High Energy Physics (Phenomenology)
The Pomeron loop as a perturbative correction to single Pomeron exchange revisited
Martin Hentschinski, Karina Mendoza-Ramírez and Miguel A. Ocaña-Bribiesca
Pomeron loops are known to arise naturally as building blocks of high energy scattering amplitudes as soon as one starts to consider corrections to single Pomeron exchange, i.e. to high energy resummation based on the Balitsky-Fadin-Kuraev-Lipatov
evolution equation. While some authors argue that Pomeron loops provide only very small corrections, a 2013 study found that the complete QCD Pomeron loop provides a large correction, which can exceed the single Pomeron contribution already at LHC energies. In this paper we carefully review the derivation of the single Pomeron loop and evaluate the resulting expression numerically, making use of a representation of the triple Pomeron vertex by Korchemsky. While we do not confirm the findings of the 2013 study, we find that the Pomeron loop can provide a 24%-39% correction at lowest currently accessible values of $x$ and hard scales at the non-perturbative boundary.
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High Energy Physics (Phenomenology)
Deciphering Matter Invariants via Renormalization Group Equations for Neutrino Oscillations
Xin Wang and Shun Zhou
We utilize renormalization group equations (RGEs) for
neutrino oscillations in matter to decipher the structure of exact matter invariants. By combining the RGEs with the $S^{}_3$ permutation covariance under relabeling of the
neutrino mass eigenstates, we recast all five algebraically independent matter invariants in the three-
flavor framework as exact first integrals. Treating the matter potential as a matter spurion and imposing the cancellation conditions for the $1/\widetilde\Delta_{ij}^{}$ poles in the RGEs, we further prove that the three-
flavor framework contains only two independent monomial invariants, which can be related to the Naumov and Toshev relations. We then extend the analysis to the four-
flavor framework, where we uncover a complete set of eleven algebraically independent matter invariants and prove that the rank-two electron–sterile spurion obstructs the common pole cancellation required for any nontrivial multiplicative monomial invariant.
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Earth and Planetary Astrophysics
A Clearer View of HAT-P-1 b: JWST NIRSpec G395H Reveals Water, Carbon Dioxide, and Possibly Hydrogen Sulfide
Reza Ashtari, Stephen P. Schmidt, Guangwei Fu et al. (+16 more)
As part of JWST's
Exoplanet Grand Tour Survey, we use panchromatic transmission spectroscopy to connect HAT-P-1 b's previously studied optical and near-infrared atmosphere to the longer-wavelength molecular bands accessible with JWST. We present JWST NIRSpec G395H transmission spectroscopy of the hot Jupiter HAT-P-1 b over 2.7–5.3~$\mu$m, and combine the new spectrum with archival HST STIS and WFC3 observations for a 0.3–5.3~$\mu$m atmospheric analysis. We independently reduce the JWST data with the Eureka!, FIREFLy, and Tswift pipelines, finding mutually consistent transmission spectra across the G395H bandpass. Atmospheric
retrievals yield strong evidence for H$_2$O and CO$_2$ with Bayes factors of $\log_{10}B_{\mathrm{H_2O}}=8.9$ and $\log_{10}B_{\mathrm{CO_2}}=52.3$, while providing tentative evidence for H$_2$S ($\log_{10}B_{\mathrm{H_2S}}=1.4$). The joint H$_2$O and CO$_2$ constraints favor an atmosphere near chemical
equilibrium, with $\log_{10} \text{M/H}=0.99^{+0.19}_{-0.14}$, corresponding to $\sim10\times$
Solar or $\sim9\times$ relative to the near-
solar metallicity host
star, and a 3$\sigma$ upper limit of C/O $<0.52$. Because H$_2$O and CO$_2$ provide a
metallicity comparatively insensitive to vertical mixing in this temperature regime, their combined detection suggests the composition is dominated by bulk enrichment rather than strong disequilibrium transport. We find no significant evidence for clouds; instead, the persistence of molecular structure across the spectrum argues against strong cloud muting. The tentative H$_2$S signal, if confirmed, would further suggest limited photochemical processing at the pressures probed. Together, the molecular inventory, enriched
metallicity, and low C/O ratio point to an oxygen-rich atmosphere and establish HAT-P-1 b as a
benchmark for comparative studies of hot-Jupiter atmospheric composition.
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All authors Reza Ashtari, Stephen P. Schmidt, Guangwei Fu, Avinash Verma, David K. Sing, Kevin B. Stevenson, Jayesh Goyal, Katherine A. Bennett, Joshua D. Lothringer, Jacob Lustig-Yaeger, Sagnick Mukherjee, Carlos Gascón, Natalie H. Allen, Patrick McCreery, Le-Chris Wang, Mei Ting Mak, Kristin S. Sotzen, Lakeisha M. Ramos Rosado, N. J. Mayne
Fluid Dynamics
Compaction in a deformable porous cylinder with elastic boundaries
Richard Mcnair, Kerstin Schirrmann, Anne Juel et al. (+1 more)
Perfusion of soft materials such as biological tissue or hydrogels is essential for the functioning of organ and laboratory systems such as chromatographic columns and bioreactors. Inspired by these applications, we model fluid-driven compaction in a long, thin cylindrical porous medium bounded by an impermeable elastic membrane and study how flow regimes relate to elastic parameters. Using a Lagrangian formulation of Darcy flow coupled to small-strain linear elasticity with porosity dependent permeability and elastic
moduli, we perform an asymptotic reduction in the small aspect ratio limit and obtain a leading-order nonlinear
diffusion equation for the porosity, which we solve numerically. Whereas rigid boundaries produce a compaction plateau, compliant walls exhibit, at most, an intermediate plateau beyond which the flow increases once the imposed pressure becomes comparable to the product of membrane stiffness and initial porosity. When the membrane is less stiff than the porous medium, flow rate can exceed that expected for a rigid medium. A parameter space map distinguishes regimes where plateau and breakthrough occur, where the steady flow rate is below (sub-Darcy) or above (super-Darcy) the undeformable-medium prediction, and delineates the small-strain domain in which the theory applies. An asymptotic solution for negligible
gravity captures the departure from the plateau and yields compact expressions for effective permeability and flow rate.
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All authors Richard Mcnair, Kerstin Schirrmann, Anne Juel, Igor L. Chernyavsky
High Energy Astrophysical Phenomena
Exploring the sensitivity of in-ice radio detectors to cosmic ray mass composition
Nathaniel Alden, Marissa Boucher, Cosmin Deaconu et al. (+2 more)
In-ice
radio detectors have been developed primarily for the detection of high-energy
neutrinos via the Askaryan effect, but have recently been shown to also be sensitive to
cosmic ray air showers impacting the ice sheet. Using CORSIKA 8 to simulate impacting air showers, we find that the lateral width of the in-ice cascade is sensitive to the atomic mass of the primary
cosmic ray. The width of the shower core is accessible through the shape of the Askaryan
radio spectrum, while the amplitude encodes the total in-ice charge excess. Using these two observables, we show that in-ice
radio detectors can be used to measure
cosmic ray mass composition in the region above $10^{17}$eV if the in-ice receivers are placed to adequately sample the Askaryan emission pattern. We also show that the in-ice core width is highly, but not exactly, correlated with the depth of maximum particle count ($\mathrm{X}_{\mathrm{max}}$), the most commonly used observable for reconstructing
cosmic ray mass composition.
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All authors Nathaniel Alden, Marissa Boucher, Cosmin Deaconu, Abigail Vieregg, Philipp Windischhofer
Quantum Physics
Hardware-Efficient Error Mitigation and Shot-Efficient Sampling on IBM Quantum Hardware
Sumit Chongder
We experimentally study error mitigation and finite-shot sampling on superconducting
quantum hardware under a constrained execution budget. The study combines calibration-aware
qubit selection,
circuit-depth scaling, zero-noise extrapolation, dynamical decoupling, readout-error mitigation, and repeated-shot estimation on an IBM
Quantum processor. Experiments are organized across ideal simulation, noise-model simulation, and physical-device execution to separate sampling uncertainty from device-induced error. We investigate how mitigation performance changes with
circuit depth, effective noise scale,
qubit connectivity, and measurement budget, and quantify accuracy using expectation-value error, mean-squared error, statistical uncertainty, and mitigation gain. A fixed hardware-execution budget is used to evaluate shot allocation strategies and repeated measurements without relying on unlimited sampling. The resulting analysis provides a hardware-aware characterization of when mitigation improves expectation-value estimation and when finite-shot fluctuations offset the benefit of additional mitigation overhead. The implementation uses contemporary Qiskit and IBM
Quantum Runtime workflows and is designed to provide reproducible experimental evidence for error-mitigation studies on current
quantum processors.
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High Energy Physics (Theory)
Positivity constraints on the dynamics of cusped impurities in CFTs
Jeevan Chandra
The cusp anomalous dimension is the universal logarithmic contribution to the free energy of a line defect with a cusp, and provides a useful observable characterizing defect dynamics. We generalize this notion to cusped line defects in the presence of a planar conformal boundary or interface. The geometry is characterized by three angles, and the distance of the cusp from the boundary or interface which separates short-distance and long-distance regimes. The resulting free energy contains two large logarithmic terms: a short-distance contribution governed by the usual
vacuum cusp anomalous dimension, and a new long-distance contribution sensitive to the boundary or interface. Using reflection positivity for transverse deformations of the defect rays, we derive several constraints on the coefficients of these logarithmic terms, which can be packaged into negative semi-definiteness of their angular Hessians. We also derive constraints on the continuation of these coefficients to Lorentzian kinematics. We compute these coefficients and verify the constraints explicitly in free scalar and Maxwell theories and in planar $\mathcal N=4$ super-Yang-Mills theory at weak coupling for various choices of boundary conditions. At strong coupling, we compute the logarithmic coefficients in the
holographic D3-D5 defect CFT and find a Gross-Ooguri-like phase transition between competing string worldsheets driven by the geometry of the cusp relative to the interface. We also observe a close connection of the cusp free energy in this setup with
holographic corner
entanglement entropy.
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Soft Condensed Matter
Hierarchical organization governs nonlinear mechanical reversibility in $\iota$-carrageenan gels
Thomas Gibaud and Loïc Hilliou
Carrageenan gels are thermoreversible polysaccharide networks whose mechanical properties emerge from ion-mediated helix association, yet how their molecular organization controls nonlinear deformation remains poorly understood. Here, we investigate the temperature-dependent rheology of $\iota$-carrageenan gels formed in KCl solutions using linear and nonlinear oscillatory rheology combined with normal-force measurements. $\iota$-carrageenan forms homogeneous and mechanically reversible gels whose elastic modulus increases continuously with quench depth. Deep quenches generate pronounced strain stiffening before yielding, associated with the development of internal stresses revealed by negative normal forces. Remarkably, large deformations preserve the small-strain elastic modulus while progressively suppressing strain stiffening, demonstrating a partial mechanical reversibility of the network. We interpret these observations using a hierarchical network picture in which a persistent intermolecular network controls linear elasticity, while a more fragile mesoscale organization enables cooperative
alignment and stress amplification under deformation. Our results highlight that nonlinear mechanics of thermoreversible polysaccharide gels are governed not only by molecular connectivity, but also by the reversible formation and eventually destruction of mechanically adaptive hierarchical structures.
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Fluid Dynamics
A physics-constrained machine-learning sub-grid-scale modeling approach for turbulent premixed flames
Seung Won Suh, Jonathan F. MacArt, Luke N. Olson et al. (+1 more)
A physics-embedded training framework is used to close the sub-grid-scale dynamics of turbulent premixed flames. The trained model augments the resolved flow equations and is trained to match its predicted flow field to trusted data. An end-to-end optimization of the coupled resolved equations and embedded model leads to a model that is robust and effective for a freely propagating premixed flame in
turbulence, modeled by a single-species, single-step, and irreversible chemical reaction. Important constraints are built into the training formulation for conservation, scalar boundedness, and equivariance. The model is scaled based on the residual of the resolved flow equations to focus its influence where the closure is needed. It outperforms other cases considered — no-model, dynamic closure, and the same machine learning model trained directly to fit the residual data — for a long-time simulation, correcting the
turbulence dissipation and flame kinematics. Finally, it is shown how the prediction-based training better informs the model than the precise residual data.
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All authors Seung Won Suh, Jonathan F. MacArt, Luke N. Olson, Jonathan B. Freund
High Energy Astrophysical Phenomena
Distinct Modes of Pulsar Glitch Activity Revealed by the Waiting-Time–Amplitude Morphology
Wen-Tong Liu, Wei-hua Wang, Xia Zhou et al. (+1 more)
Pulsar glitches display diverse behaviors. They are commonly labeled as "Vela-like" or "Crab-like," yet these qualitative categories do not provide reproducible quantitative boundaries. We constructed an objective classification scheme based on the joint distribution of backward waiting time $\Delta t_{-}$ and fractional glitch amplitude $\Delta\nu/\nu$. A sample of 349 glitches from 22
pulsars was compiled by cross-matching the Jodrell Bank and ATNF glitch databases. For each source, we used two-dimensional kernel density estimation (KDE) together with highest-density regions (HDRs) to derive
geometric descriptors, including the HDR area, anisotropy ratio, and out-of-HDR fraction. Hierarchical clustering of the KDE–HDR descriptors revealed two morphology classes independent of visual inspection. In this convention, the Compact class is associated with small HDR areas, elevated anisotropy, and limited peripheral occupancy. The Extended class is associated with broader HDR occupancy and stronger low-density extensions. We found that bootstrap resampling and hyperparameter sensitivity tests confirmed this partition for most sources. Nevertheless, two prolific
pulsars (PSR J0537-6910 and PSR J1341-6220) were found to occupy intermediate positions. Logistic regression identified the mean backward waiting time $\langle\Delta t_{-}\rangle$ as the strongest class predictor (in-sample $\mathrm{AUC}=0.88$; leave-one-out $\mathrm{AUC}_{\mathrm{CV}}=0.59$, reflecting the limited sample size). Additionally, a parallel analysis using $\Delta t_{+}$ recovered the same two-class structure but with reduced stability. The data suggest that the Compact class is consistent with near-complete reservoir depletion, whereas the Extended class reflects partial, avalanche-like releases. As a result, short-term measurements of $G$ in Extended-class
pulsars may underestimate the true crustal superfluid fraction.
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All authors Wen-Tong Liu, Wei-hua Wang, Xia Zhou, Fei-fei Kou
Solar and Stellar Astrophysics
An All-Sky Catalog of 6.5 Million Primary Red Clump Stars from Gaia DR3 XP Spectra
Zheng Yu and Bingqiu Chen
Red clump (RC)
stars are excellent standard candles for mapping the three-dimensional structure of the Milky Way. We construct an all-sky catalog of 6.5 million primary RC
stars using spectroscopic estimates of asteroseismic parameters inferred from
Gaia DR3 low-resolution XP spectra. We train a mixture density network (MDN) on a cross-matched sample. The network maps each 343-dimensional corrected XP spectrum to estimates of $\Delta\Pi_{1}$, the asymptotic period spacing of dipole
gravity modes, and $\Delta\nu$, the large frequency separation. We select primary RC
stars using these two estimates. We release two complementary catalogs defined by different parameter-space cuts and thresholds: a high-purity Tier 1 sample of 532,189
stars with 97% purity and a high-completeness Tier 2 sample of 6,534,931
stars with 86% completeness. Both catalogs cover the full celestial sphere. We provide distances and extinction values for all
stars. We obtain a median photometric distance precision of 6% for Tier 1 RC
stars. Using the resultant distances, we independently calibrate the
Gaia DR3 parallax zero-point offset. The three-dimensional density distribution traced by the Tier 2 sample extends continuously to $R\approx25$ kpc. Both catalogs are publicly available. These catalogs provide a valuable resource for
Galactic archaeology, delivering a homogeneous
dataset to trace the chemo-dynamical
evolution of the Milky Way and to calibrate models of
stellar populations.
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Materials Science
Modifying van der Waals Materials via Cavity Vacuum Fluctuations
Mohammad Hassan, Cankut Tasci, Leon Orlov-Sullivan et al. (+2 more)
In the field of cavity
quantum materials,
vacuum fluctuations of optical cavities are used for modifying ground-state properties of
quantum materials without external driving. Here, one example is the van der Waals (vdW)/dispersion interaction in layered 2D vdW materials, where non-additive long-range correlations can dominate the interlayer binding. While cavity-induced changes of such interactions have been predicted and described using ab initio methods for molecular systems, no efficient description exists yet for extended materials. In this Letter, we close this gap by introducing a periodic formulation of the
photon many-body dispersion (pMBD) functional within
quantum electrodynamical density-functional theory (QEDFT). Applying this method with efficient $\textbf{q}$-point sampling to
bilayer hBN and
graphene, we predict cavity-modified stacking, increased
equilibrium interlayer distances, and softened layer breathing modes with increasing light-matter coupling strength. Our results establish cavity
vacuum fluctuations as a tuning knob for the structural properties of vdW materials.
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All authors Mohammad Hassan, Cankut Tasci, Leon Orlov-Sullivan, Leonardo A. Cunha, Johannes Flick
Quantum Physics
Beyond sensitivity: mechanism-resolved error budgets for designing quantum sensors
Nima Leclerc, Marco Capelli, Kevin James Rietwyk et al. (+14 more)
Quantum sensors are specified by a headline sensitivity, yet applications also demand accuracy and reliability. The dominant limiter of one metric is often known, but no method resolves how interacting mechanisms combine into a signed, per-mechanism budget for each metric. We introduce a framework that computes a sensor's sensitivity, accuracy, and robustness from one open-system simulation and attributes each to its limiting mechanism. For a nitrogen-vacancy diamond ensemble the attribution inverts across metrics: dephasing limits sensitivity, the thermal ground-state shift limits accuracy, and optical leakage limits robustness. At identical sensitivity the recovered-field bias spans $8$ to $1500$\,nT, so tuning to sensitivity alone can miss the accuracy target by two orders of magnitude. The same modeling transfers to a cesium optically pumped magnetometer recording a human magnetocardiogram. As a digital twin, it predicts the gain from addressing each limiter, so sensors can be designed to the required metrics.
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All authors Nima Leclerc, Marco Capelli, Kevin James Rietwyk, Mark Dong, Dmitry Lyakh, Geoffrey Iwata, Brandon Rodenburg, Sean Oliver, Benedikt Kloss, Jin-Sung Kim, Stefan Bogdanovic, Yunheng Chen, Meysam Sharifzadeh Mirshekarloo, Cedric Weber, Marcus Doherty, Ethan Pratt, Joseph Hagmann
Chemical Physics
A reaction volume bias Monte Carlo trial for sampling chemisorption in confinement
Samiha Sharlin, Harold W. Hatch, Daniel W. Siderius et al. (+1 more)
Molecular modeling of chemisorption with Monte Carlo requires the development of new trial moves to efficiently sample complex fluids such as water in Bronsted acid zeolites. Here, we develop a reaction volume bias (RxVB) Monte Carlo trial for modeling chemisorption by combining identity-switch and aggregation-volume-bias (AVB) moves. This method aims to promote the sampling of reactions by choosing reactive pairs that are within an arbitrarily specified reaction volume. The RxVB move achieves up to a 90-fold increase in accepted reaction events over unbiased moves in a single-site slit-pore model, corresponding to a 70-fold gain in statistical efficiency after accounting for computational overhead. But when the same move is applied to water in a Bronsted acid zeolite without orientational bias, there is no measurable speedup for a single MFI unit
cell. We demonstrate a simple expression that predicts the maximum efficiency increase in the simplest case where selecting reactants that are near each other is the major sampling bottleneck. Dense water systems may require additional configuration-bias or orientational bias to improve sampling of the hydrogen bond network in order to increase acceptance. This new RxVB trial was made available with examples in the open-source Free Energy and Advanced Sampling Simulation Toolkit (FEASST) simulation package.
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All authors Samiha Sharlin, Harold W. Hatch, Daniel W. Siderius, Tyler R. Josephson
Instrumentation and Methods for Astrophysics
Fast and efficient nested sampling with BEST
Andreas Nygaard
Nested sampling is widely used for
Bayesian evidence computation, but its intrinsically sequential structure limits how efficiently it can exploit modern vectorised likelihoods and emulators. We present a new nested-sampling implementation in best, written entirely in TensorFlow and designed for efficient XLA compilation on both CPUs and GPUs. The sampler combines clustering and slice sampling with the possibility of updating several live points simultaneously. Since batching breaks the strict ordering of conventional nested sampling, we introduce sorting and history-based corrections to reduce the resulting bias in the evidence estimate. We test the sampler on Gaussian, Rosenbrock, and
multimodal likelihoods and compare its performance with JAXNS and UltraNest. The results show that accurate evidence estimates can be retained for moderate batch sizes, with $m/N_{\rm live}\lesssim 0.1$ providing a useful practical regime. Finally, using a 27-dimensional cosmological likelihood emulator, we show that batched live-point updates can substantially reduce the wall-clock time while remaining consistent with sequential sampling within the reported uncertainties. The new implementation therefore extends best with an efficient nested-sampling method tailored to fast, vectorised likelihoods and emulator-based inference.
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Quantum Physics
Sufficient positive maps between von Neumann algebras: Rényi divergences
Anna Jenčová and Lauritz van Luijk
We prove recovery
theorems for $\alpha$-$z$ Rényi divergences under normal unital positive maps between von Neumann
algebras. Previous results in this setting required 2-positivity, while recent finite dimensional work showed that this assumption can be relaxed to mere positivity. Our proof uses sufficiency for JW*-subalgebras and $L^p$-spaces over them to characterize equality in the data processing inequality. As a further application of our methods, we solve a problem discussed by Haagerup and Stormer: Every conditional expectation of a von Neumann
algebra onto a JW*-subalgebra factors through a conditional expectation onto the generated von Neumann subalgebra.
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High Energy Astrophysical Phenomena
Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms
Joheen Chakraborty, Erin Kara, Wenbin Lu et al. (+17 more)
Quasi-periodic eruptions (QPEs) are recurring bursts of X-ray radiation originating from supermassive black holes (SMBHs). They are an unprecedented type of structured, high-amplitude SMBH variability, but the physical origins of their regularity, timescales, energetics, and emission are uncertain. We present new XMM-Newton observations of the QPEs in ZTF19acnskyy/"Ansky", constituting the deepest observations of individual bursts in any source thus far. The X-ray spectra reveal time-evolving P Cygni profiles comprising blueshifted absorption and redshifted emission from L-shell transitions of Fe XIX-XXIV, with column densities $N_H\sim 10^{22-23}$ cm$^{-2}$ and bulk velocities of $|v_w/c|\sim 0.2$, indicating relativistic mass ejections during each eruption. We construct a time-dependent analytical model of a wind turning on to self-consistently compute its evolving luminosity and ionization properties, and find that the light curve and spectral lines can be simultaneously produced by a wide-angle
outflow with $\dot{M}\sim 10^{-9}-10^{-8}\,M_\odot$ s$^{-1}$ kinetically powering the X-rays with an efficiency of $L_X/\dot{E}_K\sim 0.1$. For a covering fraction $f_\Omega\sim0.5$, each eruption ejects $\sim 10^{-3}\,M_\odot$ and $\gtrsim 10^{49}$ erg of kinetic energy, setting an upper bound on the QPE lifetime of $\lesssim1000$ bursts if the underlying mass reservoir is $\sim1 M_\odot$, and implying that the bursts may result in detectable multiwavelength signatures of reverberation and feedback. These measurements provide new quantitative constraints on QPE energetics, emission mechanisms, and the mass/energy they recycle into their circumnuclear environments, as well as an observational probe for direct comparison with physical models and hydrodynamical simulations of QPEs.
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All authors Joheen Chakraborty, Erin Kara, Wenbin Lu, Brian D. Metzger, Peter Kosec, Riccardo Arcodia, Itai Linial, Olivia Aspegren, Ehud Behar, Sudip Bhattacharyya, Margherita Giustini, Lorena Hernandez-Garcia, Daniel Kasen, Giovanni Miniutti, Frits Paerels, Erwan Quintin, Claudio Ricci, Daniele Rogantini, Paula Sanchez-Saez, Fatima Zaidouni
Quantum Physics
Langevin Theory of Non-Markovian Quantum Dynamics: Application to Delayed Coherent Feedback and the Laser Linewidth
Marc Cuenca-Laràs, Ming Li, Carlos Navarrete-Benlloch et al. (+1 more)
Phase-space methods are powerful tools for the treatment of Markovian open
quantum systems: they map the reduced dynamics of a system S, in interaction with an environment E, exactly onto Langevin equations for c-number
stochastic variables, as opposed to Heisenberg-Langevin equations for operators. Langevin equations provide analytical insight in key regimes and excel at handling strong nonlinearities and couplings, where other methods often falter. Extending phase-space methods to non-Markovian dynamics, however, has remained a long-standing challenge. Here we address this gap by applying phase-space representations to the full S+E system; integrating out the environmental degrees of freedom then yields a general Langevin framework for S that incorporates both deterministic and
stochastic contributions from E. Normally ordered representations, such as the Glauber-Sudarshan P representation and its positive variant due to Drummond and Gardiner, lead to Langevin equations in which (i) non-Markovian effects emerge exclusively in the deterministic terms, via a
memory kernel, and (ii) noise contributions vanish when E is initially in the
vacuum state. To demonstrate the power of this framework, we address the paradigmatic problem of delayed coherent feedback, in which the system is driven by its own past state, and study its impact on the
laser linewidth: we recover the narrowing observed well above threshold and predict an enhanced narrowing just above it. Crucially, the number of
stochastic variables scales linearly with the system size, making the framework suitable for problems ranging from a few degrees of freedom to genuinely many-body systems. This opens the way to the systematic study of non-Markovian driven-dissipative
quantum systems using the same analytical and numerical tools that have long made phase-space methods so successful in the Markovian regime.
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All authors Marc Cuenca-Laràs, Ming Li, Carlos Navarrete-Benlloch, Germán J. de Valcárcel
Quantum Physics
Classical Commitment over Quantum Channels with Limited Entanglement Assistance
Remi A. Chou
We study classical string commitment over
quantum channels with limited preshared
entanglement. For noninteractive protocols, we determine the commitment capacity of a class of channels with input dimension $d$ that, at each use, sample a pair of classical random variables $(F,Z)$, apply one of the $d^2$ Heisenberg–Weyl operators indexed by $Z$ to the input, and deliver the transformed
quantum system together with $F$ to the receiver. If $E$ is the available
entanglement rate in bits per channel use, then the capacity is $\min\{H(Z|F),\log_2d+E\}$. This class of channels encompasses
quantum erasure and depolarizing channels, as well as families of Pauli channels. Additionally, for interactive protocols, we show that the commitment rate cannot exceed $\log_2d+E$ bits per channel use, so that when $H(Z|F)\geq\log_2d+E$, interactive communication does not increase the capacity. As a consequence, for interactive protocols, we determine the capacity of the
quantum erasure channel.
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Materials Science
Automated Dislocation Detection in Electron Channelling Contrast Imaging: A Comparative Study of Rule-Based, Neural Network, and Deep Learning Approaches
A. Holmes, C. Trager-Cowan, J. Bruckbauer et al. (+1 more)
Quantifying threading dislocations in
semiconductor materials via electron channelling contrast imaging (ECCI) is heavily bottlenecked by slow manual analysis. This work
benchmarks three automated detection pipelines on ECCI micrographs of gallium nitride (GaN) against a statistical ground truth. A classical rule-based computer
vision approach proved unreliable due to extensive per-image tuning requirements, while a convolutional neural network (CNN)-based multi-stage classification and locator method achieved 87% accuracy but required significant time for a test image and was less efficient in high-density regions. By contrast, a unified single-stage you only look once (YOLOv8) architecture achieved a counting accuracy of 98.6%, alongside 98.7% precision and 98.7% recall across 7451 dislocations over multiple images, with rapid inference times. Successful deployment of YOLOv8 required addressing two domain-specific machine learning challenges. First, to mitigate the model's scale sensitivity, an adaptive gaussian tile-sizing
algorithm was developed to optimise the field of view per image. Second, the deployed confidence threshold (0.025) differed substantially from the suggested inference default value for YOLOv8 (0.25), raising counting accuracy from 90.8% to 99.3% on a subsection of the
benchmark image. In this case, low confidence scores represented physical signal strength rather than classification ambiguity. This unified, scale-adaptive approach demonstrates practical viability for high-throughput, quantitative
semiconductor defect characterisation.
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All authors A. Holmes, C. Trager-Cowan, J. Bruckbauer, B. Hourahine
Classical Physics
Casimir-electrostatic pull-in in nanoelectromechanical actuators: Differentiable design sensitivities and the damping-dependent collapse boundary
N. S. Akintsov, A. P. Nevecheria, S. N. Andreev et al. (+1 more)
Nanoelectromechanical actuators operating at sub-100-nm gaps collapse through a pull-in instability set by competing electrostatic and Casimir forces. The quasi-static fold that bounds their safe operating range has been known in closed form for three decades, together with the Casimir ceiling above which no static
equilibrium survives, which fixes the smallest gap a given stiffness and area can hold open against the
quantum vacuum. That fold does not give the threshold reached from rest, its dependence on damping, or the design sensitivities of either. We train a physics-informed neural network in a rapidity coordinate that maps the movable pull-in pole to infinity, which keeps the residual bounded across the collapse threshold where fixed-step Runge-Kutta integration steps into unphysical states. Differentiating the trained surrogate returns pull-in-voltage sensitivities that match the closed-form fold to a relative error of $3\times10^{-6}$ and inverts a device specification to a gap of 97.036 nm at a target actuation voltage. Applied to the from-rest boundary, which carries no closed form once the damping is finite, it supplies the same sensitivities where no analytic root exists. We prove that this boundary is bracketed by two closed-form curves, that it is nondecreasing in the damping ratio, that it merges with the fold once the damping ratio exceeds $2^{-1/4}$, and that the gap closes as $(\tau_*-\tau)^{2/5}$. Numerically the merger already occurs at $0.396$, and the growth of the collapse time changes there from logarithmic to inverse square root. The classical-limit bound on the thermal Lifshitz derating is at the percent level, and the physical shift at these gaps lies orders of magnitude below it.
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All authors N. S. Akintsov, A. P. Nevecheria, S. N. Andreev, Qing-Hua Qin
Materials Science
Wyckoff-Resolved Oxidation-State Atlas and Anion-Conditioned Priors for Materials Discovery
Boris Kiefer
We introduce a Wyckoff-resolved oxidation-state atlas and assignment utility for probabilityranked, charge-neutral assignment from compositions or Wyckoff grammars. The atlas is constructed from a May 2026 snapshot of 154,879 Materials Project-derived structures by staged exact-neutral enumeration over common and known nonzero oxidation states. The learned prior assigns 106,053 materials in composition mode and 114,403 in Wyckoff mode, compared with a broad MP all-integer possible species count of 108,642. A matched MP baseline requiring at least one charge-neutral assignment with exactly one nonzero integer oxidation state per element contains 89,374 materials; relative to this baseline, composition and Wyckoff modes increase coverage by 18.7% and 28.0%. Of the 14,665 materials recovered only in Wyckoff mode, 99.98% exhibit distinct formal oxidation states for the same element on different site
tokens. The CSV/Python workflow provides a reproducible prior for structure decoration, generative
crystal models, and symbolic Wyckoff-grammar workflows.
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Quantum Physics
Approaching Resource-Theoretic Optimal Performance with Structured Environments
Lea Lautenbacher, Giovanni Spaventa, Susana F. Huelga et al. (+1 more)
Resource-theoretic approaches to thermodynamics provide powerful, model-independent bounds on the efficiency of physical processes, because they do not rely on microscopic details of the environment. Whether such bounds can be approached by realistic dynamics generated by explicit system-environment interactions remains an open question. Photoisomerization, a fundamental molecular photoreaction, offers a concrete setting to examine this issue. We introduce a tunable microscopic model of a molecular photoswitch coupled to a structured vibrational environment, which interpolates continuously between Markovian and non-Markovian regimes. Resource-theoretic analysis predicts in particular that Markovian Thermal Operations achieve strictly lower yields than general Thermal Operations. We show that environmental
memory lifts dynamical restrictions associated with Markovian thermal evolutions, thereby enlarging the set of transformations accessible to the microscopic dynamics. Approaching the thermal operation bound, however, depends on the microscopic coupling structure that generates this
memory and directs the resulting dynamics towards the target transformation.
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All authors Lea Lautenbacher, Giovanni Spaventa, Susana F. Huelga, Martin B. Plenio
Cosmology and Nongalactic Astrophysics
Enhancing Cosmological Constraints from Foreground-Cleaned CMB Maps Using Large-Scale Structure Surveys
Shu-Fan Chen and J. Colin Hill
Extragalactic foregrounds contaminate
cosmic microwave background (CMB) temperature maps at small angular scales and limit their utility for precision cosmology. The internal linear combination (ILC) is a well-known technique for suppressing these contaminants, but residual foreground power remains a limiting factor. Kusiak et al. (2023) proposed adding
galaxy number-density maps as additional ILC channels, exploiting their correlation with the large-scale structure sourcing these foregrounds to suppress contamination. Here we apply this framework to forecast the gains in CMB-based cosmological parameter constraints from near- and next-generation experiments. Using a
halo-model foreground pipeline and a Fisher forecast from joint TT+TE+EE power spectra, we quantify the improvement from
galaxy-tracer-assisted ILC cleaning across three configurations: enhanced Simons Observatory (SO) with unWISE or Rubin-like
galaxy catalogs, and a futuristic CMB-HD configuration with a hypothetical deep
galaxy survey. We find that adding
galaxy tracers reduces the residual foreground power in the cleaned temperature map by $\sim4\%$, $\sim22\%$, and $\sim32\%$ at $\ell\sim10,000$ for the unWISE, Rubin-like, and futuristic samples, respectively. For the overall variance of the cleaned map at $\ell\sim10,000$, it provides $8\%$, $24\%$, and $17\%$ improvements for each combination. The resulting reduction in marginalized parameter error bars is modest for the base six-parameter $\Lambda$CDM model: sub-percent for SO+unWISE, rising to $\sim2\%$ for SO+Rubin-like tracer. Including the effective number of relativistic species $N_{\rm eff}$, we find at most $2.2\%$ improvements for both SO+Rubin-like and CMB-HD+Futuristic tracer. These results establish the expected gains from combining near-term CMB experiments with current and forthcoming large-scale-structure surveys.
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Atomic Physics
Photoelectron interferometry with spectrally shaped polychromatic infrared pulses
E. A. Boati, G. Arvidsson, M. Ammitzböll et al. (+19 more)
Laser-assisted photoelectron interferometry is a cornerstone of attosecond science, first used to characterize attosecond pulse trains and later to study photoionization dynamics. Extending this method to spectrally shaped polychromatic infrared probe fields enables encoding of information across multiple interferometric pathways within the photoelectron spectrum. Here, we experimentally demonstrate
laser-assisted photoelectron interferometry using a spectrally shaped polychromatic infrared probe field composed of five distinct spectral components forming a Golomb ruler in the frequency domain. The measured interferograms exhibit multiple beating frequencies that agree with theoretical calculations, demonstrating the simultaneous encoding of multiple
laser-assisted
quantum beats in a single measurement. A quantitative analysis of the beating amplitudes shows that the strongly modulated temporal profile of the polychromatic probe introduces intensity- and delay-dependent distortions of the
quantum beats that cannot be explained by second-order perturbation theory. These results establish the conditions required for the quantitative interpretation of polychromatic photoelectron interferometry and highlight the opportunities offered by spectro-temporal engineering of the probe field for future developments in attosecond science.
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All authors E. A. Boati, G. Arvidsson, M. Ammitzböll, P. K. Maroju, C. Lévêque, R. Weissenbilder, V. Shiriaeva, H. Laurell, M. Li, H. Wang, C. Dittel, M. Canhota, C. Guo, R. Taïeb, J. Caillat, R. J. Squibb, R. Feifel, M. Gisselbrecht, C. L. Arnold, S. Luo, A. L'Huillier, D. Busto
Superconductivity
Gauge invariance, collective modes, and the justification of normal-state subtraction in Dirac superconductors
Hiroshi Hayasaka
In Dirac
superconductors, the unbounded spectrum of low-energy Dirac models is known to give rise to unphysical interband contributions from deep-lying states to the electromagnetic response. To eliminate these contributions, normal-state subtraction (NSS), in which the normal-state response is subtracted from the superconducting-state response, has been widely employed. However, the relation between NSS and a gauge-invariant electromagnetic response, particularly the role of the vertex correction required by the Ward identity, has remained unclear. In this work, we consider a massive-Dirac model with $s$-wave pairing and analytically investigate the electromagnetic response at zero temperature by solving the Bethe–Salpeter equation and incorporating the collective-mode contribution to the electromagnetic vertex. We show that, in the static long-wavelength limit, the vertex correction exactly cancels the bare longitudinal response with NSS, yielding the vanishing longitudinal response required by gauge invariance. In contrast, the transverse component of the vertex correction vanishes in the long-wavelength limit, so that the gauge-invariant Meissner weight coincides with that obtained from the bare transverse response with NSS. Moreover, within the class of isotropic and analytic UV regularization terms, we show that gauge invariance uniquely fixes the regularization term in the static long-wavelength limit to the value prescribed by NSS. Our results thus provide a microscopic justification for NSS.
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Computational Physics
Modelling platelet dynamics in blood flow: an unresolved DEM approach
Francesca Zucchelli, Carmine Porcaro, Mahdi Saeedipour et al. (+2 more)
Computational models of blood flow are caught between fully resolved
cell-based methods, which faithfully reproduce the dynamics of individual
cells but are computationally prohibitive at vessel scale, and continuum models, scalable yet blind to particle motion. We present an unresolved, mesoscale computational fluid dynamics-discrete element method (CFD-DEM) model of platelet dynamics that bridges this gap and, coupled with an existing unresolved description of deformable red blood
cells, moves closer to a scalable model of whole blood. Within this framework, implemented on the open source OpenFOAM-LIGGGHTS coupling, platelets are represented as rigid oblate particles advanced by orientation dependent drag, lift and hydrodynamic torque closures. The model is first validated against resolved simulations and experiments in cylindrical microvessels of diameter $100-200\,\mu m$, across wall shear rates $\dot{\gamma}=150-1650\,s^{-1}$ and hematocrit Ht $=10-20\%$ then used to characterize platelet margination. The model quantifies
diffusion coefficient, CFL formation and their dependence on shear rate, Ht and channel size. In particular, platelet diffusivity grows with vessel size and shear rate, while remaining insensitive to Ht, whereas CFL thickens with shear rate and thins with Ht. We further show that even at this mesoscale level, the model remains sensitive to platelet shape: oblate platelets marginate faster and diffuse nearly an order of magnitude more than their spherical surrogates, reaching a comparable steady state distribution but along markedly different temporal paths. Together these results demonstrate that shape driven platelet dynamics can be recovered at a fraction of the cost of fully resolved methods.
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All authors Francesca Zucchelli, Carmine Porcaro, Mahdi Saeedipour, Bastien Chopard, Jonas Latt
Mesoscale and Nanoscale Physics
ScatterWorks: A Python package for building and solving scattering network models
R. Johanna Zijderveld, Hélène Spring and Anton R. Akhmerov
Network models provide an efficient framework for studying non-interacting transport and wave-propagation phenomena in disordered and topological systems. We introduce ScatterWorks, an open-source Python package for building and solving network models. The package uses a compact network representation with composable transformation operations (tile, cut, relink, and union) to enable flexible construction of periodic and finite networks. Local scattering
matrices on nodes can be assigned by node labels or explicit indexing, assembled into global scattering equations, and used to compute quasienergies and transport observables. The package supports sparse scattering
matrices, allowing transport observables to be evaluated with Schur-based solvers. We demonstrate the package workflow on a symbolic Fabry-Perot interferometer and a numerical Chalker-Coddington model, recovering analytical expressions and the expected near-critical transport behavior of the
quantum Hall transition. Plotting utilities with label-aware rendering are included to streamline debugging and reproducible setup for larger, custom network geometries.
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Instrumentation and Methods for Astrophysics
pyEDITH: the coronagraphic exposure time calculator for the Habitable Worlds Observatory
Eleonora Alei, Miles H. Currie, Corey Spohn et al. (+7 more)
To support the development of next-generation missions for the search and characterization of habitable
planets, high-fidelity tools for astrophysical and instrumental noise simulations are needed. In this paper, we introduce pyEDITH, the Python-based coronagraphic exposure time calculator built for the next recommended NASA flagship mission, the Habitable Worlds Observatory (HWO), tasked with searching for signs of habitability and life in dozens of nearby
exoplanet systems. pyEDITH is designed to simulate wavelength-dependent exposure times and signal-to-noise ratios (S/N) for synthetic HWO direct imaging observations, considering realistic engineering specifications and user-defined target information. Its modular architecture ensures flexibility as mission requirements evolve. pyEDITH enables a streamlined integration with modern astronomical workflows and was designed to be used by the scientific community at all skill levels for understanding the capabilities and limitations of different HWO architectures for
exoplanet analyses. The code has been validated against existing exposure time calculators and released open-source on GitHub and Zenodo, as well as made accessible through a Graphical User Interface. The pyEDITH package includes API documentation, tutorial notebooks, and has been used in forthcoming scientific publications.
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All authors Eleonora Alei, Miles H. Currie, Corey Spohn, Christopher C. Stark, Aki Roberge, Avi M. Mandell, Enrico Biancalani, Samantha Gilbert-Janizek, Jacob Lustig-Yaeger, Sarah Steiger
Quantum Physics
Input-Output Analysis of Quantum Dot SUPER Excitation
Johannes Kerber, Christoph Hotter, Helmut Ritsch et al. (+1 more)
The Swing-UP of the
quantum EmitteR population (SUPER) two-color pulsed excitation scheme allows for robust and close to 100% excitation of a two-level
quantum emitter using only red detuned light. We analyze the underlying counterintuitive dynamics using a full
quantum input-output description of the in- and outgoing light pulses for the case of two coherent free-space input pulses at realistic
photon numbers. At the microscopic level, the SUPER mechanism exhibits its nonlinear three-
photon Raman-type character, leading to a net
photon-number change of $-2$ in one mode and $+1$ in the other, as was first guessed from cavity-enhanced model descriptions at low
photon numbers. We confirm that in free space, a sufficiently high pulse
photon number, much larger than one, is required to achieve high-fidelity inversion. To treat the large coherent-state amplitudes (
photon numbers) relevant for SUPER, we extend the
quantum input-output formalism to include a cumulant expansion approach. With an interaction-picture formulation, the few exchanged
photons that govern the nontrivial dynamics enable direct full-
quantum calculations in truncated
Hilbert spaces, including treatments in a displacement frame and for initial Fock-state pulses.
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All authors Johannes Kerber, Christoph Hotter, Helmut Ritsch, Klaus Mølmer