Optics
Evaluating the predictive power of pump-probe imaging contrast of melanin for metastatic outcome: A 71-patient study
David Grass, Emma Bao, Martin C. Fischer et al. (+3 more)
Significance: Most melanoma deaths arise from metastatic spread, yet current staging imperfectly identifies which primary tumors will progress. Melanin structure is altered during malignant transformation, and pump-probe microscopy (PPM) measures melanin excited-state dynamics in standard biopsy sections, offering molecular contrast that is complementary to morphology-based assessment. Aim: To determine whether PPM-derived melanin excited-state dynamics in primary cutaneous melanoma can predict metastatic outcome. Approach: We imaged unstained sections from 71 primary cutaneous melanomas and 18 melanoma metastases. Transient absorption curves were fit to a biexponential excited-state model, and the fit parameters were used as features for learning classifiers to predict metastatic outcome. Results: Melanin dynamics separated primary from metastatic tissue: both excited-state lifetimes were shorter in primaries, with common-
language effect sizes up to 0.26. The same parameters did not separate primary tumors by outcome (effect sizes 0.41-0.61), and univariate logistic regression found no significant association for either the excited-state lifetimes or the ESA/GSB ratio. The best classifier reached 74% patient-level accuracy (AUC 0.73), a plateau reached by several unrelated architectures. Conclusions: PPM robustly distinguishes primary from metastatic melanoma tissue, consistent with progressive melanin disaggregation. While it is clear that pump-probe features of melanin thus correlate with tissue differences, melanin dynamics in single sections of the primary tumor, confounded by heterogeneity, do not give robust predictions of metastatic outcome.
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All authors David Grass, Emma Bao, Martin C. Fischer, M. Angelica Selim, Georgia M. Beasley, Warren S. Warren
Quantum Physics
Dual-Trigger of Series Nanowire Detector for Event-Based Photon Number Assignment
Stefanie Grotowski, Daniel Landes, Fabian Wietschorke et al. (+6 more)
Photon-number-resolving (PNR) detectors are essential components of photonic
quantum technologies. However, conventional single-channel edge-triggered readout struggles to resolve the
photon number $n$ in real time or to characterize how timing jitter depends on $n$. In this work, we use a dual-trigger method on a three-pixel series-connected superconducting nanowire single-
photon detector (SNSPD) that triggers on both the rising and falling edges of the detection pulse. By doing so, we preserve the precise arrival time of the detection event while mapping the
photon number onto the time interval between the rising and falling edges, allowing clear separation of the events. Using this technique, we assign each detection event to $n = 1, 2,$ or 3
photons with $99\,\%$ posterior confidence across all three classes. The timing jitter decreases as $n$ increases, reaching values below $41\, \text{ps}$ for $n \geq 2$. Comparing edge-triggering with constant-fraction discrimination (CFD) for arrival-time extraction, we find that CFD yields lower jitter for single-
photon events and a nearly constant mean arrival time. Altogether, our results establish dual-triggering as a robust, low-latency readout scheme for PNR detectors, while revealing a
photon-number dependence of the timing jitter relevant to timing precision achievable in heralded photonic
quantum applications.
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All authors Stefanie Grotowski, Daniel Landes, Fabian Wietschorke, Paul Pucknus, Rasmus Flaschmann, Torsten Langer, Torsten Krause, Kai Müller, Jonathan J. Finley
High Energy Physics (Phenomenology)
Neutrino mass, scalar dark matter, and collider signatures in a radiative doublet-triplet model
Isaac Bamwidhi, Mohamed Belfkir, Mohamed Amin Loualidi et al. (+1 more)
We explore a radiative
neutrino mass model based on the
topology T4-3-i, which is a one-loop completion of the Weinberg operator. We focus on its T4-3-i-C1 realization, containing an inert scalar doublet, a real scalar triplet, a Majorana
fermion triplet, and a Dirac singlet
fermion. An exact $Z_2$
symmetry forbids the tree-level type-III term and stabilizes the lightest $Z_2$-odd particle, leaving the one-loop
topology as the leading source of
neutrino mass. The model accomodate a neutral CP-even scalar dark matter candidate and predicts a rank two
neutrino mass
matrix, and thus one
neutrino is massless. A combined analysis incorporating theoretical and experimental constraints reveals viable solutions to both
neutrino mass orderings, with the inverted ordering predicting larger values of $m_{\beta\beta}$, $m_\beta$, and $\sum_i m_i$, thereby enhancing its testability through future beta-decay, neutrinoless double beta decay, and cosmological probes. Within the same viable parameter region, the observed dark matter relic abundance is accounted for by annihilation and coannihilation processes, while the electroweak triplet sector gives rise to
prompt, displaced, or long-lived particle signatures, offering complementary
collider probes to dark matter and low-energy searches.
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All authors Isaac Bamwidhi, Mohamed Belfkir, Mohamed Amin Loualidi, Salah Nasri
Materials Science
Contrasting roles of the superexchange and direct exchange interactions in the metal-insulator transitions of the 2D ferromagnetic $1T$-Fe$X_2$ ($X$=Cl, Br, I) monolayers
Hongxu Luo, Baoyang Zhou and Sai Lyu
Within the rapidly growing family of two-dimensional (2D) materials, 2D
ferromagnetic (FM) materials have attracted a great deal of recent
attention. The ferromagnetism in 2D FM materials originates from the underlying exchange interactions. In particular, metal-
insulator transitions (MITs) in 2D FM materials induced via various modulation strategies is critical to the design of 2D electronic devices with reduced sizes (e.g. transistor). However, the critical behaviors of exchange interactions and their effects on the Curie temperatures near MITs remains to be clarified. By taking the 2D FM 1T-FeX2 (X=Cl, Br, I) monolayers as the testbeds, we computationally study the critical behaviors of the exchange interactions in the vicinity of the MITs driven by the on-site Coulomb electron-electon interactions. The FM superexchange interactions and the direct exchange interactions are found to energetically favor the halfmetallic and semiconducting states, respectively. In addition, the halfmetallic states have the stronger FM couplings and thus the higher Curie temperatures. This study provides a comprehensive understanding of the interrelations between MITs and exchange interactions and could be useful for the device design requiring both MITs and exchange-interaction related
magnetic properties, particularly robust
magnetic ordering and higher Curie temperatures, in 2D FM materials.
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High Energy Astrophysical Phenomena
Enabling new sampling strategies for continuous-wave analyses by integrating Bilby into PyFstat
Maria-Antonia Ferrer-Martinez and David Keitel
Continuous-wave searches for rotating
neutron stars usually cover wide parameter spaces and produce a large number of candidate signals.
Stochastic sampling methods therefore play an important role in candidate follow-up and parameter estimation. We present the integration of the
Bayesian inference library BILBY into the open-source continuous-wave analysis package PyFstat, enabling access to the broad range of
stochastic samplers available through BILBY while preserving the existing PyFstat analysis infrastructure. The implementation is validated through injection studies in Gaussian noise for two representative single-stage follow-up configurations: candidates from a directed search and candidates from an all-sky search. Using the nested sampler DYNESTY, we obtain detection efficiencies consistent with the theoretical sensitivity predictions. In this setup, DYNESTY performs comparably to the existing PTEMCEE-based implementation of PyFstat for the directed case, and also provides an effective single-stage approach for the all-sky candidate follow-up considered here, where we did not identify a PTEMCEE setup with similar recovery performance. Percentile-percentile tests for DYNESTY further show well-calibrated credible intervals, demonstrating reliable parameter estimation. While a full exploration of DYNESTY settings, multi-stage setups, and other samplers is left for future work, these results demonstrate that this flexible and publicly available framework opens useful new possibilities for
Bayesian continuous-wave analyses.
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Physics Education
From data to structure: Construction, breakdown, and reconstruction of an empirical representation in a black-box RC circuit
Kazumasa Kushida
In introductory physics laboratories, a central instructional goal is to help students construct, evaluate, and revise mathematical representations from experimental data rather than apply given formulas. We present a guided data-driven activity in which an RC
circuit is treated as a black box defined through observable input-output relations. Experimental and graphical procedures are provided, while standard RC
circuit theory is initially withheld. Students first examine discharging data obtained under different nominal values of R and C. They rescale time using T=t/RC and compare the normalized voltage v=V/E across
circuit conditions, bringing the discharging data closer to a common trajectory. Graphical linearization through a plot of lnv versus T provides a basis for proposing an empirical representation and allows RC to be interpreted as a time scale rather than being assigned that meaning a priori. When the representation proposed for discharging is tested with charging data, logarithmic linearity is lost despite the continued organization of the data by T. Replacing v with the distance from the steady state, 1-v, restores linearity, and the resulting linear relation provides a basis for proposing a revised representation for charging. The activity thus uses a familiar physical system to make representation construction, breakdown, and reconstruction experimentally explicit. It also emphasizes that an empirical representation must be accompanied by a specified domain of validity and that standard
circuit theory can be introduced a posteriori to interpret the physical meanings that emerge from representational constraints.
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Mathematical Physics · Cross-listed from math.AP
MIT bag model and infinite mass limit in non-smooth domains
Badreddine Benhellal, Noah Körner, Dylan Machado et al. (+1 more)
The work is devoted to the study of Dirac operators with MIT bag boundary conditions in Euclidean domains with compact Lipschitz boundaries in arbitrary dimensions. It is shown that such operators are self-adjoint on suitable definition domains and can be recovered as the norm-resolvent limits of Dirac operators in the whole space with a large mass term outside the domain, under the assumption that an associated Robin-
Laplacian eigenvalue has a prescribed asymptotic behavior with respect to a parameter in the boundary condition. This assumption is shown to hold for a class of non-smooth domains, which includes convex domains and, more generally, domains that can be "locally convexified" by suitable diffeomorphisms. To the best of our knowledge, this represents the first infinite mass interpretation for the MIT bag model in the sense of resolvent convergence for non-smooth domains. Most results are extended to the generalized MIT bag boundary conditions with the help of the recently established congruence transform.
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All authors Badreddine Benhellal, Noah Körner, Dylan Machado, Konstantin Pankrashkin
High Energy Astrophysical Phenomena
Compton-induced HE – VHE $\gamma$-rays from pair cascade emissions in the SEDs of radio galaxies: NGC 1275
Mfuphi Ntshatsha, Markus Böttcher and Soebur Razzaque
In the scheme of active
galactic nuclei (AGNi), the blazar subclass is particularly bright in $\gamma$-rays. This is because of their emissions being beamed into our line of sight, as opposed to their misaligned parent population,
radio galaxies. This work presents results of a Monte-Carlo code that propagates jet-collimated $\gamma$-rays through the magnetized AGN environment, leading to secondary cascade emissions from relativistic electron-positron pairs. The resulting multi-wavelength emissions are used to fit the broadband spectral energy distribution (SED) of the
radio galaxy NGC 1275. Using known physical parameters of NGC 1275 from the literature, we find that cascade emissions from
stochastic processes have the potential to reproduce the broadband SEDs of
radio galaxies. We also find that the interplay between
accretion disk and broad-line region (BLR)
photons may provide insights into the production region(s) of $\gamma$-rays in AGNi. While dense
accretion disk and BLR radiation fields are vital to the development of cascades, excessive densities lead to the suppression of cascade synchrotron emission and attenuation of \,TeV $\gamma$-rays. Furthermore, the
magnetic field is important in shaping the cascade $\gamma$-ray spectrum.
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High Energy Physics (Phenomenology)
Chiral matching of dimension-7 baryon-number-violating operators and application to $\Delta I=3/2$ nucleon decays
Xiao-Dong Ma
We study
chiral matching of dimension-7 (dim-7)
baryon-number-violating operators in low-energy effective field theory. We show that all dim-7 operators can be classified into two distinct Lorentz structures and their chirality-flipped counterparts, and we derive their leading-order hadronic realizations in
chiral perturbation theory. As an application, we systematically investigate $\Delta I=3/2$ nucleon decays, including $n\to \ell^-\pi^+$, $p\to \ell^- \pi^+\pi^+$, and $n\to \ell^- \pi^+ (\pi^0, \eta)$, with $\ell=e,~\mu$. Using existing experimental bounds on $n\to \ell^-\pi^+$, we set stringent constraints on the relevant Wilson coefficients and derive improved lower limits on the partial lifetimes of the six three-body modes from their correlations with the two-body modes. We further present a concrete ultraviolet model that generates the dim-7 operators and the associated $\Delta I=3/2$ nucleon decays at leading order. Our results pave the way for exploring dim-7 contributions to nucleon decays and motivate future searches for these exotic modes.
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Astrophysics of Galaxies
Design and commissioning of a windowless gas-target system for high-current beams at JUNA
Xuyang Wang, Fuqiang Cao, Weike Nan et al. (+20 more)
Windowless gas targets avoid the beam-energy loss and straggling introduced by entrance foils and are therefore well suited for direct measurements of low-energy
nuclear reactions. A windowless gas-target system designed for operation with milliampere beams has been developed for the Jinping Underground
Nuclear Astrophysics facility (JUNA). The system combines three-stage differential pumping, closed-loop gas recovery and purification, a constant-temperature power-compensation calorimeter, and a position-resolved target-thickness monitor based on secondary elastic scattering. Stable operation was achieved over a target-pressure range of 1-3 mbar, with pressure fluctuations below 1% during 8 h of continuous circulation, while the accelerator-side pressure was maintained at approximately \(10^{-4}\) Pa. The closed-loop gas-circulation system maintained stable target conditions, while gas-transport calculations indicated that the axial pressure nonuniformity remained within approximately 1.6% under representative operating conditions. Calorimeter measurements were consistent with the thermal calculations, supporting the sensitivity correction used for beam-power determination. Beam commissioning with \(^{14}\mathrm{N}(p,\gamma)^{15}\mathrm{O}\) and \(^{12}\mathrm{C}(p,\gamma)^{13}\mathrm{N}\) at the 600 kV Cockcroft-Walton accelerator of the China Institute of Atomic Energy (CIAE) demonstrated stable operation of the gas-target and \(\gamma\)-ray detection systems and provided information on the influences of reaction position and beam heating. These results demonstrate the operating stability and diagnostic capability of the system for future high-current, low-energy
nuclear-reaction measurements at JUNA.
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All authors Xuyang Wang, Fuqiang Cao, Weike Nan, Gang Lian, Wei Nan, Hongwei Huang, Yuchen Jiang, Jingyu Dong, Minghao Zhu, Yuwen Chen, Yihui Liu, Jinlong Ma, Yueran Wang, Jie Chen, Yunju Li, Shengquan Yan, Youbao Wang, Xiao Fang, Luohuan Wang, Yangping Shen, Bing Guo, Weiping Liu, JUNA collaboration
Computational Physics
Structure-Informed Bayesian Inference of Anomalous Transport and Hidden Molecular Trapping in Amorphous Media
Andrey Ananev, Maria Potapova, Nikolay Kondratyuk et al. (+2 more)
Molecular
diffusion in fluctuating amorphous and macromolecular media governs key transport processes across soft-matter physics, energy storage, and biological membranes. Extracting localized trapping states from single-particle tracking trajectories remains a fundamental challenge; because thermal structural breathing continuously reconfigures pore boundaries, conventional
geometric algorithms suffer from severe systematic biases, erroneously merging distinct localized states during cyclic molecular returns. Here, we address this deadlock by shifting the paradigm from local
geometric recurrence to a structure-informed
Bayesian regularization. Leveraging discrete Morse theory, we extract the time-invariant topological skeleton of the fluctuating host
matrix to construct robust, gas-specific physical priors that account for individual molecular dimensions. Trajectory steps are sequentially partitioned via a two-stage probabilistic refinement that dynamically adapts to the transport landscape. Benchmarked against a rigorous environment where synthetic particles explore the actual interconnected
matrix graph, our approach eliminates systemic biases, restricting macroscopic trapping parameter deviations to just a few percent under optimal linear $O(N)$ computational scaling. Applied to hydrogen and methane transport within a type-I kerogen
matrix, serving as a prototype for highly tortuous, flexible macromolecular networks, the method successfully decodes the hidden microscopic mechanisms of confined
diffusion. To ensure immediate broad impact, the documented open-source code and data are made publicly available, offering an accessible strategy readily adaptable to a broad spectrum of tracking phenomena, from ion transport in battery
polymers to
protein trafficking within cellular environments.
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All authors Andrey Ananev, Maria Potapova, Nikolay Kondratyuk, Timur Vostroknutov, Aleksey Khlyupin
Astrophysics of Galaxies
Weak cool core, weak turbulence: XRISM, XMM-Newton and Chandra spectroscopy of the core of Abell 1413
Egemen Gormez and Murat Hudaverdi
We present the first XRISM spectroscopy of the core of Abell 1413 (z = 0.143), combining 104.7 ks of Resolve with archival XMM-Newton and Chandra spectra of a matched sky region. A1413 is hot, massive and relaxed but lacks a strong cool core (t_cool = 6.4 Gyr), a regime in which the low
turbulence reported to date has been tested only once, in A3571. The Resolve spectrum requires a single velocity-broadened component with kT = 7.06 (+0.33, -0.43) keV and a line-of-sight velocity dispersion sigma_v = 170 (+25, -24) km/s (M_3D = 0.217). The bulk velocity relative to the brightest cluster
galaxy, v_bulk = -24 +/- 26 (z_ICM) +/- 71 (z_BCG) km/s, is limited by the optical
redshift rather than by Resolve, and disfavours coherent line-of-sight sloshing. The non-thermal pressure fraction, 2.5 +/- 0.7 per cent, implies a hydrostatic mass bias b < 2.5 per cent, comparable to the strong cool-core cluster A2029 (2.6 +/- 0.3 per cent) and, at matched sampling scale, if anything below it. With A3571 (1.3 +/- 0.3 per cent), to which A1413 rescales within 0.2 sigma, two weak cool cores now show that this quiescence does not require central cooling. The resolved Fe-K He-alpha complex gives Fe = 0.38 +/- 0.03 (stat) +/- 0.04 (sys)
solar; Ni/Fe, separated from Fe K-beta for the first time, is
solar, as is the pattern as a whole. The Ne, Mg and Si lines that set Ne/Fe, Mg/Fe and Si/Fe lie below 2 keV, where our instruments disagree by 10-20 per cent; we therefore do not regard the SNIa fraction as constrained.
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Nuclear Theory
Separable representations of two-body interactions for Faddeev calculations of light nuclei
M. M. Nishonov
Separable representations of the Ernst–Shakin–Thaler type are constructed for the charge-dependent Bonn (CD~Bonn) nucleon–nucleon potential ($j\le4$; $nn$, $np$, $pp$), for the Kanada–Kaneko–Nagata–Nomoto (KKNN) $\alpha N$ interaction, and for the Buck–Friedrich–Wheatley (BFW) $\alpha\alpha$ interaction. They are the input for momentum-space Faddeev calculations of $A=3$, $6$, $9$, and $12$ systems. The representations are tested against six acceptance criteria: off-shell accuracy at the pair energies sampled by the three-body kernel, phase shifts, effective-range parameters, bound and resonant states, and numerical stability.
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Chemical Physics
Examination of Cluster Based Methods to Fermionic Systems
Jeffrey Keyes and Carlos Jimenez-Hoyos
We present the cluster mean field(cMF) and its extensions into perturbation theory(cPT) and coupled cluster(cCC) methods for fermionic systems. We discuss how the commutation rules for fermionic systems modifies the method as well as other computational details. We then perform calculations on the Hubbard model and a few select conjugated molecules to demonstrate the efficacy of the method. We will also use these examples to compare cluster methods to CAS-SCF.
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Astrophysics of Galaxies
Detection prospects for heavy WIMP dark matter around M31* in microwave band
Andrei E. Egorov
This work analyzes the detection prospects for weakly interacting massive particles (WIMPs) in dark matter (DM) density spike around the supermassive black hole (SMBH) in Andromeda
galaxy M31 in microwave band. WIMP annihilation produces relativistic electrons and positrons, which generate the synchrotron emission in strong
magnetic field of the
accretion flow medium at microwave frequencies. Properties of this emission, as well as their dependence on DM and medium parameters, were modeled. Atacama Large Millimeter Array (ALMA) sensitivity to this emission and underlying WIMP parameters was estimated. It was obtained that M31* in microwave band represents the unique target, where DM spike signal can be detected in case of realistic spike and
halo density profiles. In such case ALMA may reach the thermal s-wave annihilating WIMPs with masses up to around 1 TeV with just 10–100 hours exposure. Optimistic parameter configurations may allow probing all possible WIMP masses up to 100 TeV. Related systematic uncertainties are discussed.
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Instrumentation and Detectors
Non-destructive 3D doping imaging of silicon sensors
Xiangyu Xie, Anna Bergamaschi, Maria Carulla et al. (+9 more)
Silicon sensors are the foundational detection medium for X-rays and charged particles. While their bulk dopant distribution determines device performance, it is conventionally assumed homogeneous because traditional profiling is destructive, spatially restricted, and insensitive at the relevant concentrations. Here we introduce a non-destructive 3D doping imaging technique that turns the readout electronics of a charge-integrating hybrid pixel detector into a massively parallelized capacitance-voltage profiler. With a few tens of micrometres of 3D resolution over wafer-scale areas at concentrations on the order of $10^{11}$ cm$^{-3}$, we image the bulk doping concentration of operational sensors. Macroscopically, we resolve depth-evolving concentric doping rings; microscopically, we uncover scattered doping anomalies that distort local electric fields. The rings modulate the depletion voltage, while the anomalies disrupt local charge collection, a previously overlooked cause of pixel yield and performance degradation. By bridging manufacturing signatures with microscopic defects, this approach provides a non-destructive framework for sensor characterization and yield optimization.
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All authors Xiangyu Xie, Anna Bergamaschi, Maria Carulla, Roberto Dinapoli, Erik Fröjdh, Viktoria Hinger, Davide Mezza, Aldo Mozzanica, Jonathan Mulvey, Bernd Schmitt, Saverio Silletta, Jiaguo Zhang
Strongly Correlated Electrons
Examining Convergence of Cluster Perturbation Theory and Cluster Coupled Cluster for J1-J2 Heisenberg Spin Lattices
Jeffrey Keyes and Carlos Jimenez-Hoyos
In previous work, it was shown that using the cluster mean field(cMF) wavefunction as the zeroth order wavefunction for perturbation theory and coupled cluster produces a reasonable approximation for the J 1-J 2 Heisenberg model in the thermodynamic limit(TDL). However, this work was limited to cPT4 and cCCSD. The central claim of cMF is that it takes strongly correlated systems and makes them weakly correlated so that PT weakly correlated methods can be used. To confirm that this claim is true, it is important to show that the PT and CC series converge. In this paper, we extend the previous calculations to cPT7 and cCCSDTQ5 where we show that the energy is converging. We also discuss how to perform cluster based calculations efficiently in the thermodynamic limit, which is crucial for these more expensive calculations.
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Data Analysis and Statistics
Quantity, quality, and timing: Guiding glacier data assimilation strategies in the high Arctic
Wenxue Cao, Kristoffer Aalstad, Louise S. Schmidt et al. (+1 more)
Accurate simulation of glacier surface mass balance is essential for predicting sea level rise and freshwater resources, but it is constrained by uncertainties in meteorological forcing and model parameters. Here, we deploy glacier data assimilation strategies to assess the value of observations for improving surface mass balance simulation, focusing on observation quantity, quality, and timing. We perform synthetic twin experiments on Kongsvegen glacier, Svalbard, using a Particle Batch Smoother with 1000 ensemble members. Synthetic observations of albedo, snow depth, and surface temperature are assimilated at two quality levels, under two climatic scenarios, and over 12 years. Assimilation benefit is measured as the percentage improvement in the continuous ranked probability score of the posterior glacier surface mass balance relative to the prior. A single optimally timed high quality observation yields mean improvements of up to 80%. Larger numbers of low quality observations partially compensate for lower improvement. In the accumulation zone, however, additional snow depth observations degrade performance through particle degeneracy. Optimal timing is governed by the seasonal transitions of the truth trajectory rather than by prior ensemble spread alone. The optimal windows shift by up to six weeks between early and late melting years. Joint assimilation adds value through temporal diversity rather than observational diversity, while independently timed observations outperform same day combinations. The asynchronously optimally timed combined assimilation of three variables sustains improvements of 85 to 97% across all years in the ablation zone. These findings provide guidelines for adaptive observation scheduling in glacier monitoring and reanalysis.
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All authors Wenxue Cao, Kristoffer Aalstad, Louise S. Schmidt, Thomas V. Schuler
High Energy Physics (Phenomenology)
Theory updates for parton distributions in Hessian formalism
Petja Paakkinen, Hannu Paukkunen and Sami Yrjänheikki
We present a new extension to the toolbox of parton-distribution reweighting methods, which enables a general user to study the impact of an updated theory prediction on the results of a pre-existing parton-distribution global analysis. This new method is a combination of the well-known reweighting method with a new deweighting variant where a
dataset is removed from the original analysis in an approximate way. Specific use cases of this method could include e.g. testing the impact of updating the treatment of an observable from N$^n$LO to N$^{n+1}$LO precision in the global analysis, or including previously ignored electroweak, mass, resummation, or higher-twist effects, or even testing the impact of some beyond-standard-model physics. We discuss the implementation of this method in the Hessian formalism, and show its use in a single case study, where we update the treatment of dimuon production in
neutrino-induced DIS with the novel semi-inclusive DIS approach.
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High Energy Physics (Phenomenology)
Backward Compton scattering with three vortex particles
Yi Liao, Zhaolong Teng and Hao-Lin Wang
We investigate backward Compton scattering in which an incident
vortex (vx)
photon collides head-on with a plane-wave (pw) electron and both final-state particles are projected onto
vortex states, $\gamma_{\rm vx}+e^-_{\rm pw}\to\gamma_{\rm vx}+e^-_{\rm vx}$. We derive analytically the scattering amplitude and differential cross sections in the energy and cone angle of either final particle. Rotational
symmetry implies a selection rule associated with the conservation of the total angular momentum along the collision axis. A Bessel-Gaussian wave packet is adopted for the incident
photon to provide a physical normalization and regularize the boundary singularities of ideal Bessel states. We present numerical results for a $10~{\rm MeV}$ electron colliding with a
vortex photon of central energy $1~{\rm MeV}$ or $10~{\rm keV}$. The final-
photon distributions exhibit strong energy–angle correlations, topological-charge-dependent interference fringes, and systematic shifts of their dominant peaks, allowing different topological charge sectors to be enhanced through angular or energy post-selection. For a longitudinally polarized incident electron, the dominant channels favor final
photons of matching helicity. For the $1~{\rm MeV}$
photon benchmark, the final electron can likewise be produced as a MeV-scale
vortex state with a sizable cone angle and a large angular-momentum projection. These results demonstrate that triple-
vortex backward Compton scattering offers a potential means of generating and controlling high-energy
vortex photons and electrons.
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High Energy Astrophysical Phenomena
A Two-Parameter Framework for the Diffuse Supernova Neutrino Background
Cecilia Lunardini and Xingyun Yang
Following important experimental developments, tests of the Diffuse
Supernova Neutrino Background (DSNB) are entering a new phase that might lead to a discovery. This motivates the development of simple and broadly applicable tools for comparing theoretical predictions and interpreting experimental results. We show that, over the energy range relevant to current detectors, the DSNB is well described by an exponential spectrum, characterized by the differential flux at 20 MeV, $\phi_{20}$, and a spectral energy scale, $E_0$. We fit the spectra of 24 representative models and demonstrate that the exponential description provides an excellent approximation. We then recast the recent Super-Kamiokande results in the $(\phi_{20},E_0)$ plane, showing that model-specific best fits and upper bounds can be interpreted naturally within this framework. Our results indicate that, above realistic detection thresholds, and until the precision phase is reached, the observable DSNB is effectively a two-parameter phenomenon. We advocate that the $(\phi_{20},E_0)$ parameterization be adopted as a standard, to be used routinely to report future theoretical predictions and experimental results.
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Quantum Physics
Quantum speed limits based on quantifiers of quantum-state texture
Yuhang Xie, Yanjun Chu, Chenyang Cui et al. (+1 more)
Quantum speed limits impose intrinsic lower bounds on the shortest time scale for
quantum system
evolution. As an emerging paradigm in
quantum resource theory,
quantum-state texture has attracted research interest amid the rapid advancement of
quantum theory. Herein, we investigate the interplay between
quantum speed limits and
quantum-state texture via several canonical quantifiers, including trace distance, state rugosity and Jensen-Shannon divergence. To demonstrate our findings, we analyze the minimum
evolution time of physical systems subject to dephasing and dissipative dynamics. For the Jensen-Shannon divergence, we further explore nonunitary dynamics described by completely positive and trace-preserving maps, taking the amplitude damping channel as a typical example. In addition, we explore the tightness of these bounds in the considered dynamical models. Our results reveal that
quantum speed limits derived from
quantum-state texture capture the fundamental constraints on
quantum evolutionary speed, with promising applications in
quantum computing,
quantum control and
quantum metrology.
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All authors Yuhang Xie, Yanjun Chu, Chenyang Cui, Shao-Ming Fei
Mesoscale and Nanoscale Physics
Decorated electronic kagome lattice in twisted bilayer germanene
Dennis J. Klaassen, Rian A.M. Ligthart, Andrés R. Botello Mendez et al. (+10 more)
Artificial kagome
lattices provide a route to electronic flat bands,
geometric frustration, and correlation driven phases, but their realization in atomically controlled two-dimensional materials remains scarce. Here, we show that commensurate twisted
bilayer germanene on Ge2Pt produces two electronically distinct large-angle moiré phases. Scanning tunneling microscopy measurements and density functional theory calculations reveal that commensurate twisted
bilayers that are odd under an exchange of sublattices are semiconducting, whereas the twisted
bilayers with an even parity are metallic. The twisted
bilayers with an even parity host an empty state resonance that exhibits an emergent decorated kagome structure with a C3
symmetry. These results establish large-angle twisted germanene as a platform for engineering kagome-like electronic states in a buckled two-dimensional material.
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All authors Dennis J. Klaassen, Rian A.M. Ligthart, Andrés R. Botello Mendez, Lumen Eek, Esra van 't Westende, Paul L. de Boeij, Y. Wang, D. Vanmaekelbergh, Pantelis Bampoulis, Cristiane Morais Smith, Ingmar Swart, Zeila Zanolli, Harold J.W. Zandvliet
Optics
Dynamic Chirality in Photonic Time Crystals
Jianming Mai, Chenwen Yang and Shubo Wang
Temporal modulation offers a fundamentally distinct degree of freedom for active wave control beyond static spatial structuring. Photonic time
crystals (PTCs), based on periodic modulation of electromagnetic parameters in time, have expanded photonic band engineering from space to time by enabling controlled energy exchange between light and the modulation. Yet, the use of PTCs to synthesize rotational dynamics and thereby control chirality and circular dichroism (CD) remains largely unexplored. Here, we propose a spatiotemporal PTC whose central cylindrical element is driven by an azimuthally traveling-wave permittivity modulation. Although the structure is geometrically static, its dielectric profile evolves as an effectively rotating pattern in time. This synthetic rotation lifts a static modal degeneracy and produces two nondegenerate counter-rotating states with opposite orbital angular momenta. These
chiral modes selectively couple to left- and right-circularly polarized light, giving rise to tunable CD. In addition, the spatiotemporal modulation induces orbital angular-momentum conversion between the Floquet replica bands. Our work reveals the microscopic origin of dynamic
chiral response and establishes a strategy for reconfigurable
chiral photonics without mechanical motion.
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Quantum Physics
Uniqueness, Cramér-Rao Efficiency and Concentration Bounds for Quantum U-Statistics
Ayanava Dasgupta, Naqueeb Ahmad Warsi and Premanshu Chatterjee
We study unbiased estimation of scalar-valued
polynomial functionals of
quantum states from independent copies. We establish an equivalence between the first-order marginal of a permutation-invariant finite-copy observable and the functional gradient. We then prove that, among unbiased permutation-invariant
estimators, the
quantum U-statistic is the unique extension to an arbitrary number of copies. We further derive a universal variance expansion in which the leading $1/n$ term is determined by the variance of the functional gradient, while higher-order contributions are of order $O(1/n^2)$. This leading variance coincides with the multiparameter
quantum Cramér–Rao limit, establishing asymptotic efficiency of
quantum U-statistics. We also characterize the higher-order scaling at points where the variance of the first-order gradient vanishes. As an application, we analyze the Bures $\chi^2$-divergence and show that a spectral lower bound on the reference state is sufficient but not necessary for bounded-variance estimation. Beyond asymptotic variance, we establish variance-sensitive exponential concentration bounds, deriving a closed-form Bernstein-type inequality to capture finite-sample tail behaviour, and establish the Moderate Deviation Principle to characterize the intermediate asymptotic regime.
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Materials Science
The absence of a central metal ion destabilizes phthalocyanine on In$_2$O$_3$(111)
Viktoria Waidbacher, Sarah Tobisch, Faith J. Lewis et al. (+5 more)
Metal phthalocyanines (MPc) are a versatile molecular platform for applications ranging from organic optoelectronic devices to single-atom catalysis (SAC). Their adsorption and layer formation on the prototypical transparent electrode substrates of organic optoelectronic devices is directly relevant for charge injection and transport across the organic-
oxide interface. Moreover, the well-defined M-N$_4$ coordination of the metal cation defines their activity as SACs for (electro-)catalysis. Here, the adsorption of the metal-free phthalocyanine (H$_2$Pc) is characterized on In$_2$O$_3$(111) using low-temperature STM, nc-AFM, and STS. In$_2$O$_3$ is not only a model system of indium tin
oxide (ITO) but also an active catalytic material for CO$_2$ reduction. H$_2$Pc adsorbs in the same site and configuration reported for copper phthalocyanine [J. Mater. Chem. C 13, 17650-17661 (2025)] and for the majority of cobalt phthalocyanine [Surf. Sci. 722, 122065 (2022)]. Despite this shared preference in adsorption site, H$_2$Pc cannot be organized into extended and ordered monolayer structures by gentle annealing: the molecule starts to decompose at $\approx$50$^\circ$C, well below the temperature used to grow monolayers of CoPc and CuPc. Self-metalation is not observed on stoichiometric In$_2$O$_3$(111). On the reduced surface where In$^0$ adatoms are present, new H$_2$Pc-related features appear but cannot be identified by imaging only. The comparison of H$_2$Pc with CoPc and CuPc identifies distinct roles of the central metal ion in the metal-Pc/In$_2$O$_3$(111) systems: it acts as a structural anchor that stabilizes the macrocycle against decomposition on the surface, and it modifies the frontier-orbital character in ways that determine whether a second adsorption configuration is populated.
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All authors Viktoria Waidbacher, Sarah Tobisch, Faith J. Lewis, Moritz Eder, Michael Schmid, Gareth Parkinson, Ulrike Diebold, Margareta Wagner
High Energy Astrophysical Phenomena
A Unified Timescale Relation for Quasi-Periodic Eruptions and Repeated Nuclear Transients
Shifeng Huang, Tinggui Wang, Ning Jiang et al. (+9 more)
Quasi-periodic eruptions (QPEs) and recurrent
nuclear transients (RNTs) exhibit recurrent high-amplitude
flares from
galactic nuclei, yet their characteristic timescales remain poorly understood. In this work, we compile a sample of these systems and investigate empirical scaling relations between
flare timescales and black hole masses. We find that the recurrence timescale exhibits a positive but highly scattered dependence on black hole mass in the combined QPE and RNT sample, approximately following $t_{\rm rec}\propto M_{\rm BH}^{1.19^{+0.52}_{-0.47}}$ with an intrinsic scatter of 0.95 dex. Remarkably, we uncover a tight nearly linear relation between recurrence time and
flare timescale for QPEs and RNTs, described by $t_{\rm rec}\propto t_{\rm rise}^{1.00\pm0.07}$ with an intrinsic scatter of 0.29 dex. This relation extends across timescales from hours for QPEs to months and years for
nuclear transients. We further find that QPEs and RNTs approximately follow a common empirical relation between recurrence time and
flare rise time, although the physical origin of this relation remains uncertain. Our findings reveal a common phenomenological timescale link across RNTs, providing a practical framework for characterizing their temporal behavior.
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All authors Shifeng Huang, Tinggui Wang, Ning Jiang, Yibo Wang, Zhenfeng Sheng, Tian-Yu Xia, Jiazheng Zhu, Zheyu Lin, Jie Lin, Ji-an Jiang, Kenta Taguchi, Keiichi Maeda
Materials Science
Study on Thickness and Temperature Dependence of Thermoelectric Properties in SnS Nanofilms
Liqi Chen, Ziyang Wang, Donghao Li et al. (+5 more)
SnS as an environmentally friendly, cost-effective, and earth-abundant narrow-bandgap
semiconductor material, has demonstrated significant application potential in the field of medium-temperature thermoelectric conversion. However, the thermoelectric performance of its bulk counterpart is inherently constrained by intrinsic point defects (e.g., vacancies) and the material's specific band structure. Low-dimensional engineering has emerged as a pivotal strategy for overcoming these limitations and enhancing thermoelectric performance. In this work, we systematically investigate the thermoelectric properties of SnS nanofilms with distinct thicknesses (82 nm, 199 nm, 616 nm, and 813 nm) across a temperature range of 300-600 K. Measurements were conducted using time-domain thermoreflectance (TDTR) and a dedicated thin-film thermoelectric parameter test system (ZEM-3). Our results confirm that low-dimensionalization effectively boosts the thermoelectric performance of SnS, with the thermoelectric figure of merit (ZT) displaying a pronounced dependence on both film thickness and temperature. All four SnS thin films exhibit thermoelectric performance that is markedly superior to that of bulk SnS. This enhancement is primarily attributed to the
quantum confinement effect, energy filtering effect, and intensified
phonon scattering, all of which are induced by the low-dimensional structural characteristics. This work provides not only experimental evidence and theoretical insights for the performance optimization of SnS nanofilms but also establishes a foundational framework for the development of high-efficiency, eco-friendly medium-temperature thermoelectric materials, thereby holding significant scientific value and practical implications.
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All authors Liqi Chen, Ziyang Wang, Donghao Li, Jingye Wang, Ning Zhao, Jun Zhou, Jie Zhu, Dawei Tang
Quantum Physics
On the Power of Adaptivity in Testing Quantum States in Fidelity
Jan Seyfried, Sayantan Sen and Marco Tomamichel
We study the problems of
quantum state certification, equivalence testing and independence testing. In certification, given samples of an unknown
quantum state $\rho$ and the description of a state $\sigma$, the goal is to test whether $\rho=\sigma$, or whether $\rho$ and $\sigma$ are far in a given distance measure. In equivalence testing, $\sigma$ is also unknown and only accessible via samples. Independence testing decides whether $\rho_{AC}=\rho_A\otimes\rho_C$, or is far from being a product. The sample complexities of these problems are now well-understood for a decision gap $\varepsilon$ in trace distance: in the single-copy measurement setting with $d$-dimensional states, all three tasks can be solved using the same non-adaptive approach, which uses $\Theta(d^{3/2}/\varepsilon^2)$ samples and is optimal in general, even without adaptivity. In this work, we consider decision gaps expressed in fidelity and study possible separations between these problems and how adaptivity can help. We prove that certification with respect to fidelity for a state $\sigma$ of rank $r$ does not benefit from adaptivity and requires $\widetilde{\Theta}(r^{3/2}/\varepsilon)$ samples. For equivalence testing and independence testing, we provide adaptive
algorithms using $\widetilde{O}(\min\{d^{3/2}/\varepsilon^2,d^{9/4}/\varepsilon\})$ and $\widetilde{O}(\min\{(d_Ad_C)^{3/2}/\varepsilon^2,d_A^{9/4}d_C^{3/4}/\varepsilon\})$ samples, for $d_A\geq d_C$, respectively. Our main technique is a framework that uses partial learning and a reduction to testing in $\ell_2$-distance, adapted from the distribution testing literature. We show that adaptivity matters for equivalence testing in fidelity by proving that $\widetilde{\Omega}(1/\varepsilon^2)$ samples are necessary in the non-adaptive case even for
qubits, showing a separation from certification.
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High Energy Astrophysical Phenomena
Stratified Wind Geometries of GRS 1915+105: Density Profiles and Radii
Noa Keshet, Ehud Behar, Jon M. Miller et al. (+1 more)
The low-mass X-ray binary GRS 1915+105 exhibits dramatic spectral and flux variability, often accompanied by highly ionized
outflows. In this work, we analyze four archival Chandra/HETG observations spanning over a decade, which vary greatly in their ionizing spectrum from soft (low inner disk temperature) to hard (high inner disk temperature). We measure the wind properties, using the insightful tool of the absorption measure distribution (AMD, a distribution of column density with ionization). While the soft epoch reveals a steep, monotonically rising AMD, hard epochs feature a distinct turnover at high ionization parameter ($\log\xi>3.3$). This is the first time we observe a negative AMD slope in an
outflow, which we interpret as a localized density inversion, which could point to radiation-pressure compression zones. We utilize the AMD shape and total column density measurements to calculate the density profile and distance of the wind from the central source. For the hard states, we obtain densities of $10^{12}-10^{13}$ cm$^{-3}$ at radii of $10^{10}-10^{11}$ cm. Such measurements are usually not directly possible in X-ray spectroscopy. Here we constrain the inner radius and density of the
outflow to a factor of two. The high-$\xi$ values up to $\log\xi\sim6.5$ with no turnover in the soft state imply a smaller radius of a few $10^{8}$cm, which is in tension with the slow velocities observed. We demonstrate that this is a generic tension between compact launch radii and sub-escape velocities of high-column, high-ionization
outflows observed in
stellar-mass black hole binaries.
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All authors Noa Keshet, Ehud Behar, Jon M. Miller, Joey Neilsen