Papers

We investigate the equivalence of the Jordan and Einstein frames of the Brans–Dicke theory before and after relational deparametrization of the constrained Hamiltonian system. Although the two conformal formulations are equivalent at the covariant level and related by a canonical transformation on the standard ADM phase space, their equivalence after reduction with respect to an internal clock is nontrivial. Using the Brans–Dicke scalar as a relational clock, we show that the apparent discrepancy between the reduced Hamiltonians does not indicate a physical inequivalence of the two frames. Instead, it arises from a mismatch in the canonical embedding of the clock sector prior to reduction. While the scalar configuration variable is preserved under the conformal transformation, its conjugate momentum is shifted by a contribution involving the gravitational momentum trace. Consequently, relational dynamics are determined not by the clock variable $T$ alone, but by the complete canonical clock pair $(T,P_T)$. We construct a frame-adapted canonical chart in which the clock sector is consistently transformed prior to deparameterization. The resulting reduced Hamiltonian coincides with that of the Einstein frame, restoring the equivalence of the reduced relational dynamics. Our results identify the canonical clock sector as the fundamental structure governing relational evolution in Brans–Dicke theory and provide a general framework for understanding frame dependence in scalar–tensor gravity and reduced phase-space quantization.

A comprehensive study of novae in the Large Magellanic Cloud (LMC) is presented. A total of 66 nova eruptions have been reported in the LMC over the past century ($1926 \unicode{x2013} 2025$). Of these, a total of 48 eruptions from 39 unique progenitor systems (nine eruptions are recurrences of four known recurrent novae) have sufficient photometric data to permit the maximum magnitudes and rates of decline to be reliably estimated. These data confirm earlier studies showing that LMC novae are, on average, slightly more luminous and faster evolving compared with novae in the Andromeda galaxy (M31) or the Milky Way. For the first time, the nova models of Yaron et al. have been used in conjunction with the light-curve data to estimate the fundamental properties of the LMC nova population. The models suggest that LMC novae are characterized by generally higher white dwarf (WD) masses and higher expansion velocities compared with M31 novae. The higher average WD masses have resulted in a higher percentage of recurrent nova eruptions in the LMC ($\sim$20.6%) compared with that seen in M31 ($\sim$6.40%). Future observations made possible by the Vera Rubin Observatory promise to revolutionize our understanding of nova populations in the LMC and in galaxies beyond the Local Group.

Random quantum satisfiability is a natural quantum analogue of random constraint satisfaction and a basic model for frustration-free local Hamiltonians. Despite extensive work on its satisfiable and unsatisfiable regimes, the quantitative location of the random quantum \(k\)-SAT threshold has remained poorly understood, with the best general upper bounds leaving a large gap to the known lower bounds. In this paper we prove a new upper bound on the satisfiability threshold of random quantum \(k\)-SAT. Our result improves the previously known asymptotic upper bound by a factor of order \(k\), giving a bound of order \(2^k/k\). The improvement is also significant at small values of \(k\); in particular, for random quantum \(3\)-SAT we obtain a substantially smaller explicit upper bound than the one previously available. The proof combines the geometric formulation of generic quantum satisfiability with a dimension-decay analysis of the full satisfying subspace. The key input is a multiplicative Shearer-type inequality for tensor-product subspaces, which quantifies how global dimension forces nontrivial local dimension on typical sets of qubits.

Exact simulation of high-resolution NMR spectra requires block diagonalization of the spin Hamiltonian, whose dimension grows exponentially with the number of spins $N$; symmetry is the principal tool for taming this growth, yet which permutation groups can occur as the full symmetry group of a scalar-coupled spin system has lacked an exhaustive treatment. Formulating the spin system as an undirected edge-weighted complete graph, we prove an exact realizability criterion: a subgroup of $S_N$ is realizable if and only if it coincides with its symmetrized (undirected) Wielandt 2-closure. In particular, purely rotational symmetry of a single spin ring is impossible, yet chiral spin systems do exist as multi-orbit twisted stacks, and we determine the minimal spin count $\mu^{*}(C_n)$ for every cyclic group, including the counter-intuitive realizations $C_8$ and $C_9$ at $N = 12$. A sequential symmetrization algorithm, completed by an orbit-partition decomposition, yields a provably exhaustive enumeration of all realizable symmetry types up to $N = 14$: the apparently new sequence $a(N) = 1, 1, 3, 8, 11, 27, 36, 90, 131, 282, 394, 948, 1316, 2866$ with the tower law $a(N) = a(N-1) + f(N)$ - a catalogue of 6112 entries in all, organized by canonical identifiers and a structural grammar extending the Pople nomenclature. Finally, we present a hierarchical methodology for exact block diagonalization without physical approximations: factorization by the conserved total spin projection, Schur-Weyl contraction of magnetically equivalent composites, orbit-weight deduplication of the spin configurations, and isotypic projection over the representations of the factor group, with a uniform treatment of non-abelian groups and complex characters.

We develop a fully vectorial, semiclassical scattering formalism for optically levitated dipolar scatterers, expressed within the angular spectrum representation and applicable to arbitrary trapping-field configurations as well as to high–numerical-aperture focusing. Within this framework, we introduce the information radiation pattern to characterize the angular distribution of position-dependent information and use a Richards–Wolf projection of the scattered field onto the local-oscillator mode to quantify the resulting mode-matching efficiency, yielding experimentally realistic forward- and backward-detection efficiencies. As a worked example, we apply the formalism to a radially polarized trapping beam and confirm that the axial recoil heating rate is reduced relative to a conventional linearly polarized Gaussian tweezer. The theoretical framework is implemented in LevitationToolbox, an open-source Python package intended to support the design and optimization of near-Heisenberg-limited levitated optomechanical experiments.

Rotating circular cylinders are employed in a variety of engineering applications, one prominent example being Flettner rotors for wind-assisted ship propulsion. Besides optimizing the aerodynamic performance of the cylinder itself, passive flow-control devices placed in its vicinity offer additional potential for manipulating the resulting aerodynamic forces. The present work introduces a topology-based adjoint sensitivity analysis for rotating circular cylinders over a wide operating envelope covering Reynolds numbers from 1E+01 to 1E+07 and spinning ratios between 0 and 2 pi. Local sensitivity fields associated with drag, lift, and torque are derived using a porous-medium formulation and validated by dedicated forward simulations employing both distributed Darcy-type source terms and a sensitivity-informed passive flow-control structure. Particular emphasis is placed on the combined sign distribution of the drag and lift sensitivities, yielding intuitive design maps that directly identify regions where local momentum extraction simultaneously improves or deteriorates both objectives. A systematic investigation of the resulting sensitivity spectra reveals that the large-scale topology of the sensitivity fields is governed primarily by the spinning ratio, whereas the influence of the Reynolds number remains comparatively weak over large parts of the investigated operating envelope. The resulting sensitivity atlas provides practical design guidance for passive flow-control concepts and demonstrates that robust solutions may exist over moderate operating ranges.

The formation, extension, and morphology of extra-tidal stars around globular clusters depend on the internal kinematics of the host cluster and the Galactic potential. Tracing the kinematics of faint tidal tails sheds light on their formation and contribution to the Milky Way halo. NGC 7492 is an outer halo globular cluster with conflicting evidence regarding the presence of tidal tails. If present, the tails are expected to be faint and overlap on the sky with the Sagittarius stream, located at a similar heliocentric distance but with distinct kinematics. We carried out a GIRAFFE spectroscopic follow-up of ten fields covering the expected tidal tails of NGC 7492. Gaia parallaxes were used to remove foreground contaminants, while only loose proper-motion constraints were applied in the target selection. Radial velocities and metallicities were derived for more than 700 stars, from the red giant branch to the upper main sequence. Cluster and extra-tidal stars were identified from their proper motions, radial velocities, and metallicities. This population extends at least 1.8 deg from the cluster center, confirming the tidal tails previously detected only photometrically, with positions consistent with particle-spray models of the cluster disruption. The Sagittarius stream is clearly identified through its distinct proper motions, radial velocities, and more metal-rich population. Despite the low spatial density of the extra-tidal stars, their kinematic signature is clearly detected, demonstrating that the tidal tails overlap on the sky with the Sagittarius stream but are physically unrelated. This spectroscopic dataset provides a robust basis for future studies of the tails at larger angular extents and fainter magnitudes.

We solve a longstanding problem, going back at least to Rivière 1998 and open even in the physically most relevant case $n=3$, by proving a sharp curl-Sobolev inequality on $\mathbb{S}^n$ when $n\equiv 3\pmod 4$: for every $\frac{n-1}{2}$-form $\alpha$, the conformally invariant quotient satisfies (with positive denominator) \[ \frac{\Big(\int_{\mathbb{S}^n}|{\rm curl}\alpha|^{\frac{2n}{n+1}}\,{\rm dV}\Big)^{\frac{n+1}{n}}}{\int_{\mathbb{S}^n}\langle{\rm curl}\alpha,\alpha\rangle\,{\rm dV}} \ge \frac{n+1}{2}\,\omega_n^{\frac1n}. \] We also classify all extremals in terms of Killing forms. By conformal invariance, the same result holds on $\mathbb{R}^n$. We then give geometric and variational applications that settle several open conjectures in geometry and mathematical physics. First, we show that on $\mathbb{S}^n$ the round metric is the unique optimizer for the conformal invariant $\mu([g_{{\rm st}}])$. Second, we prove that the unique minimizers of the $3$-energy $\int_{\mathbb{S}^3}|{\rm d} u|^3$ in the homotopy class of the Hopf map $\pi:\mathbb{S}^3\to\mathbb{S}^2$ are exactly $\pi\circ\Phi$ with $\Phi\in{\rm Conf}^+(\mathbb{S}^3)$, confirming a conjecture of Rivière. Third, for the Faddeev-Skyrme energy $\mathcal{FS}_\rho$ on $\mathbb{S}^3$, we establish global minimality of the Hopf map in the full predicted range: for every coupling constant $\rho\le \sqrt{2}$, the unique global minimizers in its homotopy class are precisely $\pi\circ R$ with $R\in\mathrm{SO}(4)$, as expected since Ward 1999. Fourth, in the presence of Dirac zero modes on $\mathbb{S}^3$, we prove the sharp lower bound $\|{\rm curl} A\|_{3/2} \ge 3\omega_3^{\frac 2 3}$ for the magnetic field and characterize equality in terms of Killing spinors; in particular, this yields a sharp criterion for the existence of zero modes and answers a question of Frank-Loss for $n=3$.

We develop a Dirac deformation theory that interpolates between twisted Dirac geometry and Poisson geometry, and prove that this deformation is compatible with the principal structural operations of Dirac geometry: reduction along strong Dirac maps, integration to quasi-symplectic groupoids, and Morita equivalence of Lie algebroids. The fundamental example is the deformation of the Cartan–Dirac structure $L_G$ on a compact Lie group~$G$ to the Kirillov–Kostant–Souriau Poisson structure on $\mathfrak{g}^*$, and its lift to a deformation of the quasi-symplectic groupoid $D(G)\rightrightarrows G$ to the symplectic groupoid $T^*G\rightrightarrows\mathfrak{g}^*$. As applications, we obtain a uniform deformation theory recovering, as special cases, the deformation of quasi-Hamiltonian to Hamiltonian reduction along conjugacy classes, the Steinberg and Sevostyanov slices to their additive (Kostant, Slodowy) counterparts, the multiplicative parabolic and unipotent reductions, the quasi-Hamiltonian implosion to symplectic implosion, and the multiplicative Moore–Tachikawa varieties to their additive analogues. In the language of quasi-symplectic groupoid presentations of $1$-shifted symplectic stacks, our main reduction theorem yields a smooth deformation of the corresponding reduced spaces.

We investigate the Uhlenbeck-Ford (UF) model as a reference system for free-energy calculations in two-dimensional (2D) fluids. The 2D virial coefficients are computed exactly up to tenth order and combined with molecular simulation data to construct highly accurate numerical representations of the equation of state and the excess Helmholtz free energy. We then determine the phase diagram of the model in order to establish the thermodynamic stability limits of the fluid phase and thereby identify the range of applicability of the UF model as a fluid reference system. In the course of this analysis, we identify the solid, hexatic, and fluid phases, and show that the fluid remains the only thermodynamically stable phase, independent of density, for scaling parameters up to $p\lesssim 70$. Finally, we demonstrate the practical applicability of the 2D UF model as a reference system through thermodynamic integration calculations of the free energy of a two-dimensional Lennard-Jones fluid.

Quantum teleportation has evolved from single-qubit, unidirectional communication to multi-qubit and multidirectional protocols. However, most existing schemes rely on protocol-specific entangled resources, motivating the development of universal quantum channels capable of supporting multiple communication tasks simultaneously. In this work, we demonstrate that a single twelve-qubit entangled channel exhibits such versatility by enabling the bidirectional teleportation of arbitrary three-qubit states and the cyclic teleportation of arbitrary two-qubit states through local Bell-state measurements and single-qubit operations. Both protocols are further generalized to multi-qubit and multi-party configurations, establishing the scalability of the proposed framework. To assess its practical applicability, the protocols are analyzed under amplitude-damping, phase-damping, bit-flip, phase-flip, and depolarizing noise channels by plotting the teleportation fidelity as a function of both the input-state parameters and noise strength. The analysis reveals distinct noise sensitivities, with the bidirectional protocol remaining perfectly faithful under bit-flip noise for all input states and noise strengths, while the cyclic protocol is consistently more vulnerable to environmental disturbances. The proposed schemes achieve an intrinsic efficiency of $25\%$, which is compared with several existing protocols. The framework therefore provides a scalable and resource-efficient approach to unified quantum communication in realistic noisy quantum networks.

Environment-assisted approaches to nonclassical light offer a practical path to strong squeezing in imperfect, lossy platforms. In this paper, we study a degenerate parametric oscillator in which a coherently driven cavity is coupled to a broadband squeezed reservoir via a single-port mirror. At the same time, the intracavity dynamics include non-Hermitian (gain-loss-imbalanced) terms. Within input–output theory, we obtain closed-form expressions for the steady-state quadrature variances, the output squeezing spectrum, and the power spectrum, and map their dependence on the reservoir squeeze factor, the coherent drive amplitude, and the parametric gain. We find that the non-Hermitian contributions open operating windows in which the intracavity quadrature noise is markedly suppressed below the standard quantum limit and, depending on the parameter set, either sharpen or amplify spectral squeezing and power-spectral features at the output. The non-Hermitian coefficients are treated as effective, low-order drift parameters that describe calibrated imbalance between engineered source and sink channels after auxiliary degrees of freedom have been eliminated. The analysis is restricted to the stable Gaussian regime in which the drift matrix is stable, and the squeezed-reservoir diffusion matrix remains physical. The results demonstrate an environment-assisted approach in which reservoir engineering and coherent driving work together to enhance squeezing. The resulting parameter maps identify experimentally testable windows, rather than a unique device prescription, for combining reservoir squeezing, coherent driving, and controlled gain/loss imbalance in cavity-QED and nonlinear photonic settings.

We present a method that enables efficient simulations of coarse-grained electrolyte solutions inside a narrow slit pore with an anisotropic dielectric permittivity tensor. The electrostatic equations for polarizable surfaces are solved using a 2D periodic Green's function method combined with a slab-corrected anisotropic 3D Ewald summation. We apply this approach in Monte Carlo simulations to study 1:1 electrolytes confined between both polarizable dielectric and metallic surfaces. Our results show that dielectric anisotropy aggressively reshapes the double-layer structure. While a coordinate stretching transformation demonstrates that individual ion-image interactions depend strictly on the bulk-like parallel permittivity, the suppression of the perpendicular permittivity dramatically amplifies direct in-plane ion-ion correlations. Under strong anisotropy, these lateral correlations dominate the thermodynamics completely, rendering the structural profiles of mutually opposing dielectric and metallic boundaries practically identical by forcing the smaller cations directly into the contact plane of the larger anions.

Photothermal interaction in nanoscale systems has emerged as a versatile tool for selective heat deposition and robust tuning of optical responses with a myriad of applications from hyperthermal medical treatment to switching and routing of optical signals. However, to date a comprehensive theory of transient photothermal interaction is missing. Development of such a theory is particularly challenged when optical excitation duration is comparable to the timescale related of heat transport, an emergent regime with a mutually interconnected transient interplay of light abortion and heat-induced change of optical responses. Here, we develop a coupled mode theory that captures intricate transient photothermal phenomena in a wide range of nanoscale systems. We further reveal conditions for optimal energy deposition and heating. As an example scenario we apply our model to design metasurfaces with high contrast and efficient temperature and optical switching, demonstrating fast cooling to the rest state (within 40 ns). Beyond exquisite control of both transient temperature profiles and optical responses, our theory offers deep physical insights onto photo-thermal interaction at the nanoscale which can find use in variety of fields from medical treatment to active photonics and manufacturing.

The Wide-Field Spectroscopic Telescope (WST) is a 12-m class, Alt-Az optical telescope providing two simultaneous foci, 2 degrees and 3 by 3 arc minutes respectively, for Multi-Object Spectroscopy (MOS) and Integral Field Spectroscopy (IFS) at visible wavelengths. Within the framework of the Horizon Programme, the project has been approved for phase A funding by the EC in 2024 and is currently undergoing intensive development. The optical design relies on a corrected Cassegrain solution feeding multi-object spectrographs through fibres, while the central area of the field is propagated to a gravity-stable Integral Field Station housing an array of spectrographs. We report progress of the design, of the functional and physical definitions of key subsystems, and of the design of high-performance coatings of the telescope optics. The telescope would be located near ESO Paranal - Armazones observatory and protected by a VLT-like enclosure. With a view to minimising risks, from capital investment to operations, designs build extensively on VLT and ELT solutions. Owing to the optical configuration, the telescope can be wavefront-controlled at both foci, with little if any crosstalk between MOS and IFS controls. The optical path is constrained to provide natural guide star, ground-layer adaptive correction at the IFS field, within existing technology. Finally, from its earliest stage of development the system is being scrutinized for its properties in relation to sustainability.

Context. M dwarfs are favorable hosts for small transiting planets. A transit-detection and statistical-validation pipeline was previously developed and validated at the photometric noise frontier, on M3-M6 dwarfs observed in few sectors. Aims. That pipeline is applied uniformly to the full active ExoFOP M-dwarf TOI population, 461 hosts (M0-M6) each hosting a confirmed planet (CP) or planet candidate (PC), to test its recovery and classification of the cataloged signals and to prioritize the candidates for follow-up. Methods. The pipeline chains two complementary blind searches merged per host, a full-baseline transit-least-squares scan and a segmented, semi-coherent search across the gapped multiyear baseline. It adds an event-time-coherence test that rejects signals with incoherent per-transit timing (window-function aliases of stellar variability), all-sector TRICERATOPS false-positive probabilities, and Gaia DR3 background and aperture-localization analysis. Results. Of 193 in-range CP, 165 (85.5%) are re-detected, none rejected as a false positive, and 147 (76.2%) reach a Gaia-verified disposition. Of 286 in-range PC, 225 (78.7%) are re-detected, of which 11 are flagged as false positives and 87 ranked as planet candidates for follow-up. Beyond the catalog, 13 new transit candidates of 0.7-2.0 Earth radii emerge, including two new members of a compact, dynamically stable near-resonant three-planet candidate system; four cataloged single- or dual-transit TOIs have their orbital periods determined, two of them in the optimistic habitable zone. Conclusions. The recoveries and new candidates are released as a uniform, prioritized follow-up target list.

The discovery of scaling laws has motivated training neural networks on ever increasing quantities of data. This is typically done with a constant decoupled weight decay which causes the network weights to shrink steadily over the course of training. Taking inspiration from the Robbins–Monro conditions, we propose to scale weight decay by the fraction of the peak learning rate $\eta/\eta_{\max}$. We prove that this scaled weight decay preserves the asymptotic stationarity guarantees of the corresponding unregularized methods for both stochastic gradient descent and the non-Euclidean spectral optimizer Muon, thereby avoiding the additional asymptotic bias introduced by constant decoupled weight decay. This retains the stability benefits of weight decay without changing the asymptotic optimization target. Using a steady-state analysis, we explain why under standard weight decay the weight norm shrinks steadily as training proceeds, whereas under scaled weight decay it settles to a roughly constant value. When applied to the training of mixture-of-experts models, Muon with scaled weight decay (Muon-SW) consistently outpaces Muon with identical hyperparameters, reaching the same validation loss $\mathbf{30\%}$ faster at our largest scale across models from $72 - 930$ million parameters trained at $\sim 600$ tokens per active parameter. If this trend continues to hold, the method promises to substantially accelerate the pre-training of frontier models while requiring only a few lines of code to implement.

Planck-scale signatures of quantum gravity may emerge semiclassically not only through modifications of spacetime geometry but also through the geometry of momentum space. In this work, we develop a $(2+1)$-dimensional framework in which a noncommutative algebra of spacetime localization operators reconstructs a locally anti-de Sitter momentum-space geometry in the classical limit. The resulting momentum-space curvature deforms the phase-space structure, modifies particle kinematics, and leads to a finite renormalization of the particle mass. Using an effective configuration-space action, we derive the corresponding stress-energy tensor that consistently sources the classical Einstein equations without modifying the gravitational dynamics. The resulting spacetime is a deformed BTZ black hole whose conserved mass, horizon radius, Hawking temperature, and Bekenstein-Hawking entropy acquire finite Planck-scale corrections. We further investigate Hawking radiation using the Hamilton-Jacobi tunneling formalism and show that the return time of an emitted massless particle receives two distinct contributions: a geometric correction induced by curved momentum space and a dynamical correction arising from Hawking backreaction. Remarkably, the null geodesic equations remain unchanged, indicating that the observable effects originate entirely from the deformation of the effective spacetime geometry rather than from modifications of particle trajectories. These results provide a concrete semiclassical mechanism through which quantum kinematics encoded in curved momentum space can generate observable gravitational phenomena without requiring a quantization of spacetime itself, thereby offering a phenomenological bridge between quantum geometry and black-hole physics.

We examine the spatial correlation of emission from polycyclic aromatic hydrocarbons (PAH) (3.3 $\mu$m, 7.7 $\mu$m, and 11.3 $\mu$m) with the far-ultraviolet (FUV), near-ultraviolet (NUV), and H$\alpha$ emission from star-forming complexes (SFCs) in different regions of NGC 628. We use the James Webb Space Telescope to detect PAH emission, along with the Ultraviolet Imaging Telescope and Multi Unit Spectroscopic Explorer observations to sample the UV and H$\alpha$ emission, respectively. We investigate the correlation of PAH luminosities with FUV, NUV, and H$\alpha$ luminosities for the extracted SFCs. We find that the arm and spur SFCs show bright PAH emission, except for those with only NUV emission, located primarily in bubbles and superbubbles. We also examine these correlations in the phantom void, the largest superbubble in NGC 628. We investigate the trend for FUV-NUV and the Initial mass function (IMF) index $\alpha_2$ derived from the ratio of B stars with PAH band ratios (F335M/F1130W, F770W/F1130W, and F335M/F770W). We find that PAH band ratios increase as the IMF becomes more top-heavy and the SFCs become bluer, consistent with enhanced PAH excitation and ionisation in stronger UV radiation fields. However, $\alpha_2$ of spur SFCs shows a flat trend with PAH band ratios compared to arms. Upon closer examination, two SFCs in the shell region of the phantom void showed a flatter IMF compared to the SFC located near the elongated bubble. This is likely due to gas accumulation, possibly through feedback mechanisms in the shell region, while the SFC near the elongated bubble may have formed in a region affected by shear.

The quantum separability problem asks whether a bipartite density matrix is separable or is $\eta$-far from every separable state. We give a randomized polynomial-time algorithm for this problem for every fixed constant gap $\eta>0$, when distance is measured in the Euclidean norm.

Strongly disordered solids exhibit distinctive properties at the nanoscale, where conventional continuum theory breaks down. We show that their disorder-averaged linear response can be described by a modified continuum theory in which the response coefficients are local but depend nonlocally on the structural properties. The stability criterion requires the response operator to be positive semidefinite, which naturally leads to a correlated Wishart disorder. In the limit of strong disorder, the resulting theory reduces the long-wavelength response to a scalar disorder-induced contrast field. In elasticity, this field describes the formation of a stiffened interphase around rigid nanoparticles and boundaries, whose characteristic extent is set by the nonaffine length. The predictions are confirmed by molecular-dynamics simulations of a Lennard-Jones glass and a model polymer. Direct calculations of the nonlocal elastic kernels show that their spatial range is much shorter than the extent of the stiffened interphase, demonstrating that the latter does not require long-range constitutive nonlocality.

We study the Berry curvature effects of the Bogoliubov quasiparticles in chiral superconducting rhombohedral graphene. Using a two-band Bogoliubov-de Gennes Hamiltonian to describe the superconducting quasiparticles, we calculate the momentum-space Berry curvature, orbital magnetic moment, and anomalous thermal Hall, spin Nernst, and orbital Nernst transport of chiral $p$-wave superconducting states. We investigate the impact of normal-state band warping in rhombohedral graphene, which can generate Bogoliubov Fermi surfaces for quasiparticle excitations. We find that Bogoliubov Fermi surfaces qualitatively modify the anomalous transport responses, inducing a deviation of the thermal Hall conductivity from the quantized value and strongly enhancing the spin and orbital Nernst responses.

The near horizon region of a generic non extremal black hole has been extensively studied in terms of a Carrollian geometry with two null directions, also called a string Carroll geometry. We investigate how this string Carroll geometry evolves to a Lorentzian throat as the four dimensional Reissner-Nordström (RN) black hole approaches extremality. We identify the quadratic temporal contribution that is suppressed in the non extremal description but is required to recover the $\mathrm{AdS}_2$ curvature. Approaching the outer horizon and extremality simultaneously, scaling the horizon separation together with the radial distance and correspondingly rescaling Killing time, brings this contribution into the leading longitudinal metric alongside the Rindler sector. In ingoing Eddington-Finkelstein coordinates, the string Carroll metric alone has a Lorentzian limit with a flat longitudinal sector. The quadratic temporal term arises from the bilinear of the leading and subleading longitudinal coframe fields and supplies the missing curvature, while higher radial contributions vanish. The reconstructed limiting geometry is already locally $\mathrm{AdS}_2\times S^2$ at finite positive scaled horizon separation; setting this parameter to zero makes the selected horizon extremal without changing the local curvature. The limiting metric and Maxwell field satisfy the Einstein-Maxwell equations. In static coordinates, the temporal component again follows from the quadratic term, while the radial component requires summing contributions from all radial orders. The reconstruction provides a geometric starting point for investigating which expansion data must be retained when extending calculations based on the non extremal string Carroll description into the throat regime, including their implications for string, particle and field dynamics.

In fluid-fluid displacements in porous and fractured materials, viscous friction in microscale interfacial (Haines) jumps is intimately linked to macroscale energy dissipation and the associated pressure-saturation (retention) hysteresis. The mode of control (flow rate vs. pressure) and the driving rate (from quasistatic to finite) can substantially affect hysteresis. Despite the significance of hysteresis and dissipation in various technological and natural processes, a quantitative understanding of the link between the micro- and macro-scales, and of the impact of the inherent heterogeneity of porous media, remains elusive. An “imperfect” Hele-Shaw cell of variable aperture is a simple model system which allows to study all these in details. However, simulating fluid-fluid interface evolution in heterogeneous media, even in such a simple system, is computationally prohibitive, as multiple length and time scales need to be resolved simultaneously. We develop here a spectral computational approach for interface evolution and energy dissipation and validate it via comparison to computational fluid dynamics simulations and experiments. Computational efficiency is demonstrated by following interface evolution in a cell with a single “defect”, as well as with random roughness; in both, disparate length scales lead to nontrivial dynamics over many orders of magnitude in time. We also show theoretically that, in the quasi-static limit, while viscous forces during Haines jumps fully account for the energy dissipated between consecutive metastable equilibria, viscosity does not change the total dissipated amount, merely the relaxation time. Our approach provides a stepping stone towards upscaling of fluid-fluid flows in porous media.

We propose a quantum-information-theoretic perspective on the Weak Gravity Conjecture through the behavior of Krylov spread complexity. For a charged thermofield double state holographically dual to an AdS Reissner–Nordström black hole, we show that the extremal limit on the black-hole side is accompanied by an effective freezing of Krylov spreading. In this regime, the return amplitude becomes effectively a pure phase, and the corresponding Krylov spread is suppressed. We then incorporate charged matter and study the effect of Schwinger pair production in the near-horizon region. Within this semiclassical near-extremal analysis, the frozen behavior is lifted once an allowed discharge channel is opened, and the dynamics become nontrivial again. This suggests a possible complexity-based diagnostic of a characteristic physical consequence of the Weak Gravity Conjecture: the availability of a superextremal charged state that can mediate discharge. More broadly, our results point to a connection between the swampland program, black-hole physics, and quantum information theory.

We propose a reformulation of quantum mechanics as a theory of unresolved uncertainty. This theory of potentiality is formulated in the language of complex-valued measure theory, regarded as a pre-probabilistic counterpart of ordinary probability theory. In this formulation, additivity, conditioning, independence, mixtures, transition kernels, and temporal divisibility retain natural linear forms at the potentiality level, while non-classical probability-level features such as interference arise from the nonlinear Born map. Measurement is described as Bayesian-type conditioning of potentialities on actualized information, and non-selective measurement as the replacement of coherent potentiality by statistical mixtures of conditional potentiality branches. Mixed states, decoherence, composite systems, entanglement, and Bell-type correlations are also given a unified potentiality-level interpretation. The density matrix is interpreted as a coherence kernel whose off-diagonal blocks encode retained phase relations. For pure bipartite states, potentiality independence is shown to be equivalent to factorization of the Born distribution in every pair of local contexts. The resulting formulation is empirically equivalent to standard quantum mechanics, but it makes explicit a pre-probabilistic description of physical reality that is usually implicit in the Hilbert-space formalism.

Magnetic fields in interplanetary coronal mass ejections (ICMEs) often display a flux rope structure at large scales and a turbulent cascade of fluctuations at smaller scales. However, the nature of fluctuations at transition scales between the flux rope and turbulence - i.e., at mesoscales - has not been previously examined in detail. Mesoscale fluctuations of the magnetic field in 142 ICME intervals with clear flux rope signatures at 1 au have been examined using wavelet power spectra, with "mesoscale" defined here as spacecraft-frame frequencies $10^{-4}\ \text{Hz}<f_\mathrm{sc}< 10^{-3}\ \text{Hz}$, equivalent to timescales $2.8\ \text{hr}\gtrsim \tau \gtrsim 17\ \text{min}$. The spectra were found to be significantly less steep at mesoscales than at larger and smaller scales, with an average spectral slope close to $-1$ at these intermediate scales. The mesoscale fluctuations had relatively high cross helicity magnitudes and low compressibility, suggesting a significant degree of Alfvénicity, while also having more negative residual energy than the turbulent fluctuations found at smaller scales. Uncertainties in the spectral slope values at mesoscales were used to distinguish between spectra showing a relatively smooth power-law behavior or (less commonly) a more bumpy trend; the smoother power-law intervals had a balanced cross helicity distribution while the more bumpy spectra had a predominantly antisunward cross helicity. Slow wind intervals were similarly analyzed, and showed similar properties to the ICMEs. These results indicate that a spectrally narrow $1/f$ range is typically present in ICMEs at mesoscales.

Context. A significant fraction (>30%) of planet-forming disks and planetary are misaligned with respect to the rotational axis of their host stars, yet the dominant mechanism responsible for these misalignments remains unclear. Aims. We aim to observationally constrain the angular momentum of Class II protoplanetary disks and assess whether late-stage infall of material can bring sufficient angular momentum to tilt them. Methods. We first computed the angular momenta of 15 disks with surface density profiles inferred from dynamical modeling of high angular resolution ALMA observations. Based on this sample, we derived a relation linking disk angular momentum to stellar mass, disk mass, and the radius enclosing 90% of the 13CO flux and used it to estimate angular momenta of 18 more disks. We then compared disk values with theoretical predictions for late-stage accretion from clouds and observed streamers. Results. Angular momentum for most disks is lower than what theoretical models predict for late infall. This is also in qualitative agreement with comparison with streamer observations, however, characterization of mass of reservoirs feeding the streamers is needed to confirm this picture. Conclusions. Interactions with nearby clouds, resulting in late-stage infall of material onto Class II disks, can potentially explain the observed misalignments within disks and planetary systems.

We present the first calculation of the radiative decays $J/\psi,\psi(2S)\rightarrow\gamma\eta^{(\prime)}$ in perturbative QCD that includes the order-$q^{2}$ relativistic corrections in all three short-distance contributions, namely the quark-antiquark, two-gluon, and QED contributions. The amplitudes are found to be remarkably insensitive to the light-cone distribution amplitude and to the light-quark mass, a robustness that persists through order $q^{2}$ and makes the predictions correspondingly reliable. The relativistic correction enhances the $J/\psi$ branching ratios by roughly a factor of 2, narrowing their shortfall from experiment, whereas for the $\psi(2S)$ it is about twice as large as for the $J/\psi$ and the low-order expansion converges poorly. In two representative $\eta$–$\eta^{\prime}$ mixing schemes, the ratio $\mathcal{R}_{1S}=\mathcal{B}(\gamma\eta^{\prime})/\mathcal{B}(\gamma\eta)$ proves sharply sensitive to the mixing angle and favors the smaller of the two. The predicted $\psi(2S)$ rates lie well above the data in both channels, already at leading order, and most severely for the anomalously small $\gamma\eta$ channel. Such a discrepancy suggests that a mechanism beyond the hard perturbative process is at work. As a physically motivated attempt, we explore the $\eta_{c}$-mixing contribution, which adds coherently to the perturbative one and is comparable to it in the $\gamma\eta$ channel, and find that the interference can bring the $\psi(2S)$ rates into agreement with the data, although its extraction is limited by a strong sensitivity to the mixing parameters.

The critical slip distance $D_c$ - the characteristic displacement over which a fault dynamically weakens from peak to residual strength - is a key parameter in earthquake rupture dynamics, controlling the nucleation process and slip evolution. Nevertheless, its physical origin and scaling remain debated: Dc is observed to span from micrometers in lab experiments to meters on natural faults, a scaling which cannot be explained within the standard friction framework, which interprets Dc as a material constant related to the contact population and provides no mechanism linking it to fault structure or event size. Here, we propose a first-principles derivation showing that Dc is a structural property of faults, governed by their self-affine roughness belonging to the Kardar-Parisi-Zhang universality class. We further demonstrate that rate-and-state friction emerges as the mean-field limit of the underlying fractal asperity dynamics and provide analytical formulas for its parameters: the state variable represents the population-averaged contact age, while the critical distance identifies the geometric unlocking of the dominant pinning bumps. Rate-and-state friction is therefore an emergent phenomenology whose mathematical form reflects the statistical mechanics of the underlying contact population, and its parameter values are strictly scale-dependent. This allows us to better characterize fault stability from a multiscale perspective; hence, we introduce a new concept named "fault retentivity”: the ability of a fault to arrest a nucleated rupture before it degenerates into run-away via the multiscale barrier population encoded in the fault structure. Retentivity determines whether a fault hosts only small earthquakes or can occasionally nucleate large ones. The key implication is that assessing fault stability requires to understand the hierarchical architecture of the fault system.