Materials Science
Correlation Between Dopant Atom Evaporation Field and Measured Site Preference in Atom Probe Tomography
Kasper A. Hunnestad, Constantinos Hatzoglou, Frida H. Danmo et al. (+6 more)
Complex
oxides possess a wide range of electric,
magnetic, and optical properties that can be precisely tuned by chemical doping. The atomic-scale analysis of the property-controlling dopants, however, becomes increasingly difficult towards low doping levels. Atom probe
tomography (APT) offers chemical sensitivity and spatial resolution to image individual dopant atoms down to a few parts per million. To reliably extract such information, detailed knowledge about the atom-specific field evaporation processes is required. Here we demonstrate a first insight into the APT-measured atomic position of dopant atoms and the field evaporation conditions, using Zr-doped ErMnO3 as a model system. Our analysis reveals a substantial preferential retention of both
matrix and dopant atoms which strongly affects the dopant site determination and can lead to an incorrect interpretation. The retention effect is determined by intrinsic and extrinsic parameters, such as the dopant's evaporation field and concentration and the analysis temperature, respectively, as we explain based on field-evaporation simulations. Our results are important for the APT-based analysis of individual dopant atoms in solid systems and the understanding of field evaporation dynamics at the atomic level in general.
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All authors Kasper A. Hunnestad, Constantinos Hatzoglou, Frida H. Danmo, Zewu Yan, Edith Bourret, Francois Vurpillot, Antonius T. J. van Helvoort, Sverre Selbach, Dennis Meier
Physics and Society
Learning to cooperate in a changing world: How caring about the future promotes cooperation across scales
Yuxin Geng, Xingru Chen, Xin Wang et al. (+4 more)
In social dilemmas, individuals need to forgo short-term temptations to achieve synergistic collective outcomes through cooperation. Previous work has examined mechanisms through which cooperation can evolve, including direct reciprocity, indirect reciprocity, environmental stochasticity, network reciprocity, and demographic stochasticity. These mechanisms have largely been studied under natural selection or social learning, where strategies with higher payoffs are more likely to spread. It is equally important to study cooperation under self-learning, where individuals adapt through their own experiences. Here, we focus on multi-
agent reinforcement learning and derive analytical conditions under which these mechanisms stabilize cooperation under learning dynamics across scales. We find that reinforcement learning can steer self-interested individuals toward cooperation when they value the future over short-term temptation. Our work provides a unified approach to identifying the determinants of learning to cooperate in a changing world, thereby paving the way for the advancement of cooperative artificial intelligence.
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All authors Yuxin Geng, Xingru Chen, Xin Wang, Hongwei Zheng, Longzhao Liu, Shaoting Tang, Feng Fu
Mesoscale and Nanoscale Physics
Topological chiral edge modes in the continuum of a trivial bulk
Li Ge
Chiral edge modes in topological states of matter are routinely found inside band gaps, which may be deformed and shifted as a function of the
lattice momentum. Here we show that they can exist inside a bulk band instead, i.e., in the continuum. These
chiral edge modes in the continuum (CEMICs) are induced by introducing an imaginary
magnetic flux to an otherwise topologically trivial two-dimensional system, realized by imposing asymmetric couplings along the edge. While the stronger couplings provide a preferred circulation direction, we find that the edge localization of CEMICs does not originate from the non-Hermitian skin effect, which is typically associated with systems featuring asymmetric couplings and the open boundary condition. Instead, this edge localization is due to the energy exchange between the system and the environment at the asymmetric coupling junctions, which leads to a parity-time (PT) transition in the Brillouin zone. Intriguingly, the onset of CEMICs is independent of the system size in the macroscopic limit, which is given by the golden ratio between the asymmetric couplings and their
geometric average.
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Quantum Physics
QBX: A Compiler for 2-local Qubit Hamiltonian Simulation on Quantum Chiplets
Zikun Li, Zhuoming Chen and Zhihao Jia
2-local
qubit Hamiltonian simulation, a fundamental task in
quantum computing, is widely applied in various applications. This paper presents QBX, the first
quantum compiler designed for 2-local
qubit Hamiltonian simulation on
quantum chiplet architectures. Existing general-purpose
quantum compilers for chiplet architectures target
quantum programs at the gate level and miss optimizations requiring high-level semantics of
Hamiltonian simulation. Conversely, existing domain-specific compilers for
Hamiltonian simulation are designed for monolithic architectures, and their limited scalability and inability to adapt to the heterogeneity of chiplet architectures lead to sub-optimal
circuit outputs. QBX implements a scalable hierarchical approach to reduce both the amount and distance of cross-chiplet communications. It integrates the highway mechanism, a chiplet-oriented solution for efficient long-range
qubit communication, to diminish cross-chiplet interaction costs. Furthermore, QBX efficiently aggregates 2-local Pauli strings into multi-target controlled gates, harnessing highways for deep optimization. Our evaluations show that QBX markedly outperforms both general-purpose and domain-specific compilers in
circuit depth and operation count, while scaling to much larger 2-local
Hamiltonian simulations.
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Plasma Physics
A packet-level digital hardware twin for commissioning megahertz diagnostic edge AI and plasma control system integration in tokamaks
Semin Joung, Abhilasha Dave, Luca Scomparin et al. (+6 more)
High-bandwidth
plasma diagnostics increasingly provide inputs to machine learning and signal-processing
algorithms intended for real-time tokamak control, but the complete path from diagnostic sampling to control-system handoff is difficult to commission because of their sampling rates. We develop a packet-level digital hardware twin for the megahertz diagnostic edge-AI architecture. The simulator represents a 64-channel, 1 MHz beam emission spectroscopy (BES) diagnostic embedded in a 96-channel dual-carrier acquisition system, two 48-channel streams with SPAD0 sample counters, 10 GbE Hardware UDP transport, packet loss and network jitter, FPGA parsing and dual-carrier
alignment, causal preprocessing and edge inference, a compact Ethernet result packet, receiver-side shared state, and a 1 kHz PCS-like control cycle. Binary UDP payloads and PCAP files are generated rather than emulating transport only at the array level. With a baseline of 20 samples per packet, each carrier generates 50,000 packets s$^{-1}$ and 100 MB s$^{-1}$ of user payload. A 110 ms reference run produces 11,000 HUDP packets; an intentionally dropped 20-sample packet is detected by the sample-counter continuity logic and invalidates the two overlapping 128-sample inference windows without silent interpolation. For valid windows, the configured engineering latency model gives a median last-input-to-shared-
memory latency of 91.6 us and a 99th percentile of 108.1 us. A separate operating-system loopback test sends binary FPGA-result datagrams through a UDP receiver into POSIX shared
memory and preserves packet sequence and CRC for 20/20 packets. Interactive GUI interfaces expose timing, packetization, network faults, inference thresholds, and control-state inspection. The framework provides a reproducible environment for testing diagnostic-to-accelerator interfaces and fail-safe behavior for deployment on fusion devices.
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All authors Semin Joung, Abhilasha Dave, Luca Scomparin, Filipp Khabanov, Zheng Yan, Benedikt Geiger, George McKee, Ryan N. Coffee, David R. Smith
High Energy Physics (Experiment)
First measurement of the antihydrogen production cross section through the charge-exchange reaction of low-energy antiprotons with orthopositronium
GBAR Collaboration: P. Adrich, I. Belosevic, M. Chung et al. (+41 more)
The GBAR experiment has measured the formation rate of antihydrogen from antiproton impact on a positronium cloud for antiproton kinetic energies of 4 and 6 keV. This is the first charge-exchange cross section measurement performed using antiproton beams, which are provided by the AD-ELENA facility at CERN. The measured cross section values are $(14.1 \pm 1.3 \mathrm{(stat)} ^{+2.2}_{-1.4} \mathrm{(sys)}) \times 10^{-16}$~cm$^2$ at 6.2 keV energy and $(8.7 \pm 2.4 \mathrm{(stat)} ^{+1.5}_{-0.09} \mathrm{(sys)}) \times 10^{-16}$~cm$^2$ at 4.15 keV energy, and agree with recent theoretical three-body calculations for antihydrogen formation. These measurements are an important input for experiments with antimatter, e.g the planned measurements of antihydrogen gravitational acceleration in the GBAR collaboration.
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All authors GBAR Collaboration: P. Adrich, I. Belosevic, M. Chung, P. Cladé, P. Comini, P. Crivelli, P. Debu, A. Douillet, S. Geffroy, S. Guellati-Khelifa, P. Guichard, P.-A. Hervieux, L. Hilico, P. Indelicato, S. Jonsell, J.-P. Karr, B. Kim, S. Kim, E.-S. Kim, N. Kuroda, B. Lee, L. Liszkay, D. Lunney, G. Manfredi, B. Mansoulié, V. Martimort, M. Matusiak, V. Nesvizhevsky, F. Nez, K. Park, N. Paul, E. Perez, P. Pérez, C. Regenfus, C. Roumegou, J.-Y. Roussé, F. Schmidt-Kaler, K. Szymczyk, T. A. Tanaka, B. Tuchming, D. P. van der Werf, D. Won, S. Wronka, P. Yzombard
Quantum Physics
Swapping Quantum Annealing Errors into a Cavity
Hao Zhang
Quantum annealing is a promising form of
quantum computation, but it slows down at a small energy gap $\Delta$ during the anneal, and the errors it makes there remain undetected. We introduce cavity
quantum annealing, in which a cavity mode of frequency $O(1)\gg\Delta$, coupled mid-schedule, swaps these errors into
photons. In the $p$-
spin model, this reduces the annealing time to nearly the square root of that required without the cavity. Moreover, counting the
photons certifies the result: high-
photon runs, with an $O(1)$ yield, reach a ground-state fidelity above $99.99\%$ orders of magnitude sooner, a gain that grows exponentially with system size. A pre-loaded
photon instead runs the swap in reverse, preparing an excited state. More broadly, our work shows that cavities can enhance computations performed with
qubits, paving the way toward high-fidelity
quantum state preparation by
quantum annealing.
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Quantum Physics
Hardness of Approximating Quantum Code Distance Beyond $\sqrt{N}$
Upendra Kapshikar
We study the computational complexity of approximating the minimum distance of a stabilizer code. Classically, the minimum distance problem is NP-hard to approximate even to within an additive gap linear in the block length. For
quantum codes, however, the reductions of Kapshikar and Kundu and of Grigorescu, Jha and Samperton reach only an additive $O(\sqrt{N})$ gap in the block length $N$. We close this gap and, in a separate direction, initiate the fine-grained study of the problem. We show that no randomized
algorithm approximates the distance to within an additive $\alpha N$, for a constant $\alpha > 0$, unless $\mathsf{NP} \subseteq \mathsf{coRP}$. In the fine-grained setting, for every $\varepsilon > 0$, no randomized $2^{(1-\varepsilon)\kappa}\,\mathrm{poly}(N)$-time
algorithm computes the distance of a code with $\kappa$ logical
qubits unless SETH falls; and no randomized $2^{o(N)}$-time
algorithm approximates the distance to within a linear additive gap, on instances where block length, number of logical
qubits, and gap are simultaneously linear, unless non-uniform Gap-ETH falls.
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High Energy Physics (Phenomenology)
Sub-MeV gamma-ray lines from an endothermic interpretation of the LZ recoil candidate
Maíra Dutra, Jacinto P. Neto and Clarissa Siqueira
Endothermic upscattering of heavy dark matter offers a compelling interpretation of the high-energy
nuclear-
recoil candidate recently reported by LUX-ZEPLIN (LZ), with a characteristic
recoil energy $E_R \propto \delta$, where $\delta$ is the mass splitting between the dark matter states. Cosmological and experimental constraints motivate the depletion of the
primordial heavier state, which can be regenerated in the
Galactic halo. We show that, if the heavier state decays radiatively, the same mass splitting sets the energy of a gamma-ray line, $E_\gamma \simeq \delta$. For our
benchmark, this leads to a sub-MeV line within the projected reach of the Compton Spectrometer and Imager (COSI), scheduled for launch in 2027. The confirmation of the LZ candidate event as a dark matter signal would therefore motivate dedicated searches for sub-MeV gamma-ray lines, with COSI providing a timely opportunity to test this interpretation.
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Physics Education
Activity Report on the Ninth African School of Fundamental Physics and Applications (ASP2026)
Kétévi A. Assamagan, Mounia Laassiri, Bobby Acharya et al. (+2 more)
The African School of Fundamental Physics and Applications, also known as the African School of Physics (ASP), was initiated in 2010, as a three-week biennial event, to offer additional training in fundamental and applied physics to African students with a minimum of three-year university education. Since its inception, ASP has grown to be much more than a school. ASP has become a series of activities and events to support academic development of African students, teachers, high school pupils (learners) and faculties. We report on the ninth African School of Physics, ASP2026, organized in Kenya, on July 5–19, 2026. ASP2026 included programs for university students, high school teachers and learners.
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All authors Kétévi A. Assamagan, Mounia Laassiri, Bobby Acharya, Christine Darve, Fernando Ferroni
High Energy Physics (Theory)
Vacuum polarization by charged matter fields in AdS spacetime in the presence of a cosmic string
E. R. Bezerra de Mello
In this paper we revisited the analyse the
vacuum polarizations effect associated wit charged matter fields in a higher-dimensional anti de-Sitter (AdS) spacetime in the presence of an idealized
cosmic string carrying
magnetic flux running along its core. Specifically we will consider, separately, charged bosonic and fermionic fields propagating in this
manifold. Our main objective is to calculate the
vacuum expectation values (VEV) of the energy-momentum tensor, $\langle T^\mu_\nu\rangle$, associated with both matters fields. As will see, these VEVs are even function of the
magnetic flux running along the string's core, with period equal to the
quantum flux $\Phi_0=\frac{2\pi}{e}$. Because the results obtained are expressed in terms of special functions, and a clear behavior for them are not very enlightening, we provide some graphs exhibiting their behavior as function of the distance to the string considering different values for the parameters presented in the model considered.
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Quantum Physics
Quantum-Computing Self-Consistent Kohn-Sham DFT: Plane-Wave-Orthonormalized Orbitals with a Dual-Basis Quantum Eigensolver
Lazaro Calderin
We present a first-quantization, all-electron, full-potential Kohn-Sham density functional theory method for
quantum computers, based on a classically optimized
quantum-
circuit eigensolver for the self-consistent field (SCF) eigenproblems in any orthonormal basis. The plane-wave-orthonormalized-orbital (PWOO) basis combines plane waves with atomic orbitals (AOs) orthonormalized against them and one another. The eigensolver has a dual-basis form: after full-basis bootstrap steps, it solves each SCF step in a contracted basis of $K$ functions ($\lceil\log_2 K\rceil$
qubits), updated in the full basis when the residual outside it exceeds a threshold. For an H$_8$ chain (SVWN, $K=8$), the state-vector-emulated SCF agrees with classical calculations within 0.02 mHa for 32768 plane waves and PWOO bases up to cc-pVTZ; contraction changes these PWOO energies by at most 5.7 $\mu$Ha. With emulated shot noise, the STO-3G PWOO SCF converges near the noise-free fixed point. On IonQ Forte-1, three-
qubit-register readout reproduces the noise-free PWOO-AO energy difference within one standard deviation.
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Solar and Stellar Astrophysics
Carrington's Last Sunspot Drawing in 1870
Hisashi Hayakawa and E. Thomas H. Teague
Richard Christopher Carrington carried out extensive sunspot observations from 1853 to 1861 and left numerous scientific legacies. However, despite his fame, consulting his original manuscripts, we have found Carrington's last sunspot drawing, which he never published. We date this drawing 23 Dec 1870, when Carrington was based at his Churt Observatory. The drawing allows us to count 3 sunspot groups and 10 individual sunspots and measure the group positions at N14{\deg} W37{\deg}, N11{\deg} W46{\deg}, and S08{\deg} W08{\deg}, where our longitude values represent longitudinal distance from the central meridian. In comparison with the existing
datasets, his raw group counts look slightly lower than the contemporaneous observers. His position data look consistent. These additions contribute to the ongoing efforts for the sunspot number recalibration and butterfly diagram constructions, as long as we follow the standard assumption for the homogeneity of the "Schmidt backbone". Otherwise, this case instead questions the validity of the common assumption of "Schmidt backbone" keeping the data homogeneity. This sunspot drawing is unlikely to represent the tip of a huge, lost iceberg, but rather an isolated drawing that he left from his Churt era. Carrington may have temporarily revived his interest upon the
solar eclipse of 22 Dec 1870. Otherwise, Carrington's references to his sunspot research in his Churt era are confined to priority claims in response to Chevalier's RAS obituary and a local newspaper report. The former confirms that Carrington was probably the first person, who counted and published sunspot data from Thomas Harriot's original sunspot drawings.
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Adaptation and Self-Organizing Systems
Rare but stable: hidden states in the 1D swarmalator model
Rommel Tchinda Djeudjo, Kevin P. O'Keeffe and Timoteo Carletti
The one-dimensional swarmalator model is usually understood through three macroscopic states: synchrony, the phase wave, and asynchrony. We show that the identical model also contains a much larger set of hidden stable
equilibria - families of q-twisted and m-clustered states - which random initial conditions almost never reach, because many are embedded in a degenerate neutral
manifold of vanishing global basin. They are nonetheless locally robust: under Gaussian perturbations of per-coordinate amplitude {\epsilon} their survival radii shrink only algebraically, as 1/q and 1/m, in sharp contrast to the Gaussian basins and winding ceiling of twisted states on a nearest-neighbour Kuramoto ring, both removed by mean-field coupling. A block-circulant Jacobian fixes the stability in closed form, and far-kick experiments indicate the basins are compact cores rather than tentacled sets. Several patterns reported in extended swarmalator models thus already exist, stable or neutrally stable, in the minimal one.
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Astrophysics of Galaxies
Constraining the Light Curves of Magnified Stellar Events at z ~ 0.725
Carter Meyerhoff, Hayley Williams, Rafael Ortiz III et al. (+5 more)
Extreme magnification by
lensing galaxy clusters allows the detection of high-luminosity
stars during cluster caustic transient events at cosmological distances. The Dragon Arc at z=0.725 is a frontier target for identifying transient events due to its high frequency of microlensing events, and so far >100 of these events have been detected. The high frequency of events and high cadence of observations allow for the measurement of minimal flux variation between epochs, and therefore the magnification
evolution as a source approaches or recedes from a microcaustic can be measured from light curves. In this work, we model the light curves of 10 transient events in the Dragon Arc across eight epochs from two JWST/NIRCam medium-band filters taken over four days. Injected synthetic observations demonstrate that with additional observations, individual transient light curves allow the of apparent degeneracies between
stellar characteristics and properties of motion.
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All authors Carter Meyerhoff, Hayley Williams, Rafael Ortiz III, Gibson B. Bowling, Rogier A. Windhorst, Zach Borowiak, Hunter Sparks, Charles L. Steinhardt
Instrumentation and Methods for Astrophysics
Lidar-monitoring of atmospheric fluctuations for millimeter-wave astronomical observations
Jacques Delabrouille, Patrick Chazette, Étienne Burtin et al. (+15 more)
Ground-based millimeter-wave astronomical observations suffer from strong contamination by the emission of inhomogeneous water vapor in the Earth's atmosphere. This emission reduces the observing efficiency and data quality even from a high-altitude, dry location such as the Atacama plateau in Chile. We propose to continuously monitor atmospheric water vapor with a co-pointing dedicated Raman
lidar system. We show, with numerical simulations and proof-of-concept observations, how a synergistic use of atmospheric
lidar data has the potential to substantially improve the quality of astronomical data sets.
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All authors Jacques Delabrouille, Patrick Chazette, Étienne Burtin, Christophe Chailan, Josquin Errard, Shamik Ghosh, Manuel Gonzalez, John Groh, Reijo Keskitalo, Valérian Le Lorec, Sotiris Loucatos, Christophe Magneville, Jean-Baptiste Melin, Michel Piat, Damien Prêle, Julien Tang, Timothée Tollet, Julien Totems
Instrumentation and Methods for Astrophysics
A Probabilistic Method for Estimating VLBI Jet-Component Ejection Epochs. Application to MOJAVE 15 GHz VLBA Kinematics
Vladislav A. Makeev, Yuri Y. Kovalev, Cecilia Degli Agosti et al. (+1 more)
Ejection epochs of parsec-scale jet components in active
galactic nuclei (AGN), tracked with Very Long Baseline Interferometry (VLBI), are commonly estimated by extrapolating fitted trajectories back to the VLBI core. However, trajectory uncertainties, non-radial motion, acceleration, and the finite size and position variability of the core can make such estimates uncertain and restrict usable samples. We develop a probabilistic framework for estimating VLBI-component ejection epochs, including accelerated features, and for quantifying how consistently each backward-extrapolated trajectory is associated with an effective VLBI core region. We apply the framework to 1923 jet-component trajectories from the 15 GHz MOJAVE kinematic sample. Ejection epochs are defined as the times of closest approach of the extrapolated trajectories to the core, with trajectory uncertainties propagated through Monte Carlo sampling. The effective core radius is treated as a random variable, whose population-level scale is calibrated from the distribution of closest-approach positions. Each component is then assigned a model-dependent probability that its closest approach lies within this effective core region. The method yields 1589 ejection epochs. The fitted effective core-region scale is $\sigma_{\rm c}=0.16\pm0.02$ mas, corresponding to an average core radius of $0.20\pm0.03$ mas, and gives a population-level upper limit of $\lesssim0.16$ mas on the characteristic 15 GHz core wander perpendicular to the jet. Using the same probability weighting, the full probabilistic sample has $N_{\rm eff}=624$, 2.8 times the legacy MOJAVE value of 222, while the overlapping ejection epochs remain consistent with previous estimates. The framework provides a flexible basis for population studies and cross-correlation analyses of jet structural
evolution and AGN variability.
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All authors Vladislav A. Makeev, Yuri Y. Kovalev, Cecilia Degli Agosti, Daniel C. Homan
High Energy Physics (Phenomenology)
Gottfried-Jackson polarization filters for holographic dilaton and transverse-traceless gluon responses in near-threshold $J/\psi$ photoproduction
Arkadiy I. Syamtomov
Within the Hatta-Yang
holographic graviton-dilaton amplitude for near-threshold $J/\psi$ photoproduction, we identify exact dilaton-null
spin-projection channels in the Gottfried–Jackson basis. The $m=0$ and $m=-\lambda_\gamma$ amplitudes receive no dilaton contribution; for
photon polarization normal to the reaction plane the $m=0$ channel further isolates $A_g(t)+B_g(t)$ and requires nucleon
spin transfer. Standard beam-polarization
spin-density-
matrix elements then furnish a TT-sensitive combination and a second bilinear containing linear dilaton-TT interference. Comparison with modern GlueX and CLAS12 cross sections shows substantial sensitivity to the shape of the original
holographic parameterization. The polarization observables therefore provide direct probes of the tensor structure of the production amplitude.
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Mathematical Physics
Homogenized graphs with spectrally embedded defect states
Kirill D. Cherednichenko and Stephen P. Shipman
By homogenizing high-contrast periodic metric graphs, we create continuous media that admit bound states produced by local defects at energies embedded in the continuous spectrum. This is achieved by fitting two copies of a
lattice graph simultaneously into space and coupling them by connecting edges. The homogenization of an ODE on a graph to a PDE in space is achieved by representing the associated operators in a common functional space through interpolation by
Fourier analysis. The two coupled graphs result in an effective medium with internal degrees of freedom that allow a decomposition into two orthogonal spaces of hybrid states. Critical high contrast retains microscopic resonances in the effective medium and allows a spectral band of one hybrid state space to overlap a spectral gap of the other. This serves as the mechanism for creating bound states at frequencies embedded in the continuous spectrum of the effective medium. These bound states in the continuum persist for $\varepsilon$-scale metric graphs due to $O(\varepsilon)$ operator-norm estimates for reduced resolvents on the defect region.
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Biological Physics
Harmonic Theory of Behavior
Mohammad Salahshour and Iain D. Couzin
Traditional models of collective behavior rely on prescribed interaction rules, leaving unresolved the question of how behavior arises from neural representations of space. Here, we develop a first-principles theory in which movement, decision-making, and collective organization emerge by coarse-graining fast neural dynamics on a topological representation of directional space. For a ring
manifold encoding heading, this reduction yields a macroscopic theory of behavior: a decision landscape over directions that admits a harmonic decomposition. In this framework, behavior is governed by a spectral organization of directional information rather than ad hoc rules. We demonstrate that target-seeking, avoidance, choice, spatial decision-making, and diverse forms of collective motion arise as distinct organizations of the underlying harmonic landscape. The theory unifies neural representations, behavioral decisions, and collective dynamics in a single mathematical description.
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Mathematical Physics · Cross-listed from math.FA
Modulation spaces: from Feichtinger's original definition to modern Gabor and symplectic characterizations
Antonio Caputo, Elena Cordero, Gianluca Giachi et al. (+1 more)
We present an expository excursus on modulation spaces, from Feichtinger's original construction on locally compact abelian groups to recent
symplectic formulations. We trace the same local-global principle through bounded uniform partitions of unity, the short-time
Fourier transform, coorbit methods, and Gabor coefficients, while distinguishing equivalent descriptions from the weighted, quasi-
Banach, and Gelfand-Shilov extensions of the underlying functional setting. We also discuss Gabor
matrices, convolution and
embedding estimates, and an application to a nonlinear dispersive equation. The final part is devoted to metaplectic Wigner distributions $W_{\mathcal A}$. In the shift-invertible case these representations are, up to chirps and a linear change of phase-space variables, rescaled short-time
Fourier transforms. This structural fact explains both their characterization of modulation and Wiener amalgam spaces and their discretization by metaplectic Gabor frames, and places the recent
symplectic theory naturally within Feichtinger's modulation-space framework.
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All authors Antonio Caputo, Elena Cordero, Gianluca Giachi, Luigi Rodino
High Energy Physics (Phenomenology)
Constraining Ultra-Light Vector Bosons via Solar Neutrino Oscillations: The Gauged $L_\mu - L_\tau$ Model and Prospects for JUNO and XLZD
Ilídio Lopes
We present an extension of the Standard Model based upon the gauged $U(1)_{L_\mu - L_\tau}$
symmetry, featuring an ultra-light vector
boson that couples to the difference of
muon and tau
lepton numbers. This anomaly-free construction, historically motivated by the
muon's anomalous
magnetic moment, is employed here as an independent phenomenological framework for
solar neutrino physics. Through kinetic mixing with the
photon, the $Z^\prime$
boson generates an effective matter potential within the
solar interior, thereby modifying
neutrino flavour oscillations via the Mikheyev–Smirnov–Wolfenstein mechanism. Utilising recent
solar neutrino measurements from Borexino, SNO, and Super-Kamiokande, together with an up-to-date standard
solar model, we constrain the
boson mass to be below $5.7\times 10^{-17}\,{\rm eV}$, a potential ultra-light dark matter candidate. The optimal model, with coupling parameter $\eta_o \approx -2$, yields $\chi_\nu^2 = 2.7$, compared with $\chi_\nu^2 = 3.1$ for the standard three-flavour scenario. This best fit corresponds to an effective four-
fermion coupling $g_{Z^\prime}^2 \varepsilon / m_{Z^\prime}^2 \approx 6.6 \times 10^{-23}\,{\rm eV}^{-2}$, approximately $5.7$ times the
Fermi constant, equivalent for $\varepsilon \approx 1$ and a reference mediator mass of $1\,{\rm eV}$ to a gauge coupling $g_{Z^\prime} \approx 8\times 10^{-12}$. We also present projections for forthcoming experiments: the Jiangmen Underground
Neutrino Observatory (JUNO), operating since August 2025 with world-leading precision on oscillation parameters, together with the XLZD consortium, should substantially refine these constraints. Such ultra-light particles may address long-standing discrepancies in
galaxy simulations within the cold dark matter paradigm, whilst terrestrial long-baseline
neutrino experiments provide complementary probes of this parameter space.
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High Energy Physics (Phenomenology)
Heavy Higgsino Dark Matter With Low Reheating in View of the LZ High-Recoil Event
C. Pallis
We show that a heavy higgsino $\tilde h$ with mass $m_{\tilde h}\sim0.1~{\rm PeV}$, which can be made consistent with the recent LUX-ZEPLIN event avoiding constraints from direct and indirect detection, can account for the present cold dark matter abundance of the universe, if the reheating temperature is bounded as $T_{\rm rh}\lesssim 595~{\rm GeV}$. These values can be achieved by a possible out-of-
equilibrium decay of a modulus $\phi$ with mass $m_{\phi}\gg m_{\tilde h}$ and a non-vanishing branching ratio into $\tilde h$'s which plays a decisive role in reducing $T_{\rm rh}$ below its upper limit via the non-thermal $\tilde h$ production. The modulus $\phi$ can be identified with the scalar component of the goldstino superfield which is involved in the generation of the $\mu$ parameter of MSSM (with $\mu\simeq m_{\tilde h}$) via the Giudice-Masiero mechanism.
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Quantum Physics
Nonlinear engineering of Hong-Ou-Mandel interference with structured light
Simon Darveau and Bienvenu Ndagano
A pair of
photons entering a Hong-Ou-Mandel interferometer will bunch or anti-bunch depending on the
symmetry of their state in the measured degree of freedom, resulting in constructive or destructive interference. For
photon pairs generated through spontaneous parametric down-conversion, this
symmetry can be engineered through linear transformations and projections applied to the
photon pairs, or by tailoring the pump field. Here, we adopt the latter approach to demonstrate that the pump's parity affects the shape and frequency of the transition from constructive to destructive interference. We demonstrate this concept theoretically and experimentally using a rotating structured pump mode encoded in the Hermite-Gaussian and Laguerre-Gaussian bases. In the former case, we show that the transition exhibits a rich structure unique to the mode family, resulting in enhanced sensitivity as the mode order increases. In the latter case, we demonstrate, as with NOON states, an integer enhancement in angular resolution by a factor proportional to the orbital angular momentum content, thereby opening the possibility of Hong-Ou-Mandel-enhanced rotation sensing.
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Medical Physics
DAFNet: Dual-path Adaptive Fusion Network for High-Fidelity Cross-Modality Brain MR Image Synthesis
Jialin Liu and Xiaoliang Zhang
Cross-modality MRI synthesis using deep learning can streamline clinical workflows, compensate for missing image contrasts, and reduce examination time; however, existing methods often require substantial computational resources, limiting their practical accessibility. To address this limitation, we propose and investigate a lightweight yet effective framework, termed the Dual-path Adaptive Fusion Network (DAFNet), for T1-to-T2 images synthesis. DAFNet is based on cGAN (conditional generative
adversarial networks) structure, and the generator employs a dual-path encoder that adaptively combines depth-wise separable convolutions and dilated convolutions to capture both fine-grained details and broader contextual features. A novel Dual-path Adaptive Fusion Module (DAFM) is introduced to dynamically combine these feature streams through channel-wise complementary weighting, enabling efficient and adaptive feature integration. This fusion mechanism is further applied to the final skip connection to enhance reconstruction fidelity, while the decoder adopts a standard transposed convolution architecture. Coupled with a conventional conditional GAN discriminator, the proposed model maintains low computational complexity while improving perceptual image fidelity. Experimental results demonstrate that DAFNet achieves superior performance compared with baseline U-Net and conventional cGAN models, reaching a peak signal-to-noise ratio (PSNR) of 26.43 dB while significantly reducing model size. This result indicates that DAFNet provides an effective balance between synthesis fidelity and computational efficiency, making it a promising solution for deployment on standard computing hardware and for broader clinical and research applications in MRI contrast synthesis.
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Computational Physics · Cross-listed from cs.DC
Performance vs Portability in Heterogeneous HPC Environments: Why Pre-execution Benchmarking is Required
Mindaugas Macernis
Cloud computing and high-performance computing (HPC) typically follow different paradigms: cloud services are often orchestrated using Kubernetes, whereas HPC workloads are managed through batch schedulers such as Slurm. Growing demand for shared computational resources increases the need for interoperability between these environments. This study uses Podman as a user-accessible tool to
benchmark quantum chemistry software distributed as precompiled executables. Containerized and on-system execution are compared across CPU-optimized builds and multiple compute nodes, without additional network optimizations. The results demonstrate that performance depends on software compilation, startup overhead, and execution configuration. Container preparation can dominate short-task workflows, while long-running calculations require monitoring of computational progress. These findings highlight the importance of workload-specific benchmarking and user-level monitoring when deploying scientific applications in containers on HPC systems.
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Accelerator Physics
Circular-Mode Optics for High-Intensity Beams and High-Luminosity Colliders
Onur Gilanliogullari, Brahim Mustapha and Pavel Snopok
We study circular-mode optics as a framework for transporting and accelerating intrinsically flat beams while maintaining a round transverse projection in physical space. Motivated by the strong degradation of flat beams under low-energy space-charge forces, we develop a coupled-optics description of circular modes, analyze their formation and preservation, and derive
lattice design conditions for conserving canonical angular momentum and coupling phase. These conditions motivate rotationally invariant transport and ring
cells based on solenoids, symmetric alternating-gradient structures, and indexed dipoles. We further derive space-charge tune-shift and tune-spread expressions for circular-mode beams in uncoupled and coupled
lattices, showing that they preserve the leading-order space-charge behavior of round beams while retaining intrinsic eigenemittance flatness. Particle-in-
cell simulations with TRACK and ImpactX confirm the generation, transport, and acceleration of circular-mode beams in representative
lattices, including regimes with strong space charge. Circular-mode optics therefore provides a promising route toward high-intensity
hadron beams and high-luminosity
collider applications.
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Quantum Physics
Dynamic Sculpting of Photon Statistics in a Raman-Coupled Cavity QED System
Amir Rahmani and Alireza Dehghani
Controlling
photon statistics is pivotal to many applications in classical and
quantum photonics. While steady-state
photon statistics have been widely studied, dynamically manipulating these statistical properties in time remains elusive. Herein, we propose a scheme to actively control
photon statistics between bunching and antibunching regimes through
quantum interference. Our approach relies on a Raman-coupled cavity-atom system with parametric amplification, where time modulating the detuning of the intermediate state allows us to either deepen the
photon blockade or enhance
photon bunching. Simultaneous modulation of the cavity and intermediate-state detunings produces antibunching that cannot be achieved under static conditions or by modulating either detuning alone. Because the modulation is periodic, the antibunching reappears at regular time intervals, enabling time-gated
photon antibunching under continuous-wave operation at a repetition rate determined by the modulation frequency. These results show a versatile mechanism based on Raman-assisted
quantum interference for dynamically engineering
photon correlations.
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High Energy Physics (Theory)
Quantization of the electroweak Volkov-Proca theory
Tudor Pătuleanu
We quantize the charged sector of the electroweak theory in an external electromagnetic plane-wave background after spontaneous
symmetry breaking, which we refer to as the electroweak Volkov-Proca theory, and analyze its global $U(1)$
symmetry and continuous residual translation subgroup together with the associated conserved charges and momentum components that label the states. We further derive the completeness and orthonormality relations for the Volkov-Proca states in Ritus form, and construct the off-shell and on-shell propagators, including their representation in terms of the scalar Volkov propagator. Finally, we derive the Källén-Lehmann spectral representation and the LSZ reduction formula for the Volkov-Proca states.
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Materials Science
Democratizing Atomistic Simulation Workflows for the AI Era with the Quantum Accelerator
Andrew S. Rosen, Naisargi Goyal, Brad Ayers et al. (+25 more)
We present the
Quantum Accelerator (QuAcc), an open-source workflow library for atomistic simulations with an emphasis on
quantum-mechanical calculations. QuAcc provides predefined workflow recipes spanning first-principles electronic-structure methods, semiempirical and tight-binding approaches, classical potentials, and foundation machine-learned interatomic potentials (MLIPs). A central design feature of QuAcc is its separation of domain-specific scientific logic from the workflow engine used to orchestrate and execute calculations. Workflows are written as ordinary Python functions and can be executed with multiple supported workflow engines without modifying the underlying source code, lowering the barrier to developing and contributing new workflows. QuAcc also streamlines the evaluation of foundation MLIPs by providing a unified platform for generating ab initio reference calculations consistent with the model of interest, mitigating methodological drift when assessing model performance. Together, these features make QuAcc a flexible and accessible framework for atomistic simulation workflows that have become central to the current era of machine learning and artificial intelligence.
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All authors Andrew S. Rosen, Naisargi Goyal, Brad Ayers, Vineet Bansal, Julia H. Baratta, Samuel M. Blau, Yuan Chiang, Sihoon Choi, Orion Archer Cohen, Blake Dallmann, Tom Demeyere, Will Engler, Yue-Wen Fang, Isabella Furrick, Eliu Huerta, Honghui Kim, Hironori Kondo, Anup Kumar, Jaehong Kwon, Osman Mamun, Charles B. Musgrave III, Hananeh Oliaei, Aryan Saha, Davide Sarpa, Benjamin X. Shi, Yuliang Shi, Xing Wang, Robert B. Wexler