Plasma Physics
Cold atmospheric plasma decontaminates Arabidopsis thaliana seeds and remodels seedling fungal microbiota
Lena Taras, Nicole Chaumont, Caroline Kunz et al. (+2 more)
Seed-associated microorganisms influence seed quality, seedling establishment, and plant health and also constitute a major source of seed-borne pathogens. Cold atmospheric
plasma (CAP) has emerged as a promising alternative to chemical seed treatments because of its antimicrobial activity, although its effects on fungal communities associated with developing seedlings remain poorly understood. Here, Arabidopsis thaliana seeds from two ecotypes (Columbia and Landsberg erecta) were exposed to CAP for 5 or 15 min. Seed decontamination efficiency was assessed by culturing on malt extract agar and nephelometric analyses, while fungal communities associated with seedlings derived from treated and untreated seeds were characterized by ITS1 amplicon sequencing. CAP efficiently reduced fungal contamination without affecting seed germination. CAP altered the composition of fungal communities associated with developing seedlings, but the magnitude of these changes depended on seed batch and ecotype. Dominant taxa markedly declined after treatment, whereas several low-abundance taxa increased in relative abundance. These findings demonstrate that CAP is an effective pesticide-free technology for seed decontamination and can also reshape fungal communities associated with developing seedlings, highlighting broader ecological consequences of
plasma-based seed treatments.
Read the full abstract ▾
All authors Lena Taras, Nicole Chaumont, Caroline Kunz, Thierry Dufour, Christophe Bailly
High Energy Physics (Experiment)
Search for compressed electroweak SUSY production in final states with two $\tau$-leptons in $\sqrt{s} = 13$ and $13.6$ TeV $pp$ collisions with the ATLAS detector
ATLAS Collaboration
Searches for the production of $\tau$-sleptons ($\tilde{\tau}$), charginos ($\tilde{\chi}^{\pm}_1$), and neutralinos ($\tilde{\chi}^0_2$) in events with at least one hadronically decaying $\tau$-
lepton are presented, targeting compressed mass spectra scenarios. For charginos and neutralinos, the cascade decays producing either a $\tau$-slepton or a $\tau$-sneutrino are considered. Two final selections are studied, requiring either one hadronically decaying $\tau$-
lepton and one other charged
lepton, or two or more hadronically decaying $\tau$-
leptons. To enhance sensitivity to the compressed mass spectra, production modes with initial-state radiation (ISR) jets are considered. The searches use 140 $\mathrm{fb}^{-1}$ and 53 $\mathrm{fb}^{-1}$ of
proton-
proton collision data recorded by the ATLAS detector at the Large
Hadron Collider during 2015-2018 at a centre-of-mass energy of $\sqrt{s} = 13$ TeV and 2022-2023 at a centre-of-mass energy of $\sqrt{s} = 13.6$ TeV, respectively. The searches provide sensitivity to the compressed mass spectra scenarios with light $\tau$-sleptons. The results are generally consistent with the Standard Model, although several deviations with local significances of $2.1-2.4 \sigma$ are observed. These deviations weaken the observed exclusion limits. For direct $\tau$-slepton production, in the ISR channel alone the limits are set for $\Delta m(\tilde{\tau}, \tilde{\chi}^0_1) = 30$ GeV for $\tau$-slepton masses up to $115$ GeV at 95% confidence level. Given the observed data, no exclusion limits are set for direct $\tau$-sleptons production when statistically combining all considered channels. For electroweakino production, limits are set for $\Delta m(\tilde{\chi}^0_2, \tilde{\chi}^0_1) = 30$ GeV for $\tilde{\chi}^0_2$ masses up to $200$ GeV. For pure chargino pair-production, limits are set for chargino masses up to $175$ GeV for the same mass splitting.
Read the full abstract ▾
Geophysics
Finite-Horizon Triggering Cores of Earthquake Sequences
Didier Sornette and Giuseppe Petrillo
Models of triggered seismicity commonly aggregate the contributions of all past earthquakes into a total predicted rate. This aggregation does not distinguish a forecast dominated by one recent earthquake from an equal-rate forecast supported by many events distributed across a longer history, even though these configurations can have different persistence and sensitivity to catalog and parameter uncertainties. We introduce the finite-horizon triggering core size \(N_{p,T}(t)\), defined as the minimum number of past earthquakes whose expected contributions account for a fraction \(p\) of the total triggering potential over the future interval \([t,t+T]\). The definition applies to any triggering model that assigns nonnegative event-specific expected contributions over a specified future window. We develop its theory for marked Hawkes and epidemic-type aftershock sequence processes, where the weights are the expected numbers of direct offspring produced by individual past earthquakes. The finite horizon makes the observable well defined for every normalized Omori kernel with exponent \(\theta>0\), including the long-
memory regime in which the corresponding infinite-horizon quantity diverges. We derive continuum and marked-Poisson
benchmarks, an exact representation of the marked-Poisson distribution, and high-\(p\) distributional laws. For finite-horizon Omori
memory, the triggering core grows as \((1-p)^{-1/\theta}\) with a realization-dependent amplitude controlled by the total triggering weight; for exponential
memory, the growth is logarithmic.[...]
Read the full abstract ▾
Quantum Physics
Encoding and Node Choices in Transversal Fault-Tolerant Distributed Quantum Computations: An Initial Study
Seng W. Loke
We compare and study different Bivariate-Bicycle (BB) encodings and node choices for distributed
quantum operations such as transversal non-local CNOTs. We observe that while some encodings have more physical
qubits requiring more ebits for a distributed computation, reducing ebit consumption alone might not be the best criterion for selecting an encoding for the logical
qubits, if the goal is to reduce the logical error rate of the distributed computation; for example, one should also consider encodings with a larger distance, which using more physical
qubits can provide. We consider distributed, or non-local, CNOTs and computation of the global gate (GCZ) over distributed logical
qubits as examples. The choice of encoding enables particular concurrent operations; e.g., we show that a transversal physical GCZ on a self-dual $[[120,8,12]] BB$ code can realize eight concurrent logical GCZ operations after accounting for the logical permutation induced by transversal Hadamard.
Read the full abstract ▾
Quantum Physics
Near-Optimal Quantum Algorithm and Complexity Analysis for Riccati Problems
Jingyao Wang, Yanqiao Wang, Bowen Li et al. (+2 more)
We develop
quantum algorithms that construct block-encodings of solution
matrices for continuous- and discrete-time algebraic Riccati equations (CAREs and DAREs), differential Riccati equations (DREs), and finite Riccati recursions. The
Quantum Weighted Riesz Method, unifying four kinds of Riccati problems, constructs projectors onto the solution graphs using weighted Riesz branching operators and recovers the solution
matrices. Under the stated access and normalization assumptions, our
algorithms for CAREs and DAREs have near-optimal query complexity $\Theta(\mathcal R\alpha)$ up to logarithmic factors, with the generalized singularity factor $\mathcal R$ that reflects spectral separation, and the output normalization $\alpha$. For DREs and finite-horizon problems, the query complexity has an additional initialization conditioning factor $\kappa_{\rm init}$. We establish product query lower bounds for specified input-oracle families, demonstrating necessary joint dependence on spectral separation and initialization or output scale. We also prove that selected-value promise problems are BQP-complete on explicit
circuit-generated families of single-control discrete-time algebraic and zero-terminal differential Riccati equations. Applications include classical feedback evaluation for linear-quadratic control, a query-complexity comparison for stable random-phase approximation Riccati equations in
quantum chemistry, and heated boundary control with numerical validation.
Read the full abstract ▾
All authors Jingyao Wang, Yanqiao Wang, Bowen Li, Jin-Peng Liu, Zhengfeng Ji
Quantum Physics
Optimal Entanglement Routing in Quantum Repeater Chains: Beyond Fixed Operation Order and Purification Schedule
Aikaterini Mandilara, Antonia Tsili, Dimitris Syvridis et al. (+1 more)
Entanglement routing establishes entangled pairs between distant nodes of a
quantum network by purifying and swapping pairs generated on elementary links. Existing methods typically restrict the decision space along two axes: the operation order, often fixed to purify-then-swap (PtS), and the purification schedule of each link, often restricted to pumping. Focusing on linear repeater chains with finite link capacities, we relax both restrictions and study the maximization of the expected end-to-end throughput subject to a fidelity threshold under two
quantum-noise models. We develop a unified capacity-aware optimization framework comprising an exact mixed-integer linear program (MILP) under PtS, instantiated with either pumping or general tree purification schedules, and an exact dynamic program (DP) over arbitrary operation orders. Under symmetric Pauli noise, we prove that pumping converges to a fidelity strictly below unity, imposing a capacity-independent feasibility bound and a maximum chain length on every pumping-based PtS method, whereas general tree schedules yield a capacity-dependent bound. We further prove that post-swap purification never increases the throughput, so a free operation order can only increase feasibility. Numerical evaluations confirm the bounds: tree schedules serve over 90% of the requests that pumping cannot at moderate fidelity thresholds; within the pumping class, a free operation order recovers much of this advantage; but once links use tree schedules, the tree-based MILP and the order-exact DP serve identical request sets throughout. Operation order and purification schedule are thus substitutes, with the purification schedule the dominant factor governing feasibility under symmetric Pauli noise.
Read the full abstract ▾
All authors Aikaterini Mandilara, Antonia Tsili, Dimitris Syvridis, Konstantinos Christodoulopoulos
Statistical Mechanics
The Spectral Cost of Detecting Nonequilibrium at Finite Temporal Resolution
Murad Aznagulov
A detector that cannot take two snapshots closer than a time $\tau_0$ still identifies a fully observed finite Markov generator exactly, provided its gaps are randomized by two clocks. Identification is not detection. For a normal nonequilibrium network, the number of snapshots needed to reject every hidden
equilibrium explanation grows as $e^{2\gamma_{\mathrm{irr}}\tau_0}$, where $\gamma_{\mathrm{irr}}$ is the slowest damping of rotating modes. No adaptive schedule beats this rate, and a test on one dependent trajectory attains it.
Read the full abstract ▾
Materials Science
Engineering Synaptic Dynamics in Ag-Modified TaO$_x$ Memristive Devices
R. Leal Martir, W. Quiñonez, A.J.T. van der Ree et al. (+4 more)
Engineering not only the magnitude but also the dynamics of synaptic weight updates is an important challenge for memristive neuromorphic hardware. Here, we show that Ag modification of TaO$_x$ memristors introduces an electrically selectable degree of freedom in synaptic depression through the interplay between Ag-related and oxygen-vacancy dynamics. Reference devices exhibit conventional bipolar switching, whereas Ag-modified devices display symmetric table-with-legs hysteresis loops, metastable intermediate states, and a strongly non-monotonic dependence of depression dynamics on programming amplitude. By varying only the pulse amplitude, the same device can be driven among three regimes: gradual sigmoidal depression, an abrupt update concentrated within a few pulses, and a broadly distributed
evolution extending over more than one hundred pulses. A minimal coupled-state model, in which a vacancy-related switching variable interacts with a slower Ag-related internal degree of freedom, reproduces this gradual–abrupt–gradual crossover using two individually monotonic field-activated processes. The functional impact is assessed in a memristor-based multilayer perceptron. For MNIST, the abrupt, sigmoidal, and slowly evolving responses yield accuracies of approximately 50%, 85%, and 88%, respectively, while the gradual regime reaches approximately 72% for Fashion-MNIST. These results show that coupling Ag-related and oxygen-vacancy dynamics can transform synaptic depression from a fixed device characteristic into an electrically programmable property.
Read the full abstract ▾
All authors R. Leal Martir, W. Quiñonez, A.J.T. van der Ree, M. H. Aguirre, G. Palasantzas, M. J. Sánchez, D. Rubi
Fluid Dynamics
Probabilistic Symbolic-Distillation Model of Droplet Collision for Spray Simulation at High Ambient Pressures
Weiming Xu, Tao Yang and Peng Zhang
Droplet collision governs droplet population dynamics in many chemical engineering processes, such as spray drying, spray cooling, agricultural spraying, and combustion. Existing analytical models impose deterministic, pairwise boundaries between collision outcomes, whereas machine-learning classifiers lack the explicit functional form required of analytical collision submodels. In this study, we develop a probabilistic symbolic-
distillation model using nearly forty thousand experimental events spanning eight regimes and five dimensionless parameters, including over five thousand data for ambient pressure up to 50 atm. A machine-learning teacher learns the joint outcome-probability landscape from these data, and symbolic regression subsequently distils it into eight class-specific expressions that jointly define a coupled analytical model. The resulting analytical field replaces abrupt regime switching with finite-width fuzzy boundaries. It outperforms the evaluated conventional analytical boundary models and reveals that their main limitation is the inability of zero-width boundaries to represent gradual probability transitions. The "biased-dice" sampling scheme provides a statistically consistent and practically convenient model implementation for Eulerian-Lagrangian spray simulation.
Read the full abstract ▾
Quantum Physics
Encoding universal quantum computation into quantized Berry phases: Hardness results and classical algorithms
Kazuki Sakamoto and Keisuke Fujii
The Berry phase is a fundamental
geometric quantity for characterizing the geometry and
topology of
quantum many-body systems. Previous work established a super-
polynomial quantum advantage in Berry phase estimation at inverse-
polynomial precision, given an ansatz state approximating the initial ground state. However, whether this hardness persists for Berry phases quantized by
symmetry, which can be distinguished at constant precision, remained open. In this work, we characterize the computational complexity of quantized Berry phase estimation. First, we prove that deciding whether the Berry phase is exactly $0$ or $\pi$ is $\mathsf{BQP}$-complete when the spectral gap is inverse-polynomially small. This result implies that distinguishing the quantized Berry phase still has a super-
polynomial quantum advantage, assuming $\mathsf{BPP}\neq \mathsf{BQP}$. To prove this result, we introduce an encoding that maps the output of any
quantum computation to a Berry phase that is exactly $0$ or $\pi$. Second, we extend this hardness to physically motivated
Hamiltonians on a 2D square
lattice, including Heisenberg and XY interactions. Third, we provide a classical
polynomial-time
algorithm for geometrically local
Hamiltonians on fixed-dimensional
lattices with constant spectral gaps. Therefore we identify that the spectral gap is a key resource for the classical tractability, rather than precision. These results establish a super-
polynomial quantum advantage for computing a quantized topological invariant that is unchanged under
symmetry- and gap-preserving deformations, and provide new steps towards practical
quantum advantage in
quantum physics.
Read the full abstract ▾
Quantum Physics
Non-Canonical Quantum Otto Engine
Wei Wu and Jun-Hong An
The fast-developing
quantum technology is propelling thermal machine, which lies at the heart of thermodynamics, into a new golden era. Being
stochastic because of the non-negligible thermal and
quantum fluctuations, the efficiency and power of a finite-time
quantum heat engine exhibit a trade-off, preventing the simultaneous achievement of high power and high efficiency. Conventional studies treat the statistics of a heat engine by assuming canonical thermalization, which is valid only under weak-coupling conditions. We here investigate the noncanonical effect on the statistics of the efficiency and power for a finite-time
quantum Otto cycle. It is revealed that their average values and variances are highly controllable by engineering the energy spectrum structure of the composite system consisting of the working substance and the bath. Near the
quantum critical point induced by the formation of a bound state in the energy spectrum, the average efficiency and power can be boosted simultaneously, meanwhile, both of their variances are decreased. Deepening our understanding of the usefulness of
quantum reservoir engineering in thermodynamics, our result lays the foundation for the realization of efficient and stable
quantum energy devices.
Read the full abstract ▾
Quantum Physics · Cross-listed from cs.NE
Adaptive Rotation for iSOMA: Geometry, Benchmarking, and Noise Robustness in Variational Quantum Objectives
Vojtěch Novák and Ivan Zelinka
We study whether the coordinate dependence of the improved Self-Organizing Migrating
Algorithm (iSOMA) can be reduced while retaining its inexpensive leader-directed migration mechanism. We introduce iSOMA-AR, which learns a basis from successful migration displacements and selectively applies the standard perturbation mask in that basis. On the complete noiseless BBOB suite, iSOMA- AR significantly outperformed baseline iSOMA across matched conditions, with the largest gains on geometrically difficult landscapes. A targeted ablation shows that the learned orientation is beneficial on a rotated ill-conditioned landscape and that moderate changes of the gate threshold and rotation cap preserve the qualitative result. On CEC 2011 Real World Optimization Problems, iSOMA-AR outperformed iL-SHADE on most problems, although its advantage over baseline iSOMA was not statistically significant. A canonical-jSO rerun is reported as a post-hoc sensitivity check alongside the original jSO-derived comparator. On frustrated-
spin variational
quantum objectives, adaptive rotation improved most transverse-field conditions, while gains on the diagonal and anisotropic models were absent or selective. Under strong effective sampling noise, the SOMA variants were the most robust population-based methods in the comparison, but iSOMA-AR was not significantly better than baseline iSOMA. Repairing all-zero PRT masks greatly reduced repeated-point evaluations without changing endpoint quality significantly, making this implementation detail unlikely to explain the noise result. Overall, adaptive rotation is most useful on coordinate-sensitive deterministic problems, while the observed noise robustness appears to arise mainly from the underlying SOMA migration mechanism.
Read the full abstract ▾
Strongly Correlated Electrons
Uniform-Charge-Density $d$-Wave Superconductivity in the Pure $t$-$J$ Model at $1/8$ Doping on an Infinite Cylinder
Guangyu Yu and Zheng Zhu
The ground state of the square-
lattice $t$-$J$ model at $1/8$ hole doping has been the subject of a long-standing controversy, with conflicting numerical reports of stripe order versus superconductivity. Here, we address this debate using the variational uniform
matrix product state (VUMPS) method, which optimizes the wave function directly in the thermodynamic limit along the cylinder axis and eliminates the boundary pinning effects that can arise in finite-cylinder calculations. On an infinite cylinder of circumference $L_y = 8$, we find a uniform-charge-density $d$-wave superconducting ground state with quasi-long-range pairing correlations. The dominant pairing occurs at zero center-of-mass momentum, while no sizable finite-momentum pairing component is detected. Twisted-boundary-condition calculations reveal a finite superconducting phase stiffness, with the order-parameter phase winding smoothly to follow the applied flux, providing an independent probe of the robustness of the superconductivity. Moreover, both charge and
spin correlations decay rapidly, with no signatures of long-range stripe or
magnetic order, in contrast to an $L_y=6$ cylinder at $1/6$ doping where the same method readily identifies stripe order. Our results provide methodologically distinct evidence in the long-standing stripe–superconductivity debate in the pure $t$-$J$ model and reveal uniform $d$-wave superconductivity in a minimal model of doped Mott
insulators.
Read the full abstract ▾
Astrophysics of Galaxies
MEGATRON: Dwarf Galaxy Quenching in the Epoch of Reionization
David Attard, Ilian T. Iliev, Martin P. Rey et al. (+3 more)
Low-mass
galaxies during the Epoch of Reionization are expected to form
stars in short bursts separated by periods of inactivity, but what regulates this cycle, and how sensitive it is to the modelling of
stellar feedback, remains unclear. We use the MEGATRON high-
redshift zoom simulation suite, in which four
star-formation and
stellar-feedback prescriptions are evolved from identical initial conditions, to study the regulation of
stellar mass growth in
galaxies with $M_{*} \sim 10^{4} - 10^{8} M_{\odot}$ at $z = 8.5$. We classify
galaxies as
Star-Forming, Mini-Quenched (no significant
star formation over the last 10 Myr), or Quenched (no significant
star formation over the last 100 Myr). The feedback prescription controls both how often
galaxies are quiescent and how this depends on mass. Models with stronger or more clustered feedback yield larger quiescent fractions compared to the fiducial and Varying IMF models. Duty cycles at fixed mass also differ by factors of several between models. The cold gas profiles of Quenched
galaxies are consistent with two physically distinct modes of quenching: mechanical gas evacuation, producing compact, cold gas-poor systems, and thermodynamic suppression, retaining a cold but
star-formation-inactive reservoir. At these masses, quiescent
galaxies fall below un-lensed JWST/NIRCam detection limits, whereas
star-forming
galaxies of the same mass do not, and consequently flux-limited samples will be biased towards active phases. Measuring the quiescent fraction as a function of
stellar mass in
lensing fields would provide a direct test of
stellar-feedback models at
Cosmic Dawn.
Read the full abstract ▾
All authors David Attard, Ilian T. Iliev, Martin P. Rey, Harley Katz, Corentin Cadiou, Nicholas Choustikov
High Energy Physics (Phenomenology)
Pion structure in magnetized nuclear medium at finite temperature
Fathimath Shifa N K, Navpreet Kaur, Abi Jebarson A et al. (+3 more)
We investigate the structure of the pion in a magnetized
nuclear medium at finite temperature by analyzing the in-medium modifications of its parton distribution functions (PDFs) and electromagnetic form factors (EMFFs). We use a unified framework combining the
chiral SU(3)
quark mean field (CQMF) model and the light-cone
quark model (LCQM) where the in-medium
quark masses are evaluated using the CQMF model and subsequently employed as inputs in the light-cone formalism. The study systematically explores the effects of
magnetic field,
baryon density, temperature, and isospin asymmetry on the pion structure. In addition, Dirac sea contributions are incorporated to account for
vacuum polarization effects in the medium. Our results of PDFs and EMFFs provide valuable insights into the modification of pion properties under extreme conditions, highlighting the significant role of the surrounding medium in altering its internal structure.
Read the full abstract ▾
All authors Fathimath Shifa N K, Navpreet Kaur, Abi Jebarson A, Arvind Kumar, Suneel Dutt, Harleen Dahiya
Solar and Stellar Astrophysics
On the frequency-dependent time lags of the intermediate polar V709 Cas
Zackery A. Irving, Noel Castro Segura, Diego Altamirano et al. (+9 more)
Cataclysmic variables (CVs) are binary systems in which a white
dwarf (WD) primary accretes material from a late-type secondary, typically via a disc. To date, only six CVs, all of which are non-
magnetic, have been found to exhibit lags (delayed variability in one band with respect to another). In all six cases, these lags are “red” (i.e., red lags blue) with a time lag of order seconds. While there is no generally accepted mechanism for producing red lags in CVs, current theories suggest reprocessing in the disc, either on the thermal or recombination time-scales, or inside-out shocks propagating through the disc. Using $g$-, $r$-, and $i$-band data from the OPtical TIming CAMera (OPTICAM), we report the discovery of frequency-dependent red lags from V709 Cas: a
magnetic CV of the intermediate polar (IP) subclass. These red lags reach a maximum of $\sim$4–6 s on time-scales of 7.4–13.0 min, similar to previously-reported lags in non-
magnetic CVs. The detection of lags in an IP is significant as the WD's
magnetic field truncates the
accretion disc, limiting disc-based lag mechanisms to large radii; as a result, characteristic
accretion disc time-scales cannot explain the observed lags. However, recombination can occur on second time-scales, even in systems with truncated discs. For example, we show that recombination in the disc's bright spot, where overflowing material from the secondary meets the outer-edge of the disc, plausibly explains V709 Cas's optical spectrum, the prominence of optical
spin-orbit beat pulsations, and the red lags found in this work.
Read the full abstract ▾
All authors Zackery A. Irving, Noel Castro Segura, Diego Altamirano, Martina Veresvarska, Mariano Mendez, Federico Garcia, Domitilla de Martino, Simone Scaringi, Federico Vincentelli, Angel Castro, Federico Soto, Raul Michel
Mesoscale and Nanoscale Physics
Jie-Cheng Feng, Xinle Cheng, Itai Keren et al. (+5 more)
Vacuum fluctuations can be engineered using optical cavities, resonators, and surface-polaritonic modes, but extending such control deep inside a material remains challenging. Here we show that the
vacuum field inside a
hyperbolic material can be reshaped by a much thinner overlayer with opposite hyperbolicity. This effect requires overlap between the
hyperbolic bands of the two materials and modifies the coupling between the
vacuum field and matter excitations within the bottom material, without changing its intrinsic dielectric properties. As an application, we use Eliashberg theory to study a two-dimensional superconducting layer inside the bottom material, showing that the overlayer can remotely change its critical temperature. Our results may shed light on recent experiments reporting changes in superconductivity arising from a frequency-matched
hyperbolic overlayer, and suggest an on-chip route to long-range control of matter excitations and collective material properties.
Read the full abstract ▾
All authors Jie-Cheng Feng, Xinle Cheng, Itai Keren, Dante M. Kennes, Abhay N. Pasupathy, Dmitri N. Basov, Emil Vinas Bostrom, Angel Rubio
General Relativity and Quantum Cosmology
Closing the Loop: from EPRL-FK spinfoams to Regge dynamics
Matteo Bruno, Pietro Donà and Gowrisankar Sreeram
We study the semiclassical limit of the EPRL-FK model on a fixed simplicial complex. We ask what additional condition is needed for its variational principle to reproduce the equations of motion of Regge calculus, the standard discretization of General Relativity. This limit differs and complements the definition of the semiclassical regime in which, for suitable boundary states and a sufficiently refined simplicial complex, spinfoam amplitudes approximate gravitational transition amplitudes to a prescribed accuracy. We recast the EPRL-FK model in wedge-holonomy variables and identify
geometric closure as the missing condition. We prove that imposing
geometric closure as an additional constraint alongside local flatness allows us to reconstruct curved geometries. On a regular, nondegenerate Lorentzian branch with spacelike tetrahedra, these constraints define a surface equivalent to the space of length-Regge geometries, modulo gauge. The wedge action restricted to this surface becomes the Regge action, and variations tangent to this surface yield the length-Regge equations. We propose a way to implement
geometric closure directly in the spinfoam amplitude. With this additional constraint, the EPRL-FK model is equivalent to Regge calculus in its semiclassical regime on a fixed simplicial complex.
Read the full abstract ▾
Earth and Planetary Astrophysics
Chondrule size averaging in two and three dimensions
Emmanuel Jacquet
Chondrule sizes are an important discriminant of chondrite groups and chondrule formation theories. Yet most studies report 2D sizes without attempting the somewhat tedious corrections to 3D proposed in the past literature. I show here that 3D size averages can be simply calculated directly from 2D averages of appropriate powers of sizes (and vice-versa), without having to reconstruct 3D distributions, although explicit formulas to that end are also provided. This illuminates the comparison between 3D and 2D arithmetic size averages, which are confirmed to be little different for the published
datasets. Yet I suggest another type of average, the "sphere-weighted average" (i.e. weighted by the chondrule equal-volume sphere area), a measure of the surface/volume ratio of the chondrule population, which is more robust against omission of small chondrules. While larger than the arithmetic averages, it is best in line with previous literature estimates based on less exhaustive surveys of chondrules.
Read the full abstract ▾
Statistical Mechanics
Accurate ground-state entropies from population Monte Carlo: The antiferromagnetic Ising model on the Shastry-Sutherland lattice
Denis Gessert, Wolfhard Janke and Martin Weigel
We demonstrate how the population annealing Monte Carlo simulation method can be used to compute the ground-state
entropy to high precision. This approach is tested for the classical
antiferromagnetic Ising model on the Shastry-Sutherland
lattice with diagonal couplings chosen twice as strong as the nearest-neighbor interactions. In the absence of an external
magnetic field, the model is known to be disordered at all temperatures, with a macroscopically degenerate ground state. We find the ground-state
entropy to be $0.458\,777\,78(10)$ per site, which is in good agreement with the estimate of a recent study using the corner transfer
matrix renormalization group method. The sampled ground-state configurations are analyzed by considering the bond configurations, the local-energy configurations, and the
spin-
spin correlations. While all observations are consistent with the disordered nature of the ground state, the numerical data suggest a power-law decay of the size distribution of clusters of sites with local energies different from the ground-state level.
Read the full abstract ▾
Chemical Physics
Adaptive Expansions of the Optimized Effective Potential in Physically Motivated Response Spaces
Gabriel Chirchir, Aditi Singh, Yan Lukashevich et al. (+4 more)
The optimized effective potential (OEP) method provides an exact framework for incorporating orbital-dependent exchange within Kohn-Sham (KS) density-functional theory (DFT). Its practical implementation requires representing the exchange-response potential in a suitable auxiliary space, yet conventional choices are not necessarily adapted to the physical structure of the OEP response. Here, we introduce a general response-space strategy in which physically motivated response functions from existing model exchange potentials are repurposed as adaptive auxiliary directions for the OEP equation. Specifically, response functions associated with the Becke-Johnson (BJ), R"as"anen-Pittalis-Proetto (RPP), Gritsenko-van Leeuwen-van Lenthe-Baerends (GLLB), Krieger-Li-Iafrate (KLI), and localized Hartree-Fock (LHF) constructions are incorporated into compact auxiliary spaces, while their coefficients are determined directly from the projected OEP equation rather than fixed by the underlying model potentials. This establishes a systematic connection between model exchange potentials and finite-basis OEP: model potentials provide physically informed response directions, while OEP determines their system-dependent amplitudes. The framework encompasses one- and multidimensional response spaces, including occupied-orbital and occupied-pair representations, without modifying the underlying OEP condition. We show that these physically adapted spaces capture the dominant spatial structures of the OEP exchange response with substantially fewer degrees of freedom than conventional auxiliary expansions. The proposed approach therefore provides a general route to compact, adaptive representations of exchange-only OEP potentials and a systematic framework for developing low-dimensional OEP approximations from physically motivated model response functions.
Read the full abstract ▾
All authors Gabriel Chirchir, Aditi Singh, Yan Lukashevich, Igor Sawicki, Bogumiła Jezierska, Subrata Jana, Szymon Śmiga
Optics
Optically-Induced Modulation and Programming of Diamond Photonic Cavities
Yuchun Zhu, Amirali Arabmoheghi, Nicolas Le Thomas et al. (+3 more)
Single-
crystal diamond combines exceptional optical, thermal, and mechanical properties while hosting optically addressable and
spin-coherent colour centres, making it a promising platform for integrated
quantum and nonlinear photonics. However, practical post-fabrication mechanisms for dynamically controlling and tuning monolithic diamond photonic
circuits remain limited. Here, we demonstrate all-optical modulation and long-lived tuning of suspended diamond Fabry–Perot nanobeam cavities containing nitrogen-vacancy centres. Under 532~nm illumination, the infrared (1000 to 1100~nm) cavity response is governed by two competing contributions: a well-understood thermo-optic red-shift, and a novel charge-mediated blue-shift that we attribute to the free-carrier
plasma dispersion effect. With 10~mW of 20~kHz-modulated green light, we achieve an infrared modulation depth of approximately 45% of the available reflection contrast. Green illumination also produces quasi-permanent photo-refractive resonance blue-shifts, with a maximum observed tuning of 3.15~nm (0.87~THz), without measurable degradation of the cavity linewidth or contrast. Achieving the same cavity shift in a lithium-niobate Pockels modulator would require 200 to 500~V across a \(5~\mu\mathrm{m}\) electrode gap. These results establish a monolithic diamond nanophotonic platform combining agile and reversible modulation with long-lived optical reconfiguration, two key ingredients in photonic technologies.
Read the full abstract ▾
All authors Yuchun Zhu, Amirali Arabmoheghi, Nicolas Le Thomas, Niels Quack, Valentin Goblot, Christophe Galland
Earth and Planetary Astrophysics
Astrometric Evidence for Outer Giant Planets in Known Exoplanet Systems
Clarissa R. Do Ó, William Thompson, Dori Blakely et al. (+19 more)
Outer
giant planets can influence the formation and dynamical
evolution of their planetary systems. However, their long orbital periods make them difficult to detect using transit and radial velocity (RV) techniques. Measurements from Hipparcos,
Gaia DR2 and DR3 (G23H) can detect the
stellar reflex motion induced by distant companions before the release of
Gaia DR4 epoch astrometry. Using the G23H catalogue, we identify 29 outer companion candidates ($a_{median}$ $>$ 8.4 AU) in known transiting and RV systems. Starting from 170
exoplanet hosts with $P(\mathrm{companion})>0.75$ and posterior support for $0.3$–$13\,M_{\rm J}$ companions, we retain 29 systems where each selected component has a median semi-major axis beyond the outermost known
planet with every known
planet outside its 95% highest posterior density region in mass and semi-major axis. We incorporate published RV and imaging data from the literature to further constrain the outer candidate's mass and semi-major axis. In eight systems present in the sample, an RV variation or trend has already been reported in the literature. The reported candidates could potentially explain these RV variations, but joint astrometric and RV fits are needed to establish whether the same companions produce both signals. These results provide a set of high priority targets for further RV monitoring and joint orbit analysis with
Gaia DR4. If these companions are confirmed, their orbital constraints will provide a starting point for studies of their influence on the dynamical
evolution of the known inner
planets.
Read the full abstract ▾
All authors Clarissa R. Do Ó, William Thompson, Dori Blakely, Aniket Sanghi, Jerry W. Xuan, Dimitri Mawet, Jessica Speedie, Sarah Blunt, Simon Blouin, Jingwen Zhang, Doug Johnstone, Jean-Baptiste Ruffio, Eric Nielsen, Brendan P. Bowler, Alexandre Bouchard-Côté, Kyle Franson, William Roberson, Ryan Cloutier, Andre Fogal, Kaitlyn Hessel, Christian Marois, Alexandra Rochon
Materials Science · Cross-listed from cs.LG
GLASS: Global Latent Aggregation with Slot-based Set Decoding for Scalable All-Atom Crystal Generation
Hendrik Kraß, Seyed Mohamad Moosavi and Mathias Niepert
Generative models for
crystals enable the discovery of novel structures, but scaling all-atom generation to larger systems such as metal–organic frameworks remains challenging. We connect this difficulty to the correspondence problem of particle-space generation. Even on a single fixed target set, index-free permutation-equivariant particle flows require substantially more training for reliable generation as set size and density increase, under both independent and optimal-transport couplings. To resolve this challenge, we introduce GLASS—Global Latent Aggregation with Slot-based Set Decoding, which encodes structures in a permutation-invariant global latent space and learns their distribution via flow matching. A learned-slot decoder constructs all atoms in parallel, removing atom-wise correspondence from generative transport. On MP20, GLASS is competitive with particle-space models, and flow training can reach the validity of the training data at every structure size. On a QMOF subset, GLASS generates MOFs with up to 150 atoms per unit
cell without conditioning on building blocks,
topology, or composition, and approaches the structural validity of the training data. On both
datasets, flow training exposes a validity–novelty tradeoff, and MOF novelty remains limited by autoencoder generalization on the available data. These results show that separating correspondence assignment from generative transport provides a simple route toward high-validity generation of larger atomistic systems.
Read the full abstract ▾
High Energy Physics (Phenomenology)
Impact of Open Heavy-Flavour Production on nCTEQ Nuclear PDFs
Jan Wissmann, Tomáš Ježo, Michael Klasen et al. (+2 more)
We present nCTEQ26OHF, a global analysis of
nuclear parton distribution functions (nPDFs) within the nCTEQ framework. In this analysis, constrasting the main nCTEQ26 release, we replace the
Crystal-Ball function, an effective
matrix element that is used in nCTEQ26 for open heavy-
flavor (OHF) and quarkonium production, by an SACOT GM-VFNS calculation for the OHF predictions. The resulting nCTEQ26OHF PDFs are compatible with the nCTEQ26 PDFs within uncertainties, implying that the OHF data alone provide ample constraint.
Read the full abstract ▾
All authors Jan Wissmann, Tomáš Ježo, Michael Klasen, Ingo Schienbein, Hubert Spiesberger
Quantum Physics
A quantum thermal machine surpassing the classical thermodynamic limit on precision
Simon Sundelin, Ludvig Nordqvist, Khalak Mahadeviya et al. (+4 more)
Precision in nonequilibrium processes comes at a thermodynamic cost: suppressing fluctuations generally requires increased dissipation. Thermodynamic uncertainty relations (TURs) make this trade-off quantitative by linking current fluctuations to
entropy production in classical
stochastic dynamics. In the decade since its discovery, the canonical steady-state TUR and its finite-time generalizations have become a cornerstone of non-
equilibrium thermodynamics, constraining the performance of molecular machines and allowing heat dissipation to be inferred from observable fluctuations. Whether the canonical TUR can be violated in a controlled
quantum device remains an outstanding experimental question, in part because doing so requires resolving extremely small steady-state currents as well as their fluctuations. Here we experimentally show that steady-state
quantum transport can surpass the precision permitted by the canonical TUR. We observe this violation in a superconducting
quantum thermal machine coupled to a microwave waveguide acting as a cold bath and to a classical noise source providing an effective infinite-temperature bath. We observe a TUR ratio $Q = 1.71 \pm 0.17$, in violation of the classical bound $Q \geq 2$. Our results demonstrate a fundamental distinction between classical and
quantum thermodynamics, paving the way for
quantum thermal devices that achieve enhanced precision at reduced energy cost.
Read the full abstract ▾
All authors Simon Sundelin, Ludvig Nordqvist, Khalak Mahadeviya, Vyom Kulkarni, Mohammed Ali Aamir, Mark T. Mitchison, Simone Gasparinetti
High Energy Physics (Experiment)
Measurements of electroweak penguin $B$ decays with missing energy at Belle and Belle II
Lorenz Gärtner
Electroweak penguin $B$ decays with
neutrinos or $\tau$
leptons in the final state are sensitive probes of physics beyond the Standard Model. Using the full Belle and Run 1 Belle II
datasets, the first search for $B^0 \to K^0_S\tau^+\tau^-$ sets the upper limit on the branching fraction to $\mathcal{B} < 8.3 \times 10^{-4}$, the search for $B^+ \to K^+\tau^+\tau^-$ sets $\mathcal{B} < 5.6 \times 10^{-4}$, and their isospin combination gives $\mathcal{B}(B \to K\tau^+\tau^-) < 5.4 \times 10^{-4}$, all at 90% confidence level (CL$_s$). The first search for inclusive $B \to X_s\nu\bar\nu$ decays at Belle II sets $\mathcal{B} < 3.3 \times 10^{-4}$. Finally, the Belle II $B^+ \to K^+\nu\bar\nu$ result is reinterpreted in the Weak Effective Theory using its published likelihood. The data prefer an enhanced vector contribution and mildly favour a nonzero tensor contribution.
Read the full abstract ▾
Quantum Physics
Margenau-Hill distribution as a Necessary and Sufficient Signature of Measurement Incompatibility
Partha Patra and A. K. Pan
Measurement incompatibility and the negativity of quasi-probability distributions both demonstrate the signature of nonclassicality. However, their relations largely remained qualitative, and no explicit operational connection has been established. We provide an operational link between measurement incompatibility and the Margenau-Hill(MH) quasi-probability distribution associated with two dichotomic observables. { We first derive the joint measurability (measurement compatibility) condition for any pair of dichotomic observables in arbitrary finite dimension $d$.} We then rigorously prove that for any pair of unsharp dichotomic measurements in dimension $d$, the positivity of the MH distribution is equivalent to joint measurability i.e., the MH distribution is positive if and only if the measurements are jointly measurable. We further introduce the MH-like quasi-probability distribution for $n$ dichotomic unsharp observables in arbitrary finite dimension and derive a sufficient condition of joint-measurability when the observables are mutually anticommuting. Finally, we propose an interferometric setup, inspired by
quantum-switch architectures, that directly reconstructs MH quasi-probability which in turn provides a test of incompatibility.
Read the full abstract ▾
Quantum Gases
Second-order coherence properties of ultrafast polariton dynamics in plasmonic lattices
Evgeny A. Mamonov, Lukas Freter, Sioneh Eyvazi et al. (+2 more)
The first-order coherence properties of strongly coupled systems supporting polariton lasing and Bose-Einstein condensation (BEC) have been thoroughly studied and show consistent results. In contrast, second-order coherence properties have been found to vary for different systems, and the second-order coherence function can deviate from the value of one, typical for atomic BEC, revealing super-Poissonian fluctuations even above the BEC/polariton lasing threshold. This calls for a deeper understanding of the emission statistics and dynamics in light-based condensates, especially in the non-
equilibrium regime. Here we demonstrate a coherent state of polariton emission from a plasmonic
lattice measured as the second-order coherence function value separately for $\mathrm{\Gamma}$- and non-$\mathrm{\Gamma}$-point radiation (ground state and high-energy tail). We observe a high degree of coherence with the value $g^{(2)}(\tau=0)-1<10^{-4}$. We also demonstrate the ultrafast ($>$1 THz) nature of the dynamics. The process can be interpreted as a BEC with ultrafast, sub-50-fs thermalization, but we also suggest an alternative explanation as superradiance in a system where the emitters have vibrational degrees of freedom.
Read the full abstract ▾
All authors Evgeny A. Mamonov, Lukas Freter, Sioneh Eyvazi, Elliot W. Lloyd, Päivi Törmä
Quantum Physics
Arbitrary high-dimensional entanglement purification with the superposition of paths
Zi-Han Zheng, Wen-Qiang Liu, Chen-Ming Bai et al. (+1 more)
High-dimensional
quantum entanglement offers significant advantages over its two-dimensional counterparts in various
quantum information processing tasks. We propose a scalable method for implementing an arbitrary high-dimensional
entanglement purification protocol (HDEPP) using path superposition. By selecting appropriate single-qudit gates, qudit-flip errors and phase-flip errors can be purified. Counterintuitively, the HDEPP becomes more robust for higher-dimensional systems and exhibits enhanced purification fidelity as the dimension increases. Our HDEPP not only requires fewer operational resources but also in principle can achieve unity fidelity through multiple rounds of iteration. Furthermore, we develop feasible optical schemes to purify the frequency degree of freedom of
photons suffering from qudit-flip and phase-flip errors using hyperentanglement. This work paves the way toward high-dimensional
quantum communication and
quantum networks.
Read the full abstract ▾
All authors Zi-Han Zheng, Wen-Qiang Liu, Chen-Ming Bai, Hai-Rui Wei