arXivDaily arXiv每日学术速递 周一至周五更新
2601.11521 2026-01-19 astro-ph.HE

X-ray Polarization of the Intrabinary Shock in Redback Pulsar J1723$-$2837

Andrew G. Sullivan, Jack T. Dinsmore, Roger W. Romani

Comments 7 pages, 4 figures, accepted for publication in the Astrophysical Journal

详情
英文摘要

The intrabinary shocks (IBS) in spider pulsars emit non-thermal synchrotron X-rays from accelerated electrons and positrons in the shocked pulsar wind, likely energized by magnetic reconnection. The double-peaked X-ray light curves from these shocks have been well characterized in several spider systems. In this paper, we analyze Imaging X-ray Polarimetry Explorer (IXPE) observations of the redback pulsar J1723$-$2837 to examine the expected synchrotron polarization. Using advanced extraction methods that include spatial, temporal, and particle background weights, we constrain the polarization of the IBS. We compare different models for the magnetic field in the radiation zone and find that the best fit prefers a striped pulsar wind model over other polarized models, with maximum polarization degree of the IBS emission component $Π_{\rm IBS}=36^{+16}_{-15}\%$, in addition to an unpolarized non-IBS component. Since this is only 2.4$σ$, we cannot claim strong preference over an unpolarized model; we report a $99\%$ confidence level upper limit on the total polarization of both IBS and non-IBS components $Π_{99}<36\%$, which is improved over the $50\%$ limit obtained in previous work. The best-fit polarization of the IBS component is consistent with numerical simulations. Detailed tests of such models are accessible to future measurements.

2601.11519 2026-01-19 cond-mat.supr-con

Vacuum-selected timescales in driven Josephson systems

Sebastian Allende, David Galvez-Poblete

详情
英文摘要

In this work, we demonstrate that the intrinsic timescale of a Josephson junction can be controlled through dynamical vacuum selection. By applying a Kapitza-like high-frequency drive to the system, the effective Josephson potential is reshaped, allowing for the stabilization of inphase or antiphase configuration. As a result, the Josephson plasma frequency, that is, the clock frequency of the junction, becomes a tunable property of the selected vacuum. Our findings establish a vacuum-controlled Josephson clock principle, in which the dynamical vacuum acts as an internal reference that fixes the operational timescale of Josephson oscillations, rather than this scale being imposed externally.

2601.11509 2026-01-19 cond-mat.mtrl-sci

Predictive autoencoder-transformer model of Cu oxidation state from EELS and XAS spectra

Brian Lee, Linna Qiao, Samuel Gleason, Guangwen Zhou, Xiaohui Qu, Judith Yang, Jim Ciston, Deyu Lu

详情
英文摘要

X-ray absorption spectroscopy (XAS) and electron energy-loss spectroscopy (EELS) produce detailed information about oxidation state, bonding, and coordination, making them essential for quantitative studies of redox and structure in functional materials. However, high-throughput quantitative analysis of these spectra, especially for mixed valence materials, remains challenging as diverse experimental conditions introduce noise, misalignment, broadening of the spectral features. We address this challenge by training a machine learning model consisting of an autoencoder to standardize the spectra and a transformer model to predict both Cu oxidation state and Bader charge directly from L-edge spectra. The model is trained on a large dataset of FEFF-simulated spectra and evaluates model performance on both simulated and experimental data. The results of the machine learning model exhibit highly accurate prediction across the domains of simulated and experimental XAS as well as experimental EELS. These advances enable future quantitative analysis of Cu redox processes under in situ and operando conditions.

2601.11506 2026-01-19 cond-mat.other

Broadband Terahertz Time-domain Spectroscopy of Quantum Materials in a Dilution Refrigerator

Robert J. Vukelich, Tenzin Norden, Tracy G. Hastings, Mohan Giri, Michelle Caldwell, Shabnam Forutan, John L. Reno, David J. Hilton

Comments 10 pages, 5 figures

详情
英文摘要

We have constructed a terahertz time domain spectroscopy system using a Bluefors dilution refrigerator with a 7 T split-coil magnet. Using a gallium arsenide single quantum well sample, terahertz waveforms were measured at 145 mK in a magnetic field range from 0 to 6 Tesla to measure cyclotron resonance. Effective mass is found to be $0.073 m_{e}$, which is larger than the commonly accepted bulk value of $0.068 m_{e}$.

2601.11504 2026-01-19 cond-mat.str-el cond-mat.mes-hall cond-mat.mtrl-sci

Visualization of Tunable Electronic Structure of Monolayer TaIrTe$_4$

Sandy Adhitia Ekahana, Aalok Tiwari, Souvik Sasmal, Zefeng Cai, Ravi Kumar Bandapelli, I-Hsuan Kao, Jian Tang, Chenbo Min, Tiema Qian, Kenji Watanabe, Takashi Taniguchi, Ni Ni, Qiong Ma, Chris Jozwiak, Eli Rotenberg, Aaron Bostwick, Simranjeet Singh, Noa Marom, Jyoti Katoch

详情
英文摘要

Monolayer TaIrTe$_4$ has emerged as an attractive material platform to study intriguing phenomena related to topology and strong electron correlations. Recently, strong interactions have been demonstrated to induce strain and dielectric screening tunable topological phases such as quantum spin Hall insulator (QSHI), trivial insulator, higher-order topological insulator, and metallic phase, in the ground state of monolayer TaIrTe$_4$. Moreover, charge dosing has been demonstrated to convert the QSHI into a dual QSHI state. Although the band structure of monolayer TaIrTe$_4$ is central to interpreting its topological phases in transport experiments, direct experimental access to its intrinsic electronic structure has so far remained elusive. Here we report direct measurements of the monolayer TaIrTe$_4$ band structure using spatially resolved micro-angle-resolved photoemission spectroscopy (microARPES) with micrometre-scale resolution. The observed dispersions show quantitative agreement with density functional theory calculations using the Heyd-Scuseria-Ernzerhof hybrid functional, establishing the insulating ground state and revealing no evidence for strong electronic correlations. We further uncover a pronounced electron-hole asymmetry in the doping response. Whereas hole doping is readily induced by electrostatic gating, attempts to introduce electrons via gating or alkali metal deposition do not yield a rigid upward shift of the Fermi level. Fractional charge calculations demonstrate that added electrons instead drive band renormalization and shrink the band gap. Taken together, our experimental and theoretical results identify the microscopic mechanism by which induced charges reshape the band topology of monolayer TaIrTe$_4$, showing that doping can fundamentally alter the electronic structure beyond the rigid band behaviour that is typically assumed.

2601.11498 2026-01-19 cs.IT cs.NI eess.SP math.IT quant-ph

Convergence Properties of Good Quantum Codes for Classical Communication

Alptug Aytekin, Mohamed Nomeir, Lei Hu, Sennur Ulukus

详情
英文摘要

An important part of the information theory folklore had been about the output statistics of codes that achieve the capacity and how the empirical distributions compare to the output distributions induced by the optimal input in the channel capacity problem. Results for a variety of such empirical output distributions of good codes have been known in the literature, such as the comparison of the output distribution of the code to the optimal output distribution in vanishing and non-vanishing error probability cases. Motivated by these, we aim to achieve similar results for the quantum codes that are used for classical communication, that is the setting in which the classical messages are communicated through quantum codewords that pass through a noisy quantum channel. We first show the uniqueness of the optimal output distribution, to be able to talk more concretely about the optimal output distribution. Then, we extend the vanishing error probability results to the quantum case, by using techniques that are close in spirit to the classical case. We also extend non-vanishing error probability results to the quantum case on block codes, by using the second-order converses for such codes based on hypercontractivity results for the quantum generalized depolarizing semi-groups.

2601.11494 2026-01-19 physics.class-ph gr-qc

Conformal Symmetry and the Thermal Effects of Acceleration in Classical Physic

Timothy H Boyer

Comments 29 pages

详情
英文摘要

An accelerating Rindler frame in Minkowski spacetime acting for a finite time interval is used to carry a box of particles or waves between two relativistic inertial frames. The finite spatial extent of the box allows treatment of the equations of motion for particles or for waves, while the Rindler acceleration provides a substitute for scattering to test for thermal equilibrium. In the case of equilibrium for relativist particles, the Juttner distribution is derived. For relativistic waves, a full derivation of the Planck spectrum including zero-point radiation is obtained within classical theory. For relativistic waves, relativistic behavior and conformal symmetry are crucial. It is emphasized that the classical two-point correlation function for classical zero-point radiation depends upon the geodesic separation between the spacetime points and is independent of the coordinate system choice. The classical point of view here does not give any support for the idea that a system in uniform acceleration through classical zero-point radiation finds a thermal system.

2601.11485 2026-01-19 astro-ph.HE

Analytical approaches to the study of the phase of the visibility function

S. V. Chernov

详情
英文摘要

In radio interferometric observations, the main source of information is the complex visibility function, which includes amplitude and phase. In this paper, the dependence of the phase of the visibility function on the base projection is investigated when used in radio interferometry with space bases up to six Earth diameters. The dependence of the phase of the visibility function on the projection of the base and direction is obtained. It is shown that for small values of the base projections, this dependence has a universal character and is consistent with the results of numerical magnetohydrodynamic models.

2601.11484 2026-01-19 gr-qc

Source-Driven Tails in Kerr Spacetime: Nonlinear effects in Late-Time Behavior

Som Dev Bishoyi, Subir Sabharwal, Gaurav Khanna

Comments 7 pages, 2 figures, 3 tables, comments and feedback are welcome

详情
英文摘要

We present the long-duration time-domain simulations of scalar-field tails in Kerr spacetimes driven by \emph{outgoing} multipolar sources. Extending the recent work in the literature from Schwarzschild to rotating black holes, we evolve sources with $\ell'=\{0,1,2,3,4\}$ on backgrounds with dimensionless spin $a/M=\{0.0, 0.8, 1.0\}$ and extract the late-time decay rates of measured modes $\ell\le4$ for a nonlinearity-inspired outgoing source with a $1/r^2$ fall-off. In all cases we find the inverse power-law index $p_{\ell\ell'}$ to be larger than the source-free Price law values by one unit, i.e. $p^{\text{sourced}}_{\ell\ell'} = p^{\text{Price}}_{\ell\ell'} + 1$. We also include a power-law index value computation for a similar source-driven gravitational wave case $(\ell,m)=(4,4)$ and confirm closely related results in the recent literature.

2601.11477 2026-01-19 astro-ph.GA

Galactic core-tail structure in BEC dark matter with Kapitza potential

Itauany do Nascimento Barroso, Hermano Velten

Comments 12 pages; 16 figures

详情
英文摘要

Recently, the experimental realization of a Kapitza potential in a Bose-Einstein Condensate (BEC) has been reported for the first time in literature, motivating further theoretical investigations of such system. At the same time, in the astrophysical context, BEC dark matter models have been widely studied as a possible phenomenological explanation for the dark matter phenomena. We model the galactic structure with an inner cored profile obtained from the ground state equilibrium solution of the Schroedinger-Poisson together with a Kapitza-BEC like interaction for the tail region. We find reasonable agreement of the model with representative galaxy rotation curves available in the SPARC catalogue.

2601.11476 2026-01-19 astro-ph.SR astro-ph.GA

Fundamental Properties of Novae in M31

Allen W. Shafter, Kamil Hornoch

Comments 26 pages, 11 figures, 8 tables; accepted for publication in The Astrophysical Journal Supplements

详情
英文摘要

The peak luminosities and rates of decline for a large sample of novae recently published by Clark et al. have been analyzed using the Yaron et al. nova models to estimate fundamental properties of the M31 nova population. The apparent white dwarf (WD) mass distribution is approximately Gaussian with a mean $\langle M_\mathrm{WD} \rangle = 1.16\pm0.14~M_{\odot}$. When corrected for recurrence-time bias, the mean drops to $\langle M_\mathrm{WD} \rangle = 1.07~M_\odot$. The average WD mass of the M31 nova sample is found to be remarkably similar to that found by Shara et al. in their study of 82 Galactic novae, but $\sim0.15~M_\odot$ more massive than the mean recently determined by Schaefer in his comprehensive study of more than 300 systems. As expected, the average WD mass for the recurrent novae included in the M31 sample, $\langle M_\mathrm{WD} \rangle = 1.33\pm0.08~M_{\odot}$, is significantly higher than that for novae generally. Other parameters of interest, such as the accretion rate, velocity of the ejecta, and the predicted recurrence time, are characterized by skewed distributions with large spreads about means of $\langle \log \dot M ~(M_\odot~\mathrm{yr}^{-1}) \rangle \simeq -9.27$, $\langle V_\mathrm{max} \rangle \simeq 1690~\mathrm{km~s}^{-1}$, and $\langle \log P_\mathrm{rec}~\mathrm{(yr)} \rangle \simeq 4.39$, respectively. The role of hibernation in affecting the $\dot M$ and $P_\mathrm{rec}$ distributions is briefly discussed. Finally, the nova properties were studied as a function of apparent position (isophotal radius) in M31, with the preponderance of evidence failing to establish any clear dependence on stellar population.

2601.11466 2026-01-19 astro-ph.GA astro-ph.HE

Pseudo Little Red Dot: an Active Black Hole Embedded in a Dense and Dusty, Metal-Poor Starburst Galaxy at z=5.96

Karina I. Caputi, Ryan A. Cooper, Pierluigi Rinaldi, Rafael Navarro-Carrera, Edoardo Iani

Comments 15 pages, including 9 figures and 2 tables. Submitted to the ApJ. Comments welcome!

详情
英文摘要

We present a study of Pseudo-LRD-NOM (Pseudo little red dot with no metal lines), a highly magnified low-mass galaxy behind the lensing cluster Abell 370 at z=5.96. We classify this object as a pseudo-LRD because its red rest-frame optical colour is mainly driven by a prominent Halpha line (with EW0 >~ 800 Angstroms) present in its JWST NIRSpec spectrum. Halpha is dominated by a narrow component and also has a minor broad component indicative of an active black hole with M_BH = 2.9x10^6 Msun. A narrow Hbeta emission line is also detected (with S/N = 8), producing a Balmer decrement (narrow) Halpha/Hbeta = 11. The rest-frame UV spectral slope is beta_UVspec = -1.2. All these features can be ascribed to high dust attenuation. However, no [OIII]5007 or any other metal lines are detected in the spectrum, so [OIII]5007/Hbeta < 0.25, at odds with a simple dust-attenuation explanation. Accounting for all the spectral properties requires the model of a starburst with moderate colour excess E(B-V)=0.18-0.45, high gas density (n_H >~ 10^6 cm^{-3}) and extremely low gas/stellar metallicities (Z = 0.01-0.1 Zsun). The demagnified stellar mass is 1.62^{+1.54}_{-0.79} x10^7 Msun and the stellar-mass surface density is Sigma* = 418^{+725}_{-310} Msun/pc^2, similar to that of massive/nuclear star clusters. Pseudo-LRD-NOM provides evidence of massive black-hole growth occurring in a high-density, dusty starburst which is at the early stages of its chemical enrichment, and is likely a precursor to a real LRD.

2601.11458 2026-01-19 astro-ph.IM

Five Years of Mini-EUSO Observations from the ISS: Summary of Key Results

Matteo Battisti

详情
英文摘要

Mini-EUSO is the first space-borne detector of the JEM-EUSO (Joint Exploratory Missions for Extreme Universe Space Observatory) program, operating on the International Space Station (ISS) since October 2019. Designed to search for Ultra-High Energy Cosmic Rays (UHECRs) above 10$^{21}~$eV and capable of placing a stringent upper limit on their flux at these extreme energies, paving the way to future space-based UHECR observatories, Mini-EUSO has completed more than 150 observation sessions over five years, accumulating approximately 750 hours of data. The mission has produced the first global UV emission maps of Earth and provided valuable insights into lightning phenomena and Transient Luminous Events (TLEs), such as elves, as well as artificial light sources and meteors. Notably, Mini-EUSO has conducted the first systematic space-based meteor survey, detecting over 22,000 meteors and identifying three interstellar candidates. Among the observed TLEs, the most interesting class of phenomena are elves, which appear as expanding ring-shaped structures occurring at $\sim$90 km altitude. Mini-EUSO has detected elves with varying structures and different numbers of concentric rings, from single-ring up to five rings. Thanks to its imaging capabilities, fast time resolution, and favorable observational geometry, Mini-EUSO is uniquely suited to studying this kind of lightning phenomena, providing unprecedented insight into their dynamics. Additionally, the instrument has demonstrated the capability of a space-based detector to identify short light transients resembling extensive air shower signals while distinguishing them from those produced by UHECRs. This contribution presents a comprehensive summary of the Mini-EUSO mission, its status, and main results.

2601.11454 2026-01-19 physics.chem-ph cond-mat.mtrl-sci physics.comp-ph

The rise and fall of stretched bond errors: Extending the analysis of Perdew-Zunger self-interaction corrections of reaction barrier heights beyond the LSDA

Yashpal Singh, Juan E Peralta, Koblar Alan Jackson

Journal ref J. Chem. Phys. 160, 124105 (2024)

详情
英文摘要

Incorporating self-interaction corrections (SIC) significantly improves chemical reaction barrier height predictions made using density functional theory methods. We present a detailed, orbital-by-orbital analysis of these corrections for three semi-local density functional approximations (DFAs) situated on the three lowest rungs of the Jacob's Ladder of approximations. The analysis is based on Fermi-Löwdin Orbital Self-Interaction Correction calculations performed at several steps along the reaction pathway from the reactants (R) to the transition state (TS) to the products (P) for four representative reactions selected from the BH76 benchmark set. For all three functionals, the major contribution to self-interaction corrections of the barrier heights can be traced to stretched bond orbitals that develop near the TS configuration. The magnitude of the ratio of the self-exchange-correlation energy to the self-Hartree energy (XC/H) for a given orbital is introduced as an indicator of one-electron self-interaction error. For the exact, but unknown density functional, XC/H = 1.0 for all orbitals, while for the practical DFAs studied here, XC/H spans a range of values. The largest values are obtained for stretched or strongly lobed orbitals. We show that significant differences in XC/H for corresponding orbitals in the R, TS, and P configurations can be used to identify the major contributors to the SIC of barrier heights and reaction energies. Based on such comparisons, we suggest that barrier height predictions made using the SCAN meta-generalized gradient approximation may have attained the best accuracy possible for a semi-local functional using the Perdew-Zunger SIC approach.

2601.11450 2026-01-19 q-bio.BM cond-mat.soft physics.bio-ph

Principles of Client Enrichment in Multicomponent Biomolecular Condensates

Aishani Ghosal, Nicholas E. Lea, Lindsay B. Case, Trevor GrandPre

详情
英文摘要

Biomolecular condensates are commonly organized by a small number of scaffold molecules that drive phase separation together with client molecules that do not condense on their own but become selectively recruited into the dense phase. A central open question is how client recruitment feeds back on scaffold interactions to determine condensate composition. Here we address this problem in a reconstituted focal adhesion system composed of focal adhesion kinase (FAK) and phosphorylated p130Cas (Cas) as scaffolds and the adaptor protein paxillin (PXN) as a client. We show that both FAK phosphorylation and PXN recruitment produce a common compositional response in which FAK becomes enriched while Cas is depleted within the condensate. To interpret these observations, we develop two complementary theoretical descriptions. First, within a two-component Flory-Huggins framework, we show that phosphorylation can be captured by either strengthening heterotypic FAK-Cas interactions or increasing the effective number of interaction-relevant segments on FAK, both of which bias partitioning toward FAK-rich condensates. Second, we introduce a minimal three-component Flory-Huggins theory without an explicit solvent and map it onto an effective two-component description, demonstrating that client recruitment renormalizes homotypic and heterotypic scaffold interactions. Analytical predictions for the location of the critical point are tested in reconstituted multicomponent systems through PXN addition, showing that client recruitment alone tunes proximity to criticality and reshapes condensate composition. Together, our results reveal distinct yet convergent physical routes by which post-translational modification and client recruitment control scaffold composition in multicomponent condensates.

2601.11449 2026-01-19 cond-mat.quant-gas cond-mat.str-el

Pathway to Kondo physics in ytterbium atom chains with repulsive spin impurities

Jeff Maki, Lidia Stocker, Oded Zilberberg

Comments 16 pages, 7 figures, 3 appendices

详情
英文摘要

The Kondo effect is a paradigmatic model of strongly-correlated physics, where a magnetic impurity forms a many-body singlet with a fermionic environment. Cold gases of ytterbium (Yb) atoms have been proposed to be an ideal platform to study the Kondo effect since different internal states of the atom can be used to create both the impurity and the fermionic environment. In Yb gases, however, the atomic impurity interacts with the fermionic environment both through magnetic and potential scattering. These two scattering mechanisms counteract one another, raising the question of how robust Kondo screening remains. Here, we show that potential scattering can quench the Kondo screening in one-dimensional Yb gases; yet, strikingly, Kondo physics survives this quench in well-defined regimes. Combining analytical renormalization-group theory for a Luttinger liquid with density matrix renormalization group (DMRG) simulations, we identify a transition from a strongly- to a weakly-entangled impurity as potential scattering is increased. The two approaches show excellent agreement concerning the stability of Kondo physics throughout the different parameter regimes considered. Our results provide a quantitative criterion for the emergence of Kondo screening in one-dimensional Yb gases and delineate experimentally accessible regimes for its realization in cold-atom platforms.

2601.11446 2026-01-19 quant-ph

Coupling free electrons to a trapped-ion quantum computer

Elias Pescoller, Santiago Beltrán-Romero, Sebastian Egginger, Nicolas Jungwirth, Martino Zanetti, Dominik Hornof, Michael S. Seifner, Iva Březinová, Philipp Haslinger, Thomas Juffmann, Johannes Kofler, Philipp Schindler, Dennis Rätzel

Comments 15 pages, 5 figures

详情
英文摘要

Freely propagating electrons may serve as quantum probes that can become coherently correlated with other quantum systems, offering access to advanced metrological resources. We propose a setup that coherently couples free electrons in an electron microscope to a trapped-ion quantum processor, enabling non-destructive, quantum-coherent detection and the accumulation of information across multiple electrons. Our analysis shows that single electrons can induce resolvable qubit excitations, establishing a platform for practical applications such as quantum-enhanced, dose-efficient electron microscopy.

2601.11436 2026-01-19 physics.soc-ph

An Epidemiological Modeling Take on Religion Dynamics

Bilge Taskin, Teddy Lazebnik

详情
英文摘要

Religions are among the most consequential social institutions, shaping collective identities, moral norms, and political organization across societies and historical periods. Nevertheless, despite extensive scholarship describing conversion, competition, and secularization, there is still no widely adopted formal model that captures religious dynamics over time within a unified, mechanistic framework. In this study, we propose an epidemiologically grounded model of religious change in which religions spread and compete analogously to co-circulating strains. The model extends multi-strain compartmental dynamics by distinguishing passive believers, active missionaries, and religious elites, and by incorporating demographic turnover and mutation-like splitting that endogenously generates new denominations. Using computer simulations, we show that the same mechanism reproduces canonical qualitative regimes, including emergence from rarity, rapid expansion, long-run coexistence, and transient rise-and-fall movements. A reduced calibration variant fits historical affiliation trajectories with parsimonious regime shifts in effective recruitment and disaffiliation, yielding interpretable signatures of changing social conditions. Finally, sensitivity analyses map sharp regime boundaries in parameter space, indicating that modest shifts in recruitment efficacy or retention among active spreaders can qualitatively alter long-run religious landscapes. These results establish a general, interpretable framework for studying religion as a dynamical diffusion process and provide a tool for comparative inference and counterfactual analysis in sociological research.

2601.11434 2026-01-19 astro-ph.GA

FEAST: Probing Hierarchical Star Formation with the Spatial Distributions of Young Star Clusters

Drew Lapeer, Daniela Calzetti, Kathryn Grasha, Angela Adamo, Bruce G. Elmegreen, Arjan Bik, Giacomo Bortolini, Anne Buckner, Michele Cignoni, Matteo Correntim, Debra Meloy Elmegreen, H. Faustino Vieira, Max Hamilton, Kelsey Johnson, Thomas S. -Y Lai, Sean T. Linden, Subhransu Maji, Matteo Messa, Göran Östlin, Alex Pedrini, E. Sabbi, Linda J. Smith

Comments 23 pages, 12 figures, 4 tables, accepted at ApJ

详情
英文摘要

We apply the angular two-point correlation function (TPCF) to the spatial distribution of young star clusters (YSCs) in four nearby star forming galaxies (NGC 628, NGC 4449, M51, and M83) in order to investigate their underlying hierarchical structuring. Using newly constructed catalogs of YSCs in the emerging phase (eYSCs), identified in the infrared with JWST, and optical YSCs detected in archival HST data, we compute TPCFs for various cluster samples and age bins across the four galaxies as part of the FEAST (Feedback in Emerging extrAgalactic Star ClusTers) program. We find clear evidence of hierarchical structuring, especially in eYSCs and YSCs with ages < 10 Myr (referred to as oYSCs), which show similar TPCFs within each galaxy. NGC 628 exhibits a clear distinction between the TPCFs of eYSCs and oYSCs, implying a shorter randomization timescale. In contrast, clusters aged 10 to 300 Myr exhibit progressively more random spatial distributions, becoming effectively random after $\sim$ 100 Myr, consistent with earlier studies. The two-dimensional fractal index $D_2$ of the YSCs underlying distribution is calculated from model fits to TPCFs. Our values of $D_2$ derived from the youngest YSC populations align better with the expected value of $D_2 \sim $1.3 for a universal star formation process compared to previous findings.

2601.11424 2026-01-19 cond-mat.soft physics.flu-dyn

Confinement-induced motion of ciliates

G. C. Antunes, H. Stark

详情
英文摘要

The time dynamics of flagellar and ciliary beating is often neglected in theories of microswimmers, with the most common models prescribing a time-constant actuation of the surrounding fluid. By explicitly introducing a metachronal wave, coarse-grained to a sinusoidal surface slip velocity, we show that a spatial resonance between the metachronal wave and the corrugation of a confining cylindrical channel enables a ciliate to swim even when it cannot move forward in a bulk fluid. Using lubrication theory, we reduce the problem to the Adler equation that reveals an oscillatory and ballistic swimming regime. Interestingly, a ciliate can even reverse its swimming direction in a corrugated channel compared to the bulk fluid.

2601.11416 2026-01-19 physics.optics math-ph math.MP

Wigner picture of partially coherent accelerating beams

Sergey A. Ponomarenko, Morteza Hajati

详情
英文摘要

We advance a phase-space theory of partially coherent accelerating, non-diffracting beams employing the Wigner distribution function (WDF). We derive a general expression for the WDF of any accelerating, diffraction-free beam of arbitrary degree of spatial coherence and find an elegant closed-form expression for the WDF of such beam with a Gaussian energy spectrum of noise. We also show how partially coherent accelerating beams of finite power can be constructed within the Wigner picture.

2601.11415 2026-01-19 astro-ph.IM cs.LG physics.data-an

Zero-Shot Detection of Elastic Transient Morphology Across Physical Systems

Jose Sánchez Andreu

Comments 17 pages, 6 figures. Supplemental material included

详情
英文摘要

We test whether a representation learned from interferometric strain transients in gravitational-wave observatories can act as a frozen morphology-sensitive operator for unseen sensors, provided the target signals preserve coherent elastic transient structure. Using a neural encoder trained exclusively on non-Gaussian instrumental glitches, we perform strict zero-shot anomaly analysis on rolling-element bearings without retraining, fine-tuning, or target-domain labels. On the IMS-NASA run-to-failure dataset, the operator yields a monotonic health index HI(t) = s0.99(t)/tau normalized to an early-life reference distribution, enabling fixed false-alarm monitoring at 1-q = 1e-3 with tau = Q0.999(P0). In discrete fault regimes (CWRU), it achieves strong window-level discrimination (AUC_win about 0.90) and file-level separability approaching unity (AUC_file about 0.99). Electrically dominated vibration signals (VSB) show weak, non-selective behavior, delineating a physical boundary for transfer. Under a matched IMS controlled-split protocol, a generic EfficientNet-B0 encoder pretrained on ImageNet collapses in the intermittent regime (Lambda_tail about 2), while the interferometric operator retains strong extreme-event selectivity (Lambda_tail about 860), indicating that the effect is not a generic property of CNN features. Controlled morphology-destruction transformations selectively degrade performance despite per-window normalization, consistent with sensitivity to coherent time-frequency organization rather than marginal amplitude statistics.

2601.11413 2026-01-19 quant-ph

Quantum-enhanced optimization for patient stratification in clinical trials

Laia Domingo, Christine Johnson

详情
英文摘要

Clinical trials are notorious for their high failure rates and steep costs, leading to wasted time and resources spend, prolonged development timelines, and delayed patient access to new therapies. A key contributor to these failures is biological uncertainty, which complicates trial design and weakens the ability to detect true treatment effects. In particular, inadequate patient stratification often results in covariate imbalances across treatment arms, masking treatment effects and reducing statistical power, even when therapies are effective for specific patient subpopulations. This work presents an optimization-based, quantum-enhanced approach to patient stratification that explicitly minimizes covariate imbalance across numerical and categorical variables, without altering protocol design or trial endpoints. Using real clinical trial data, we demonstrate that hybrid quantum-classical optimization methods achieve high-quality stratification while scaling efficiently to larger cohorts. In our benchmark study, the quantum-enhanced pipeline delivered over a 100x improvement in computational efficiency compared to classical approaches, enabling faster iteration and practical deployment at scale. This report shows how improved stratification can lead to decision-relevant gains, including up to a fivefold increase in statistical significance in treatment effect estimation, reducing treatment-effect dilution and increasing trial sensitivity. Together, these results show that optimization-driven stratification can strengthen clinical trial design, improve confidence in downstream decisions, and reduce the risk of costly late-stage failure.

2601.11411 2026-01-19 physics.optics

Hysteresis in the complex nonlinear refractive index of a homogeneous and isotropic medium

Igor Kuzmenko, Y. B. Band, Yshai Avishai, Marek Trippenbach

Comments 6 pages, 5 eps figures

详情
英文摘要

We calculate the permittivity, $ε(ω)$, for a medium with a quadratic electro-optic effect, modeling it as a Duffing oscillator. The nonlinear refractive index $n(ω, E(ω))$ and the nonlinear absorption coefficient $α(ω, E(ω))$ exhibit hysteresis when the light intensity is varied [here $E(ω)$ is the electric field strength at angular frequency $ω$], and when the light frequency is varied. $n(ω, E(ω))$ can be negative when the resonances in the permittivity and permeability are close to one another.

2601.11410 2026-01-19 physics.optics

Resolving topological obstructions to vectorial structured field control

An Aloysius Wang, Yuxi Cai, Yifei Ma, Patrick S Salter, Chao He

详情
英文摘要

The use of structured matter, such as optical retarders, for vectorial control is a well-established and widely employed technique in modern optics, and has driven continued advances in the manipulation of complex, spatially varying vectorial fields. However, achieving arbitrary field conversion typically requires the use of cascaded elements, as intrinsic physical and fabrication constraints fundamentally limit individual devices to a restricted subset of transformations. This results in an overall continuous transformation potentially failing to be continuous at the level of the parameters of the cascade, leading to detrimental engineering consequences such as the introduction of complex, discontinuous aberrations that disrupt important topological properties of the underlying matter field. In this work, we establish a novel mathematical framework for analyzing the topological difficulties that emerge in the decomposition of an overall transformation into individual layers, and for determining the minimal depth required to overcome them. The strategy introduced provides a general pathway for optimizing designs for vectorial field control and matter field generation, with particular significance for the manipulation of topological phases in optical polarization fields, such as Stokes skyrmions, where continuity is of vital importance.

2601.11405 2026-01-19 physics.optics

General in situ feedback control of cascaded liquid crystal spatial light modulators for structured field generation

An Aloysius Wang, Yuxi Cai, Zhenglin Li, Ruofu Liu, Yifei Ma, Patrick S Salter, Chao He

详情
英文摘要

Cascaded liquid crystal spatial light modulators provide a versatile strategy for the generation of structured light and matter fields, with applications including optical communications, photonic computing, and topological field engineering. However, experimental imperfections, such as temperature-dependent liquid crystal response, variations between individual pixels, and alignment errors, present significant engineering challenges in generating high-quality fields. Moreover, changes in experimental conditions over time mean that calibrating each component once is insufficient for maintaining long-term, high-quality field generation. To address this, we present a general engineering approach based on a bespoke, physically informed, and manifold-constrained gradient-descent scheme that enables in situ feedback control, compensating for such errors in real time without the need to alter the experimental setup. We further demonstrate the correction efficacy of our proposed strategy through experiments in both spatially varying light and matter field generation, including scenarios in which complex vectorial aberrations are artificially introduced into the setup. Together, these demonstrations underscore the practicality of our method and its suitability for deployment in real-world experimental environments, paving the way for robust operation of cascaded architectures for structured field generation.

2601.11399 2026-01-19 astro-ph.GA

Star-forming compact groups: Tracing the early evolutionary stages of compact group environments

Ortiz-Gómez S., Torres-Flores S., Monachesi A., Montaguth G. P., Véliz Astudillo S., Mendes de Oliveira C., Olave-Rojas D. E., Lima-Dias C., Demarco R., Pallero D., Lopes A. R., Cortesi A., Telles E., Kanaan A., Ribeiro T., Schoenell W

Comments Accepted for publication in Astronomy & Astrophysics 18 pages, 28 figures, 4 tables

详情
英文摘要

In the context of pre-processing -- a scenario in which galaxies quench their star formation within substructures before falling into clusters -- we investigate the impact of environment on the physical and morphological properties of galaxies in Compact Groups (CGs), focusing specifically on a sample of Star-Forming Compact Groups (SFCGs). Our aim is to characterize the physical and morphological properties of galaxies in SFCGs, analogues of the Blue Infalling Group, and to understand how the environment influences their evolution. We use photometric techniques to derive stellar masses and star formation rates (SFRs). Morphological parameters are extracted from DECaLS images, obtaining parametric properties such as the Sérsic index ($n$) and effective radius ($R_{\mathrm{e}}$) using GALFITM, as well as non-parametric indices -- including the Gini coefficient, $M_{20}$, and asymmetry -- from the same data. These indicators allow us to classify galaxies into E/S0/Sa, Sb/Sc/Ir, and merger types. All measurements are compared to a control sample of field galaxies to assess environmental effects. We find no significant differences in $n$ and $R_{\mathrm{e}}$ between SFCG and field galaxies, in contrast to results reported for other CG samples. However, SFCG galaxies exhibit higher specific star formation rates (sSFRs) than their field counterparts. Approximately $16\%$ of SFCG galaxies show merger features and elevated asymmetry. These mergers also present enhanced SFRs compared to both other SFCG types and the field population. We propose that SFCGs represent an earlier evolutionary phase of CGs, supported by their lower velocity dispersions and moderate crossing times, in addition to the observed SFR enhancement and the absence of pronounced morphological transformation. Galaxy mergers in this phase appear to enhance, rather than suppress, star formation.

2601.11391 2026-01-19 cond-mat.soft physics.comp-ph

NAVIS: A LAMMPS-Python framework for efficient computation of nanochannel velocity and thermal interfacial slip

Sleeba Varghese, Sobin Alosious, Jesper Schmidt Hansen, Billy Dean Todd

Comments 11 pages, 6 figures

详情
英文摘要

We present NAVIS (NAnochannel Velocity and thermal Interfacial Slip), a LAMMPS-Python scripted toolkit for computing the Navier (hydrodynamic) friction coefficient and Kapitza (thermal) resistance at arbitrary solid-fluid interfaces. NAVIS is based on equilibrium molecular dynamics (EMD) methods for calculating the linear response friction and thermal resistance at the interface, as well as the corresponding velocity and temperature slips. The methodology is based on our previous studies (Hansen, et al., Phys. Rev. E 84, 016313 (2011); Varghese et al., J. Chem. Phys. 154, 184707 (2021); Alosious, et al., J. Chem. Phys. 151, 194502 (2019); Alosious, et al., Langmuir 37, 2355-2361 (2021)), and in this work we provide a pedagogical framework for the implementation of this toolkit on two systems: (i) a water-graphene system (for hydrodynamic slip) and (ii) a water-CNT system (for thermal slip). We provide detailed instructions for performing the EMD simulations using the LAMMPS package and processing the simulation outputs using Python modules to obtain the desired quantities of interest. We expect the toolkit to be useful for computational researchers studying interfacial friction and thermal transport, key factors for efficient and practical applications of nanofluidic systems.

2601.11390 2026-01-19 nucl-ex nucl-th

The unfinished picture of low-energy antineutron interactions: open issues and hints for future research possibilities

A. Filippi

Comments 10 pages, 18 figures

详情
英文摘要

This report examines the open questions that remain unsolved following the measurements with antineutrons ($\bar n$) as probes conducted up to the 1990s at the LEAR facility at CERN. It also presents suggestions for possible new experiments at a future, upgraded AD complex, which can potentially provide access to new areas of physics.

2601.11381 2026-01-19 cond-mat.mtrl-sci physics.chem-ph

Chemical Origin of Exciton Self-trapping in Cs$_3$Cu$_2$X$_5$ Cesium Copper Halides

Zijin Wu, Shuxia Tao, Geert Brocks

详情
英文摘要

Copper halides Cs3Cu2X5 (X=Cl, Br, I) are promising materials for optoelectronic applications due to their high photoluminescence efficiency, stability, and large Stokes shifts. In this work, we uncover the chemical bonding origin of the Stokes shift in these materials using density functional theory calculations. Upon excitation, one [Cu2X5]3- anion undergoes sizeable local distortions, driven by Cu-X and Cu-Cu bond formation. These structural changes coincide with the formation of a self-trapped exciton, where particularly the hole is strongly localized on one anion. Analysis of the electronic structure and bonding reveals reduced antibonding interactions and enhanced bonding character in the excited state, stabilizing the distorted geometry. Our results establish a direct link between orbital-specific hole localization and bond formation. It provides a fundamental understanding of the excitation mechanism in Cs3Cu2X5 and offers design principles to tune optical properties in 0D copper halides.