Solar and Stellar Astrophysics
Panchromatic JWST Observations and Models of the Dim Type Iax Supernova 2024vjm at 200 days
E Baron, J. M. DerKacy, C. Ashall et al. (+23 more)
We report JWST spectra and photometry of the underluminous SN Iax 2024vjm obtained 202.8 restframe days post-explosion. The spectrum exhibits a rich set of forbidden lines from low-ionization, intermediate-mass, and iron-group elements, notably the [Ni II] 6.64 micron resonance line, which is a direct indicator of stable nickel. Strong CO and SiO emission is detected alongside a warm
dust continuum; the spectral properties are consistent with pre-existing rather than newly formed
dust. Synthetic spectra were computed with the generalized
stellar atmospheres code PHOENIX/1D using simplified ejecta models. The models reproduce the overall spectral energy distribution and the molecular emission features reasonably well, but substantially underestimate the strength of the mid-infrared atomic forbidden lines, leaving the synthetic spectrum dominated by molecular emission. Experiments in which the molecular opacity is suppressed do not recover the forbidden lines; instead, the emission peak migrates to Co and Fe transitions near 2 microns. We attribute this discrepancy to poorly constrained collisional rates and possibly to an excess of iron-group material in the current ejecta models. A prominent feature at 12.8 microns is not well accounted for by the [Ne II] 12.81 micron line, indicating that the 12.8 micron feature may be largely due to [Fe III]. The presence of CO, SiO, and stable nickel together with the non-detection of neon places tight constraints on the total ejecta mass and the nucleosynthetic yields of SNe Iax progenitor systems.
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All authors E Baron, J. M. DerKacy, C. Ashall, M. Shahbandeh, Peter H. Hauschildt, T. Barman, J. P. Aufdenberg, C. R. Burns, N. Morrell, M. D. Stritzinger, P. Hoeflich, K. Medler, E. Fereidouni, C. M. Pfeffer, T. Mera, W. B. Hoogendam, S. Shiber, P. J. Brown, Divya Mishra, Inma Dominguez, L. Galbany, Paolo Mazzali, E. Y. Hsiao, Huangfei Xiao, T. de Jaeger, S. Kumar
Plasma Physics
Electron Dynamics in a Wakefield Accelerator Driven by Laser Pulses Carrying Orbital Angular Momentum
Q. Qian, M. Li, Y. Ma et al. (+21 more)
Laser pulses carrying orbital angular momentum (OAM) provide a new degree of freedom for controlling
plasma-based accelerators. Here, we experimentally demonstrate OAM-driven
laser wakefield acceleration, producing electron beams with a two-beamlet structure that indicates unique azimuthal dynamics inside the
plasma wake. Particle-in-
cell simulations reproduced the observed spectral features and revealed helical electron trajectories driven by OAM-pulse-driven wakefields. These results show that the
laser driver's phase structure can shape electron acceleration dynamics, opening a route to optimal control of beam structure in compact
laser-driven accelerators.
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All authors Q. Qian, M. Li, Y. Ma, P. T. Campbell, C-H. Chang, E. Denis, N. Ernst, R. Fedosejevs, B. Hou, A. James, M. W. von der Leyen, K. Krushelnick, C. Kuranz, A. Longman, A. Maksimchuk, J. Nees, P. Norreys, T. Nutting, J. B. Ohland, J. Palastro, A. G. R. Thomas, R. Timmis, L. Willingale, M. Burger
Quantum Physics
Optimized EIT-Based Multi-Target CNOT^k Gates in Heteronuclear Rydberg Atom Arrays
Zeyu Zhou, Xian-Lei Sheng, Peng Xu et al. (+1 more)
Efficient stabilizer readout requiring multi-
qubit coupling is a core bottleneck for
quantum error correction. One feasible method is direct implementation of the controlled-U gate between one ancilla
qubit and the data
qubits assigned to stabilizer U measurements. We systematically analyze the native multi-target $\mathrm{C}^1\mathrm{NOT}^k$ gates proposed by Müller et al., which is realized via electromagnetically induced transparency (EIT) and Rydberg blockade mechanisms. Using a microscopic open-system model, we analyze the gate's scaling with target number k and identify spontaneous emission, Doppler dephasing, target atom inter-coupling, and technical noise as major error contributions. We further optimize the protocol combining two-
photon STIRAP control, heteronuclear interaction engineering, and waveform optimization. Our optimized heteronuclear protocol reaches fidelities of 98.03% ($\mathrm{C}^1\mathrm{NOT}^{1}$) and 96.54% ($\mathrm{C}^1\mathrm{NOT}^{4}$), in the presence of all primary noise sources and realistic experimental parameters. These results demonstrate that EIT-based multi-target gates serve as a practical building block for low-depth stabilizer readout.
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All authors Zeyu Zhou, Xian-Lei Sheng, Peng Xu, Jian Cui
Optics
Reconfigurable microwave photonic Fano filters based on optical Kerr microcombs
Qi Zou, Jiayang Wu, Yang Sun et al. (+9 more)
Microwave photonic (MWP) Fano filters, featuring asymmetric filter shapes that enable steep spectral transitions, are attractive for high bandwidth microwave signal processing such as frequency discrimination. However, achieving both steep spectral transitions and a high degree of reconfigurability remains challenging for conventional methods relying on direct mapping of Fano resonances generated by optical filters. Here, we propose and experimentally demonstrate a new way for realizing MWP Fano filters based on a microcomb-driven transversal filter system. Leveraging the large number of comb lines provided by microcombs as discrete taps, the transversal filter system can synthesize filter response that closely resembles Fano resonances, yielding high rolloff rates and slope rates up to 33.8 dB / GHz and 25.7 dB / GHz in our experiments, respectively. In addition, by simply programming the tap coefficients without changing any hardware, highly reconfigurable filter response can be realized. We experimentally demonstrate independent tuning of all three Fano characteristic parameters, including the asymmetry factor, resonance linewidth, and center frequency. These results verify the effectiveness of our approach for implementing highly reconfigurable MWP Fano filters with steep spectral transitions, offering strong versatility for meeting diverse requirements in practical applications.
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All authors Qi Zou, Jiayang Wu, Yang Sun, Yang Li, Guanghui Ren, Thach G. Nguyen, Xingyuan Xu, Bill Corcoran, Sai T. Chu, Roberto Morandotti, Arnan Mitchell, David J. Moss
Strongly Correlated Electrons
Quantum Many-Body Scars, Magnon-Pair Condensation, and Hilbert Space Fragmentation in an Anisotropic Heisenberg Model
J. Y. Liu-Sun and Z. Song
We investigate a
spin-$1/2$ anisotropic Heisenberg model on a
lattice consisting of two identical bipartite sublattices. A family of exact eigenstates generated by the restricted spectrum generating
algebra (RSGA) constitutes
quantum many-body scar states, characterized by subextensive
entanglement entropy and supporting. These scar states are
magnon-pair condensates exhibiting off-diagonal long-range order (ODLRO). At the resonance point of the inter-sublattice interaction, the model exactly maps onto a mixed
spin-$1$ and
spin-$0$ XY model on a bipartite
lattice, which decomposes into independent sub-
Hamiltonians labeled by all possible
spin configurations. Each
spin-$0$ particle is dynamically isolated from its neighbors and acts as a kinetic constraint, giving rise to emergent
Hilbert space fragmentation (HSF). Our work establishes an exactly solvable platform in which
quantum many-body scars,
magnon-pair condensation exhibiting off-diagonal long-range order, and
Hilbert space fragmentation naturally coexist.
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Optics
Imaginary Gauge Fields for One-Way Transparency and Absorption in a Passive Metasurface
Qingdong Yang, Zhongfu Li, Xinhua Wen et al. (+3 more)
Electromagnetic nonreciprocity enables waves to respond differently when their propagation direction is reversed, forming the basis of isolation, directional routing, and asymmetric energy control. A central challenge is to achieve high transmission in one direction while inducing strong absorption in the opposite direction within a single passive element, as passive material dissipation typically attenuates both propagation channels equally. Here we demonstrate that an imaginary artificial gauge field can redistribute net dissipation between opposite directions in a passive structure. By synthesizing a moving-type magnetoelectric response from gyromagnetic elements and subwavelength metallic resonators, we realize a polarization-independent metasurface in which the forward wave weakly excites the dissipative resonance through destructive current interference, whereas the backward wave strongly activates the same lossy mode through constructive interference. The fabricated metasurface transmits more than 80% of the incident power from one side while absorbing more than 80% from the opposite side, with low reflection from both directions. Near-field mapping of the surface electric field provides direct real-space evidence of this gauge-controlled, direction-dependent charge accumulation and dissipation. This work establishes imaginary gauge fields as a powerful route for engineering dissipative landscapes in open wave systems and opens a pathway toward compact, passive, reflectionless isolators and nonreciprocal absorbers.
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All authors Qingdong Yang, Zhongfu Li, Xinhua Wen, Oubo You, Yi Wang, Shuang Zhang
Applied Physics
Voltage-Controlled Phosphate Precipitation Gating in Solid-State Nanopore Memristors
Weihong Wang, German Lanzavecchia, Ali Douaki et al. (+9 more)
Nanofluidic memristors preserve a record of electrical activity via ion migration and alterations in conductance that depend on the history of the device s state. These characteristics make them suitable for aqueous, energy efficient, and biologically compatible neuromorphic systems. To establish the viability of fluidic memristors for mimicking the
brain s dynamic behavior, a more thorough understanding of the memristive materials and the underlying switching processes is required. In this study, we systematically examined a recently introduced memristive device based on inpore chemical reactions, where the combined influence of electrolyte composition and pore architecture on precipitation gated
memory remains poorly understood. To address this, we constructed an asymmetric electrochemical system using CaCl2 and phosphate solutions separated by SiNx solid state nanopores. We explored how variations in pH, phosphate concentration, pore geometry, and voltage pulsing regimens affect the electrical characteristics and memristive performance. Comparison of the single pore and the array showed that parallel pores produced smoother pH and concentration dependent hysteresis and pulse responses, whereas the single pore retained larger, nonmonotonic changes.
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All authors Weihong Wang, German Lanzavecchia, Ali Douaki, Shukun Weng, Yanqiu Zou, Huaizhou Jin, Alberto Giacomello, Lorenzo Iannetti, Roman Krahne, Shangzhong Jin, Makusu Tsutsui, Denis Garoli
Materials Science
Network Topology of Hafnia-Based Amorphous Optical Coatings by Grazing-Incidence X-ray Total Scattering and Atomic Modeling
K. Prasai, B. LaBell, K. H. Lee et al. (+4 more)
Amorphous hafnia-based films are promising optical-coating materials for cryogenic GW detectors, but their performance depends on how doping and annealing modify the atomic network. We combine grazing-incidence X-ray total scattering measurements with experimentally constrained atomic modeling to study the as-deposited HfO$_2$ and 27% SiO$_2$-doped HfO$_2$ films annealed at 150$^\circ$C and 400$^\circ$C. Pure amorphous HfO$_2$ is a dense, high-coordination network of Hf-centered polyhedra with substantial edge- and face-sharing connectivity. Incorporating SiO$_2$ introduces stable SiO$_4$ tetrahedra, lowers the Hf and O coordination, and replaces highly connected Hf-rich oxygen environments with mixed Si–O–Hf bridges. This produces a chemically mixed network rather than isolated SiO$_2$-rich regions, and shifts the cation
topology toward corner-sharing connectivity. Annealing to 400$^\circ$C produces only modest additional structural relaxation. These results provide an atomic-scale description of how SiO$_2$ modifies the
topology of amorphous HfO$_2$-based coatings and suggest structural descriptors relevant to understanding their mechanical-loss behavior.
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All authors K. Prasai, B. LaBell, K. H. Lee, A. Mehta, B. Shyam, M. M. Fejer, R. Bassiri
Soft Condensed Matter
Shear effects in active models of normal and cancer cells
Souvik Sadhukhan, Rajsekhar Das, Lin Zhao et al. (+2 more)
Mechanical properties of biological tissues, driven by passive and active forces, play a vital role in several processes ranging from development to cancer metastasis. However, the dynamical responses of
cells in tissues, subject to mechanical deformations such as shear and the associated rheological properties, are not well characterized. Here, we use three-dimensional
agent-based models for normal and cancer tissues to investigate their responses to simple shear as a function of
cell stiffness and
stochastic active forces. In the normal epithelium, with uniform strength of active force, the yield stress as a function of shear rate follows the Herschel-Bulkley form over a range of
cell volume fraction. Strikingly, the shear rate dependence and the elasticity-dependent changes in the yield stress fall on master curves upon suitable scaling. To model cancer-like behavior, a certain fraction ($N_p$) of
cells was chosen to have enhanced activity and decreased stiffness. As $N_p$ increases, the extent of collective
cell movement decreases, transitioning from affine (collective) to non-affine (individualistic) movement, a finding that is in accord with imaging experiments. Simulations of a model of a stiff solid tumor, with radius $R_s$ embedded in normal tissue, show that as $R_s$ increases, the yield stress increases. Interestingly, the
cells migrate collectively as $R_s$ increases. A Gaussian Mixture Model (GMM) and a mean field theory quantitatively account for the simulation as well as experimental results on cancerous, non-cancerous, and a mixture of these two types. The combined theoretical and experimental study establishes that heterogeneity in stiffness and activity determines non-affine movements in normal and cancer tissues.
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All authors Souvik Sadhukhan, Rajsekhar Das, Lin Zhao, Wolfgang Losert, D. Thirumalai
High Energy Physics (Theory)
Spinning Conformal Correlators from Neural Networks
Manas Dogra, James Halverson and Joydeep Naskar
We construct spinning conformal fields from neural networks and the
embedding formalism, computing their two-, three- and four-point functions in examples, building on scalar conformal field techniques introduced in \cite{Halverson:2024axc}. For a particular ensemble of i.i.d.
neurons we recover the 4d Maxwell CFT in the infinite-width limit.
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General Relativity and Quantum Cosmology
Boundary Obstructions and Lapse Freedom in Static Spherical Hollow Cores
Nelson Bolívar, Gabriel Abellán and Ivaylo Vasilev
We analyze a sharply delimited comparison problem for a static spherical hollow core: an empty, flat cavity surrounded by a positive matter wall. In the unit-lapse, flat-slice radial Painleve–Gullstrand (PG) class the Type-I source obeys $p_r=-\rho$ and $p_\perp=-\rho-r\rho'/2$. A regular nonnegative density that rises out of the cavity must therefore violate the transverse null and weak energy conditions. We quantify this boundary obstruction by an exact weighted onset budget and a depth–width bound, and show that the sharp limit has the same negative tangential pressure as its
symmetry-invariant regularized Israel layer. We then close the adjacent unit-lapse, curved-slice route under a monotone areal-radius hypothesis. Finally, when only the lapse is released, an incomplete-beta family gives regular hollow shells with flat cavities, Schwarzschild exteriors, no thin shells, and NEC/WEC/SEC/DEC on an explicit compactness interval. The family is conditionally characterized in the minimum-degree and $p_r=0$ sectors and admits a fixed-ADM-mass cavity
redshift benchmark. The result is a static boundary
theorem and construction, not a general hollow-shell existence
theorem, a transport result, or an experimental feasibility claim.
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High Energy Physics (Theory)
History-Dependent Mode Selection in a Driven Holographic Superfluid
Bo-Xuan Ge
We study finite-rate mode selection among competing Landau-unstable modes in a
holographic superfluid. The selected mode is not generally the instantaneous fastest-growing one, while time-dependent linear
evolution on the driven background reproduces the full dynamics. Protocols with identical present driving conditions can exhibit opposite modal ordering, revealing
memory of the preceding drive. This
memory is quantitatively captured by the accumulated difference between the QNM growth rates of the competing modes.
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Quantum Physics
PAS-QFL: Personalized Ansatz Selection for Quantum Federated Learning under Client Data Heterogeneity
Jindi Wu and Qun Li
Quantum federated learning (QFL) lets multiple
quantum clients collaboratively train
quantum neural networks (QNNs) without sharing private local data. However, existing QFL methods commonly assume that all clients use the same ansatz, overlooking how heterogeneous client data affects ansatz suitability. Under class-imbalanced non-IID data, different clients may favor different ansatz structures, so a fixed ansatz can lead to unstable and unfair performance across clients. In this paper, we propose PAS-QFL, a Personalized Ansatz Selection framework for QFL under client data heterogeneity. Rather than treating the ansatz as a monolithic structure, PAS-QFL decomposes each client QNN into a globally shared ansatz and a client-specific private ansatz, and personalizes the structure of the private ansatz rather than only its parameters. The shared ansatz is placed first and selected by a stability-aware cross-client criterion so that its parameters can be reliably aggregated, while the private ansatz serves as a personalized decision head, selected per client by local Macro-F1 to adapt the shared representation to its local data. During training, each client updates both its shared and private parameters locally but uploads only the shared parameters, so
federated aggregation stays well-defined while each client keeps its own private structure. PAS-QFL uses Macro-F1 as the primary selection metric to avoid misleading accuracy under class imbalance. Experiments on heterogeneous QFL tasks show that PAS-QFL improves average Macro-F1 over the existing fixed-ansatz QFL baselines, demonstrating the value of personalizing the ansatz structure for practical QFL.
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Materials Science
Discovering Physically Interpretable Mathematical Expression for Predicting CO2 Adsorption in Metal-Organic Frameworks via Machine Learning-Symbolic Regression
Yimin Shao, Shengluo Ma, Shenghong Ju et al. (+2 more)
This work presents a machine learning-symbolic regression (ML-SR) strategy to develop a physically interpretable formula for predicting low pressure CO2 adsorption capacity in hypothetical metal-organic frameworks (hMOFs). Four ML models were trained on a small
dataset of 1,000 samples, and five key descriptors-largest cavity diameter, pore limiting diameter, void fraction, gravimetric surface area, and number of hydrogen atoms-were identified through SHAP and feature importance analyses. Symbolic regression was then employed to derive a concise adsorption formula, Q=aA, where a represents an adsorption baseline (mmol/g) and A is a dimensionless adsorption number incorporating four structural descriptors. We interpret A as the ratio between an adsorption binding force and a
diffusion driving force, revealing how pore
topology and surface chemistry jointly influence adsorption. Validation against a comprehensive
dataset of 137,652 hMOFs demonstrates that this formula achieves over 70% prediction accuracy for 62,448 structures, confirming strong applicability within defined structural and operational ranges. Unlike conventional black box ML models, the proposed physics-guided expression enables efficient prediction and provides clearer insight into adsorption mechanisms.
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All authors Yimin Shao, Shengluo Ma, Shenghong Ju, Yijun Shi, Wei Li
Astrophysics of Galaxies
Aromatics and Aliphatics in Local Star-Forming Galaxies as Probed by AKARI
Junhao Peng, Xuejuan Yang and Aigen Li
Polycyclic aromatic hydrocarbon (PAH) molecules are abundant and widespread in
galaxies and their infrared (IR) emission traces
star formation. PAH molecules in astronomical environments often have aliphatic contents as revealed by the detection of the 3.4 micron aliphatic C–H stretch, a weak satellite feature accompanying the 3.3 micron aromatic C–H stretch. Here, we selected 102 local
star-forming
galaxies from the AKARI archive, including 66
galaxies each of which hosts an active
galactic nucleus (AGN). We analyzed their AKARI near-IR spectra, which exhibit pronounced 3.3 micron aromatic and 3.4 micron aliphatic C–H emission. We also compiled their multi-wavelength photometric data and performed a decompositional analysis of their spectral energy distributions (SEDs) from the ultraviolet (UV) to the far-IR to derive the
star formation rates (SFRs),
stellar masses,
metallicities, and luminosity of the
galaxies. We explored the 3.3 micron PAH emission luminosity ($L_{3.3}$) as a calibrator of the SFR and found a close agreement with previous studies. We also found that $L_{3.3}/L_{\rm IR}$ and $L_{3.4}/L_{\rm IR}$ exhibit a strong dependence on
metallicity, but remain nearly constant above 12+log(O/H)$\sim\,$8.5, where $L_{\rm IR}$ is the total luminosity emitted by
dust, and $L_{3.4}$ is the luminosity of the 3.4 micron aliphatic emission. We derived from $L_{3.4}/L_{3.3}$ the PAH aliphatic fractions, defined as the fractions of carbon atoms in aliphatic units, to be in the range of $\sim\,$0.38%–6.8%, with a median fraction of $\sim\,$3.1%. The PAH aliphatic fractions are lower in AGN hosts and show a weak negative correlation with the SFR and $L_{\rm IR}$, suggesting that UV
photons in regions with AGN or strong
star formation activities may photodissociate the aliphatic structures associated with PAH molecules.
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High Energy Astrophysical Phenomena
An ALMA view of the Jet-Arc CO clouds toward the TeV $\gamma$-ray source HESS J1023-575 and Westerlund 2; Evidence for the footprints of microquasar jets, the very powerful cosmic-ray accelerator in the Galactic disk
Yasuo Fukui, Kisetsu Tsuge, Hidetoshi Sano et al. (+7 more)
The TeV $\gamma$-ray source HESS J1023-575 (HESSJ 1023 hereafter) is one of the brightest H.E.S.S. sources near the young massive cluster Westerlund 2. HESS J1023 shows a remarkable positional
alignment with the Jet and Arc CO clouds on its eastern and western sides over 170 pc length. We have carried out sub-pc scale observations of the CO clouds with ALMA and have discovered that the clouds consist of numerous thin filamentary features of $\sim$0.5 pc width and 10–20 pc length at distance of 7.5 kpc, which are well aligned with the Jet-Arc axis. Based on the magneto-hydrodynamical model of microquasar jets launched from {the center of the $\gamma$-ray source} HESS J1023-575, we present an interpretation that the thin filamentary clouds are the footprints of the microquasar jets on the HI gas. The model also explains the dissimilar Jet vs. Arc clouds in terms of HI density difference on each side. By using the density of the CO and HI gas and the $\gamma$-ray luminosity, we have calculated the
cosmic ray
proton energy $W_{\rm p}$ to be 7$\times$10$^{48}$ erg under the hadronic scheme, which is ten times larger than those derived in the TeV $\gamma$-ray SNRs RX J1713.7-3946 and RX J0852.0-4622. It is likely that HESS~J1023 has been active over 1-10 Myr, which is significantly longer than the duration of
cosmic ray acceleration of the SNRs. HESS~J1023 is therefore an outstanding source of
cosmic rays equivalent to at least 1000 SNRs, and is possibly the most powerful CR accelerator in the
Galactic disk. A high energy compact source in HESS~J1023, which is likely a Myr-old black hole or
neutron star, remains veiled due to heavy extinction.
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All authors Yasuo Fukui, Kisetsu Tsuge, Hidetoshi Sano, G. R. Bhuvana, Rin I. Yamada, Ryoji Matsumoto, Yuta Asahina, Tsuyoshi Inoue, Tim Lukas Holch, Emma de Oña Wilhelmi
Astrophysics of Galaxies
Detection of Aliphatically Deuterated Aromatic Hydrocarbons in the Large Magellanic Cloud 30 Doradus Star-Forming Complex
Junhao Peng, Xuejuan Yang and Aigen Li
The unidentified infrared (IR) emission (UIE) bands at 3.3, 6.2, 7.7, 8.6, 11.3 and 12.7 micron are ubiquitously seen in a wide variety of astrophysical environments. While the exact assignment of these UIE bands remains controversial, they are generally ascribed to C–H and C–C stretching and bending vibrations of aromatic hydrocarbon molecules. Here, based on observations made with the Near Infrared Spectrograph (NIRSpec) and the Mid Infrared Instrument (MIRI) aboard the James Webb Space
Telescope (JWST), we report that the UIE emitters in the 30 Doradus
star-forming complex in the Large Magellanic Cloud (LMC) are deuterated and have an appreciable amount of aliphatic content. The spatially resolved NIRSpec and MIRI spectra of 30 Doradus reveal a widespread detection of the 3.4 and 6.85 micron emission features attributed to aliphatic C–H stretch and deformation, respectively, as well as the 4.65 micron feature attributed to aliphatic C–D stretch. Notably, the 6.85 micron feature exhibits three complex substructures at ~6.83, 6.86 and 6.88 micron that have never been reported before.
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Mesoscale and Nanoscale Physics
Symmetry-Tunable Skyrmions and Merons in Magnetic Nanodisks via Spatially Engineered Anisotropy
X. D. Wang, J. F. Oliveira da Silva, Z. H. Tao et al. (+3 more)
We demonstrate that spatially engineered
magnetic anisotropy can stabilize skyrmion and meron
spin textures in
magnetic nanodisks even in the absence of Dzyaloshinskii-Moriya interaction (DMI). Using a constrained analytical model and micromagnetic simulations, we show that competing perpendicular and in-plane anisotropies can generate non-collinear topological textures in non-
chiral magnetic systems. We further show that DMI and dipolar interactions lift the helicity degeneracy and select preferred
chiral configurations; micromagnetic simulations were used to identify physically stable states. These results establish anisotropy-patterned nanodisks as a platform for studying DMI-free topological
spin textures and their controllable
magnetic response. We also show that arrays of anisotropy-engineered skyrmions can control
spin-wave transmission by manipulating their vorticity arrangement, pointing to reconfigurable magnonic elements based on non-
chiral topological textures.
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All authors X. D. Wang, J. F. Oliveira da Silva, Z. H. Tao, H. M. Dong, K. Chang, M. V. Milošević
Quantum Physics
Qudit-ADAPT-VQE: an adaptive variational algorithm with counterdiabatic-inspired improvements for qudits
Joaquín Molina, Herbert Díaz-Moraga, Dardo Goyeneche et al. (+1 more)
Variational
quantum algorithms based on qudits have attracted significant
attention in recent years. However, as in their
qubit-based counterparts, challenges such as barren plateaus and the design of efficient ansatz remain major obstacles. In this work, we propose to address these issues through a qudit implementation of the ADAPT-VQE
algorithm, which constructs the ansatz iteratively. Specifically, we introduce an operator pool inspired by adiabatic
evolution enhanced with counterdiabatic driving for ansatz construction and employ it to solve Max 3-Cut. We show that the warm-start strategy inherent to ADAPT-VQE, together with an ansatz construction based on counterdiabatic operators, achieves higher accuracy and lower native gates implementation than approaches on fixed ansatz. Furthermore, we show that, in qudit-based
quantum computing, ADAPT-VQE with a counterdiabatic operator pool can navigate rough optimization landscapes with local traps through the burrowing mechanism, suggesting robustness against barren plateau effects and providing a scalable framework for variational
quantum algorithms with qudits.
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All authors Joaquín Molina, Herbert Díaz-Moraga, Dardo Goyeneche, Diego Tancara
Chemical Physics
Quantum Boltzmann Equation Self-Consistent-Field for the Entropic Regularization of Mean-Field Singularities
Romit Chakraborty
We present a
Quantum Boltzmann Equation self-consistent-field (QBE-SCF) formulation for molecular electronic structure in which the one-electron reduced density
matrix is propagated in an atomic orbital basis and relaxed by a Bhatnagar-Gross-Krook collision operator toward a
Fermi-Dirac
equilibrium defined by the instantaneous Fock
matrix. At stationarity, the converged density and Fock
matrices satisfy $[\mathbf{F},\mathbf{P}]=0$, the Hartree-Fock condition. While the zero-temperature
equilibrium target reduces to the integer Aufbau projector, the damped collision operator ensures the steady-state density
matrix is not necessarily idempotent. This kinetic relaxation affords a dual pathway to resolve mean-field singularities. For spatial degeneracies, such as H$_3$ symmetric dissociation, zero-temperature kinetic ergodicity fractionalizes the active space to recover the Generalized Valence Bond (GVB) limit. For the conical intersection in BeH$_2$ and the H$_4$ structural distortion ($D_{2h} \rightarrow D_{4h} \rightarrow D_{2h}$), finite-temperature entropic regularization recovers correlated adiabatic surfaces from a real-valued single-reference density. By maintaining stable numerical convergence across basis-set hierarchies and resolving static correlation without multi-reference wavefunctions, these results establish kinetic relaxation as a synthesis of single-reference electronic structure and
quantum statistical mechanics.
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Chaotic Dynamics
An Idealized Delay-Differential Model of Scuba Diver Porpoising and Runaway Ascent
Sandy Hardian Susanto Herho, Faizal Ade Rahmahuddin Abdullah, Iwan Pramesti Anwar et al. (+5 more)
A scuba diver holding constant depth balances on an unstable
equilibrium: the gas carried in the suit and buoyancy compensator compresses with depth, so the buoyant force falls as the diver sinks and rises as the diver ascends. We represent the diver as a proportional-derivative controller that regulates this compressible-buoyancy saddle after a finite reaction delay, and we derive the governing delay differential equation from the vertical force balance and the isothermal gas law, reducing it to a damping ratio, two control gains, and a dimensionless delay. The characteristic spectrum, obtained by pseudospectral collocation of the
semigroup generator and checked against a direct Newton solution of the characteristic equation, locates the
Hopf boundary that separates stable hovering from sustained porpoising; for the baseline diver the critical reaction delay is 3.36 s and the onset period is 28.8 s. The bifurcation is supercritical, and because the saturating force is the quadratic hydrodynamic drag, the limit-cycle amplitude grows in proportion to the delay excess rather than as its square root. The safe-operating envelope shows that runaway ascent is triggered by saturation of the compensator, not by loss of linear stability, so a stable and an unstable diver can share the same escape threshold. As onset is approached, the lag-one autocorrelation and variance rise while the fitted recovery rate falls and matches the spectral abscissa, giving an
eigenvalue-exact early warning of the transition.
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All authors Sandy Hardian Susanto Herho, Faizal Ade Rahmahuddin Abdullah, Iwan Pramesti Anwar, Faruq Khadami, Alfita Puspa Handayani, Karina Aprilia Sujatmiko, Rusmawan Suwarman, Dasapta Erwin Irawan
General Relativity and Quantum Cosmology
Revisiting environmental effects on black hole quasibound-state spectra with relativistic perturbation theory
Yin-Da Guo, Qi-Xuan Xu, Richard Brito et al. (+1 more)
We present a relativistic framework for computing corrections to the eigenfrequency spectrum of a massive scalar field in perturbed black-hole spacetimes, including first-order shifts to decay rates and second-order mode-mixing effects. We also clarify the regime of validity of non-relativistic treatments and show that the accuracy of completeness-based descriptions is limited, highlighting the non-Hermitian nature of the spectrum. Using
galactic halos and
accretion disks as physically motivated perturbations, we
benchmark the relativistic perturbative predictions to the eigenfrequency shifts against non-perturbative numerical solutions. We also present first-order relativistic eigenfrequency shifts induced by binary companions, whose potentially stronger impact on superradiant dynamics of massive scalar fields around spinning black holes motivates future dedicated analyses. Our results suggest that previous estimates of the termination of superradiance due to binary companions and disks should be revisited within a relativistic framework.
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All authors Yin-Da Guo, Qi-Xuan Xu, Richard Brito, Enrico Cannizzaro
Quantum Physics
Floquet-Liouville Theory for Strongly Driven Open Quantum Systems
Kamran Akbari and Stephen Hughes
Periodically driven
quantum systems are commonly modeled using master equations constructed in the eigenbasis of an undriven
Hamiltonian, implicitly assuming that environmental dissipation couples to static energy transitions even under strong time-periodic driving. The validity of this approximation beyond weak or near-resonant driving remains poorly understood. To address the need for a more self-consistent
quantum theory approach, we formulate a nonsecular Floquet–Markov generalized master equation (F-GME) in the quasienergy basis, treating interaction-induced (internal) and drive-induced (external) nonperturbative dressing on an equal footing. We subsequently investigate dissipation in two minimal driven open
quantum systems—a harmonically driven two-level system and a harmonically driven coupled-two-level-system—each weakly coupled to a Markovian bath. Comparing the F-GME to a time-independent dressed-basis master equation, we show that even for a flat-bath spectral density and weak dissipation, the two approaches can yield qualitatively different steady-state populations and emission spectra. We resolve dissipation into drive-assisted sideband processes decaying via Floquet extended-space quasienergy channels, and show these channels can hybridize through nonsecular couplings into collective Floquet–Liouville modes governing observable spectral resonances. This analysis demonstrates that time-independent dissipative descriptions can incorrectly weight multiphoton Floquet transitions by collapsing quasienergy-resolved decay pathways into static energy gaps. The F-GME framework provides a systematic diagnostic for identifying regimes where Floquet-consistent dissipation is essential and clarifies the physical origin of discrepancies between commonly used master-equation approaches.
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Biological Physics · Cross-listed from q-bio.PE
Social Discounting Enables Fast and Reliable Collective Escape
Zachary P Kilpatrick
Solitary animals face a tradeoff when detecting threats: faster detection means accepting more false alarms. We show that groups can manage this tradeoff better by treating an undisturbed neighbor as evidence against a threat, becoming both faster and more accurate than lone individuals. Modeling each animal as a noisy evidence-accumulator that flees when its belief crosses a threshold, we find that a neighbor's flight signals danger while its stillness signals safety. A naive responder reacts only to flights and inflates false alarms as the group grows; a
Bayesian responder weighs both, approximated by a single social discounting rate that interpolates between these limits. This yields closed-form expressions for group performance, including cascade branching ratios that stay strongly subcritical in safety and turn supercritical under threat, so the rate at which an animal discounts a threat while its neighbors stay still can be inferred from behavior alone, and it sets a ceiling on how many neighbors an animal can attend before discounting alone can no longer hold its false-alarm rate. Wild sulphur molly shoals under bird attack are best described by discounting rates well above what individually
Bayesian updating supplies over any neighborhood they could plausibly attend, and the same model, at the inferred value, predicts a false-alarm rate that stays constant as shoals grow.
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Astrophysics of Galaxies
Infrared Spectroscopy of Cyanonaphthalenes under Interstellar Relevant Conditions and Their Potential Connection with Astronomical Aromatic Infrared Bands
Jiaqi Xin, Jianzhi Xu, Piero Ferrari et al. (+1 more)
Context. Aromatic infrared bands (AIBs) are widely observed in diverse astrophysical environments and are generally attributed to vibrational emission from polycyclic aromatic hydrocarbons (PAHs). The recent interstellar detection of 1-cyanonaphthalene (1-CNN) and 2-cyanonaphthalene (2-CNN) has motivated detailed infrared spectroscopic studies of cyano-substituted PAHs. Aims. We aim to characterize the infrared spectra and vibrational modes of neutral 1-CNN and 2-CNN under cold and gas-phase conditions and to assess their possible spectroscopic relevance to the astronomical AIBs. Methods. The gas-phase infrared spectra of neutral 1-CNN and 2-CNN were measured in a cold molecular beam using ion-dip spectroscopy. The observed bands were assigned with the aid of harmonic and anharmonic calculations at the B3LYP/N07D level. Infrared emission spectra were subsequently simulated from the experimental spectra within a single-
photon approximation framework. Results. We report the infrared spectra of neutral 1-CNN and 2-CNN measured under cold and gas-phase conditions relevant to the interstellar medium. Their vibrational features were assigned in detail, including fundamental vibrations as well as overtone and combination bands. The simulated emission spectra exhibit features in several wavelength regions associated with prominent AIBs, including the aromatic CH stretching region near 3.3 micron, the CC stretching region near 6.2 micron, the mixed CH in-plane bending and CC stretching region at 8.6-8.9 microns, and the CH out-of-plane bending region between 10 and 15 microns. Conclusions. The present spectra provide laboratory reference data for small cyano-substituted PAHs and offer useful clues for interpreting selected AIB regions. These results suggest that cyanonaphthalene molecules are promising contributors to the aromatic infrared bands.
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All authors Jiaqi Xin, Jianzhi Xu, Piero Ferrari, Gao-Lei Hou
Materials Science
Probing three-dimensional structures of complex colloidal quantum dots at the single-atomic level
Qikai Wu, Meng Pei, Jiancheng Zhang et al. (+6 more)
Colloidal
quantum dots (QDs) are promising optoelectronic materials due to their size-tunable properties, yet their three-dimensional (3D)
quantum confinement makes electronic states highly sensitive to structural and chemical heterogeneity, which critically impacts their optoelectronic performance. Accurately resolving the 3D atomic structure with sub-angstrom precision is thus essential for rational design. Here, we applied atomic electron
tomography (AET) to determine, for the first time, the 3D atomic structure of complex core/shell QDs, resolving over 14,000 atoms per particle. Our reconstructions reveal surface morphology, eccentric cores, and nearly atomically abrupt heterovalent interfaces and identify anisotropic shell growth directed by twin boundaries. Utilizing an AET-derived atomic structure, we performed large-scale
quantum mechanical calculations to uncover an orientation-dependent strain accommodation mechanism where the heterogeneous strain is compensated at interfaces and twin boundaries. Furthermore, our results reveal strain-induced localized states near the band edge, which contribute to the key features of the experimental ensemble absorption spectrum. This work sets a new
benchmark for atomic-level characterization, establishing a powerful framework for the rational design of next-generation nanomaterials.
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All authors Qikai Wu, Meng Pei, Jiancheng Zhang, Wei Xu, Tianding Xu, Colin Ophus, Zaiping Zeng, Botao Ji, Yao Yang
Instrumentation and Detectors
Development of a 10 mol% Rubidium-doped CsI Crystal for $^{87}$Rb Beta-Spectroscopy and Sterile Neutrino Searches
W. K. Kim, K. W. Kim, L. T. Truc et al. (+3 more)
The third-forbidden non-unique beta-decay of $^{87}$Rb to $^{87}$Sr (Q$_\beta = 282.275(6)$ keV) has long served as an important
benchmark for understanding forbidden beta-decay. To investigate this, we have developed a novel CsI scintillator with a 10 mol% Rb concentration using the Bridgman method. The incorporated $^{87}$Rb serves as an intrinsic radioactive source, enabling a source-in-detector configuration with high detection efficiency and minimal energy loss for low-energy electrons from beta-decay. We investigated both Rb doped and Tl co-doped CsI
crystals and characterized their scintillation properties, including light yield, energy resolution, and non-linear response. We report distinct scintillation characteristics for the CsI:Rb and CsI:Tl,Rb
crystals, with light yields of $1.38\pm0.01$ and $4.73\pm0.13$ PE/keV, respectively. Using the measured $^{87}$Rb beta-spectrum, we search for a keV-scale sterile
neutrino admixture through the characteristic kink-like distortion induced by a heavy
neutrino mass eigenstate. This study provides a basis for future sterile
neutrino searches using rubidium doped CsI
crystal.
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All authors W. K. Kim, K. W. Kim, L. T. Truc, H. S. Lee, H. J. Kim, Y. D. Kim
Nuclear Experiment
Best Reaction Target To Determine Proton Distribution Radii of Atomic Nuclei
Jun-Yao Xu, Bao-Hua Sun, Isao Tanihata et al. (+29 more)
We found that a heavy target such as Pb is most suitable for determining the
proton distribution radii of unstable
nuclei through charge-changing cross-section ($\sigma_\text{cc}$) measurements. As a heavy ion probe, low-$Z$ targets are routinely used to determine nucleon distribution radii of unstable isotopes. This approach has recently been extended to study
proton distribution radii from $\sigma_\text{cc}$ measurements. However, empirical scaling factors have to be introduced to apply the Glauber models. In the present work, we systematically investigated the scaling factor using 39 new $\sigma_\text{cc}$ data of 18 $p$-shell
nuclei on hydrogen, carbon, silver, and lead targets at around 240 MeV/nucleon. Together with the existing data, we reveal a universal dependence of the scaling factor on both the masses of target
nuclei and the separation energies of projectile
nuclei. The scaling factors decrease with increasing target-
nucleus mass and converge to 1 for the highest-$Z$ target, making the scaling unnecessary. We conclude that instead of a low-$Z$ target, employing a heavy target such as Pb in $\sigma_\text{cc}$ measurements is the best option to determine the
proton distribution radii of unstable
nuclei.
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All authors Jun-Yao Xu, Bao-Hua Sun, Isao Tanihata, Satoru Terashima, Jian-Wei Zhao, Ji-Chao Zhang, Ge Guo, Shi-Tao Wang, Lei Shen, Jun Su, Xiao-Dong Xu, Andrej Prochazka, Guang-Shuai Li, Xiu-Lin Wei, Chang-Jian Wang, Feng Wang, Meng Wang, Jing Wang, Liu-Chun He, Chuan-Ye Liu, Wen-Jian Lin, Wei-Ping Lin, Zhong Liu, Pei-Pei Ren, Yu Zhang, Mei-Xue Zhang, Ya-Zhou Sun, Zhi-Yu Sun, Chen-Gui Lu, Xue-Heng Zhang, Jin-Rong Liu, Tian-Yu Wu
Atmospheric and Oceanic Physics
Generative data assimilation highlights fronts as key regulators of ocean energy cascade
Scott A. Martin, Georgy E. Manucharyan and Patrice Klein
Mesoscale eddies are fundamental to the ocean circulation, yet the extent to which submesoscale motions, a few kilometers across, influence mesoscale eddy energetics through a kinetic energy cascade remains uncertain. High-resolution simulations predict that submesoscale fronts are key regulators of the cascade, transferring energy both downscale towards dissipation and upscale to sustain and shape the seasonality of mesoscale eddies. Testing these predictions has remained difficult because existing observations and state estimates cannot resolve submesoscale currents over sufficiently broad domains. Here we map the ocean's submesoscale energy cascade by combining multi-source satellite observations with a generative deep learning framework, reconstructing gap-free, kilometer-scale surface currents with physically plausible dynamics learned from simulations. Applying this to the eddy-rich Agulhas Current system, we find that submesoscales energize the mesoscale through an upscale energy cascade above 10 km, contributing to the seasonality of mesoscale eddies. Below 10 km, convergence at submesoscale fronts drives a downscale cascade towards dissipation. Both upscale and downscale pathways concentrate within fronts, where cross-scale transfer is up to an order of magnitude more efficient. Despite their limited extent, fronts account for a substantial fraction of the domain-integrated cascade, establishing them as key regulators of the cascade and targets for next-generation eddy parameterizations.
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Fluid Dynamics
Domain-filling rolls in two-dimensional fixed-flux Rayleigh-Bénard convection
Mathew D. B. Lewis, Zehan Zheng and David Goluskin
Rayleigh-Bénard convection of large horizontal extent sometimes self-organizes into domain-filling structures. In two dimensions, domain-filling rolls persist - from some but not all initial conditions - when velocity boundary conditions are stress-free. When velocity boundary conditions are no-slip, domain-filling rolls are not found with fixed-temperature thermal boundary conditions, but they have not been sought with fixed-flux thermal boundary conditions. Here we explore the latter missing case, which is hard to predict because no-slip boundaries do not encourage domain-filling rolls, but fixed-flux boundaries give domain-filling structures in three dimensions for either boundary condition on velocity. We simulate convection with fixed-flux, no-slip boundaries in two-dimensional domains with horizontal period 20 times their height and at various combinations of the fixed-flux Rayleigh number R and Prandtl number Pr. Domain-filling rolls, which are easily found when they are weakly nonlinear at small R, are continued to other (R,Pr) by changing these parameters slowly in time. The (R,Pr) regime where we find domain-filling rolls is substantial but has a boundary. When R is too large or Pr too small, relative to each other, a domain-filling roll pair breaks up into two pairs. These findings contrast with other combinations of dimension and boundary conditions, where scale selection has not been seen to depend strongly on parameter values. The present case helps disentangle competing effects of dimension and boundary conditions, and it offers a more stringent test for explanations of scale selection that have been proposed.
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