $a_p$. This reparameterization leaves the underlying CPL cosmology unchanged and allows the two models to be compared using parameters with a direct physical interpretation at the epoch where the data are most sensitive. Accordingly, following the DESI DR2 results, we compare a newly proposed $f_a f_b$CDM parameterization, based on a second-order Taylor expansion of the normalized dark energy density, with the standard $w_0w_a$CDM model. In particular, we constrain the original and pivoted parameterizations using compressed cosmic microwave background (CMB), DESI DR2 baryon acoustic oscillations (BAO), cosmic chronometers (CC), and Pantheon+ Type Ia supernovae data, with the SH0ES prior imposed on $H_0$. We find that applying the same density-level pivot prescription to the $w_0w_a$CDM model substantially reduces the correlation between its dark energy parameters and provides tighter and more stable constraints. The statistical comparison shows that this model remains favored over the Taylor expansion of the dark energy density, even when both models are analyzed in the optimized parameter basis. Moreover, the pivoted CPL parameterization accurately reproduces the background evolution of quintessence models, providing a reliable phenomenological approximation to the underlying dark energy dynamics, better than the $f_af_b$CDM model. We conclude that changing the parameter basis improves the performance of the $w_0w_a$CDM model, which emerges as the most suitable framework to describe the dark energy sector within the class of models considered here.

We performed a rigorous theoretical and numerical investigation into the polarization function, plasmon excitations, and plasmon damping in the Kek-$\alpha$ model, a two-dimensional material combining the key features of the $\alpha-\mathcal{T}_3$ lattice and Kekule-distorted graphene. Unlike conventional Kek-Y graphene, the Kekule modulation in the Kek-$\alpha$ model affects only one of the two sublattices, giving rise to a fundamentally new model with unusual electronic properties. The low-energy spectrum consists of two degenerate flat bands and two inequivalent Dirac cones with different Fermi velocities, referred to as the fast and slow cones. The particle-hole continuum responsible for Landau damping exhibits two distinct branches associated with transitions involving these Dirac cones. An additional particle-hole mode originates from electron transitions associated with the fast Dirac cone, appearing above the main diagonal. As the parameter $\alpha$ increases, the contribution from the fast Dirac cone becomes dominant. The additional transitions involving the flat bands and the fast Dirac cone substantially reduce the region where undamped plasmons can exist, similarly to the conventional $\alpha-\mathcal{T}_3$. Consequently, stable plasmons are observed only for relatively small values of $\alpha$ or at very small wave vectors. These unusual electronic and collective properties make the Kek-$\alpha$ model a promising platform for future plasmonic and nanoscale electronic applications.

In ordered intermetallics, slight variations in lattice site occupancy and specific interlayer spacings have been identified as the sources of significant changes in critical resolved shear stress and therefore how a given phase may affect alloy properties. So far, atom positions and lattice site occupancies have traditionally been characterised by high-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD), which are methods that offer either local detail or high statistical significance but not both. Electron backscatter diffraction (EBSD), by contrast, provides high spatial resolution across large sample areas and therefore, has the potential to enable the local investigation of interlayer spacing and site lattice occupancy with improved statistical reliability. The objectives of the study are to benchmark EBSDs capability for resolving these subtle features and to correlate them with compositional and mechanical properties. In this case study, we therefore show that EBSD can resolve key crystallographic features of mu-phase intermetallics, specifically interlayer spacings. We combine pattern matching with large-scale dynamical simulations of template libraries guided by XRD based information on lattice parameters. For this, we generate structures that vary in the spacing between triple-layer and Kagome layer and in the site lattice occupancy of the 3a site. This approach successfully predicts the change of interlayer spacing between Kagome and triple layers in Nb-Co and Nb-Ni mu-phases, in good agreement with XRD and HR-TEM.

Ising spin-orbit coupling in bulk systems has drawn considerable interest for its ability to conveniently construct spin-orbit environments and enable exotic quantum phenomena. In this work, we synthesize intercalated 2Hb-TaSe$_2$ bilayers with noncentrosymmetric structure and, through multifaceted analysis, present multiple lines of evidence for the emergence of bulk Ising superconductivity. Resistivity measurements reveal anisotropic superconducting behavior, with a remarkably large in-plane upper critical field $B_{c2}^{\|}$ that exceeds the Pauli limit $B_{p}$. Band structure calculations further show band splitting accompanied by out-of-plane spin polarization. Collectively, these observations point to the presence of Ising superconductivity. Additional measurements of the thickness-dependent ratio $B_{c2}^{\|}$/$B_{p}$ and the superconducting diode effect not only further support the Ising superconducting nature of this material, but also reveal additional features of bulk Ising superconductivity evolving with thickness. Our findings provide valuable insights that may contribute to the search for bulk Ising superconductors.

We investigate how thermodynamic phase transitions are reflected in the quasinormal modes (QNMs) of charged anti-de Sitter (AdS) black holes surrounded by perfect fluid dark matter (PFDM). In the extended phase space, increasing the positive PFDM parameter raises the critical temperature and pressure while reducing the critical horizon radius. We compute the fundamental QNMs of a massless scalar perturbation using a Chebyshev pseudospectral method and analyze their evolution along isobaric and isothermal processes below the critical point. The small and large black hole branches trace clearly separated QNM trajectories and display sharply different slopes near the first-order transition, providing a dynamical signature of the branch change. Along isotherms, this evolution results from the competing effects of the horizon radius and pressure, or equivalently the AdS radius, rather than from the horizon radius alone. At the critical point, however, the QNM frequencies vary smoothly with the horizon radius and show no sharp signature of the second-order transition. Along the coexistence curve, the separation between the small and large black hole QNMs decreases as the Gibbs free energy swallowtail shrinks and vanishes at criticality. These results show that PFDM shifts both the thermodynamic phase structure and the associated QNM response, while the fundamental scalar QNM spectrum remains sensitive to the first-order small/large black hole transition.

Atomic steps have strong influences on surface two-dimensional superconductors. Josephson vortices formed at the atomic steps under magnetic fields may dominate transport phenomena at low temperatures, but its experimental verification is still lacking. Here, we report the vortex transport properties of atomic-layer superconductor Si(111)-$(\sqrt{7}\times\sqrt{3})$-In with vicinal surfaces, for which Josephson vortices are directly observed by scanning tunneling microscopy. A sharp drop in resistance with decreasing temperature $T$, detected under out-of-plane magnetic field $B$, reveals a distinctive anisotropy with respect to the atomic step direction. The anisotropy of sheet resistance, proportional to that of vortex mobility, amounts to the order of $10^3$ at intermediate magnetic fields. In the high-$T$ and low-$B$ region, Josephson vortices exhibit thermally excited creep motions with anisotropic activation energy $U_\mathrm{act}$. A further increase in $B$ suppresses $U_\mathrm{act}$ toward zero anisotropically, resulting in one-dimensional pinning-free vortex flow at $0.10 \lesssim B \lesssim 0.20$ T. At the lowest temperatures, the vortex motion is governed by quantum tunneling. A $B$-$T$ phase diagram constructed based on these measurements reveals multiple regions characterized by directionally dependent vortex-transport mechanisms.

Artificial intelligence has been transformed by deep neural networks, yet the search for new learning architectures continues. Quantum machine learning offers one such direction, and hybrid quantum neural networks, which combine classical neural-network components with quantum information processing units, have emerged as a practical framework for near-term quantum technologies. However, the rapid development of the field across diverse architectures, benchmarks and hardware assumptions makes it difficult to assess the utility of various proposals, identify where genuine advantages may arise, and determine how practitioners can use these models. While recent benchmarks caution that such gains have not yet been demonstrated at scale, theoretical work has identified tasks on which quantum models hold provable advantages, and hybrid approaches have delivered promising results on practical problems using deliberately compact quantum components and substantially fewer trainable parameters. Here, we review hybrid quantum neural networks for the machine-learning and quantum-machine-learning communities. We summarize their main theoretical and methodological foundations, survey some of the most promising architectures developed so far, and examine their implementation challenges and reported performance. By consolidating these perspectives, this review provides a structured view of the state of the field and helps identify promising paths for future research and application-driven development.

Short-range nucleon-nucleon correlations are a defining feature of the nuclear many-body wave function, yet they are invisible in the one-body density and therefore inaccessible to observables that measure a nuclear size. We show that proton-proton femtoscopy supplies the missing sub-femtometer sensitivity. In $^{16}$O+$^{16}$O collisions at $\rm \sqrt{s_{NN}}=$ 200 GeV, we compare three nuclear-structure inputs spanning mean-field, low-resolution cluster, and short-range-correlated descriptions. The $p$-$p$ correlation function separates all three, most sharply in peripheral collisions, where the ab initio input suppresses the extracted source radius by $\sim5\%$ relative to the mean-field baseline. Under identical conditions $\pi^{+}$-$\pi^{+}$ correlations respond an order of magnitude more weakly, and the $C_{pp}/C_{\pi^{+}\pi^{+}}$ double ratio retains the full effect, pointing to the short-distance weighting of the $^{1}S_{0}$ pair rather than to an overall rescaling of the source. The signal survives the leading theoretical systematic, the choice of strong-interaction potential, which we quantify explicitly. These results identify $p$-$p$ femtoscopy as a short-distance-resolved probe of light-nucleus structure, complementary to flow observables that constrain only the low-order moments of the initial geometry.

We investigate how peer and institutional incentives jointly shape the evolution of cooperation, social welfare, and enforcement efficiency in social dilemmas. In a Prisoners Dilemma with four strategies, unconditional cooperators (C), defectors (D), social punishers (SP), and social rewarders (SR), we allow decentralised peer incentives and centralised institutional incentives to act simultaneously, with the institution able to reward or punish any subset of strategies. In infinite well-mixed populations, we analyse the resulting four-strategy replicator dynamics, and in structured populations we use agent-based simulations on square lattices to study spatial effects and network reciprocity. Intervention schemes are evaluated by equilibrium states and evolutionary flow for infinite well-mixed populations, by cooperation levels and social welfare for structured populations, defined as aggregate population payoff net of institutional cost. We find that peer punishment most strongly promotes cooperation, whereas peer reward is more beneficial for social welfare. Institutionally rewarding peer incentive strategies substantially improves both cooperation and welfare, while subsidising unconditional cooperators has little impact. Under institutional punishment, directly penalising defectors is the only consistently effective policy; punishing peer incentive strategies dismantles decentralised incentives, reduces cooperation, and harms social welfare, showing that maximising cooperation does not necessarily optimise overall societal benefit. Our findings provide design principles for institutions seeking to balance cooperation promotion with welfare maximisation.

Time-periodic modulation introduces a synthetic degree of freedom to manipulate topological phases. This synthetic dimension can trigger a phase transition that localizes a boundary state at the temporal interface. Noise is widely deemed a fundamental threat to topological protection, universally anticipated to weaken or even destroy topological states. Here, we introduce periodically repeated temporal noise and fully random temporal noise into a 2D periodically driven non-Hermitian system. Paradoxically, under ensemble averaging, such temporal noise drives an exponential enhancement of the response intensity at the temporal interface. An averaged superoperator analysis shows that the noiseless band structure is preserved under both types of noise. Yet the noise increases the growth rate of growing modes while suppressing the decay rate of decaying ones. Finally, we experimentally realize the noise-enhanced temporal boundary state in a robotic metamaterial network. This finding establishes temporal noise as a constructive ingredient, enabling the unambiguous emergence of topological states and conferring exceptional robustness upon topological devices.

A set of pairwise non-orthogonal quantum states cannot be perfectly discriminated, and this remains true even when one bit of classical partial information is available prior to the measurement. Contrary to the usual intuition that earlier information is at least as valuable as later information, we show that the same bit can be more useful when it arrives after the measurement. We present a framework for state discrimination in which the sender provides classical information in response to a request from the receiver, which we refer to as a query. In some cases, pairwise non-orthogonal states can be perfectly discriminated when the query is allowed to depend on the measurement outcome. We give a general method for finding the optimal strategy in this setting, which turns out to be the standard minimum-error discrimination problem for an auxiliary ensemble.

Electromagnetic cascades initiated by TeV gamma rays from distant blazars provide one of the cleanest indirect probes of the intergalactic medium and, in particular, of intergalactic magnetic fields. However, their interpretation is not completely clear because of an open theoretical question: the extent to which the electron-positron beams generated in the cascade can lose energy through collective plasma processes. If this occurs before inverse Compton scattering produces secondary gamma rays, then the cascade is quenched. Here we present grplinst, a plugin for the CRPropa framework that models plasma-instability cooling acting on electrons and positrons during propagation. We describe the implementation of several prescriptions proposed in the literature, and present illustrative examples. The code is suitable both for bracketing theoretical uncertainties and for performing systematic studies of how plasma-instability assumptions propagate into gamma-ray observables and inferred intergalactic magnetic-field constraints, which is essential for interpreting current and forthcoming observations by high-energy gamma-ray observatories.

The tracking condition $\dot{\phi}^2=\gamma H^{-m}$ for single scalar field theory leads to analytic inflationary solutions, which are compatible with the current cosmic microwave background radiation experiments. To our knowledge this is the only analytic solution of inflation which is compatible with the data, to date. In this work we seek for some theoretical basis that can lead to the tracking condition $\dot{\phi}^2=\gamma H^{-m}$. As we show, if the Universe is seen pre-inflationary as a quantum statistical system, the scalar field may emerge as a collective condensate of the quantum degrees of freedom. In the quantum-to-classical transition of the Universe, the scalar field two point function yields the susceptibility of the theory with an inherent correlation length. Using information theoretic motivation and Wilsonian quantum field theoretic arguments, we demonstrate that the tracking conditions $\dot{\phi}^2=\gamma H^{-m}$ emerge from this framework.

Reverberation mapping of active galactic nuclei provides one of the most direct probes of the geometry and kinematics of the broad-line region by measuring time delays between continuum and line variability. Modern RM surveys frequently suffer difficulties with lag measurements due to poor signal to noise and aliasing, whereby multimodal lag posterior distributions arise due to seasonal gaps in our data. These challenge the reliability of commonly used fitting tools such as JAVELIN, which can return a high rate of false positives. We implement a new lag measurement package, LITMUS, and introduce a new framework that uses Bayesian evidence to identify false positive lag measurements, as well as examine the question of how many AGN present detectable lags in high redshift industrial scale surveys like OzDES and SDSS. Our analysis differs from previous RM studies in six key respects: (i) our inference is robust to the previously under-diagnosed numerical component of aliasing, (ii) we use a consistent methodology for all sources, (iii) uncertainty in the underlying AGN variability is fully marginalised, (iv) lag significance is assessed via Bayesian model comparison rather than heuristic metrics, (v) false-positive rates are quantified by comparison against random-chance recoveries and (vi) we use marginal likelihoods to distinguish between sources where a lag is not detectable in our data and sources that show no evidence of reverberation. Applied to the OzDES sample, we find that previous RM studies are likely to have overestimated the confidence of recovered lags, and we find a stark contrast between a low reverberation percentage for the MgII line (3-28% depending on assumptions) and much higher percentages in the CIV and especially the H$\beta$ line, which is consistent with 100%. We also present a re-analysed set of lags from the OzDES sample with better quantified reliabilities

Over the past decade, Machine Learning Interatomic Potentials (MLIPs) have emerged as a powerful technique for performing molecular dynamics (MD) simulations with nearly ab initio accuracy. Alongside the development of new descriptors and advanced machine learning architectures, sophisticated procedures for the generation of diverse and accurate reference datasets have been established. To date, research has focused primarily on MLIPs for crystalline or amorphous inorganic and small molecular systems; however, large macromolecules such as polymers remain underrepresented in the literature, despite beeing an important class of materials. In this work, we investigate several aspects of developing MLIPs for polymers, utilizing polyethylene as a representative, yet simple model system. First, we compare various local atomic descriptors, identifying the Atomic Cluster Expansion (ACE) as the most effective for this application. Second, we implement and automatized active learning scheme to efficiently generate diverse training data and demonstrate that ACE potentials fitted on small oligomers are transferable to larger polymers. Given that the accurate reproduction of the density depends critically on a correct description of intermolecular interactions, which are far more complex to learn than intramolecular interactions, we carefully evaluate the performance of the ACE potentials with respect to non-bonded interactions. By utilizing the computationally efficient OPLS-AA force field as a ground truth reference, we are able to perform a direct comparison of nanosecond-scale MD trajectories resulting from the ACE and reference potential. We find that the ACE potential accurately reproduces key thermodynamic, structural and dynamical properties.

One-way spatial marching methods separate upstream- from downstream-propagating disturbances using a rational approximation of a spectral projector. Among existing one-way Navier–Stokes (OWNS) formulations, the recursive variant, OWNS-R, is the most economical, evaluating the approximation as a product of $N$ resolvent factors. This product amplifies rounding errors multiplicatively, imposing a flow-dependent upper limit on the approximation order that cannot be known in advance. We reformulate the same approximation as an additive partial-fraction sum (OWNS-Summation, OWNS-S). In exact arithmetic, the recursive and summation evaluations are equivalent when supplied with identical weights and poles; in floating-point arithmetic, they are not. Each of the $N$ resolvent solves acts on the same input state and contributes independently to a weighted sum, preventing multiplicative error amplification. The approximation order $N$ therefore becomes a pure convergence parameter, and the solves can run in parallel. Using the same auxiliary poles as OWNS-R, OWNS-S remains accurate in every configuration tested, showing that the recursive evaluation, rather than the poles, is the dominant source of instability. A paired greedy parameter-selection procedure is also introduced, with candidates drawn from analytic estimates of the upstream and downstream spectral regions, avoiding eigen-decomposition during the numerical march. OWNS-S is validated on incompressible, hypersonic and transonic boundary layers. In the transonic case, the disturbance spectrum reorganises from a subsonic to a supersonic topology during the march. The one-way computation proceeds continuously through this transition at a streamwise resolution unattainable by the parabolised stability equations.

We test whether bare codimension-two areas in the D7-brane open string metric (OSM) reproduce the leading probe-brane contribution to boundary entanglement entropy in the massless finite-density D3-D7 system at zero temperature. The established Chang-Karch-Uhlemann benchmark contains shape-dependent volume terms in a controlled probe regime. By contrast, the connected strip family terminates at a maximal width and the selected strip finite part saturates at the disconnected-reference value, while the lower-area spherical branch is area-like rather than volume-like at large radius. The OSM construction nevertheless detects the density-induced crossover scale, and its geometric landmarks occur at order-one multiples of a pole-defined longitudinal response length. A low-temperature regulator shows that no density-controlled horizon-volume term survives the zero-temperature limit. Bare OSM areas therefore diagnose open-sector crossover physics but do not, in general, compute flavour entanglement entropy.

Using the thermodynamic approach introduced in e-Print: 2206.09124 [hep-th] to the case of Kerr-NUT solution, we demonstrate the existence of a new conserved quantity that is dual to the angular momentum, in the same way that the nut charge "n" is dual to the mass "m". This quantity exists regardless of the presence of the Kerr rotation parameter $a$, but only affects its thermodynamics when $a\neq 0$. The thermodynamic quantities calculated together with the two charges $N_{c}=cn$ and $N_{n}=n$ lead to consistent thermodynamic relations. That is, the first law, Smarr's and Gibbs-Duhem relations are all satisfied.

Efficient preparation of Dicke states and, more generally, permutation-symmetric states is important for quantum metrology, quantum networking, and collective quantum information processing. Measurements and classical feedforward enable low-depth preparations of these states, with a cost of ancillary qubits. In this work, we introduce an exact constant-depth adaptive preparation protocol for arbitrary Dicke-$(n,k)$ states and further symmetric states. We first provide a protocol preparing the uniform subset superposition state, as a primitive, using constant-depth adaptive circuit with $O(k^2\log^2 n)$ ancillary qubits and success probability at least $1/k$. This yields an exact, probabilistic, constant-depth Dicke-state preparation protocol using $O\left(n^2+k^2\log^2 n+kn\log n\log\log n\right)$ ancillary qubits. Parallel repetition suppresses the failure probability exponentially without increasing the quantum depth. Moreover, the uniform subset superposition state is also of independent interest as the uniform vertex state of the Johnson graph and as the compact uniform subset state appearing in quantum-walk and topological-data-analysis algorithms. We further establish a general lifting framework that coherently combines clean unitary Dicke-state preparation circuits to prepare arbitrary symmetric states with only polynomial ancillary overhead. Combined with recent constant-depth unitary Dicke-state constructions, this gives an exact constant-depth preparation protocol for arbitrary $n$-qubit symmetric states using $O(n^3\sqrt{\log n})$ ancillary qubits.

Foldable proteins exhibit funnel-like energy landscapes, but their evolution under selection for function remains unclear. We study this in a lattice protein model, defining fitness as the equilibrium probability of a fixed active-site motif and using multicanonical sequence sampling. At intermediate temperature, rare high-fitness sequences show funnel-like energy and double-well free-energy landscapes. At very low temperature, abundant high-fitness sequences retain glass-like landscapes. Thus, thermal fluctuations turn a local functional requirement into a global structural constraint.

We combine three-dimensional intrinsic densities from ab initio nuclear lattice effective field theory with a deformed Glauber model to study high-energy reactions of {7-12}Be. To connect the correlated many-body configurations to the core-plus-neutron reaction formalism without imposing a single-particle orbital, we introduce a configuration-resolved prescription that identifies the spatially outermost valence neutron after the two-cluster decomposition. For Be projectiles on 12C and 9Be targets at 790 MeV/A, explicit orientation averaging lowers the calculated reaction cross section of 11Be by up to approximately 50 mb relative to a calculation with the spherically averaged density. The deformed calculation reproduces the pronounced increase from 10Be to the established one-neutron halo nucleus 11Be for both targets. We further calculate the momentum distribution of the fragments after the one-neutron removal reaction of 11Be + 9Be , finding good agreement in shape with the measurement at 63 MeV/A and providing a prediction at 790 MeV/A. These results quantify how intrinsic deformation and weak binding are transmitted from microscopic many-body densities to reaction observables.

We develop a constructive framework for the three-point higher spin conformal correlation function, originally introduced in our previous work, and apply it as the foundation for constructing the quantum effective action of the corresponding higher spin conformal gauge theory. Employing a symmetric refinement of the earlier construction, we analyze the principal singularity of the three-point function and the associated effective action. This leads to a general method for extracting the dominant singularity and investigating the anomalous local contributions to the effective action.

Quantum relative entropies play a fundamental role in quantum information theory. In the classical setting, Rényi relative entropies constitute, up to linear combinations, the most general class of relative entropies, naturally motivating the search for their minimal and maximal quantum extensions. The minimal extension is known to be the reverse sandwiched Rényi relative entropy for $\alpha\in[0,1/2)$ and the sandwiched Rényi relative entropy for $\alpha\geq 1/2$. In contrast, the maximal extension had previously been identified only for $\alpha\in[0,2]$, where it is given by the geometric Rényi relative entropy. In this work, we complete this characterization by proving that for $\alpha>2$, the maximal extension is given by the $\alpha$-$z$ Rényi relative entropy with $z=\alpha-1$. As an application, we determine when an energy-incoherent state can be transformed into an energy-coherent state by a Gibbs-preserving operation assisted by an uncorrelated catalyst, thereby fully characterizing the coherence-generating power of this class of operations in the catalytic setting.