Cosmology and Nongalactic Astrophysics
Direct shear $\times$ kSZ correlation: controlling baryons without modeling galaxies
Anoma Ganguly, Emmanuel Schaan, Elisabeth Krause et al. (+1 more)
Baryonic feedback redistributes gas within and around dark matter
haloes, suppressing the small-scale matter power spectrum at a level that is now the leading systematic for upcoming weak-
lensing surveys. The kinetic Sunyaev-Zeldovich (kSZ) effect directly probes this redistributed gas, but existing measurements around
galaxies are either tied to the properties of the chosen
galaxy sample or are susceptible to biases from other extragalactic foregrounds. We address both by cross-correlating a kSZ template constructed from the tomographic weak-
lensing convergence maps and the radial velocity maps reconstructed from
galaxy surveys via the continuity equation, with the observed CMB temperature. We forecast the detectability for Rubin LSST Y10 and Roman kinematic
lensing samples combined with ACT, SO, and CMB-HD, finding signal-to-noise ratios of $\sim$ 5-15 for current and upcoming CMB data and $\gtrsim 100$ for CMB-HD, corresponding to few-per-cent and sub-per-cent constraints, respectively, on the baryonic suppression of the matter power spectrum. This method should thus achieve sufficient statistical precision to model baryonic feedback effects for Rubin, without the systematic challenge of modeling any
galaxy-matter connection.
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All authors Anoma Ganguly, Emmanuel Schaan, Elisabeth Krause, Tim Eifler
Data Analysis and Statistics
Learning transferable event representations for charmed baryon physics at BESIII
Kaixuan Huang, Yangu Li, Junpeng Zhao et al. (+6 more)
Deep learning has become an essential tool in high-energy physics, where the ability to learn transferable event representations can significantly improve model generalization across related physics processes. In this work, we present a Particle
Transformer-based framework for learning such representations for charmed
baryon physics in the BESIII experiment. The framework is implemented through large-scale pre-training on Monte Carlo simulation samples and subsequent fine-tuning for downstream analyses. Using the production and decays of the charmed
baryon $\Lambda_c^+$ as a
benchmark, we develop pre-trained models for both event classification and momentum-direction regression. The classification model learns discriminative event representations for the dominant physics categories, rejecting 97.0% of background events at a signal efficiency of 90.0%. Across 12
benchmark $\Lambda_c^+$ decay channels, fine-tuning from the pre-trained model achieves performance comparable or better than training from scratch, with particularly clear improvements in low-statistics regimes. For the regression task, the pre-trained model improves the momentum-direction prediction across the same
benchmark channels. Further improvement is obtained after fine-tuning in the representative semileptonic decay $\Lambda_c^+ \to p K^- e^+ \nu_e$. This strategy provides a scalable solution for a wide range of physics cases at BESIII and can be extended to other high energy experiments.
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All authors Kaixuan Huang, Yangu Li, Junpeng Zhao, Peilian Li, Peirong Li, Xiaorui Lyu, Yunxuan Song, Shengsen Sun, Yangheng Zheng
Materials Science
Charge-Density-Wave Phase Selection by Janus-Induced Intrinsic Strain in Monolayer NbSSiAs$_2$
Chun-Jie Zhang, Bing Zhang, Dongliang Mao et al. (+3 more)
Controlling phase selection among competing charge-density-wave (CDW) instabilities remains challenging in two-dimensional materials. Here, first-principles calculations show that Janus-induced intrinsic tensile strain redirects the off-M soft-mode tendency of NbS$_2$ to the M point in NbSSiAs$_2$, selecting a $2\times2$ CDW reconstruction. Electron-
phonon coupling analysis identifies momentum-selective coupling between Nb-derived states and a longitudinal acoustic mode as the origin of the M-point instability. The reconstructed phase hosts two nearly degenerate Nb-trimerized configurations whose relative stability is tuned by biaxial strain. Both configurations retain
phonon-mediated superconductivity on the 6-7 K scale, indicating the coexistence of CDW order and superconductivity. Compressive strain favors the 1+3-hollow configuration and induces a band-inverted, $Z_2$-nontrivial state while preserving superconductivity. Together, these results identify Janus-induced intrinsic strain as an internal structural route for CDW phase selection, whereas external strain provides access to a regime in which CDW order,
topology, and superconductivity coexist.
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All authors Chun-Jie Zhang, Bing Zhang, Dongliang Mao, Yapeng Wu, Xiao-Ping Li, Lei Wang
Nuclear Theory
Nuclear mass staggering explains missing stable technetium and promethium
Daiki Nishimura, Takumi Hasegawa and Rinku Prajapat
Technetium (Tc) and promethium (Pm) are the only elements that lack stable isotopes in the range up to bismuth, a long-standing puzzle in physics and chemistry. We treat this absence as a problem of selecting the lowest-mass integer
proton number Z in beta-stable isobaric chains with odd mass number A. Three-point mass parabolas identify two-unit jumps in the local minimum, whereas a five-point decomposition separates the smooth quadratic component from odd-Z/odd-N mass staggering, defined here as the mass shift of odd-Z isobars relative to neighboring odd-N isobars. With this decomposition, a fitted bulk-plus-shell mass model reproduces the smooth trend and shell-driven bending near magic numbers, including conventional shell-closure skips. This model, however, does not include odd-Z/odd-N staggering and cannot account for the Tc and Pm skips. The separated odd-Z/odd-N staggering remains positive across the Tc and Pm regions and is large enough for the lowest-mass integer-Z sequence to skip Tc and Pm. Shell-model occupation analysis suggests that this regional staggering reflects an orbital-dependent tensor-force monopole effect in the
proton-
neutron interaction. We identify tensor-force-driven odd-Z/odd-N mass staggering as the origin of the Tc and Pm skips in the odd-A sequence of lowest-mass isobars.
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Astrophysics of Galaxies
Reincarnations of massive stars in active galactic nucleus discs
Jing-Tong Xing, Tong Liu and Jiao-Zhen She
The origin and
evolution of massive
stars in active
galactic nucleus (AGN) discs remain uncertain. We develop a semi-analytical model that follows the
evolution of an embedded core-collapse
supernova (CCSN) remnant and the subsequent formation and growth of a compact gas cloud. In the dense disc environment, efficient radiative cooling can strongly compress or bypass the Sedov-Taylor stage and drive the remnant rapidly into radiative snowplow
evolution. After the remnant loses its interior pressure support, partial backflow of cooled shell fragments and refilling gas may initialize a pressure-confined and tidally limited seed cloud. The cloud then grows through shear-limited Hill capture until the gravitational,
tidal, shear, photoionization, and
magnetic conditions for collapse are simultaneously satisfied. The outcome depends strongly on the supermassive black-hole (SMBH) mass and explosion radius. Models with the lowest SMBH mass yield fewer than one massive
star per event on average, whereas the most massive SMBH models can produce from several to several hundred. For a top-heavy initial mass function, massive
stars dominate the resulting
stellar mass and feedback budget. Embedded
supernovae may therefore provide a localized gas-recycling channel for second-generation massive-
star formation in AGN discs.
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Quantum Physics
On the Origin of Beyond-Classical Advantage in the Parity-Permutation Problem
Jayashree Karmakar, Biswadeep Chatterjee, Rafiuddin Gazi et al. (+6 more)
We investigate the task of identifying the parity (odd vs even) of an unknown permutation applied to $n$ particles. Classically, using fewer than $n$ distinct labels per particle limits the success probability to random guessing, whereas
quantum mechanics, exploiting
entanglement in both preparation and measurement, accomplishes the task perfectly with as few as $\big\lceil \sqrt{n}\big\rceil$ levels per particle [\href{https://doi.org/10.1103/yhyv-xnwq}{PRL 135, 260603 (2025)}]. We show that even without entangled preparation,
quantum theory still offers a probabilistic advantage over classical strategies. Moreover, such product preparations yield perfect success in locally
quantum theories, where elementary systems are
quantum but their composition follows the minimal tensor product structure of generalized probabilistic theories (GPTs). We further identify GPT models that accomplish the task with certainty without requiring
entanglement either at the preparation stage or at the measurement stage. Our central result establishes that the linear dimension of the elementary systems, rather than
entanglement, is the fundamental resource governing the existence of probabilistic advantage in the permutation parity problem. In particular, below the required dimension threshold, no amount of
entanglement can improve upon the random-guessing limit.
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All authors Jayashree Karmakar, Biswadeep Chatterjee, Rafiuddin Gazi, Ananya Chakraborty, Snehasish Roy Chowdhury, Manik Banik, Tamal Guha, Sahil Gopalkrishna Naik, Kunika Agarwal
High Energy Physics (Theory)
Line operator indices of S-fold theories
Yosuke Imamura, Masato Inoue and Akihiro Sei
We study superconformal indices in the presence of line operators in S-fold theories. We consider two types of lines, realized by fundamental strings and fivebranes, respectively, in AdS$_5 \times S^5/\mathbb{Z}_k$. For fundamental lines, we analyze the corresponding indices including finite-$N$ corrections arising from
giant graviton configurations. For $k=2$, we compare the
holographic results with line operator indices in $\mathcal{N}=4$ super Yang-Mills theories with orthogonal gauge groups. For $k=3,4$ and $6$, we focus on the rank $2$ case, in which the supersymmetry is enhanced to ${\cal N}=4$, and compare them with the corresponding Wilson-'t Hooft line operator indices. In both cases, we find improved agreement once
giant graviton contributions are included. For line operators realized by fivebranes, after confirming agreement for $k=2$, we construct BPS configurations for $k\geq 3$ explicitly using fivebrane junctions and derive the indices in the large $N$ limit by the mode analysis on the fivebrane junctions.
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Earth and Planetary Astrophysics
A Physically Driven Parameterisation of Multidimensional Atmospheres: Application to the JWST Phase Curve of WASP-121b
Yuanheng Yang, Guo Chen, Xianyu Tan et al. (+6 more)
Understanding the multidimensional structure of strongly irradiated
exoplanets is essential for interpreting their atmospheric dynamics, chemistry and energy transport, yet current analyses remain limited by the difficulty of extracting reliable phase-resolved spectra and by the lack of physically interpretable parameterisations for
retrievals. We combine a data-driven eclipse-normalisation method with an analytical three-dimensional temperature parameterisation derived from radiative, advective and diffusive energy balance and controlled by a few characteristic timescales. Applied to JWST/NIRSpec G395H observations of WASP-121b, the method yields spectra consistent with conventional phase-curve fitting, while the parameterisation reproduces the large-scale thermal structures predicted by general circulation models. The preferred
retrieval reveals a pronounced day–night contrast, a dayside thermal inversion extending to both limbs, an inversion over part of the nightside, and limb temperatures differing by several hundred kelvin. Dynamical transport strengthens with pressure, and the hotspot offset increases from $\sim4^\circ$ to $\sim9^\circ$ across the pressures probed by G395H. The confined dayside hot region and the small, pressure-dependent offsets lie closer to the $\sim$3~G GCM than to its non-
magnetic counterpart, although Rayleigh drag cannot be excluded. The spectra also favour distinct dayside and nightside chemical states, with more nightside CH$_4$ than the cooler temperatures alone can explain, pointing to disequilibrium chemistry. The retrieved thermal structure further implies an inhomogeneous cloud distribution, with condensation favoured on the nightside and cooler morning limb. The framework provides a computationally efficient, physically interpretable path from spectroscopic phase curves to multidimensional atmospheric structure.
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All authors Yuanheng Yang, Guo Chen, Xianyu Tan, Thaddeus D. Komacek, Xi Zhang, Thomas M. Evans-Soma, Fei Yan, Chengzi Jiang, Fei Dai
Atomic Physics
Strontium ${}^{1}S_{0}\!\rightarrow\!{}^{1}P_{1}$ transition frequency measurements assisted by a photonic grating chip
Jaewhan Lee, Hyun Gyung Lee, Won-Kyu Lee et al. (+15 more)
We measure the absolute frequency of the ${}^{1}S_{0}\!\rightarrow\!{}^{1}P_{1}$ transition in strontium using two methods: fluorescence spectroscopy of a thermal atomic beam source from a compact low-power oven and velocity measurements of a slow atomic beam from a two-dimensional grating magneto-optical trap (2D gMOT). The measurements for both methods are performed in the same ultra-high
vacuum chamber containing a diffraction grating chip which is placed below the strontium atoms that are being interrogated. The first method uses a probe
laser beam incident on the grating chip such that the grating acts as an end mirror, with the first-order diffracted beam providing a retro-reflected probe beam. The counter-propagating
laser beams traverse an atomic beam emitted from an oven, enabling spatially resolved fluorescence spectroscopy through CCD imaging and hyperfine-constrained multi-isotope fitting. The second method relies on a large profile cooling
laser beam normally incident onto the grating chip which
laser cools strontium atoms for a slow atomic beam source. The velocity of the atoms exiting the 2D gMOT is measured as a function of the
laser detuning and intensity from which the resonance frequency can be estimated. The two methods are consistent within their quoted uncertainties. Using three
datasets based on retro-beam spectroscopy measurements, and one
dataset using slow atom beam velocity measurements, we determine the ${}^{1}S_{0}\!\rightarrow\!{}^{1}P_{1}$ transition frequency to be $650.503\,815(5)~\mathrm{THz}$. Our result provides a re-evaluation of this $461$ nm transition demonstrated on a compact
laser cooling apparatus based on a diffraction grating platform.
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All authors Jaewhan Lee, Hyun Gyung Lee, Won-Kyu Lee, Huidong Kim, Dohyeon Kwon, Sang-Bum Lee, Meungho Seo, Taeg Yong Kwon, Sangwon Seo, Hyun-Gue Hong, Seji Kang, Sang Eon Park, Young-Ho Park, Jongcheol Park, Yeeun Na, Il-Suk Kang, Sangsik Kim, Jae Hoon Lee
Quantum Physics
Optimal complex conjugation of unknown isometry channels
Satoshi Yoshida and Mio Murao
Access to the complex conjugate of an unknown
quantum channel is a useful resource in
quantum oracle problems, motivating the question of how such access can be simulated using only a limited number of calls to the original channel. We determine the optimal deterministic protocol for approximately implementing the complex conjugate isometry $\overline{V}$ from $n$ uses of an unknown isometry channel $V: \mathbb{C}^d\to\mathbb{C}^D$. We derive a closed-form expression for the optimal fidelity and prove that a parallel protocol is optimal even among general
quantum superchannels, including adaptive and indefinite-causal-order strategies. The formula implies a query complexity $n=\Theta(d[(D-d)/\epsilon+1])$ for achieving infidelity $\epsilon$. We also present a
circuit construction based on the
quantum Schur transform and the dual Clebsch–Gordan transform, with
circuit complexity $O(\mathrm{poly}(D,1/\epsilon))$. This task is extended to the multi-copy case $V^{\otimes n}\mapsto \overline{V}^{\otimes k}$. For fixed $d<D$ and $k$, we show that the optimal fidelity for the multi-copy case is $1-kd(D-d)/n+o(n^{-1})$, and that this value is asymptotically attained by a parallel estimation-based protocol. Finally, combining the isometry protocol with random Stinespring dilations yields a protocol for complex conjugation of unknown rank-$r$
quantum channels whose query complexity is optimal up to a constant factor if the Kraus rank $r$ is constant.
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Quantum Physics
Finite-size reliability of homothetic quantum Otto engines
Gabriella G. Damas, Clebson Cruz, Norton G. de Almeida et al. (+2 more)
Homothetic
quantum Otto engines—where all populated energy gaps are rescaled by a common factor—provide a reference model in which the quasistatic
stochastic efficiency is trajectory-independent while work remains fluctuating. For arbitrary finite homothetic spectra we derive the two-point-measurement work distribution and reduce the first two work moments to endpoint energy moments. Specializing to a uniformly spaced ladder gives closed finite-$N$ expressions for the full work distribution, mean work, variance, and signal-to-width reliability. This ladder connects the
qubit and oscillator limits, reveals a finite-$N$ reliability crossover, and demonstrates that the high-temperature and infinite-dimensional limits do not commute. The noncommutation reflects a bounded-versus-unbounded spectral distinction: at fixed finite $N$ the Gibbs state has a normalizable infinite-temperature limit, whereas the oscillator retains an ever-expanding thermal tail. The exact formulas are used to compare standard mean-output prescriptions with work reliability, showing that maximum mean output and maximum dimensionless reliability select different operating points. The
benchmark is extended to incomplete diagonal reset and to finite-time
unitary strokes described by transition
matrices, with a finite-ladder protocol and a harmonic sudden-switch oscillator
benchmark as controlled examples. Weak deviations from exact homothety are treated perturbatively, showing how level-dependent gap distortions reintroduce quasistatic efficiency fluctuations and modify work reliability. Together, these results separate finite-size, incomplete thermalization, finite-time, and weak spectral-distortion contributions to work unreliability in
quantum Otto engines.
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All authors Gabriella G. Damas, Clebson Cruz, Norton G. de Almeida, Gao Xianlong, G. D. de Moraes Neto
Mesoscale and Nanoscale Physics
Emerging network model in a twisted monolayer-rhombohedral graphene
Juyoung Song, Jeyong Park and Jinhong Park
We investigate the coexistence of localized states and propagating one-dimensional (1D) modes in
graphene moiré systems. We first show within a minimal model that a spatially varying scalar potential can confine localized states, while sign changes of a staggered potential generate 1D modes along the resulting domain walls. These two types of states can coexist within the same finite energy window and form a hybrid network. We then demonstrate a microscopic realization of this mechanism in twisted monolayer-rhombohedral N-layer
graphene. Band structures, energy contours, and Bloch wave functions obtained in a realistic parameter regime reveal the coexistence of localized nearly flat-band states and propagating quasi-1D modes. Our results establish twisted monolayer-rhombohedral
graphene as a promising platform for realizing hybrid electronic networks with coexisting states of distinct effective dimensionalities.
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Optics
Broadband Control of Light through Complex Media via Automatic Self-Referencing Transmission Matrix Characterisation
Marcos Maestre Morote, Mickael Mounaix, Andrew Komonen et al. (+2 more)
Light propagation through complex media underpins critical optical technologies, from imaging distant
stars and ground-to-space communication to imaging inside biological tissue with hair-thin multimode fibre endoscopes. Central to controlling light through such disordered media lies the transmission
matrix. Inaccessible to accurate modelling, the transmission
matrix must be measured experimentally$-$yet this conventionally relies on techniques involving an external phase reference. For low-coherence or broadband sources, the stringent coherence, mode-matching, temporal-overlap, and stability requirements of that external reference can make such characterisation prohibitively difficult or fundamentally infeasible. Alternatively, existing self-referencing techniques use algorithmically fragile global optimisation methods, relying on fixed preselected internal reference(s), whose incomplete overlap with the transmitted field can create measurement blind spots. Here, we introduce an automatic self-referencing measurement technique based on spatial state
tomography that circumvents these coherence and algorithmic limitations. Rather than relying on a preselected reference or complex phase
retrieval, our approach systematically leverages the local interference among all propagating modes as distributed phase references without prior assumptions. We demonstrate this framework experimentally for a multimode fibre across coherent, low-coherence, and broadband regimes, recovering its complete optical transmission
matrix and performing high-fidelity spatial and polarisation beam shaping in each case. By enabling robust, source-matched, self-referencing transmission-
matrix measurement, our method extends light control through complex media into broadband illumination regimes relevant to biomedical imaging, optical communications, and high-power
laser applications.
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All authors Marcos Maestre Morote, Mickael Mounaix, Andrew Komonen, Martin Plöschner, Joel Carpenter
Quantum Physics
Nuclear Spin Squeezing Based on Spin-Exchange Collisions
He-bin Zhang, Yuanjiang Tang and Yong-Chun Liu
Isolation from environment leads to the days-long lifetime of noble-gas
nuclear spins, but also brings great challenges to the preparation, manipulation, and measurement of
nuclear-
spin quantum states. Here we find that
nuclear spin squeezing, with ultra-long lifetime and huge atomic number, can be efficiently obtained and manipulated based on the coherent
spin-exchange interaction between alkali-metal and noble-gas ensembles. Thanks to the considerable advantage of our proposal in preparing the
spin squeezing of the macroscopic atomic ensemble with a huge atomic number, even the
nuclear spin-squeezed state containing 10^20 atoms or more is obtainable with preexisting techniques. Further, the days-long storage and measurement of
nuclear spin squeezing can be performed by the coherent manipulation of a
magnetic field. This proposal can be implemented in hot atomic ensembles, whose ease of access and high adaptability to various environments will significantly facilitate the research and application of
nuclear-
spin nonclassical states in precision measurement,
quantum information, and fundamental physics.
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Materials Science
First-principles carrier mobility and optical absorption of strained ZnO with self-consistent Hubbard interactions
Hong-Guk Min, Wooil Yang, Sabyasachi Tiwari et al. (+2 more)
Carrier mobility and optical absorption are key performance parameters of
oxide semiconductors in transparent and flexible displays. We use a newly developed density-functional perturbation theory with a self-consistent Hubbard correction (DFPT+U) to study
phonon-limited electron transport and
phonon-assisted optical absorption in strained zinc
oxide (ZnO). This parameter-free approach accounts for electron-
phonon interactions and on-site correlation effects simultaneously. Electronic structures and
phonon dispersions are computed under three distinct uniaxial strain directions. Uniaxial tensile strain up to 4.8% along [\bar110] is found to increase the room-temperature electron mobility by 19% while leaving visible-range optical absorption essentially unchanged. These results demonstrate that moderate strain can selectively enhance carrier transport without degrading optical transparency, and establish DFPT+U as an effective framework for predicting strain-dependent transport and optical properties in wide-band-gap
oxides with implications for strain-engineered display and optoelectronic applications.
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All authors Hong-Guk Min, Wooil Yang, Sabyasachi Tiwari, Feliciano Giustino, Young-Woo Son
High Energy Physics (Theory)
Quantum Scattering in Schwarzschild Spacetime: Hawking Radiation and Black Hole Atmospheres
Victor H. Alencar, Gabriel Picanço and Carlos A.D. Zarro
In this paper, we investigate scattering of a scalar field near a Schwarzschild black hole through its $S$-
matrix. Within this framework, we obtain a novel derivation of Hawking radiation by computing the emission rate, which yields a Bose–Einstein distribution with temperature $T_H=(8\pi GM)^{-1}$, the Hawking temperature. In addition to Hawking radiation, the S-
matrix exhibits antibound states, corresponding to excitations at the threshold of becoming scattering (bound) states if the potential is decreased (increased). We interpret these excitations as constituents of the black-hole
quantum atmosphere: a thermalised region outside of the event horizon, which is the source of the Hawking radiation. Using the spectrum of antibound states, we found the atmospheric radius, $r_{\text{Atm}} \approx 2.77 r_{s}$, which is in good agreement with previous results in the literature obtained through other methods. Our results indicate that, at the macroscopic level, the
quantum atmosphere behaves like an ordinary thermalised gas at the Hawking temperature.
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Chemical Physics
An anharmonic liquid-entropy functional from the Mori-Zwanzig memory kernel
Ricardo Buarque, Mauro Gascon and Tod A. Pascal
We utilize the Mori-Zwanzig
memory kernel to separate the density of states of a
liquid into gas, cage, and harmonic-solid components. The cage
entropy is computed self-consistently as the non-Markovian excess of the full velocity response over its Markovian counterpart, and is assigned an excluded-volume
entropy reference rather than a harmonic one. Employing physically motivated constraints, the resulting Three-Phase Explicit Anharmonic Thermodynamics (3PT) method reproduces thermodynamic-integration
entropies of
liquid metals and aligns two water models with independent free-energy perturbation
benchmarks. For monoatomic Lennard-Jones
liquids, 3PT's accuracy follows a universal efficiency curve governed by the kernel's non-Markovianity. We thus establish a direct, trajectory-level mapping between
memory, transient cage dynamics, and
liquid entropy.
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Astrophysics of Galaxies
The Open Cluster Chemical Abundances and Mapping Survey XI. First Gradients from SDSS/MWM BOSS Determined Clusters
Jonah M. Otto, Peter M. Frinchaboy, John Donor et al. (+13 more)
The Milky Way Mapper program in the fifth generation of the Sloan Digital Sky Survey (SDSS-V/MWM) has observed millions of
stars, thousands of them in open clusters. The Open Cluster Chemical Abundances and Mapping (OCCAM) survey continues to create comprehensive
datasets of open clusters and their members in order to constrain
Galactic parameters. This eleventh contribution from the OCCAM survey is the first to use
stellar parameters from
stars observed with the optical
Baryon Oscillation Spectroscopic Survey (BOSS) spectrograph to determine cluster membership. We use data from SDSS-V/MWM's 20th Data Release (DR20) and curate a sample of 1883
stars in 111 open clusters, including 95 not in previous OCCAM samples based on infrared data from the Apache Point Observatory
Galactic Evolution Experiment (APOGEE) spectrograph. The sample includes 16 clusters with
stars observed using both the BOSS and APOGEE spectrographs, and we find consistent agreement in measurements of both [Fe/H] and [$\alpha/M$]. The BOSS sample includes the majority of the clusters at young ages (Age $< 150$ Myr) that complement the APOGEE sample of primarily older clusters. We use the combined BOSS+APOGEE OCCAM sample to constrain the radial
metallicity gradient with respect to $R_{guide}$ ($-0.079 \pm 0.005 \text{ dex kpc}^{-1}$) and $R_{gc}$ ($-0.082 \pm 0.006 \text{ dex kpc}^{-1}$), which agree well with results from previous OCCAM papers using only APOGEE data. Finally, the inclusion of the primarily young BOSS clusters has not changed that the OCCAM open cluster sample indicates no significant
evolution of this gradient in different mono-age populations.
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All authors Jonah M. Otto, Peter M. Frinchaboy, John Donor, Ilija Medan, Natalie R. Myers, Audrey Hauck, Katia Cunha, Gail Zasowski, Madeleine McKenzie, Jingkun Zhao, Jose Eduardo Mendez-Delgado, Amaya Sinha, Zachary Way, Dmitry Bizyaev, Andrew R. Casey, Jose G. Fernandez-Trincado
Materials Science
One-Step Epitaxial Access to Rhombohedral Graphene Flat-Band States on Step-Bunched SiC
Hao Zhong, Xingzhe Wang, Hanbin Deng et al. (+15 more)
Rhombohedral
graphene multilayers provide a moiré-free platform for correlated and topological flat-band physics, but direct, transfer-free epitaxial access to thickness-tunable multilayers remains limited. Here we report a one-step graphitization route on 4$^\circ$ off-axis 4H-SiC, in which high-temperature flash annealing simultaneously drives self-organized step bunching and multilayer
graphene formation. Atomic-resolution cross-sectional scanning transmission electron microscopy identify local ABC registry and distinguish rhombohedral from Bernal stacking. The thickness is tuned from
bilayer to more than twenty layers by varying single parameter, the annealing temperature. Angle-resolved photoemission spectroscopy directly tracks the thickness-dependent
evolution from interface-dominated low-energy states toward pronounced near-
Fermi-level flat-band spectral weight in thick multilayers. Low-temperature scanning tunneling microscopy and spectroscopy on a 17-layer film further reveal a 13.4 meV low-energy spectral reconstruction and a $\sqrt{3} \times \sqrt{3}$ Kekulé-like modulation, providing microscopic signatures consistent with an intervalley-mixed electronic texture. This one-step, transfer-free approach establishes step-bunched SiC as an epitaxial platform that links stacking engineering with moiré-free correlated flat-band electronic states.
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All authors Hao Zhong, Xingzhe Wang, Hanbin Deng, Tianyu Yang, Haixuan Cao, Renzhe Li, Qiang Wan, Shangkun Mo, Keming Zhao, Shuming Yu, Dingkun Qin, Guang Zhu, Yifan Zhou, Jianping Shi, Shuangfeng Jia, He Zheng, Jia-Xin Yin, Nan Xu
Statistical Mechanics
Charge discreteness and the energy efficiency of information erasure in dynamic random-access memory cells
Takase Shimizu, Kouki Yamamoto, Kensaku Chida et al. (+2 more)
A dynamic random-access
memory (DRAM)
cell stores information as an integer number of electrons on a capacitor, and whether this discreteness is thermodynamically relevant depends on the competition between the charging energy and thermal fluctuations. This competition is quantified by the ratio $\kappa$ of the single-electron charging energy to the thermal energy, and here we investigate how $\kappa$ affects the energy efficiency of information erasure in a DRAM
cell. Using a
stochastic-thermodynamic model of a DRAM
cell, we show that the nonquasistatic heat released during the discharge step is suppressed as $\kappa$ increases, whereas the quasistatic heat of the charge step approaches the Landauer cost. As a result, the energy efficiency increases monotonically with $\kappa$ and approaches the Landauer limit where the effect of charge discreteness is maximal and the
cell is effectively reduced to two charge states. The parameter $\kappa$ thus connects two thermodynamic regimes: a multilevel single-well
memory, whose nonequilibrium initial state prevents quasistatic erasure, and an effective two-level
memory that can attain the Landauer limit. These results identify $\kappa$ as the parameter that controls the fundamental efficiency ceiling of transistor–capacitor
memory circuits.
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All authors Takase Shimizu, Kouki Yamamoto, Kensaku Chida, Gento Yamahata, Katsuhiko Nishiguchi
Materials Science
Mechanism-Dependent Descriptors Enable Predictive Design of Oxygen Capacity in Perovskite Oxides
Shuiping Gong, Yi Li, Jie Su et al. (+9 more)
Perovskite
oxides can reversibly accommodate substantial changes in oxygen stoichiometry, making them attractive for clean-energy technologies including chemical looping and oxygen storage. Despite extensive efforts to optimize their redox properties, predictive descriptors capable of assessing oxygen capacity across diverse compositions remain under development. Here, we combine experiments and first-principles calculations to establish composition and oxygen-capacity relationships in the model perovskite series LnxSr1-xCoO3. We confirm that increasing Sr2+ content promotes the formation of high-valence Co4+, expanding the cationic redox reservoir available during oxygen release and thereby enhancing oxygen capacity. In this regime, oxygen-vacancy formation energy captures the observed trend because oxygen release is primarily compensated by Co4+/Co3+/Co2+ redox. Across the rare-earth series, however, oxygen capacity decreases from La to Lu despite progressively lower oxygen-vacancy formation energies. We reveal that this counterintuitive behavior originates from an alternative charge-compensation pathway, in which
lattice oxygen is partially oxidized to O1- -like species during oxygen removal. Heavy rare-earth compositions (Tb-Lu) preferentially stabilize these oxygen-hole species through distinct local bonding environments, with charge compensation involving both oxidized
lattice oxygen and reduced rare-earth and cobalt cations, thereby suppressing net oxygen release despite favorable vacancy thermodynamics. We further identify average metal-oxygen bond strength, quantified by integrated
crystal orbital Hamilton population, as a physically meaningful descriptor for oxygen capacity when anionic redox becomes dominant.
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All authors Shuiping Gong, Yi Li, Jie Su, Zhenhao Zhou, Xiaobo Liao, Jian Deng, Chris Wolverton, Tao Deng, Jiangang He, Runxia Cai, Chaochao Dun, Zhenpeng Yao
Cosmology and Nongalactic Astrophysics
Gravitational waves from oscillons in a generalized exponential plateau potential
Peter Lott and Tuan Q. Do
We study oscillon formation and gravitational wave production in a generalized exponential plateau inflationary potential. Using Floquet analysis, we identify parametric instability bands consistent with oscillon formation, and solve numerically for the oscillon profile, finding quasi-breather solutions with lifetimes $\tau_{\rm osc} \cdot m_{\rm eff} \sim 10^3$ — $6\times10^4$. Applying the poltergeist mechanism, we compute the induced gravitational wave spectrum and find a peak at $f_{\rm peak} \approx 2.5\times10^{10}$~Hz with amplitude $\Omega_{\rm GW,0}\,h^2 \sim 10^{-9}$–$10^{-8}$ for the
benchmark parameter $\beta_{\rm pot} = 5\times10^{-6}$. This is far below the region forbidden by big bang nucleosynthesis. For $\beta_{\rm pot} = 5\times10^{-5}$ the signal exceeds the big bang nucleosynthesis bound for all considered oscillon energy fractions, constraining the parameter space of the model. The signal falls in the GHz regime, potentially accessible to future resonant cavity experiments.
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Quantum Physics
Bell violation with path-entangled number states under realistic detection
Christoph F. Wildfeuer
A single
photon delocalised over two modes is entangled, and whether that
entanglement can violate a Bell inequality has been disputed for three decades. In principle it is settled: the surviving objection was the absence of a shared phase reference, and a local oscillator supplies one, acting as a shared frame rather than as a measurement setting. In practice it is open, and what remains is a question about the apparatus. Loss does not spoil a parity measurement so much as rescale it, carrying it into the same one-parameter family of detector operators that already contains on–off detection. Within that family we give closed correlators for path-entangled number states, or N00N states, at arbitrary efficiency, with dark counts, mode mismatch, phase noise and upstream loss. Because loss and displacement commute up to a rescaling of the displacement amplitude, loss before and after the displacement is interchangeable, and a symmetric experiment is governed by one overall efficiency: the probability that a heralded
photon is detected. For a single
photon the Clauser–Horne–Shimony–Holt threshold on that efficiency is 0.83 with on–off detection and 0.95 with parity, so the scheme that needs no
photon-number resolution is the more robust, by twelve percentage points of loss and a factor of five in tolerable dark counts. Efficiency is no longer the obstacle; the mode overlap is. The best demonstrated telecom coupling, a buildable interferometer and today's detectors give an overall efficiency of 0.86, at which the required overlap is 0.92. We show that this overlap carries the heralded
photon's single-mode weight as well as the local oscillator's mode match, so buying more of it costs heralding efficiency — and no source has reported the two together.
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Strongly Correlated Electrons
Critical Phases of the extended isotropic $XY$ chain with four-spin interaction
Nika Kurdadze, Giorgi Gogaberishvili and G.I. Japaridze
Using the Jordan-Wigner transformation we calculate exactly the ground state and low-temperature thermodynamic properties of the
spin $S=1/2$ isotropic $XX$ chain with four
spin interaction. In terms of the equivalent spinless
fermion (SF) representation the system is viewed as a
lattice fermion gas with nearest-neighbor ($J$) and next-next-next-neighbor ($J^{\ast}/4$) hopping. It is shown that with the increase of four
spin coupling, at $J^{\ast}_{c} = 4J/3$ the system experiences the Lifshitz type topological phase transition characterized by the tripling of
Fermi points. The
quantum phase transition (QPT) point marks transition from a gapless
spin-
liquid phase of standard $XX$ chain into again a gapless
spin-
liquid phase with different character of power-low decay of
spin correlations. At the transition point the free
fermion dispersion relation shows flattering at
Fermi points, what determines singular character of density of states $\rho(\omega)\sim (\omega/J)^{-2/3}$ and as a consequence unconventional temperature dependence of heat capacity of the system $C\sim (T/J^{\ast})^{1/3}$, and singular
magnetic susceptibility of the system $\chi(H)\sim (H/J^{\ast})^{-2/3}$. In the case of alternating
magnetic field the system is characterized by the rich ground state phase diagram which contains fully polarized (
ferromagnetic), gapped
antiferromagnetic (AFM) and
spin liquid phases. At the transition point from the gapped AFM phase into the gapless polarized
spin liquid phase the system shows rapid increase of magnetization $m\sim(H-H_c)^{1/6}$ and
magnetic susceptibility a singular behavior as $\chi(H)\sim (H-H_c)^{-5/6}$.
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Quantum Physics
Construction of Sets of Orthogonal Quantum States with Minimal Nonlocality in Bipartite and Tripartite Systems of Unequal Local Dimensions
Ben-Hao Zhao, Dong-Huan Jiang, Yu-Guang Yang et al. (+1 more)
The research on minimal nonlocality aims to determine the minimal cardinality of nonlocal sets of
quantum states. However, the construction of a nonlocal set of states in bipartite or tripartite
quantum systems with unequal local dimensions remains unsolved. In this paper, we first give a method to construct a set of orthogonal
quantum states with minimal nonlocality in $\mathbb{C}^{4} \otimes \mathbb{C}^{7}$
quantum system. Then we give a general method to construct a set of orthogonal
quantum states with minimal nonlocality in a bipartite
quantum system with unequal local dimensions. Furthermore, we generalize the construction method to tripartite
quantum system with unequal local dimensions, and construct a set of orthogonal
quantum states with minimal nonlocality in $\mathbb C^{d_1} \otimes \mathbb C^{d_2}\otimes \mathbb C^{d_3}$
quantum system for $5\le d_1 < d_2 < d_3$. Our work settles the construction problem of a set of orthogonal states with minimal nonlocality in both bipartite and tripartite systems with unequal local dimensions.
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All authors Ben-Hao Zhao, Dong-Huan Jiang, Yu-Guang Yang, Guang-Bao Xu
Medical Physics
MWF-MIMOSA for efficient simultaneous relaxometry and myelin water fraction mapping
Yuting Chen, Yohan Jun, Hyeong-Geol Shin et al. (+15 more)
Quantitative
magnetic resonance imaging (qMRI) provides improved sensitivity and specificity to tissue composition and pathological alterations compared with conventional contrast-weighted imaging. Among various qMRI biomarkers, myelin water imaging is of particular interest because myelin plays a central role in
brain function and its alteration is closely associated with many neurological diseases. However, conventional myelin water fraction (MWF) mapping techniques are often limited by long scan times, low spatial resolution, reduced signal-to-noise ratio (SNR), and high specific absorption rate (SAR). Here, we propose MWF-MIMOSA for efficient simultaneous T1, T2, T2* mapping,
magnetic susceptibility source separation, and MWF estimation. To achieve this, multi-contrast and multi-slice zero-shot self-supervised learning (MZS-SSL) was used to jointly reconstruct whole-
brain complex-valued images. To improve computational efficiency of the parameter estimation step, a multilayer perceptron (MLP) was trained within the GACELLE GPU-accelerated parameter estimation framework to circumvent the computationally intensive Bloch simulation process, resulting in a >100-fold computational speed-up in MWF estimation. Numerical simulations were performed to evaluate the accuracy and precision of MWF-MIMOSA, and in-vivo results further demonstrated its robustness. Comparison with existing myelin water imaging methods showed that MWF-MIMOSA is highly correlated with established approaches, while providing complementary quantitative parameter maps at higher spatial resolution and with shorter scan times. Notably, simultaneous multi-parametric mapping was achieved in 5 min at 1 mm isotropic resolution, and in 10 min at 0.7 mm isotropic resolution. These results demonstrate the potential of MWF-MIMOSA for fast, high-resolution simultaneous relaxometry and myelin water imaging.
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All authors Yuting Chen, Yohan Jun, Hyeong-Geol Shin, Shizhuo Li, Shohei Fujita, Xingwang Yong, Jiye Kim, Jongho Lee, Gian Franco Piredda, Tom Hilbert, Aneri Bhatt, Susie Y. Huang, Huafeng Liu, Huihui Ye, Shahin Nasr, Borjan Gagoski, Kwok-Shing Chan, Berkin Bilgic
Strongly Correlated Electrons
Generalized Holstein-Primakoff transformation with optimizable bosonic truncation
Yang Liu, Jia-Wei Mei, Rong Yu et al. (+3 more)
Spin-wave theory provides a quasiparticle description of excitation spectra in
quantum spin systems. In this theory, the
spin operators are usually bosonized by the Holstein-Primakoff transformation or the Dyson-Maleev transformation. In practical calculations, the bosonized
Hamiltonian has to be truncated, and thus the resulting excitation spectra depend on the choice of bosonic representation. Here, we introduce a generalized Holstein-Primakoff transformation that continuously interpolates between the conventional Holstein-Primakoff and Dyson-Maleev transformations through a single parameter. The formulation naturally extends to the SU(N)
algebra and provides a flexible framework for optimizing bosonic truncations beyond harmonic order. As an application, we investigate the
spin-1 bilinear-biquadratic model on the square
lattice. By combining the generalized Holstein-Primakoff transformation with continuous similarity transformations, we obtain excitation spectra in excellent agreement with tensor-network calculations. Our results demonstrate that optimizing the bosonic representation substantially reduces truncation errors and provides quantitatively reliable descriptions of both quasiparticle dispersions and multi-
boson continua.
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All authors Yang Liu, Jia-Wei Mei, Rong Yu, Z. Y. Xie, Hong-Gang Luo, Jize Zhao
Chaotic Dynamics
Extrapolating the emergence of Hamiltonian chaos with random-feature Hamiltonian neural networks
Jaesung Choi
Machine learning of
Hamiltonian dynamics has driven growing interest in
Hamiltonian neural networks (HNNs), which encode Hamilton's equations of motion into the learning architecture. Despite this progress, it remains unknown whether such networks can predict dynamical regimes absent from their training data, in particular the broad chaotic sea that emerges beyond the observed parameter interval. We address this question using a parameter-aware random-feature
Hamiltonian neural network (RF-HNN). Trained using data from only a small number of control-parameter values at which invariant
tori dominate, the RF-HNN predicts autonomous long-time dynamics at unseen parameter values where mixed phase space develops and chaotic regions expand, with no data from that regime used in training or model selection. The method is demonstrated across four two-degree-of-freedom
Hamiltonian families, including the Hénon-Heiles system. Using Poincaré-section geometry and finite-time Lyapunov exponents, we show that the RF-HNN reproduces the breakup of regular structures and the emergence and growth of chaotic regions, whereas conventionally trained HNNs with the same
Hamiltonian structure remain too regular. These results show that what decides parameter extrapolation is not
Hamiltonian structure alone but how the fitted
Hamiltonian continues in the control parameter. To our knowledge, this is the first demonstration that a learned
Hamiltonian can qualitatively extrapolate from predominantly regular dynamics into a broad chaotic sea absent from training.
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Plasma Physics
Pulse Shaping Increases Efficiency in Pulsed Plasma Accelerators
Patrick W. Schools, Mammadbaghir Baghirzade, Ryan Heiser et al. (+3 more)
The performance of a gas-fed pulsed electromagnetic thruster is governed by the ability to deposit electrical energy while propellant is available for acceleration. Current pulsed-power systems require tradeoffs between high-current discharges that produce high exhaust velocities and longer pulses that overlap the energy deposition with more of the gas injection. This limited control restricts the specific impulse and mass utilization of these thrusters. This work introduces programmable pulse shaping as a method to increase control over energy deposition and expand the accessible operating space. We use solid-state integrated power modules to vary the discharge delay, pulse width, peak current, and the shape of the current waveform as propellant is injected. Experiments varying pulse widths from 30 to 500 $\mu$s and peak currents from 3 kA to 16 kA show that short, high-current pulses produce higher exhaust velocities and greater impulse bits than longer, lower-current pulses at comparable discharge energy. The switches also enable multiple discharges of arbitrary positioning and duration during a single gas injection. This micro-burst operation is shown to increase specific impulse in air by 278% from 840 to 3177 s through improved propellant utilization. This same pulse shaping ability is found to increase thrust efficiency from 0.2% in single-shot operation to 3.3% in micro-burst operation while operating with air.
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All authors Patrick W. Schools, Mammadbaghir Baghirzade, Ryan Heiser, Adrian Woodley, Laxminarayan L. Raja, Thomas C. Underwood
High Energy Physics (Theory)
L. G. Barbosa
We study
chiral symmetry breaking in the Nambu-Jona-Lasinio model on a de Sitter background, treating it as a non-renormalizable effective field theory with a physical ultraviolet cutoff. Using exponential proper-time regularization, we obtain an exact solution for the constituent
fermion mass in the strong-
curvature regime via the Lambert $W$ function. The consistency condition for real-valued solutions leads to an upper bound on the cosmological constant, indicating a limitation of the mean-field description rather than a fundamental physical constraint on the spacetime geometry.
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