Papers

Single-particle cryo-electron microscopy (cryo-EM) pose estimation is traditionally solved anew for each dataset, where iterative refinement is done from scratch while the estimator learns to store the molecule in its weights. In this work, we show that pose inference is a generalizable, specimen-agnostic operation when conditioned explicitly on a reference volume. We introduce ARCHER, an amortized contrastive classifier that models the pose posterior over a discrete rotation grid. Trained across a variety of protein structures, it operates zero-shot without retraining per structure. This transferability is grounded in Fourier-space information mechanics, where all specimen dependence is captured by the reference structure's power spectrum and spatial extent. ARCHER achieves a median angular error of 5.0{\deg} on 100 held-out test structures and 2.5{\deg} on experimental particles, matching dedicated estimators within 0.16 Å in 3D reconstruction. Crucially, downstream conformational signal is preserved. The leading conformational coordinate correlates at 0.97 with deposited benchmarks, faithfully reconstructing free-energy basins and mobile domains. These results overall demonstrate that cryo-EM pose estimation can be generalized across different structures.

Coherent radio emission is observed from compact astrophysical objects with relatively weak magnetic fields, including millisecond pulsars and white dwarfs, the latter being proposed as possible sources of long-period radio transients. In such environments, the standard pair discharge mechanism—driven by curvature radiation and one-photon pair production—can fail because the low magnetic field strength suppresses photon conversion. We analyze a discharge mechanism that operates efficiently in weak-field magnetospheres, including two-vertex quantum electrodynamic processes: inverse Compton up-scattering of background photons followed by either two-photon or one-photon pair creation depending on the seed photon temperature. Using first-principles radiative particle-in-cell simulations incorporating exact QED cross sections, we demonstrate that these mechanisms robustly generate pair cascades in millisecond-pulsar magnetospheres and in hot white-dwarf environments. The resulting system exhibits limit-cycle behavior and generates electromagnetic field fluctuations capable of producing coherent radio emission, providing a natural explanation for radio activity in low-field compact objects.

We derive an exact and novel expression for an averaged two-point correlation function in the statistically stationary, forced-dissipative two-dimensional Navier-Stokes equations subject to the Coriolis force under the beta-plane approximation. This identity is related to the so-called geostrophic balance: it connects the effect of the Coriolis force to the pressure gradient through a two-point correlation function. Additionally, we provide sufficient conditions under which the asymptotics of the averaged third-order structure function at large spatial scales follow the universal third-order law of two-dimensional turbulence in the absence of the Coriolis force. This complements our previous results on small spatial scales. Together, our results provide a clear picture of the role of the Coriolis force in beta-plane turbulence. On the one hand, the spherically averaged rates of enstrophy and energy transfer are not affected by the Coriolis force. On the other hand, the Coriolis force contributes to anisotropic large-scale organization by altering the spatial distribution of energy and promoting the formation of zonal structures. The proof relies on a new formulation of the Karman-Howarth-Monin relation. For the geostrophic balance, we use a novel antisymmetric projection of the KHM relation under which only the pressure and Coriolis terms survive. For the cascade laws, we show that the Coriolis contribution to the averaged classical KHM relation vanishes identically at any scale.

We extend the finite-solid-angle general relativistic radiation transport method of C. J. White et al. (2023) to time-dependent spacetimes represented in ADM form. This Valencia-type solver retains the angular transport and local implicit matter coupling of the original HARM-type solver, but replaces its time-independent Kerr–Schild tetrad and conserved-variable normalization with an Eulerian formulation. A Cholesky-gauge spatial tetrad makes the frame and its derivatives algebraic functions of the ADM variables, providing smooth, metric-compatible angular transport. The resulting transport system couples directly to an evolving spacetime, agnostic to the gauge evolution equations. Our test suite, including flat and curved beams, radiation–fluid coupling, and time-dependent geometries, establishes the accuracy and robustness of this approach. We further apply the Valencia-type solver to a radiative circumbinary disk, illustrating its potential for multi-messenger studies of dynamical strongly gravitating systems.

Universal quantum computation requires non-Clifford gates, which stabilizer codes can provide transversally only up to a finite level of the Clifford hierarchy. Non-stabilizer codes are not subject to this bound and are the natural candidates to fill the gap. However, it is difficult to efficiently evaluate the nonstabilizerness (or magic) of non-stabilizer codes. Here, we resolve this problem for codeword-stabilized (CWS) codes by showing that the nonstabilizerness of a CWS code is determined by the difference structure of its codewords. Whenever a Sidon set of the required size exists, the most magical codes are related to the Sidon sets, whose pairwise differences are all distinct. Structural analysis demonstrates that nonstabilizerness is invariant under coset closure, giving rise to non-stabilizer codes with arbitrarily many logical qubits and constant nonstabilizerness. Nonstabilizerness of whole code families becomes exactly computable, and we obtain closed-form values for the Kerdock codes. Moreover, we reveal a tradeoff between nonstabilizerness and transversal gates. For a code with $k$ logical qubits, a diagonal transversal gate that is non-Clifford on $t$ coordinates forces the nonstabilizerness benchmark to be at most $2(k-t)$. These results reduce the search for codes with high nonstabilizerness and for transversal non-Clifford gates to classical counting problems, to which the standard tools of additive combinatorics apply.

We present a holographic model of SU(3) color superconductivity (CSC) where a global color symmetry is spontaneously broken by a diquark condensate at finite baryon chemical potential. At $\mu_b=0$, a systematic stability analysis over all SU(3) channels recovers the known SU(2) s+p competition. Based on that, the finite $\mu_b$ further generalizes the s-wave order to an S1+iS2 structure. We find that $\mu_b$ enhances the critical temperature of the S1+iS2 phase while suppressing the p-wave – the latter vanishes beyond a certain $\mu_b$ when backreaction is included. This opposite trend reshapes the phase diagram: with increasing $\mu_b$, the balanced S+ phase (S1=S2) takes over the entire color-superconducting region. Our non-Abelian framework provides a concrete holographic description of global SU(3) symmetry breaking, relevant for understanding color-superconducting phases in dense QCD and may offer new insights into the physics of neutron-star interiors.

Here, we explore component-dependent local lattice distortions in polycrystalline, equiatomic, face-centered cubic CrMnFeCoNi high-entropy alloys and their modifications induced by dilute interstitial carbon. Multi-edge extended X-ray absorption fine structure spectroscopy combined with reverse Monte Carlo analysis reveals that the Cr component experiences the most substantial local distortions, independent of the temperature of prolonged annealing treatments (993 K or 1373 K) and the nominal carbon content (0 to 0.8 at.%). The static disorder around Cr atoms was found to increase markedly and monotonically upon carbon alloying, whereas Mn, Fe, Co, and Ni demonstrate weaker and non-monotonic tendencies. The carbon-induced lattice distortions extend over several coordination shells, indicating the pronounced effect of the carbon presence on the local environment around Cr absorbers. First-principles density functional theory and finite-temperature molecular dynamics simulations confirm the greater impact of carbon on the local lattice distortions around Cr than around the other $3d$ constituent elements, based on the previous finding that carbon preferentially occupies Cr-rich interstitial sites. These results provide decisive hints towards the atomistic origin of the non-monotonic diffusion behavior previously reported for carbon-doped CrMnFeCoNi alloys, and are noticeable for understanding the carbon-induced phase transitions in compositionally complex systems.

Conventional simulation of current-driven magnetization relies on fine-step integration of the spin-transfer-torque Landau–Lifshitz–Gilbert equation, creating a computational bottleneck in parameter sweeps and control searches. In this work, we propose a physics-constrained neural flow map that learns finite-time dynamics directly on the unit sphere. The model maps the current magnetization, spin-torque strength, and requested time span to a future state in a single forward pass. Tangent-space projection and spherical retraction preserve unit magnetization during recursive, composition-consistent rollout. We validate the framework on single-spin trajectories under in-domain torques and previously unseen but stronger drive. Beyond the training horizon, it achieves an in-domain root mean square error of $0.00425$ with norm drift at the $10^{-7}$ level. The flow outperforms an adapted Long Short-Term Memory (LSTM) in in-domain accuracy and geometric stability, although the LSTM retains slightly lower out-of-distribution state error. The resulting geometry-preserving propagator reduces reliance on fine-step integration and enables physically admissible long-horizon prediction.

The $\mu$–$\tau$ reflection symmetry has attracted considerable attention owing to its prediction of a maximal atmospheric mixing angle and a Dirac CP-violating phase $\delta=3\pi/2$, consistent with indications from the T2K and NO$\nu$A experiments. Since current neutrino oscillation data exhibit small but significant deviations from the exact symmetry predictions, understanding the origin of its breaking has become an important problem. In this work, we investigate the radiative breaking of $\mu$–$\tau$ reflection symmetry within the framework of the minimal seesaw model through the renormalization group (RG) evolution of neutrino parameters. Assuming the symmetry to be exact at the flavor symmetry (seesaw) scale, we examine whether the observed low-energy neutrino oscillation data can be reproduced after RG evolution. Owing to the rank-two structure of the minimal seesaw model, one light neutrino mass eigenvalue vanishes, reducing the number of independent high-energy neutrino parameters from five to four. We perform a systematic numerical analysis to determine the allowed high-energy parameter space capable of reproducing the current experimental constraints at low energies. Furthermore, a comparative study between the conventional Type-I seesaw and the minimal seesaw frameworks is carried out by analyzing the RG evolution of the solar and atmospheric mass-squared differences.

The Stone-von Neumann theorem makes canonical quantization unique only after one imposes strong continuity of the Weyl translation groups. We show that this continuity assumption cannot be certified by any finite-resolution interrogation of the Weyl relations. A finite protocol probes only finitely many phase-space displacements and bounded expectation values, thereby determining a protocol algebra \(C_S\) generated by a finitely generated subgroup of Weyl translations, but not the regularity of an extension to the full Weyl algebra. Using the polymer representation as a canonical non-regular representation, we prove that for every regular Weyl representation, every normal state, and every finite family of bounded protocol observables, a polymer state reproduces the same expectation values to arbitrary prescribed accuracy. Thus finite agreement with Schrödinger quantum mechanics does not operationally certify the regularity hypothesis entering uniqueness. The result does not assert physical equivalence between regular and polymer quantizations, it identifies where additional input, such as Hamiltonian dynamics, energy regularity, semiclassicality, or a continuum limit, is required to distinguish or select representations. In this precise sense, non-regular polymer kinematics are not excluded by finite Weyl data alone, a point of direct relevance to quantum-gravity motivated quantizations.

Many imaging problems seek to reconstruct underlying configurations from partial observable measurements. While reconstruction algorithms operate on these measurements, the observable organization induced by the measurement process is rarely represented explicitly. We introduce TENSKEL, a combinatorial observable framework for structured measurement and reconstruction based on tensor representations defined over discrete domains. Starting from a binary latent ensemble, the framework constructs a hierarchy of tensors coupling measurement contexts to a latent Pascal organization through successive aggregation and folding operations. Each measurement context induces an observable partition of the same latent ensemble, and the resulting tensor formulation makes explicit the associated combinatorial multiplicities, shell organization, degeneracies, and induced reconstruction geometry. Rather than introducing a new reconstruction algorithm, this framework provides a mathematical representation of how latent configurations become organized under observation. The induced tensor kernel characterizes similarities between latent coordinates through their measurement-context responses, while regularized inversion provides a structured reconstruction of the latent representation from observable measurements. The binary construction further admits a natural multinomial extension to discrete simplex-supported latent representations. Connections to Pascal cellular automata and structured discrete color mappings illustrate respectively compressed and multinomial realizations of the framework. More generally, TENSKEL provides a combinatorial basis for reasoning about the organization induced by observation, with potential relevance to computational imaging, inverse problems, structured sensing, and quantum-inspired measurement formulations.

Regional climate risk assessment is critical for applications such as infrastructure design, disaster forecasting, and insurance resource allocation. However, estimating regional (i.e., high-spatial-resolution) risk with global climate models (GCMs) remains computationally prohibitive, which has driven the development of downscaling methods for coarse GCM outputs. Downscaling is vital for rare events, since quantifying their extreme properties requires high spatial resolution and very long GCM simulations. These methods non-intrusively increase GCM resolution while correcting statistical biases from unresolved fine-scale processes, thereby improving the accuracy of extreme event statistics with long return periods. A key challenge is preserving dynamical consistency, as freely evolving GCM trajectories are not expected to track the observational dataset used for training the correction operator. This is critical for causal extreme event analyses, where storyline-based risk assessment, i.e., extreme event catalogs, is necessary for effective planning. We address this challenge by introducing Dynamically and Statistically Consistent downscaling (DySCo), a non-intrusive framework yielding high-resolution climate projections consistent with coarse GCM dynamics. DySCo relies on a data-driven reformulation of nudging to create dynamically paired training trajectories without intrusive GCM modifications. Using these paired trajectories, we train a dynamically and statistically consistent, two-stage operator. We evaluate the method by downscaling the Community Earth System Model v2 Large Ensemble (LENS2) in time and space towards historical reanalysis. Results show DySCo achieves superior dynamical consistency with the coarse GCM trajectories, essentially applying a minimal, causal correction to the GCM, preserving top statistical performance comparable to state-of-the-art unsupervised models.

I provide a detailed exposition of the fundamental group calculations in the “reverse engineering" construction of an exotic $\CP ^2\#3\overline{\CP }^2$ and of an exotic $\CP ^2\#2\overline{\CP }^2$.

Previously, the QCD phase transition at finite isospin density and magnetic field was explored within the two-flavor Nambu–Jona-Lasinio model. This work extends the study to the more realistic three-flavor case, where not only strange quark contributions but also quark mass splitting in a strong magnetic field are fully taken into account. Adopting the Ginzburg-Landau approximation and the Landau representation for fermion propagators, we re-explore the transitions from the normal chiral symmetry breaking phase to pion superfluidity or rho superconductivity. Unlike the previous study, we project the mesonic fields onto the eigenstates of a charged point particle in a magnetic field and prove that the corresponding self-energies from quark loops are gauge invariant and degenerate with respect to the extra transverse degrees of freedom. However, the numerical results are qualitatively consistent with previous findings: as the isospin chemical potential increases, pion superfluidity is favored at small magnetic fields, while rho superconductivity is favored at large magnetic fields. In the three-flavor model, since the lowest energy of the rho meson increases with stronger magnetic field, the corresponding critical isospin chemical potential also increases with the magnetic field.

We present a kinetic Monte Carlo (KMC) modeling approach to describe the stochastic dynamics of a peptide molecule spanning nanosecond to second timescales. The dynamics of protein conformational changes is interpreted at a local level in terms of dihedral transitions. Taking Trp-cage miniprotein as an example, the KMC model "learns" about the transitions from multiple MD trajectories. Training is based on local divide-and-conquer strategy that identifies the discretized backbone dihedral states as building blocks for the conformational space, along with associated transition rates of dihedral flips to describe the conformational state-to-state dynamics. A key feature in our approach is the incorporation of backbone correlations, such that rates are conditioned on the local environment and steric coupling. We show that with the correlations built-in, the KMC model closely matches MD. Such an approach is shown to reach second timescales in a few CPU hours on a standard desktop computer, and can easily yield multiple stochastic realizations of the conformational dynamics. Our KMC model construction scheme should be generally applicable to a wide range of proteins, and can be used for bridging local flexibility to protein-wide dynamics.

Microscopic two-level system (TLS) defects remain a primary mechanism of decoherence and operational instability in superconducting transmon qubits, necessitating scalable and automated methods for their characterization. Here, we present and benchmark two complementary analysis pipelines for extracting TLS statistics directly from time-resolved SWAP spectroscopy: one-dimensional decay-rate fitting (1D-DRF), which detects defects via localized enhancements in the qubit relaxation rate, and a deterministic, non-parametric computer-vision framework (2D-CV) that achieves two-dimensional spectral localization by exploiting the temporal persistence of coherent population suppression. We deploy both methods on SWAP spectroscopy measurements from 52 flux-tunable transmon qubits on Rigetti processors with and without moderate ($\sim 10\%$) post-fabrication frequency trimming via Alternating-Bias Assisted Annealing (ABAA). We show that both pipelines converge on a consistent global characterization of the defect landscape while exhibiting complementary sensitivity across distinct coupling regimes. Crucially, both methods independently reveal a count–loss decoupling under moderate annealing: while the total detectable TLS defect density remains statistically unchanged, the span-integrated dielectric loss is reduced by approximately a factor of two, demonstrating selective suppression of the most strongly dissipative defect channels. These results establish an automated, non-parametric analysis framework for high-throughput hardware diagnostics and provide a statistical baseline for post-fabrication defect engineering in large-scale superconducting quantum processors.

Fully hadronic $t\bar t$ events carry the largest branching fraction and provide the down-type quark as a near-maximal spin analyzer ($\beta_d\simeq1$), yet they are rarely used for spin-correlation and entanglement studies because the down-type jets must be extracted from a difficult jet-to-parton reconstruction in the presence of a large QCD multijet background. We develop a two-stage machine-learning reconstruction for this channel: a GNN+Transformer network assigns all reconstructed jets into a legal six-jet top-pair candidate, and a second hybrid classifier resolves the four down/up hypotheses inside the two hadronic $W$ decays. The second stage combines an assignment scorer with an auxiliary conditional diffusion head; we find that the diffusion assignment score can rank hypotheses only when trained with a margin ranking objective, while standard denoising objectives leave it at the random baseline, and the two objectives are largely decoupled. We evaluate the method against a calibrated QCD background and an unmatched $t\bar t$ component using both reconstruction and spin observables. Compared with a ST1 only benchmark with random down/up labels, the learned ST2 classifier improves both the effective spin-analysis factor and the purity-weighted six-parton exact fraction at fixed event selection. A direct check of the standard spin-correlation coefficient $D$ further gives an ML-reconstructed value compatible with the truth-level value within the resampled spread. These results show that down/up identification can retain useful spin-correlation information in the all-hadronic channel.

To investigate the initial conditions of high-mass star-forming regions, we use SiO (2-1) emission to trace early shock-related kinematics toward sixteen 70 $\mu$m-dark and massive clumps with luminosity-to-mass ratios ($L/M$) $< 1\,L_{\odot}/M_{\odot}$, as part of the Multiwavelength Line-Imaging Survey of the 70 $\mu$m-dark and bright clouds (MIAO) project. Using ALMA observations at a spatial resolution of $\sim$0.06 pc and a velocity resolution of 0.21 km s$^{-1}$, we identify a total of thirty-seven outflows with a variety of morphologies. Outflow parameters were derived by integrating the HCO$^+$ (1-0) line wings, excluding the quiescent dense core component traced by H$^{13}$CO$^+$ (1-0). We find that outflow masses and velocities show moderate positive correlations with the masses of their driving cores. Owing to the high sensitivity of our observations, which yield longer projected outflow lengths compared to previous studies, the derived outflow dynamical ages span $\sim10^{3}$-$10^{5}$ yr. We detect six narrow-linewidth (0.6-1.4 km s$^{-1}$) and three broad ($>$ 2 km s$^{-1}$) SiO (2-1) features not associated with outflows driven by clearly identified protostars. Lacking coincident 3 mm dust continuum cores, their origins may be young outflows from undetected low-mass protostars, dissipating shocks, cloud-cloud collisions, or projection effects when the outflows lie close to the plane of the sky. The detection of these shocks and outflows in such extremely young environments demonstrates that protostellar activity has already begun.

The nudged elastic band (NEB) method is a widely used algorithm for determining minimum energy paths and transition states in chemical reactions and phase transitions. In this work, we present the implementation of different NEB algorithm schemes in the CRYSTAL code, a quantum mechanical ab initio program for the calculation of electronic properties of condensed matter systems, based on Hartree-Fock and density functional theory. The use of a set of localized Gaussian-type functions to expand the wavefunction permits a very efficient evaluation of the exact exchange series for the hybrid exchange-correlation functionals. Therefore, our implementation allows an accurate characterization of transition states in both molecular and condensed phase systems, at the hybrid functional level of theory. The theoretical framework, including the force projection scheme, tangent estimation, optimization strategies, as well as the extensions of the method with climbing image and variable spring constant variants, is recalled. Then, the NEB algorithm is validated through a series of benchmark tests: two molecular reactions (a collinear proton transfer process and the keto-enol tautomerization in formamide) and a proton exchange process in a periodic chabazite zeolite. Our results are in excellent agreement with experimental and previous theoretical data, confirming the accuracy and applicability of the implementation. This work opens the possibility for future studies of complex reactive processes on extended periodic systems, using hybrid functionals.

Simulations of physical systems require high-fidelity models to accurately represent reality. Simple models may be analytically tractable, but may not be sufficiently representative of reality for the given application. The cost of this simplicity is accuracy, or in the case of quantum key distribution, provable security. Sources of this accuracy gap include the difficulty of modelling physical effects which do not lend themselves well to analytical descriptions, such as afterpulsing. Here, we introduce a novel Monte Carlo based photon emission, transmission, and detection simulator, designed in the context of the Quantum Encryption and Science Satellite (QEYSSat) mission. Within this simulator, every major physical effect a photon may experience during an experiment, from emission to detection, can be accounted for in a probabilistic manner. This methodology allows for the inclusion of experimental parameters which are relevant for a satellite mission, and their impacts on secure key lengths. This simulator serves as a comprehensive baseline to predict and validate experimental data for the upcoming QEYSSat mission.

We study the $D^{+} \rightarrow \bar{K}^{0} \pi^{+} \pi^{0} \pi^{0}$ reaction, which shows two clear structures: the $\bar{K}^{*0}$ and $\rho^{+}$ in the $\bar{K}^{0} \pi^{0}$ and $\pi^{+} \pi^{0}$ mass distributions, respectively. The study is done starting from the quark level with external and internal emission and hadronizing a pair of quarks to produce a vector and two pseudoscalars. We also consider another mechanism, which does not require hadronization of quark pairs: the direct production of $\bar{K}^{*0}$ and $\rho^{+}$. With the help of six unknown parameters which are fitted to the data, we are able to get a very good agreement with experimental data for the $\bar{K}^{0} \pi^{0}$ and $\pi^{+} \pi^{0}$ mass distributions and a qualitative one for the rest of mass distributions which do not show any particular structure experimentally.

In this work we explore the imprints of self-interacting dark matter (SIDM) on the structure of simulated galaxy groups and clusters in view of future optical surveys. We find that both baryonic and projection effects lead to a significant alleviation of the SIDM core-forming behavior on the mass and density profiles, resulting in very small ($\lesssim 5\%$) deviations from standard collisionless dark matter. The opposite trend emerges for our most massive halos, where SIDM tends to significantly enhance the central density instead; we compare those halos with the observed dark matter profiles of two galaxy clusters, MACS J1206 and Abell S1063, finding that SIDM may leave potentially detectable imprints on cluster cores when considering the small observational uncertainty of current kinematic mass measurements. Finally, we find that weak lensing observations provide a promising tool for testing SIDM on cluster scales: in an idealized scenario where systematics are under control, weak lensing shear profiles exhibit up to $\sim 20\%$ level deviations for $M_{200} \gtrsim 10^{13}\ \text{M}_\odot$ halos. Conversely, the projected concentration-mass relation is only slightly modified by our SIDM models. We also discuss the limitiations of our analysis and the impact of the simulation resolution, as well as possible extension of this work. Overall, our results provide a baseline for future SIDM studies: although line-of-sight projection and baryonic effects significantly reduce SIDM imprints on halo mass profiles, weak lensing and kinematic analyses in galaxy clusters may potentially allow for robust detection and constraining of dark matter self-interactions in massive structures from megaparsec down to kiloparsec scales.

Polar molecules trapped in optical tweezer arrays offer a promising platform for quantum information processing, providing precise control and long-range interactions that enable high-fidelity gate operations. We investigate quantum error correction in this system and show the influence of underlying physical noise. A mapping is constructed from a molecular tweezer array onto a rotated surface code in which a single specification of the array, namely, which code qubits share a molecule and where those molecules are located, determines both the correlated erasure structure and the dipolar exchange graph. We compare molecular encodings with rotational qudit dimensions (D), two and four under heralded molecular loss, coherent dipolar exchange, and imperfect heralding. It is found that a D= 4 encoding with spatially dispersed pairing exhibits a finite distance crossing at approximately the same per molecule loss rate as D= 2, while using 48-49 % fewer molecules, at the cost of a 6-10 % increase in sub-threshold logical error. Fixing the encoding and varying only the spatial embedding produces substantially larger effects: pairing the two co-located qubits along a lattice direction yields a logical-sector asymmetry of approximately fifty times. Over the simulated distances (d = 5, 7, 9), the disfavoured sector shows little or no suppression of logical error with increasing code distance, whereas the favoured sector improves by a factor of 1.5-2.3. We also find that Pauli twirl of the exchange interaction overestimates the logical error rate, which we attribute to the excitation-conserving structure of the interaction. These results reveal that the spatial embedding of correlated loss units is an important design parameter for molecular architectures and that single-sector benchmarks may be insufficient when correlated loss has directional structure.

Hilbert-space ergodicity (HSE) provides a new framework for studying thermalization in driven quantum systems, complementing the eigenstate thermalization hypothesis, which is restricted to static systems. This ergodicity is hierarchical: by quantifying how randomly the dynamics explores the Hilbert space, one obtains a family of levels termed $k$-HSE. While HSE has been observed at the lowest and highest levels, finite-order HSE dynamics remains largely unexplored due to the difficulty of constructing such drives. Here, we explore this intermediate regime and uncover its distinctive physics. We first propose and prove that a family of $m$-tone drives on qubits realizes $k$-HSE up to $k = 2m{-}3$, with drive parameters determined at $O(k)$ cost. Using a single nitrogen-vacancy center in diamond, we verify this design by showing that a 3-tone drive realizes 3-HSE, with fourth-order statistics depending on the initial state. Further in-depth theoretical analysis shows that this initial-state dependence is generic across drives, demonstrating the possibility of recovering the initial state from higher-order statistics even when the dynamics is ergodic. Our work broadens the study of quantum ergodicity and reveals intriguing physics within its hierarchy.

Kaon decays provide important constraints on the axion-like particle (ALP), particularly through the $K\to\pi a$ processes. In this work, we compute the $K\to\pi a$ decay amplitudes, as well as the $K\to\pi\pi$ decay amplitudes, at leading order within U(3) chiral perturbation theory. The $\pi\pi$ final-state interaction effects in both processes are implemented by employing the chiral unitarization approach. The relevant weak low-energy constants are determined by fitting to the experimental data on $K\to\pi\pi$ decays. Our numerical analysis shows that the explicit $\eta_0$ contribution to the $K\to\pi a$ amplitudes is small, whereas the new weak operator unique to the U(3) theory can give a sizable contribution. The $\pi\pi$ final-state interactions are found to be insignificant in the $K^\pm\to\pi^\pm a$ decays, but give pronounced effects in the $K^0/\bar{K}^0\to\pi^0a$ channels. Constraints on the ALP couplings are derived from the most recent NA62 upper limit on the $K^+\to\pi^+ +invisible$ decay. For completeness, we also include constraints from the KOTO search for $K_L\to\pi^0+ invisible$, the NA62 measurement of $K^+\to\pi^+\gamma\gamma$, and the NA48 measurement of $K_S\to\pi^0\gamma\gamma$.

We study the inverse adjoint problem for a perturbative bosonic outgoing map. Within the polynomial bosonic canonical-commutation-relation (CCR) algebra, we prove a constructive integrability theorem: order-by-order preservation of the CCRs is sufficient to reconstruct recursively a formal self-adjoint generator whose exponential implements the outgoing map by adjoint conjugation. At each order, the Baker–Campbell–Hausdorff contribution determined by previously reconstructed generators is subtracted from the outgoing coefficient, and the remaining homogeneous CCR conditions determine the next generator explicitly. We apply the construction to graviton scattering in the null-surface formulation (NSF), specialized to the flat solution-space sector with Minkowski metric, null generators, affine parameter, and cone measure. The NSF outgoing map preserves the Ashtekar radiative CCRs through (\delta a_3), corresponding to order (\varepsilon^2). At this order, the scalar CCR sector uniquely selects the symmetric ordering (c=1) for the nontrivial interacting kernel. The associated linear contraction, generated by the same cubic kernel, cancels the double-contraction contribution from ([\delta a_2,\delta a_2^\dagger]). The theorem then reconstructs the self-adjoint generators (\delta T_1) and (\delta T_2), providing a formal perturbative unitary implementation. The resulting canonical organization also separates the direct (2\to2) contribution into irreducible-loop, one-particle-reducible, and factorized sectors.

We consider turbulent flow in a half-space along an infinite plane. We regard it as the limit to which the motion in the viscous sublayer of turbulent near-wall flows tends as Reynolds number increases indefinitely. In addition to the no-slip condition, an averaged shear stress value is specified on the streamlined surface. A numerical solution algorithm is proposed, based on the well-known spectral method, which demonstrates that the boundary conditions on the wall along with the physically justified constraint that the velocity components do not grow exponentially at infinity uniquely determine the turbulent flow under consideration. The implementation of the algorithm will allow us to draw conclusions about the validity of the idea that the flow in the viscous and logarithmic sublayers is independent of the external parameters of turbulent near-wall flows.

There are many methods to calculate the parton distributions. In this work, we are trying to determine the unknown parameters of valence quark and gluon densities, taking into account some constraints simultaneously. For this purpose, we consider two different approaches. At first approach, a parameterized form for the valence densities are assumed. Using the constraints imposed by the Heisenberg uncertainty and maximum entropy principles and also considering the quark number and momentum sum rules, the unknown parameters of the parton distributions are determined. In second approach, we attribute a statistical distributions to quark, anti-quarks and gluon densities which are including temperature T, volume V and chemical potential, $\mu$, as thermodynamic parameters. In this case, using only the maximum entropy principle and the quark number together with momentum sum rules, the parton distributions in terms of thermodynamic parameters are extracted. The results for valence quark densities in both approaches and additionally the gluon density in second approach are in {satisfactory match} with results from some parametrization models. By evolving these densities to the desired energy scales, we are able to calculate the nucleon $xF_3$ structure function and also the ratio of valence quark densities.

We have discovered PSR J2108+5055, an extremely luminous but sporadic mode-changing rotating radio transient (RRAT), with a period of 0.495 s using the Canadian Hydrogen Intensity Mapping Experiment/Fast Radio Burst instrument (CHIME/FRB). We show that the brightest pulse from PSR J2108+5055 has a flux density of 3.1+/-1.0 kJy, corresponding to a spectral luminosity of (7.5+/-2.3)x10^23 erg s^-1 Hz^-1, assuming a dispersion-measure-derived distance of 1.6+/-0.3 kpc. We place an upper limit on the duty cycle of PSR J2108+5055 at 0.002% and measure a surface magnetic field of 5.8x10^11 G, a characteristic age of 1.2x10^7 yr, and a spindown luminosity of 2.2x10^32 erg s^-1. Using a simple model based on the Green Bank North Celestial Cap (GBNCC) survey, we place an upper limit on the number of PSR J2108+5055-like sources with similar peak flux densities in the GBNCC survey area of ~80 RRATs. We show that if PSR J2108+5055 were placed at the edge of the Local Group of galaxies, the Five-Hundred-Meter Aperture Spherical Telescope (FAST) would detect its brightest pulse. The second brightest pulse has a peak flux density of 1.5+/-0.7 kJy, and FAST would detect such a pulse out to ~1 Mpc, covering the inner Local Group, including Andromeda.

Recent DESI DR2 observations have renewed interest in extensions of the $\Lambda$CDM cosmological model, particularly through indications of a time-varying dark energy equation of state. In this work, we investigate whether such deviations may also involve interactions within the dark sector. We consider an interacting dark energy scenario in which the dark matter density evolves as $\rho_{\rm dm}\propto a^{-3+\delta}$, with the constant $\delta$ quantifying the interaction strength, and allow the dark energy equation of state to be either constant but different from $-1$, or dynamically evolving through the CPL parametrization. The models are constrained using Planck CMB data, DESI DR2 BAO measurements, and three Type Ia supernova compilations: PantheonPlus, Union3, and DES-Dovekie. For the constant equation-of-state case, the inclusion of DESI and supernova data leads to a preference for a small negative interaction parameter, with a significance above $2\sigma$. When dynamical dark energy is allowed, the evidence for interaction becomes weak, while the data favor a quintessence-like evolving dark energy component. In both scenarios, Bayesian model comparison still favors $\Lambda$CDM. Our results show that the inferred role of dark-sector interactions depends strongly on the nature of dark energy, highlighting the importance of jointly testing dark energy dynamics and interactions in the DESI era.