Soft Condensed Matter
Non-Monotonic Exciton Transport Efficiency in Multi-layer Ring-shaped Quantum Networks inspired by Photosystem I
Yi Li, Rui Li, Kai-Ya Zhang et al. (+3 more)
Photosystem I (PSI) is one of the most efficient natural photosynthetic complexes and serves as a structural prototype for understanding excitation energy transfer (EET) and designing artificial light-harvesting systems. Here, we construct a multilayer elliptical-conical
quantum network inspired by PSI to investigate how
antenna architecture affects EET. Excitation dynamics are simulated using the
quantum jump approach combined with coherent modified Redfield theory (QJA-CMRT). The transfer efficiency exhibits a pronounced nonmonotonic dependence on pigment density, reaching a maximum of 0.86 at x=6 in the five-layer network. The optimal configuration contains 91 pigments, close to the number of core
antenna pigments in natural PSI. Our combined density-of-states and kinetic analyses reveal that this nonmonotonic dependence originates from a trade-off: at low pigment densities, enhanced band overlap promotes energy transfer, whereas at high densities, excessive
exciton delocalization compromises funnel directionality and reduces efficiency; the optimal configuration is consequently achieved at x=6. These findings provide insights into PSI
antenna organization and offer guidelines for designing efficient artificial light-harvesting systems.
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All authors Yi Li, Rui Li, Kai-Ya Zhang, Ming-Zi Jin, Tao Liu, Qing Ai
Quantum Physics
Rydberg quantum antennas for chip-interfaced single-photon source array
Yan-Lei Zhang, Dong-Qi Ma, Guang-Jie Chen et al. (+6 more)
We propose a Rydberg
quantum antenna, consisting of a one-dimensional chain of neutral atoms trapped in a standing-wave optical tweezer, as a chip-interfaced single-
photon source. Rydberg blockade induces a single collective excitation in the atomic chain, while its ordered geometry shapes the
photon emission into a directional beam, thereby realizing a
quantum antenna that emits strictly one
photon at a time. Through numerical simulations, we demonstrate single-
photon collection efficiencies into a waveguide exceeding 70% through a high-NA lens with a negligible multiple excitation probability. These performance are robust against probabilistic atom loading in the standing-wave dipole traps, requiring only ten atoms, indicating experimental feasibility. The Rydberg
quantum antenna thus offers a unique route toward scalable arrays of high-efficiency, high-purity, and identical single-
photon sources interfaced with a photonic chip, addressing key challenges in photonic
quantum information technology.
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All authors Yan-Lei Zhang, Dong-Qi Ma, Guang-Jie Chen, Qing-Xuan Jie, Liang Chen, Ya-Dong Hu, Zhu-Bo Wang, Guang-Can Guo, Chang-Ling Zou
General Relativity and Quantum Cosmology
Higher-order generalized uncertainty principle corrections to Casimir-supported traversable wormholes
Jureeporn Yuennan, Allah Ditta, Thammarong Eadkhong et al. (+2 more)
We investigate traversable wormholes supported by Casimir
vacuum energy with second-order generalized uncertainty principle (GUP) corrections. For two representative GUP models, we derive higher-order corrections to the Casimir energy and construct exact wormhole solutions in general relativity. The resulting geometries satisfy the throat,
flare-out, and asymptotic-flatness conditions. Higher-order corrections modify the wormhole mass and reduce the exotic matter required, although the null and weak energy conditions remain violated near the throat. We further analyze weak gravitational
lensing and gravitational-wave echoes, finding model-dependent signatures that may distinguish different GUP realizations. By relating the dimensionless parameter used in the solutions to the conventional phenomenological GUP parameter, we show that its physical interpretation depends strongly on the throat radius. Most current experimental bounds favor near-Planckian throats for appreciable GUP corrections, while macroscopic throats generally require much weaker corrections. These results provide a framework for confronting GUP-corrected Casimir wormholes with laboratory constraints and astrophysical observations.
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All authors Jureeporn Yuennan, Allah Ditta, Thammarong Eadkhong, Kazuharu Bamba, Phongpichit Channuie
Applied Physics · Cross-listed from cs.ET
Programming Spintronic Reservoir Computing
Yuichiro Terasaki, Yusuke Imai, Jason Z. Kim et al. (+1 more)
We present a programming framework for a spintronic reservoir computer (RC) that maps prescribed input-output relationships directly onto the readout layer, bypassing conventional data-driven black-box approaches. Our spintronic RC is based on magnetoresistive random-access
memory and exploits magnetization dynamics for computation. We introduce a general metric that quantifies the system's programmability and reveals how the governing equations and system parameters constrain the class of realizable functions. We then construct externally controllable readout layers by exploiting the explicit parameter dependence of the prescribed equations. This metric and construction enable programming explicit functions on the spintronic RC, indicating a potential route to in-
memory computing. Our demonstrations include neural-network emulation, bifurcation
embedding, and a Newton solver for fifth-order algebraic equations. In addition, we prove the universal approximation property of the spintronic RC in the limit of infinite system size and input duration, and show its consistency with programmability.
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All authors Yuichiro Terasaki, Yusuke Imai, Jason Z. Kim, Kohei Nakajima
General Physics
Groups of Worldview Transformations Implied by Einstein's Special Principle of Relativity over Arbitrary Ordered Fields
Judit Madarász, Mike Stannett and Gergely Székely
In 1978, Yu. F. Borisov presented an axiom system using a few basic assumptions and four explicit axioms, the fourth being a formulation of the relativity principle; and he demonstrated that this axiom system had (up to choice of units) only two models: a relativistic one in which worldview transformations are Poincaré transformations and a classical one in which they are Galilean. In this paper, we reformulate Borisov's original four axioms within an intuitively simple, but strictly formal, first-order logic framework, and convert his basic background assumptions into explicit axioms. Instead of assuming that the structure of physical quantities is the field of real numbers, we assume only that they form an ordered field. This allows us to investigate how Borisov's
theorem depends on the structure of quantities. We demonstrate (as our main contribution) how to construct Euclidean, Galilean, and Poincaré models of Borisov's axiom system over every non-Archimedean field. We also demonstrate the existence of an infinite descending chain of models and transformation groups in each of these three cases, something that is not possible over Archimedean fields. As an application, we note that there is a model of Borisov's axioms that satisfies the relativity principle, and in which the worldview transformations are Euclidean isometries. Over the field of reals it is easy to eliminate this model using natural axioms concerning time's arrow and the absence of instantaneous motion. In the case of non-Archimedean fields, however, the Euclidean isometries appear intrinsically as worldview transformations in models of Borisov's axioms and neither the assumption of time's arrow, nor the rejection of instantaneous motion, can eliminate them.
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General Physics
Towards a Quantum Erlangen Program
Matthew J. Lake
The classical Erlangen Program sought to classify metric spaces entirely in terms of their
symmetries. In physical spacetimes, these
symmetries define transformations between classical reference frames, yielding a one-to-one correspondence between frame transformations and the underlying geometry. More recently, the classical notion of ideal frame has been extended to the
quantum regime, by considering observers as
embodied physical systems, subject to the laws of
quantum mechanics. Here, we build on this approach, but outline an alternative definition of the term `
quantum reference frame', which differs somewhat from the mainstream view. We then show how the new definition can be used to construct a simple model of Planck-scale spacetime, which makes contact with existing
quantum gravity phenomenology. Finally, we show how classical spacetime
symmetries can be “mathematically preserved but operationally broken”, in the new model, suggesting that
quantum spacetime may be classified, at least locally, in terms of transformations between quantised frames of reference.
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Statistical Mechanics · Cross-listed from math.CO
A formal framework for higher-order spin models via hypergraphs, polymatroids, and the Tutte polynomial
Khallil Berrekkal, Joanna A. Ellis-Monaghan, Merijn Moody et al. (+1 more)
We develop a rigorous mathematical framework for statistical mechanics models on hypergraphs, and give conditions for lifting the classical connection between Potts model partition functions and the Tutte
polynomial from graphs to hypergraphs. We define hypergraphical models and their associated partition functions, and extend these to special classes of models induced by families of interaction functions. For boolean interaction families, whose interaction functions map to $\{0,1\}$, we show that the partition function is determined by a combinatorial rank function, and we establish sufficient conditions for a hypergraph deletion-contraction recurrence and for when the rank function defines a polymatroid. We illustrate the theory by applying it to three hypergraph interaction families: Parity Ising, Delta Potts, and And Ising. The induced hypergraphical models are not isomorphic to each other, but the first two reduce to the same graphical Ising models. We identify three polymatroids naturally associated with hypergraphs for these models: respectively, the binary matroid of the incidence
matrix over $\mathbb{F}_2$, the hypergraphical polymatroid, and the boolean polymatroid. For graphs, the first two reduce to the classical graphical matroid, and their partition functions recover the multivariate Tutte
polynomial. The Tutte
polynomial thus admits at least two distinct generalizations for hypergraphs, both satisfying a deletion-contraction recurrence: the Tutte
polynomial of the binary matroid of the hypergraph incidence
matrix, and a multivariate version of the Poincaré
polynomial of the hypergraphical polymatroid. The partition functions of And Ising models are likewise multivariate versions of the Poincaré
polynomial, here of the boolean polymatroid. These examples illustrate the much greater range of hypergraphical models and underscore the need for the unifying theory.
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All authors Khallil Berrekkal, Joanna A. Ellis-Monaghan, Merijn Moody, Clélia de Mulatier
Chemical Physics
Channel selection at identically vanishing dissipation difference: isolating the frenetic sector of the overdamped path measure
Shlomo Segal
Transition-state and Kramers-Langer theory determine reaction channel selection from data at a single point: the saddle. We show this is insufficient in a precise, constructive sense. Using the standard split of the Onsager-Machlup path weight into a time-antisymmetric part fixed by the
entropy flux and a time-symmetric part, the frenesy, we first settle when a dissipation-based criterion can distinguish two forward histories at all: the
entropy difference between two histories sharing endpoints equals beta times the circulation of the non-conservative force around the loop they enclose, and vanishes identically for every gradient flow. We then construct a two-channel gradient landscape whose channels share both endpoints, whose barrier heights are equal identically, and whose saddle Hessians are the same
matrix. The
entropy sector is switched off by construction, all local saddle-point theories predict 50:50 exactly, and the branching ratio isolates the frenetic sector. Langevin simulation gives P(+) = 0.4568 +/- 0.0012. We identify a covariant
geometric contribution to pathway selection within the frenetic sector, (1/2) ln det(D_perp H_perp), show that the divergence-of-drift observable proposed for this role is not coordinate-invariant whereas this one is, and find that it reproduces the measured branching to within 0.5 sigma with no fitted parameters. Stiff spectator modes cancel identically, since selection depends only on a ratio of determinants. We also give a parameter-free prediction: a solenoidal force of strength epsilon must contribute exactly 2*beta*epsilon/pi to ln[P(+)/P(-)]. These results are an exactly controlled counterexample to the sufficiency of local saddle-point data for channel selection.
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Quantum Physics
Quantum Simulation of SPAD in the Space Radiation Environment
Durgesh Tinker and Kavita Lalwani
Single-
Photon Avalanche Diodes (SPADs) are critical components of emerging
quantum communication networks that detect single
photons. They are placed in satellites for long-distance communication and are susceptible to radiation-induced displacement damage in space. This degrades SPAD performance parameters, including reduced efficiency, increased thermal dark counts, damage to the Si
crystal, and increased afterpulsing rate. This paper simulates SPAD in a space radiation environment by introducing a
quantum simulation framework, modeling the SPAD detector as a three-level
quantum system, ground state ($|g\rangle$), excited state ($|e\rangle$) and a trap state ($|t\rangle$). Furthermore, to model the
photon as a
quantum system, second quantization and Fock-space truncation are used. The interaction between the
photon-SPAD closed system is simulated using the Jaynes-Cummings model, and the open-system dynamics is governed by the Lindblad master equation and Qiskit's gate-based noise channels. The key characteristics, such as the efficiency, timing jitter, thermal dark counts, and afterpulsing & radiation effects, are obtained using
quantum simulation of SPAD. This approach differs significantly from conventional TCAD simulations, which rely on semiclassical approximations that do not capture the discrete
quantum statistics of single-
photon interactions and the dynamics of trap states.
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Geophysics
High solubility of water in post-perovskite and bridgmanite in the Earth's deep lower mantle
Megumi Semba, Naoya Sakamoto, Shuhei Mita et al. (+5 more)
Water in the Earth's mantle induces melting, giving rise to strong chemical heterogeneity, and alters its rheological and transport properties, which are keys to understanding seismic-wave speeds anomalies, convective motions and electrical conductivity. However, the abundance of water and its role in the deep mantle remain uncertain and controversial, particularly at conditions of the core-mantle boundary (CMB) region. Here we carry out melting experiments on a hydrous, natural mantle composition including both $H_2O$ and $D_2O$ over the entire pressure range of the Earth's lower mantle, in which melt coexists with bridgmanite (Bdg) and/or post-perovskite (PPv), the primary constituents of the respective lower and lowermost mantle. High-resolution secondary-ion mass spectroscopy (Cryo-SIMS) measurements reveal high water concentrations in Bdg (up to 5,500 ppm by weight) and PPv (up to 1.22 wt%) with strong enrichment in deuterium/hydrogen (D/H) relative to coexisting melt. The high solubilities of water in Bdg and PPv at CMB conditions suggest that subducting slabs do not release water when they reach the bottom of the mantle, and such a process cannot account for strong chemical heterogeneities inferred in the lowermost mantle and the topmost outer core, nor for ultralow-velocity zone (ULVZ)-like structures in seismically fast regions. Water-rich Bdg and PPv may be present in the large low shear velocity provinces and ULVZs, which may be the residue of a basal magma ocean and are predicted to host a deep low D/H water reservoir inherited from the early Earth that is occasionally sampled by plumes of a lowermost-mantle origin.
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All authors Megumi Semba, Naoya Sakamoto, Shuhei Mita, Kei Hirose, Yutaro Tsutsumi, Keisuke Ozawa, John W. Hernlund, Shiro Miwa
Plasma Physics
LoKI-GM: a global model framework for plasma chemistry studies
L. L. Alves, A. Tejero-Del-Caz, L. Marques et al. (+6 more)
Global (zero-dimensional or spatially averaged) models are widely employed to study complex chemistries in low-temperature
plasmas (LTPs). By adopting a spatially average description of the
plasma, they substantially reduce the computational cost while still providing reliable and detailed insight into the key processes taking place in the
plasma. In their most general formulation, global models involve the coupled solution of a Boltzmann solver (to describe the electron kinetics) and a Chemistry solver (to describe the heavy-species kinetics). This paper presents a tutorial on the LisbOn Kinetics Global Model (LoKI-GM) framework, developed in MATLAB and available as open-source code. The framework couples the Boltzmann solver LoKI-B, which solves the space-independent form of the two-term electron Boltzmann equation for non-magnetised non-
equilibrium LTPs, excited by DC/HF electric fields or time-dependent (non-oscillatory) electric fields, and the Chemistry solver LoKI-C, which solves the system of zero-dimensional rate balance equations for the main charged and neutral species in the
plasma and at the surface, receiving as input the kinetic schemes for the gas/
plasma/surface system under study. The inclusion of several transport models together with support for surface kinetics models are distinguishing features of LoKI-GM compared with other global chemistry models. We briefly present the formulation of LoKI-GM, including its numerical solution strategy, input/output parameters, and calculation workflow for both active discharges and afterglow
plasmas. The main differences with respect to existing global models are highlighted, and the flexibility of the code for
plasma chemistry studies is demonstrated through representative simulation results obtained across a range of gas discharge configurations and operating conditions.
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All authors L. L. Alves, A. Tejero-Del-Caz, L. Marques, P. Pereira, N. Pinhão, C. D. Pintassilgo, T. Silva, P. Viegas, V. Guerra
Physics and Society
Evolutionary dynamics of collective decision-making with local social influence on static and dynamic networks
Yuyuan Liu and Xiaojie Chen
Collective decision-making is ubiquitous across the living world and artificial societies. Individuals often choose an option based on intrinsic values of options. However, individual decision-making is also swayed by neighbors' choices, generating local social influence. Hence, an important question arises naturally, yet remains unanswered: when such social influence is integrated into the individual evaluation process for option choices, how does it affect collective decision-making outcomes in structured populations modeled by graphs. To address this, we consider a baseline model of binary options with social influence and assume that individuals not only evaluate the intrinsic values of options, but are also influenced by their neighbors' choices. We propose a perceived utility function integrating these two aspects for individual decision-making. By means of theoretical analysis, we first derive the average frequency of an option on static weighted connected graphs and present the mathematical condition under which this option prevails in the population. We find that the introduction of social influence can amplify the advantage of a superior option or compensate for the deficiency of an inferior one. We also reveal that the average degree of network exerts a dual effect on collective decision outcomes. Furthermore, we consider our evolutionary model on dynamic networks switching among distinct graph configurations. Our theoretical analysis shows that the evolutionary outcomes depend not only on the average degree of each network configuration, but also on its expected duration. We perform computer simulations to verify our theoretical predictions on static and dynamic networks.
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Materials Science · Cross-listed from eess.IV
pyALDIC: A Python Implementation of Augmented Lagrangian Digital Image Correlation with a GUI, Adaptive Meshing, and Mask-Aware Subset Splitting
Zixiang Tong and Jin Yang
pyALDIC is an open-source Python implementation of augmented Lagrangian digital image correlation (AL-DIC) for full-field displacement and strain measurement. The software combines a graphical user interface with a scriptable Python API and supports adaptive quadtree meshing, mask-aware subset splitting near cracks and holes, and selectable Local DIC and AL-DIC solver modes. Numba acceleration enables efficient analysis, while automated tests, documentation, and reproducible examples support reliable use acrossWindows, macOS, and Linux. Verification cases include synthetic displacement fields, rigid-body motion, Mode-I cracking, adaptive refinement, and experimental uniaxial tension. pyALDIC is distributed through PyPI, GitHub, and Zenodo under a BSD-3-Clause license for reproducibility. pyALDIC is openly available at https://github.com/zachtong/pyALDIC.
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Instrumentation and Methods for Astrophysics
Jointly Modeling Roman Coronagraph Astrometry and Photometry Improves Orbital Parameter Estimates
Farrah Molina, Sarah Blunt and Jason Wang
Launching in 2027, the Nancy Roman Grace Space
Telescope (Roman) has the potential to directly image
exoplanets in reflected light for the first time. Roman imaging will introduce new constraints on
exoplanet orbital parameters, since reflected-light intensity depends on orbital phase. In this Note, we discuss an addition to the open-source Python package orbitize!, which allows users to model
exoplanet orbits using joint constraints from astrometry and photometric variations due to orbital phase. To investigate the impact of adding photometric data into the orbital model, we simulated realistic measurements of partial orbits, both including and excluding photometry in our model, and computed orbital posteriors. We found that fitting both astrometry and photometry improves posterior precision relative to fitting astrometry alone. This effect was more pronounced for higher-SNR images; for example, photometric data with SNR=10 yielded 33% improvement in inclination precision when including photometry, while SNR=3 data yielded only 12% improvement.
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Mesoscale and Nanoscale Physics
Theory of Andreev reflection spectroscopy with anisotropic spin-dependent scattering
Zhiyue Li, Guoping Zhang and Tingyong Chen
Spintronic technologies require efficient generation and control of
spin-polarized currents. Conventional ferromagnet-based methods suffer from sensitivity to external
magnetic fields. Andreev reflection spectroscopy is vital for measuring
spin polarization and superconducting gaps, yet prevailing theories assume isotropic interface scattering. This neglects ubiquitous anisotropy in
heterostructures, causing misinterpretation of material properties. To resolve this, we develop a generalized model incorporating
spin-dependent anisotropic scattering. Introducing distinct interface barriers for
spin-up and
spin-down electrons extends both the Blonder-Tinkham-Klapwijk formalism and the Chen-Tesanovic-Chien extension. This unified framework describes transport from normal metals to half-metals. Solving the Bogoliubov-de Gennes equations with modified boundary conditions yields current formulae with a transmission probability judgment function identifying dominant
spin channels. In non-
magnetic metals, interfacial anisotropy generates sizable
spin-polarized currents via transmission
spin filtering, suppressing Andreev reflection and reducing sub-gap conductance. For positively polarized ferromagnets, anisotropy nonlinearly modulates polarization, enhancing Andreev reflection to a threshold before suppression. Negatively polarized materials exhibit inverse spectra, enabling unambiguous polarization sign determination via conductance comparisons. Epitaxial Co film measurements validate the model, resolving subtle anisotropies. This refines Andreev spectrum interpretation and supports interference-resistant
spin sources using non-
magnetic platforms, benefiting magnetoresistive devices and superconducting
quantum technologies.
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High Energy Physics (Phenomenology)
Application of flavor moonshine
Hirotaka Sugawara
In our previous paper [1], we presented the application of Moonshine to the
flavor physics based on the work of Cohn and Deutsch and Bagger and Wess [2], J. Conway and S. Norton [3] and T.Eguchi, H.Ooguri and Y.Tachikawa [4] laid down the mathematical basics. We present here the extension of our previous paper [1] by including the supersymmetry in addition to the modular
symmetry [1], [4]. We calculate all the
lepton masses and the
quark masses and their super partner masses by using the one input particle mass for each family. The two valued modular function is defined in equation (3.7). We define the two valued modular function of degree K in equation (3.2). We use K = 1 two valued modular function for the charged
leptons and K = 2 two valued modular function for the
neutrino and for the up
quarks, and K = 3 two valued modular function for the down
quarks, where 2K is the level of the two valued modular function. We emphasize that we have three particle masses which can be measured by the existing accelerators such as KEK B factory or CERN LHC. One is super electron mass "M_{e,s} = 24.73MeV", which is approximately 25 times that of electron. The Super d, s and b
quark masses are 0GeV, 89.165GeV, and 2964.7GeV. Super down
quark mass is 0 and super strange
quark mass can be measured both in KEKB and in CERN LHC. The super bottom
quark mass can be measured only in LHC.
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Materials Science
Effect of Al-Zn alloy wafer grain boundary diffusion on the magnetism and microstructure of sintered NdFeB magnets
Xi Liu, Wenxi Fang and Ken Perlin
This study investigates Al-Zn grain boundary
diffusion (GBD) treatment on sintered Nd-Fe-B magnets using $Al_{80}Zn_{20}$
alloy sheets as the
diffusion source. The
alloy sheets were placed at both ends of cylindrical samples and
diffusion-annealed at 900$^\circ$C and 700$^\circ$C for 7 hours under
vacuum ($\leq5\times10^{-3}$ Pa), followed by tempering at 500$^\circ$C for 2 hours.
Magnetic measurements show that coercivity increases from 951.5kA/m in the untreated sample to 1158.2kA/m at 900$^\circ$C (a gain of 206.7kA/m, 21.7%) and to 1039.6kA/m at 700$^\circ$C (a gain of 88.1kA/m, 9.3%), while remanence declines modestly from 1282mT to 1256mT after the high-temperature treatment. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometer (XRD) analyses reveal that the 900$^\circ$C treatment produces a thinner, more continuous grain boundary phase and a distinct core-shell structure around the main-phase grains. EDS mapping shows that Al preferentially enriches the shell region of the $Nd_2Fe_{14}B$ grains, while Zn predominantly resides in the grain boundary phase, where it lowers the melting point of the intergranular phase and improves its fluidity. XRD shows no detectable secondary phases, while the combined XRD, EDS results, and
lattice expansion are consistent with possible limited Al incorporation into the main-phase
lattice. Verified by computational analysis, the coercivity enhancement is attributed to three synergistic factors: improved grain boundary decoupling, the formation of a high-anisotropy shell layer that strengthens domain-wall pinning, and the smoothing of grain edges to suppress reverse-domain nucleation.
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Astrophysics of Galaxies
Stacked Reverberation Mapping of High Redshift Quasars in DESI. I. Feasibility Analysis
Rahma Alfarsy, R.E.A. Canning, Eva-Maria Mueller et al. (+49 more)
The broad line region of
quasars has long been probed by reverberation mapping techniques that measure time lags between continuum and broad emission line variations. Stacked reverberation mapping has been proposed as a less observationally expensive alternative to traditional methods. This ensemble approach also reduces biases from small-number statistics. The Dark Energy Spectroscopic Instrument (DESI) is conducting the most extensive spectroscopic survey of
quasars to date. We create mock light curves emulating expected DESI
quasar observations at
redshifts $1.48<z<5.2$ and luminosities $ 44.68 \leq \log L_{1350} \lambda / \mathrm{erg\,s^{-1}} \leq 45.99 $ to test stacked reverberation mapping feasibility using sparse spectroscopic data paired with well-sampled photometric data. The pipeline, using the lag estimation code JAVELIN, successfully recovers the simulated C IV lags within one sigma of the true values using spectroscopic light curves composed of only a few spectral epochs (2-10) with irregular cadences. We investigate how observational factors, including C IV flux error magnitude, number of stacked
quasars, and spectral epoch count, affect performance. This work motivates a pathway for future stacked reverberation mapping projects with large scale spectroscopic surveys of
quasars having $\geq 2$ spectroscopic observations. Our results suggest an economical alternative for constraining and extending the radius-luminosity relation to higher
redshifts and luminosities. Subsequently, this relation can be employed more reliably in single-epoch black hole mass measurements and
quasar cosmology in these distant regimes.
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All authors Rahma Alfarsy, R.E.A. Canning, Eva-Maria Mueller, Jessica Aguilar, Steven Ahlen, David Alexander, Davide Bianchi, David Brooks, Peter Clark, Todd Claybaugh, Andrei Cuceu, Tamara Davis, Axel de la Macorra, Saisrinivas Dhavala, Victoria A. Fawcett, Benjamin Floyd, Andreu Font-Ribera, Jaime Forero-Romero, Enrique Gaztañaga, Wei-Jian Guo, Gaston Gutierrez, Klaus Honscheid, Richard Joyce, Stephanie Juneau, David Kirkby, Theodore Kisner, Anthony Kremin, Claire Lamman, Martin Landriau, Laurent Le Guillou, Paul Martini, Hugh McDougall, Aaron Meisner, Ramon Miquel, John Moustakas, Seshadri Nadathur, Nathalie Palanque-Delabrouille, Zhiwei Pan, Swayamtrupta Panda, Ignasi Pérez-Ràfols, Francisco Prada, Ragadeepika Pucha, Graziano Rossi, Eusebio Sanchez, David Schlegel, Michael Schubnell, Tom Shanks, Małgorzata Siudek, David Sprayberry, Gregory Tarlé, Benjamin Alan Weaver, Hu Zou
Strongly Correlated Electrons
Quasi-Two-Dimensional Quantum Antiferromagnetism in the Distorted Honeycomb Compound KCuIn(PO4)2
S. Gayen, S. S. Ali, V. K. Singh et al. (+2 more)
We investigate the electronic structure and
magnetic properties of the distorted honeycomb
lattice compound KCuInP2O8 through a combination of experimental measurements, first principles calculations and
quantum monte carlo simulations. Density functional theory calculations within the GGA+U framework establishes KCuInP2O8 as an indirect gap
insulator with Cu2+ local moments and finite magnetocrystalline anisotropy arising from
spin orbit coupling. A microscopic evaluation of
magnetic exchange interactions using the
magnetic force
theorem reveals a pronounced hierarchy of couplings, with the next nearest neighbor interaction dominating over the nearest neighbor exchange, while interlayer couplings remain negligible. This exchange hierarchy naturally maps the system onto weakly coupled
antiferromagnetic spin chains embedded in a distorted honeycomb
lattice. Motivated by the ab initio estimated exchange interactions, we construct an effective
spin half
Hamiltonian and investigate its
magnetic response using large scale
quantum Monte Carlo simulations. The calculated temperature dependent susceptibility and field dependent magnetization quantitatively reproduce the experimental behavior and capture key signatures of low dimensional
quantum magnetism, including a broad susceptibility maximum and a field induced saturation at low temperatures. Our results establish KCuInP2O8 as a quasi-two-dimensional
quantum antiferromagnet composed of coupled
spin chains, providing a consistent theoretical framework that links electronic structure, exchange interactions, and collective
magnetic behavior.
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All authors S. Gayen, S. S. Ali, V. K. Singh, B. Koteswararao, S. K. Panda
Accelerator Physics
Experimental Demonstration of a Two-Dimensional Nonlinear Integrable System in a Particle Accelerator
John Wieland, Alexander Valishev, Aleksandr Romanov et al. (+4 more)
A two-dimensional nonlinear integrable system was experimentally demonstrated at the Fermilab Integrable Optics Test Accelerator. The system was implemented by inserting a special nonlinear magnet in a conventional accelerator
lattice. We characterized the system by measuring lifetimes, transverse profiles and transverse oscillation frequencies of the 150-MeV electron beam as a function of the strength of the nonlinear insert. The measured shift of the working point and the amplitude-dependent detuning were consistent with theoretical predictions. We also observed the predicted bifurcation of the stable closed orbit. A striking consequence of the system's implementation was the possibility to operate the storage ring with integer tunes without lifetime degradation. This research opens up novel ways to design particle accelerators and to stabilize particle beams.
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All authors John Wieland, Alexander Valishev, Aleksandr Romanov, Nikita Kuklev, Giulio Stancari, Sergei Nagaitsev, Sebastian Szustkowski