High Energy Astrophysical Phenomena
EP260119a: A High-Redshift Gamma-Ray Quiet Fast X-ray Transient Probing a Potentially Hidden Population of Relativistic Explosions
Camila Angulo-Valdez, Asuka Kuwata, Edilberto Aguilar-Ruiz et al. (+41 more)
Gamma-ray quiet fast X-ray transients (FXTs) provide a new approach for studying relativistic explosions that evade traditional gamma-ray triggers. In this work, we present multi-wavelength observations and analysis of EP260119a, a high-$z$ FXT detected by Einstein Probe/WXT and followed up with COLIBRÍ, the Liverpool
Telescope, and other facilities. Spectroscopy yields a
redshift of $z = 5.47$, making EP260119a the most distant FXT detected by Einstein Probe to date. Despite its luminous X-ray and optical emission, no
prompt gamma-ray counterpart was detected by SVOM/ECLAIRs, SVOM/GRM, Swift/BAT, or Konus/Wind, despite contemporaneous coverage. The broadband afterglow is well described by synchrotron emission from a uniform relativistic jet propagating into a shallowly stratified external medium close to the constant-density limit, indicating a standard relativistic explosion despite the absence of detectable gamma rays. Occupying the extreme high-$z$ end of the growing Einstein Probe FXT sample, EP260119a supports the possibility that soft X-ray surveys are uncovering relativistic transients that remain undetected by current gamma-ray instruments. Our results indicate that some explosions in the early Universe escape conventional gamma-ray surveys and demonstrate the value of combining sensitive soft X-ray discovery with rapid optical follow-up to obtain a more complete view of the high-$z$ transient population.
Read the full abstract ▾
All authors Camila Angulo-Valdez, Asuka Kuwata, Edilberto Aguilar-Ruiz, Rosa L. Becerra, Ramandeep Gill, Miguel Angel Aloy, Antonio de Ugarte Postigo, Alan M. Watson, Chen-Wei Wang, Diego López-Cámara, Daniel A. Perley, Aleksandra Bochenek, Simone Dichiara, Enrique Moreno Méndez, Nathaniel R. Butler, Benjamin Schneider, Jean-Luc Atteia, Stéphane Basa, William H. Lee, Dalya Akl, Sarah Antier, Alexis Coleiro, James DeLaunay, Damien Dornic, Jean-Grégoire Ducoin, Francis Fortin, Dmitry Frederiks, Leonardo García-García, Noémie Globus, Olivier Godet, Jamie Kennea, Gianluca Lombardi, Alexandra L. Lysenko, Francesco Magnani, Tyler Parsotan, Margarita Pereyra, Anna Ridnaia, Samuele Ronchini, Fredd Sánchez-Álvarez, Dmitry Svinkin, Anastasia Tsvetkova, Mikhail Ulanov, Peter Veres, Hui Yang
Astrophysics of Galaxies
Sequential Star-Formation and the Near-Infrared Stellar Populations within N159
Nolan Habel, E. Sabbi, Peter Zeidler et al. (+19 more)
We present the first results from a JWST/NIRCam study of the
star-forming region N159, one of the richest H II complexes in the Large Magellanic Cloud. This region stretches over $\sim$130 pc, and exemplifies large-scale sequential
star formation. We present photometric results of $>$300,000 point sources combining data from ten near-infrared JWST filters spanning 1-4.7 microns. We detect sources as faint as $\sim$27 magnitudes at F115W, corresponding to
stellar masses reaching below $\sim$0.1 $M_{\odot}$. By constructing several color-magnitude and color-color diagrams, we separate young
stars from main-sequence and older
stars within N159, finding evidence for
stellar populations younger than 0.5 Myr. Of the young population, we identify accreting, pre-main sequence
stars from their Paschen-$\alpha$ (Pa$\alpha$) excess and a population of sources bearing strong infrared (IR) excess, representing candidate young
stellar objects (YSOs). Within this population, we identify a subpopulation of sources with H$_2$O ice absorption. The IR-excess-bearing YSO candidates correlate spatially with
dust filaments and molecular gas demonstrating their embedded state. The distribution of
stellar and candidate YSO populations across N159 reveal more evolved
star-forming populations in the N159E region and newer
star formation in the N159W region, supporting the sequential
star formation scenario for this region.
Read the full abstract ▾
All authors Nolan Habel, E. Sabbi, Peter Zeidler, Tuila Ziliotto, Laurie Chu Margaret Meixner, Guido De Marchi, O. C. Jones, Alec S. Hirschauer, Beena Meena, Jeroen Jaspers, Laura Lenkic, Remy Indebetouw, Karl D. Gordon, Burcu Gunay, Suzanne Madden, James Muzerolle Page, Omnarayani Nayak, Antonella Nota, Theo Oneill, Massimo Robberto, Tony Wong, Petia Yanchulova Mercia-Jones
Astrophysics of Galaxies
A High Resolution View of Three Massive Young Stellar Objects in the Magellanic Clouds
Yu Cheng, Kei I. Tanaka, Takashi Shimonishi et al. (+4 more)
The Magellanic Clouds provide an excellent laboratory to study massive
star formation beyond typical
Galactic environments. Using ALMA band 7 long-baseline observations, we present the highest resolution (approximately 0.03", $1500{\rm\:au}$) view to date of three massive young
stellar objects (MYSOs) in the Magellanic Clouds, i.e., Lh03 and Lh09 in the LMC, and S07 in the SMC. The 0.87 mm continuum, with a sensitivity of $\sim30\:\mu$Jy beam$^{-1}$, reveals varying levels of fragmentation, from a single compact source (S07), a few (Lh03), to a cluster of compact sources (Lh09). In Lh09, we identified 17 core candidates with lowest measured mass of 2.6 Msun, and their de-projected separations peak around 6000~au. All three targets exhibit high velocity CO(3–2)
outflows, including detection of a collimated bipolar jet driven by a core in Lh09. Spectral lines from HCO$^+$, SO, and SO$_2$ are detected in all sources. We observe velocity gradients that likely trace rotating toroids (Lh03) or more complex motions (Lh09, S07). Taken together, these phenomena observed on $\sim1500$~au scales are qualitatively similar to those seen in
Galactic MYSOs, suggesting a degree of universality in the basic processes of massive
star formation across different environments. Nevertheless, the substantial source-to-source diversity in continuum morphology and dense-gas kinematics motivates larger high-resolution surveys to determine how these properties vary with source characteristics and environment.
Read the full abstract ▾
All authors Yu Cheng, Kei I. Tanaka, Takashi Shimonishi, Yichen Zhang, Suinan Zhang, Kenji Furuya, Asako Sato
Quantum Physics
Dual Boundary Condition Inference: A Two-Boundary Product Rule and Its Implications
Luis Razo and Eliahu Cohen
Many inference problems are constrained from two sides: forward information and a second constraint on outcomes. Dual Boundary Condition Inference (DBCI) multiplies them and renormalises. The rule is not new: it is the product-of-experts form and the unit-exponent member of the logarithmic-pooling family. The paper contributes a classification and reducibility characterisation. The
algebra does not fix the exponent at which the inputs combine: given the statistic log p_fwd + log p_bwd, which already builds in the product form, maximum
entropy supplies the family (p_fwd p_bwd)^lambda and selects no member. If the inputs are read as two equally weighted opinions, three requirements select lambda = 1/2: unanimity preservation, consistency under a common
Bayesian update, and minimal symmetric Kullback-Leibler divergence. If they are read as separately applied factors, two requirements select lambda = 1: a neutral second input must leave the first unchanged, and an update to one input must pass through unchanged. For a rank-one intermediate projective measurement, the Aharonov-Bergmann-Lebowitz (ABL) rule realises this form with no extra parameter. Every positive exponent orders outcomes identically, so the choice is invisible to picking the likeliest outcome, but not to scoring a class by total mass. Under the relevant identifications, the same product form gives Bayes' rule, while a final effect proportional to the identity returns the ordinary forward Born probabilities. The second result is a Two-Boundary Reducibility Criterion: DBCI factors through the forward boundary exactly when the effective backward boundary, up to positive rescaling, does. So a fixed prior or model-fixed structural constraint adds no distinctions between cases sharing the same forward boundary, though it may encode substantial information and still materially affect the result.
Read the full abstract ▾
Astrophysics of Galaxies
New Optical and Mid-Infrared RR Lyrae Period-Luminosity-Metallicity Relations for Precision Distances and Metallicity Distributions in the Magellanic Clouds
Clara E. Martínez-Vázquez, Joseph P. Mullen, Massimo Marengo et al. (+11 more)
RR Lyrae (RRL)
stars, thanks to the existence of their period-luminosity relations, have been widely used as primary standard candles within the Milky Way and the Local Group of
galaxies. We present in this work the latest empirical RRL period-luminosity-
metallicity (PLZ) and period-Wesenheit-
metallicity (PWZ) relations combining optical ($V, I$) and mid-infrared data ($W1$) using OGLE and WISE photometry, anchored to
Gaia DR3 parallaxes. We calibrate these relations with the largest, most complete, and homogeneous catalog of
Galactic halo field RRL spectroscopic
metallicities. These new PLZ/PWZ relations provide distance measurements in remarkable agreement with those derived from eclipsing binaries in the Large and Small Magellanic Clouds (MC): $(m-M)_{0, LMC} = 18.47 \pm 0.07 (stat) \pm 0.05 (sys)$ mag and $(m-M)_{0, SMC} = 18.87 \pm 0.09 (stat) \pm 0.06 (sys)$ mag (within 1% and 10% of eclipsing binary distances, respectively). We have also re-calibrated photometric
metallicity relations to derive individual [Fe/H] abundances of LMC and SMC RRL
stars. This allowed us to investigate the
metallicity gradient of the MCs and discover two distinct populations of fundamental mode RRL
stars in the LMC (only one is instead found in the SMC). Our newly derived mid-infrared period-luminosity relations are poised to become an essential tool to derive precise distances of older
stellar populations in the Local Group of
galaxies, and can easily be adapted to observations obtained in JWST NIRCam photometric bands.
Read the full abstract ▾
All authors Clara E. Martínez-Vázquez, Joseph P. Mullen, Massimo Marengo, Giuseppe Bono, Vittorio F. Braga, Santi Cassisi, Brian Chaboyer, Massimo Dall'Ora, Valentina D'Orazi, Michele Fabrizio, Giuliana Fiorentino, Matteo Monelli, Peter B. Stetson, Frédéric Thévenin
Astrophysics of Galaxies
The galactic HI-to-halo mass relation from isolated galaxies to cosmological hydrodynamic simulations
Marie Korsaga, Jonathan Freundlich, Benoit Famaey et al. (+15 more)
The relation between HI and dark matter (DM)
halo masses provides key insights into gas
accretion and the regulation of
galaxy formation. In a previous study based on SPARC and LITTLE THINGS samples, we showed that the ratio between HI mass and DM
halo mass remains approximately constant with
stellar mass for nearby disc
galaxies ($\log(M_{HI}/M_{200})=-1.90$ with a $1\sigma$ scatter of 0.37 dex). In this work, we extend that analysis by incorporating
galaxies from the Analysis of the interstellar Medium in Isolated
GAlaxies (AMIGA) sample and from the Gassendi HAlpha survey of SPirals (GHASP). The AMIGA sample provides the most rigorously selected sample of isolated
galaxies in the local Universe, well-suited for testing whether the relation found in the previous samples holds in interaction-free
galaxies. We construct mass models from high-resolution rotation curves and infrared photometry, and derive DM
halo parameters. We confirm the proportionality between HI and DM
halo masses and find a nearly constant HI-mass-to-
halo-mass ratio of $\log(M_{HI}/M_{200})=-1.90$ over nearly five orders of magnitude in
stellar mass ($7\leq\log(M_{\star}/M_\odot)\leq 11.5$), with a $1\sigma$ scatter of 0.36 dex. The AMIGA and GHASP samples are statistically consistent with the relation previously found for the SPARC and LITTLE THINGS samples, indicating that it is robust across
galaxies spanning a broad range of isolation levels. In contrast, cosmological hydrodynamic simulations such as SIMBA, IllustrisTNG, and NIHAO predict a dependence on
stellar mass, with a break at the high
stellar mass end for disc
galaxies ($M_{\star}>10^{10}M_{\odot}$). Our results thus further demonstrate that the HI-mass-to-
halo-mass ratio is remarkably self-similar across rotationally-supported disc
galaxies, hinting at mass-independent self-regulation mechanisms that are not yet understood in current theoretical models.
Read the full abstract ▾
All authors Marie Korsaga, Jonathan Freundlich, Benoit Famaey, Lourdes Verdes-Montenegro, Amidou Sorgho, Federico Baraggioni, Andrea V. Maccio, Katarina Kraljic, Laurent Chemin, Peter Kamphuis, Philippe Amram, Benoit Epinat, Roger Ianjamasimanana, Martin Bureau, Pandora Dominiak, Brenda Namumba, Julian Garrido, Susana Sanchez-Exposito
Optics
Floquet-Bloch Theory for Dispersive Time-varying Metasurfaces
Mohammad Mojtaba Sadafi, Sandeep Inampudi and Hossein Mosallaei
Light-matter interaction in time-varying metasurfaces brings about phenomena that transcend the limits of static systems. Temporal modulation enables energy exchange between light and matter, and electromagnetic fields are coupled in both momentum and frequency, with implications across a broad range of photonic applications. Nevertheless, a precise description of such systems necessitates a theory that captures the intertwined effects of spatiotemporal variations while accounting for dispersion in a causal manner, as realistic optical materials exhibit frequency-dependent response and finite temporal
memory. Here, a self-contained Floquet-Bloch theory is developed to capture the response of dispersive, time-varying metasurfaces, respecting causality through physically consistent constitutive relations. The theory treats spatial periodicity, nonadiabatic temporal modulation, and material dispersion within a unified formalism, providing access not only to the metasurface's scattering response but also to its inherent modal structure. The formulation is validated against full-wave simulations. As illustrative examples, it is first applied to asymmetric Floquet harmonic generation in an excitonic time-varying metasurface, where excitonic dispersion enables selective harmonic enhancement. It is then used to investigate metasurface-based photonic time
crystals, revealing how modal dispersion governs momentum-bandgap formation and dynamics. This work establishes a comprehensive platform for understanding dispersive, time-varying metasurfaces and their underlying physical mechanisms.
Read the full abstract ▾
Materials Science
Towards Extended Active Learning for Modelling Ferroelectric Switching: the Need for 'Gold Standards'
Jeffrey R. Reimers, Wenbin Zhang, Zhe Su et al. (+4 more)
For the purpose of modelling ferroelectric switching in wurtzite-structured materials, four cost-effective density-functional theory (DFT) methods (PBE, PBEsol, r2SCAN, and r2SCAN-rVV10) are considered and compared to various ab initio approaches based on the random-phase approximation (RPA), including RPA with singles corrections (RPAR+S), as well as second-order Møller-Plesset perturbation theory (MP2). The purpose is to determine whether an ab initio approach could act as a 'gold standard' for estimating the reliability of DFT, thus determining an optimal DFT method for use in exhaustive tasks such as the training of machine-learning interatomic potentials (MLIP) for large-scale simulations of materials of arbitrary composition and structure such as Al1-xScxN and Zn1-xMgxO, using AlN, Al0.5Sc0.5N, ZnO, and Zn0.5Mg0.5O as model materials. Applications of active learning (AL) are now common, in which results from MLIP simulations are used to enhance the DFT training data set, but future extended active learning (EAL) methods will also need to systematically assess the DFT methodology against a gold standard. Herein, the variability of the ab initio results is found to exceed that required for a robust gold standard, but the DFT and ab initio approaches appear to converge on RPAR+S and r2SCAN-rVV10 as optimal method choices to initiate EAL. The electron correlation energy is found to be dominated by covalent binding effects associated with the high-electron-density anions involved, but the van der Waals dispersion force is seen to be too significant to ignore in ferroelectric modelling.
Read the full abstract ▾
All authors Jeffrey R. Reimers, Wenbin Zhang, Zhe Su, Musen Li, Carla Verdi, Tim Gould, Wei Ren
Mesoscale and Nanoscale Physics
Detecting a large magneto-optical shift in Py/NiO bilayers
Adrielson Dias, Maria Clara, Ozéas Rodrigues et al. (+3 more)
Here, magneto-optical magnetometry measurements on Py/NiO
bilayers reveal a pronounced
magnetic-field-induced wavelength shift, demonstrating strong magneto-optical coupling in this
antiferromagnetic system. A systematic and monotonic spectral shift of up to ~ 400 nm is observed as the applied
magnetic field increases, saturating at higher fields. Quantitative analysis shows that the associated magneto-optical energy variation is on the order of 107 eV, comparable to the
magnon energy scale in NiO. Owing to the large NiO thickness, the observed effect originates from
magnons intrinsic to the
antiferromagnetic NiO layer rather than from
spin currents injected by the Py underlayer. These results provide direct experimental evidence for
magnetic-field control of
antiferromagnetic magnon energies via magneto-optical interactions, establishing Py/NiO
bilayers as a promising platform for optically probing and manipulating
antiferromagnetic spin dynamics.
Read the full abstract ▾
All authors Adrielson Dias, Maria Clara, Ozéas Rodrigues, Gabriel Henrique, José Lucas, José Holanda
Quantum Physics
Quantum-Enhanced Sampling of Schrödinger Bridges
Tom Lollier and Eyal Neuman
We consider the dynamic Schrödinger bridge problem on a finite state space and exploit its Markov structure to decompose the problem into an endpoint coupling and a collection of conditional Markov bridges. To sample from the conditional bridges, we develop a
quantum Gibbs sampler based on
quantum walks on the bridge path space. Under uniformly positive transition probabilities, we derive a spectral-gap bound and provide an explicit procedure for preparing the initial state. Compared with the update bounds of the corresponding classical Gibbs sampler, our
quantum walk-query complexity improves the dependence on the time horizon $T$ from quadratic to linear. For the endpoint coupling, we adapt a
quantum box-constrained Newton method to compute the Schrödinger potentials, improving the
matrix-scaling complexity, at fixed accuracy, from quadratic to $N^{3/2}$ in the state-space size $N$. Finally, we show that exponential reweighting extends both the Schrödinger bridge formulation and the Gibbs spectral-gap estimate to models with additive running costs.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
André José, Carlos Eduardo, Adrielson Dias et al. (+2 more)
We report the first experimental observation of resonantly enhanced propagating
phonon transport induced by
magnon pumping in a
ferromagnetic/piezoelectric
bilayer. Surface acoustic waves (SAWs) generated in a 128$^{\circ}$ Y-cut LiNbO$_3$ delay-line device resonantly excite magnetization dynamics in an adjacent Co film through magnetoelastic coupling. The enhancement of the transmitted acoustic signal occurs exclusively when the SAW frequency satisfies the
ferromagnetic resonance condition predicted by the Kittel dispersion, providing a direct experimental fingerprint of resonant
magnon-
phonon coupling. A systematic comparison between the Co/LiNbO$_3$
bilayer and the bare LiNbO$_3$ substrate demonstrates that the observed transmission enhancement originates solely from the dynamic interaction between propagating
phonons and coherent magnetization precession. Furthermore, measurements performed at different SAW harmonics reveal that only the harmonic satisfying the FMR condition produces a measurable enhancement, confirming the frequency-selective nature of the phenomenon. These findings establish an efficient mechanism for transferring energy from
magnons to propagating
phonons and provide a new strategy for actively controlling coherent acoustic transport in hybrid spintronic, straintronic, and
quantum phononic platforms.
Read the full abstract ▾
All authors André José, Carlos Eduardo, Adrielson Dias, José Araújo, José Holanda
High Energy Physics (Phenomenology)
Anomalous soft photon production can be understood as photon emission during hadronisation
Martin Völkl and Klaus Reygers
Several experiments reported measurements of soft
photons in hadronic collisions far above the predictions from QED. This work investigates possible production during the hadronisation process. It is shown that the assumption of isotropic emission of
photons during the hadronisation process leads to a consistent description of the experimental data.
Read the full abstract ▾
Instrumentation and Detectors
Investigation of Widefield NV-Center Magnetic Imaging for Non-Destructive Materials Testing
Niklas Mathes, Marvin Feuerhelm, Simon Philipp et al. (+7 more)
Due to progressing miniaturization, material fatigue is expected to gain importance on microscopic scales. Nevertheless, most non-destructive testing techniques are optimized for macroscopic scales. Therefore, new approaches applicable to miniaturized samples need to be explored. High spatial resolution imaging of a material's
magnetic stray field enables sensitive detection of microstructural changes due to the local interplay of
magnetic properties, strain, and defects. Up to now, this approach has rarely been used for materials testing since high-resolution
magnetic sensing is traditionally challenging. Novel
quantum sensing techniques offer the potential to close this gap. One of the most prominent
quantum sensors, the nitrogen vacancy center in diamond, is investigated for non-destructive testing applications within the scope of this work. An experimental system based on a widefield sensing approach was developed to image
magnetic stray field distributions within seconds to minutes over areas up to 1 x 1 $mm^2$.
Magnetic sensitivities below 10 $\mu$T/$\sqrt{\text{Hz}}$ and a spatial resolution of 1-2 $\mu$m were achieved. The technique offers high mechanical stability, which is crucial for non-destructive testing applications. Comparison with magneto-optical Kerr effect measurements showed that the
magnetic field maps are strongly correlated with the material's surface domains while containing additional information from deeper inside the sample. Characteristic changes in the
magnetic stray field distribution were detected in an electrical steel sample after cyclic loading. A potential marker for early fatigue damage was deduced from the splitting gradient distribution, while 2D
Fourier transform analysis provided additional insight.
Read the full abstract ▾
All authors Niklas Mathes, Marvin Feuerhelm, Simon Philipp, Ivan Soldatov, Philipp D'Astolfo, Peter Knittel, Thomas Straub, Jan Jeske, Rüdiger Quay, Xavier Vidal
Space Physics
The Localized 12-hour Wave Over Alaska: Leveraging Meridional Wind Measurements From the Sodium Lidar
Sophie R. Phillips, Katrina Bossert, Komal Kumari et al. (+3 more)
The 12-h wave in meridional winds in the mesosphere and lower thermosphere (MLT) during the
solar minimum 2018-2019 Arctic winter is investigated using sodium
lidar observations at Poker Flat Research Range (PFRR), Chatanika, Alaska (64N,147W). Nightly 12-h wave amplitudes increased significantly during December-January, with amplitudes exceeding 130 m/s above 97 km on several days. This was more than double the 12-h wave amplitudes observed outside this time period. Meteor radar winds over Chatanika also showed significant increase in meridional wind 12-h wave amplitudes at altitudes between 82 and 97 km during this time period with lower amplitudes than
lidar measurements. The strong variation in 12-h wave amplitudes was not correlated with SME index, though the largest amplitudes coincided with the sudden stratospheric warming (SSW) in early January. Measurements were compared to a seasonal WACCM-X model run and four days of HIAMCM. For the four dates of available HIAMCM data, 12-h wave amplitudes over Chatanika were found to be similar between both HIAMCM and WACCM-X and the
lidar below 97 km, with amplitudes measured by
lidar exceeding the models at altitudes between 97-105 km. All measurements followed a similar seasonal trend with increasing amplitudes at the end of December/early January. Fits of SW2 from WACCM-X show the SW2
tidal amplitude following similar seasonal trends to 12-h wave measurements. These high-resolution
lidar measurements indicate that localized 12-h wave amplitudes are larger than previously reported by studies using meteor radar measurements.
Read the full abstract ▾
All authors Sophie R. Phillips, Katrina Bossert, Komal Kumari, Erich Becker, Richard L. Collins, Nicholas Pedatella
Biological Physics · Cross-listed from cs.RO
Water Surface Swimming in a Centipede and its Robophysical Model
Zhaochen J. Xu, Delfin Aydin, Abdullah Mustafa et al. (+4 more)
Elongate multi-legged
robots use coordinated body waves and distributed legs to move through cluttered terrestrial environments. However, as housing actuators for independent leg control can require bulky body segments, their non-streamlined body and limb structure makes it difficult to achieve swimming capability comparable to their terrestrial locomotor performance. At the water surface, we found that the multi-legged
robots we tested unexpectedly moved backward: their body waves traveled in the same direction as their displacement, i.e., swimming with a direct wave. We found similar behavior in the centipede Lithobius forficatus, which swims with a direct body wave and periodic leg movement. To study how distributed legs contribute to direct-wave swimming, we analyze animal kinematics and develop a multi-legged robophysical model that allows independent variation of leg morphology and stiffness, body-wave direction, and leg coordination. Robophysical experiments show that direct body waves produce consistent forward motion under the tested conditions and that swimming performance depends on body–leg coordination. Additionally, directionally compliant legs increase displacement from approximately 0.08 to 0.21 body lengths per cycle relative to rigid legs under matched anti-phase actuation. These findings clarify how distributed appendages contribute to surface swimming and establish gait and morphology design principles for extending multi-legged field
robots from terrestrial locomotion into aquatic environments.
Read the full abstract ▾
All authors Zhaochen J. Xu, Delfin Aydin, Abdullah Mustafa, Margarita B. Levin, Jianfeng Lin, Tianyu Wang, Daniel I. Goldman
Astrophysics of Galaxies
CECILIA: Multi-line Constraints on Excess Nebular Emission from Low-Ionization Gas at Cosmic Noon
Caroline von Raesfeld, Allison L. Strom, Audrey Clarendon et al. (+7 more)
Spectroscopy from JWST has offered unique insights into elemental abundance patterns at
Cosmic Noon (z~2-3), most notably a growing census of sub-
solar S/O. These new measurements, coupled with new observations of [O I]{\lambda}6302 at z>1, motivate an updated study of neutral and low-ionization emission within
Cosmic Noon
galaxies. In this letter, we present a new analysis of [O I]{\lambda}6302 and [S II]{\lambda}{\lambda}6718,33 in 19
galaxies observed using ultra-deep JWST/NIRSpec spectroscopy as part of the CECILIA survey. We find that it is necessary to consider sub-
solar abundance patterns in sulfur at high-z when analyzing
galaxies on the S2-BPT, and that this correction reveals the potential of additional emission sources in CECILIA
galaxies. Using the photoionization model emulator Cue, we find that ~48% of observed [S II] and ~55% of observed [O I] emission in CECILIA
galaxies cannot be reproduced by conventional HII region models. We find no clear evidence for
turbulence or shocks driving this excess emission when comparing to existing models. Our findings imply that this excess emission may originate in diffuse ionized gas outside of H II regions, though its nature may be different than that of low-z DIG. Further, we find that including emission from gas outside of
star-forming regions can incur a small bias up to 0.1 dex in 12+log(S/H).
Read the full abstract ▾
All authors Caroline von Raesfeld, Allison L. Strom, Audrey Clarendon, Noah S.J. Rogers, Yijia Li, Nathalie A. Korhonen Cuestas, Gwen C. Rudie, Ryan F. Trainor, Menelaos Raptis, Zhuyun Zhuang
Pattern Formation and Solitons
Robustness of mKdV Breathers: A Numerical Perspective
Chandler Haight, Svetlana Roudenko, Diana Son et al. (+1 more)
We systematically investigate breather solutions in the modified Korteweg-de Vries (mKdV) equation via numerical simulations. We show that the breather solutions are stable under a variety of perturbations, including amplitude changes, modifications of internal parameters, and perturbations of the nonlinearity of the equation. Our results are not only consistent with the known analytical studies on the stability of breathers in integrable systems, extending them further, but also provide numerical evidence that such breather-type structures can persist and remain stable over the simulated time scales in some non-integrable settings with symmetric potentials.
Read the full abstract ▾
All authors Chandler Haight, Svetlana Roudenko, Diana Son, Kai Yang
Mesoscale and Nanoscale Physics
Spectroscopic signatures of persistent exciton condensation in a bulk magnetic topological insulator
Paulina Majchrzak, Chakradhar Sahoo, Manuel Tuniz et al. (+7 more)
Exciton condensates are long-sought correlated
quantum states arising from macroscopic coherence of bound electron-hole pairs. Although
equilibrium and transient excitonic states have been reported in several material platforms, direct evidence for a light-induced
exciton condensate state has been challenging to achieve as an intrinsic property of a bulk
quantum material. Here, we use time- and angle-resolved photoemission spectroscopy to investigate long-lived photoexcited carriers in the intrinsic
magnetic topological
insulator MnBi$_2$Te$_4$ with the chemical potential tuned to the topological surface state by Sb substitution. Following optical excitation, we observe the delayed emergence of a transient state whose formation coincides with depopulation of the bulk conduction band and whose lifetime extends to the microsecond timescale. The quasiparticle dispersion exhibits a pronounced flattening and develops a Mexican-hat-like profile. These spectral signatures are consistent with the formation of a metastable excitonic condensate state. Our results establish
magnetic topological
insulators as a promising platform for investigating long-lived photoinduced many-body states and their interplay with
topology and magnetism.
Read the full abstract ▾
All authors Paulina Majchrzak, Chakradhar Sahoo, Manuel Tuniz, Wibke Bronsch, Denny Puntel, Federico Cilento, Xing-Chen Pan, Jakob Kjærulff Svaneborg, Yong P. Chen, Søren Ulstrup
High Energy Physics (Phenomenology)
Inverse phase transitions via dark sector chemical equilibration
Esau Cervantes, Felix Kahlhoefer, Jonas Matuszak et al. (+1 more)
We study the cosmological
evolution of the effective potential in a dark sector with a spontaneously broken Abelian gauge
symmetry, populated out of
equilibrium through the freeze-in mechanism. Initially dilute and in the broken phase, the dark sector is described by a temperature as well as a chemical potential that reflects the low occupancy of dark sector states. We show that the thermal corrections to the effective potential depend on both of these quantities, and that they are suppressed while the sector remains dilute, but grow as internal number-changing reactions increase the occupancy and drive the system toward chemical
equilibrium. We solve the coupled
evolution of the temperature and chemical potential and the resulting impact on the effective potential to show that, for sufficiently large portal couplings, chemical equilibration can evolve the effective potential across a first-order barrier and drive the dark sector toward its symmetric phase through an inverse phase transition.
Read the full abstract ▾
All authors Esau Cervantes, Felix Kahlhoefer, Jonas Matuszak, Santiago Rosellon
Quantum Physics
Programmable Coherent Memory Kernels for Quantum Reservoir Computing in Waveguide QED
Hong Jiang, Yu Wu, Yue Ban et al. (+2 more)
Reservoir computing requires not only long
memory, but also
memory distributed over the timescales relevant to a given task. In most
quantum reservoir computing architectures, however, the
memory profile emerges from intrinsic dynamics and cannot be directly engineered. Here we introduce a waveguide-QED
quantum reservoir in which coherent
memory return is controlled by the coupling geometry. The reservoir consists of a driven Kerr-nonlinear resonator coupled to a one-dimensional waveguide at spatially separated points. An unmeasured propagating field carries information about past inputs and coherently returns it to the resonator after a finite propagation time, forming a non-Markovian feedback channel without intermediate measurement or classical reinjection. Delay-resolved
memory benchmarks reveal two complementary functions: waveguide propagation determines when past information returns, whereas Kerr dynamics convert the returned field into nonlinear temporal features accessible through a linear readout. NARMA-$n$ prediction shows that the optimal feedback delay shifts systematically with task order and approximately tracks the explicit input-product lag. These results establish coherent delayed feedback as a mechanism for engineering task-relevant
memory in
quantum reservoir computing.
Read the full abstract ▾
All authors Hong Jiang, Yu Wu, Yue Ban, Xi Chen, Juan José García-Ripoll
Mesoscale and Nanoscale Physics
Thermodynamic Uncertainty Relations in Chaotic Andreev Billiards
I. R. A. C. Lucena, T. J. A. Mori, M. M. Soares et al. (+2 more)
We investigate how particle-hole
symmetry,
quantum interference, and tunnel barriers shape thermodynamic uncertainty relations in chaotic Andreev billiards. Using random-
matrix theory and the Mahaux-Weidenmüller scattering approach, we study charge conductance and shot noise across the four Altland-Zirnbauer
symmetry classes, from the single-channel extreme
quantum limit to the multichannel semiclassical regime and from ideal to opaque contacts. We characterize thermodynamic precision through two complementary ensemble observables: either by averaging the sample-resolved noise-to-conductance ratio, or from the separately averaging noise and conductance. Their pronounced discrepancy in the extreme
quantum regime reveals the non-self-averaging character of mesoscopic transport and persists over a broad range of barrier transparencies. For ideal contacts, the first provides a sensitive fingerprint of the Altland-Zirnbauer
symmetry class. In the opaque regime, this hierarchy changes. Despite these strong
symmetry- and barrier-dependent effects, the standard thermodynamic uncertainty relation remains satisfied throughout all regimes investigated. Our results establish thermodynamic uncertainty as a
symmetry-sensitive probe of universal transport in chaotic normal-superconducting systems.
Read the full abstract ▾
All authors I. R. A. C. Lucena, T. J. A. Mori, M. M. Soares, D. Bazeia, A. R. Rocha
Fluid Dynamics
A catalog of exact steady states in Kolmogorov flow
Matthew Golden
Two-dimensional Kolmogorov flow is a common proving ground for the dynamical systems picture of
turbulence. Hundreds of unstable periodic orbits have been found for this system across many Reynolds numbers and domain sizes, although the most well explored is Re$=40$ on a square $2\pi\times 2\pi$ domain with a forcing wavenumber of $k=4.$ Here I present a catalog of 8952 exact steady states of the flow in this canonical parameter regime. These solutions provide a fixed constellation informing the dynamics of both
turbulence and transients.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Disk truncation triggers relativistic jet launching of a highly accreting supermassive black hole
Hirofumi Noda, Kazuhiro Hada, Hiroto Maruyama et al. (+10 more)
Relativistic jets are among the most energetic phenomena in the Universe and influence
galaxy evolution through energetic feedback, yet the physical connection between
accretion flows and jet launching remains unresolved. Jet production is widely attributed to the Blandford-Znajek mechanism, which extracts black hole rotational energy via large-scale
magnetic fields sustained by an
accretion flow. Although this mechanism is observationally well supported for hot, geometrically-thick
accretion flows, highly accreting environments with strong jets present a paradox, as they are typically dominated by cold, geometrically-thin disks incapable of sustaining large-scale
magnetic fields. Here, we report coordinated X-ray microcalorimeter spectroscopy achieved by X-ray Imaging and Spectroscopy Mission (XRISM) and millimeter/
radio interferometric observations by Global Millimeter VLBI Array (GMVA), Very Long Baseline Array (VLBA), and East Asian VLBI Network (EAVN) on the broad-line
radio galaxy 3C120. High-resolution X-ray spectroscopy reveals a relativistically-broadened Fe-K$\alpha$ line, indicating that the cold, geometrically-thin disk is truncated at $\sim 20~R_{\rm g}$ ($R_{\rm g}$ is the gravitational radius), with the inner region replaced by a hot, geometrically-thick flow. Concurrently,
radio imaging indicates that jet profile extrapolation toward the black hole horizon yields a radius comparable to or even narrower than the disk truncation radius. These results demonstrate that, even at high
accretion rates, jet launching is linked to a hot inner flow, possibly via the Blandford-Znajek process, providing evidence for a universal disk-jet connection via
geometric transition.
Read the full abstract ▾
All authors Hirofumi Noda, Kazuhiro Hada, Hiroto Maruyama, Taishu Kayanoki, Kenji Toma, Taiki Kawamuro, Yoshiyuki Inoue, Tomohisa Kawashima, Soyeon Yeo, Ilje Cho, Keiichi Asada, Yasushi Fukazawa, Yoshihiro Ueda
Physics Education
A Simple Miniaturized Stellar Interferometer: Measuring the Angular Diameter of Venus with a Masked Telescope
Eric J. Friedman and Michelle Goman
We describe a simple, visually compelling demonstration/laboratory of astronomical interferometry using a standard planetary
telescope and a thin piece of opaque plastic punched with two small holes. By observing the disappearance of interference fringes as the hole spacing is increased, students can directly estimate the angular diameter of Venus. The demonstration is a tabletop analogue of the landmark 1921 Michelson-Pease measurement of Betelgeuse and scales naturally from that measurement: where Michelson and Pease required a 6.1 m baseline to resolve a disk 47 mas (milli-arcsecond) across, a 15 mm baseline suffices for Venus, when it is approximately 10-15$''$ (arc seconds). The lab works reliably in ordinary atmospheric seeing conditions, and a side-by-side comparison of Venus (or Jupiter) with a bright
star such as Sirius provides an immediate visual demonstration of the difference between extended and point sources. It works equally well as a laboratory at a variety of difficulty levels. Furthermore, it does not require advanced knowledge or skills with optical
telescopes. While the underlying ideas are well known, we are unaware of any source that presents them in an accessible, unified form.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
On quantum confinement without barriers
I.A. Kokurin
Usually in
semiconductor heterostructures, such as
quantum wells, the
quantum confinement is realized by means of heterobarriers, which are simply the band offsets in adjacent materials. Here the arguments are provided, that the energy dispersions in materials (in simple case determined by effective masses) are important as well. Using a simple model system, such as
quantum well with an additional heterojunction, it is shown the predominant localization of the carrier density in the regions with higher effective mass. The possibility of different spatial localization of wave function for different subbands is predicted. This can be applied in
semiconductor structures such as
quantum cascade
lasers.
Read the full abstract ▾
Quantum Physics
Equivalence of maximal and generic reachability for non-universal Variational Quantum Circuits
Vishal S. Ngairangbam and Michael Spannowsky
Employing problem-specific non-universal Variational
Quantum Circuits aligned with a suitable state preparation has become a standard approach to counter the difficulty in training universal ansätze. However, due to their non-universality, diagnosing their reachability and trainability remains reference-state-specific. In this work, we establish the equivalence of maximal reachability and generic reachability over arbitrary reference states as a consequence of the principal orbit-type
theorem. Thereafter, assuming that the global minimum of the cost function is achieved on a subset that can be described as the image of a smooth function, we derive necessary and sufficient conditions for non-zero probability of reachability under generically sampled reference states. Furthermore, when the solution set is assumed to be realised through a real analytic map that embeds a solution
manifold, we show that local surjectivity is generically obtained on the entire solution
manifold if it is attained at a single point. As a practical design rule, the need for local surjectivity automatically translates to a necessary dimensional criterion: reachability requires the target set's topological dimension to be at least as large as the co-dimension of the generic orbit. Numerical simulations show that finite-depth optimisation consistently fails when the dimensional obstruction applies, while unobstructed cases show improved convergence.
Read the full abstract ▾
High Energy Astrophysical Phenomena
In-Situ Star Formation in a Thick Disk: A Model for Metal Enrichment of Mrk 573
Hannalore J. Gerling-Dunsmore, Mitchell C. Begelman, Jared A. Goldberg et al. (+2 more)
Recent observations of the nearby Seyfert
galaxy Mrk 573 found that the
galactic nucleus and bicone regions surrounding the jet are significantly metal-enriched. In this paper, we develop a simple model for the observed metal enrichment, assuming a population of
stars in the $10 - 30 \, M_{\odot}$ range formed in-situ in the
accretion disk. We assume the
stars form according to a Salpeter initial mass function and generate the typical metal yields expected of field
stars of the same mass. We find that in the thick disk ($H/r \sim 0.1$) case, a Salpeter population of
stars can easily explain the observed metal enrichment and provide limits on the formation model; we also argue that a thin disk ($H/r \lesssim 0.01$) is incompatible with the observed metal enrichment. In our model, AGN
metallicity scales most strongly with disk thickness, implying a potentially powerful observable diagnostic.
Read the full abstract ▾
All authors Hannalore J. Gerling-Dunsmore, Mitchell C. Begelman, Jared A. Goldberg, Taeho Ryu, Dominika Ł. Król
Solar and Stellar Astrophysics
A Multiband Catalog of Infrared-Excess Sources in the Vela-Carina Region: VVVX, DECaPS, and GLIMPSE
R. M. Torres, R. K. Saito, V. Fermiano et al. (+4 more)
Multiwavelength surveys of the
Galactic midplane enable the identification of infrared-excess sources, signatures of circumstellar material, though high extinction and crowding hinder detection. We construct a homogeneous catalog of infrared-excess candidates in a $\sim$7.0 deg$^2$ field of the Vela-Carina region, characterizing their excess emission via spectral energy distribution (SED) analysis. We combine optical photometry from DECaPS, near-infrared photometry from VVVX, and mid-infrared photometry from Spitzer/GLIMPSE using hierarchical positional cross-matching. Candidates are selected via photometric quality and MIR color diagnostics, and their SEDs are analyzed with VOSA using theoretical atmosphere model grids. Photogeometric distances are adopted, while
Gaia DR3 and NEOWISE variability provide complementary diagnostics. From the matched 249,719-source VVVX-GLIMPSE-DECaPS catalog, we identify 1,512 MIR-excess objects, of which 191 have complete 12-band photometry with S/N > 10, enabling detailed SED analysis. Photogeometric distances are statistically consistent with
geometric distances for nearly the entire sample. SED analysis independently supports the MIR-excess nature of most sources, indicating emission beyond
stellar photospheres. About 15% of sources are flagged variable by
Gaia, while NEOWISE light curves reveal MIR variability of a few tenths of a magnitude. Comparisons with published YSO and variability-selected catalogs show limited overlap, particularly with variability-selected samples, indicating that MIR-excess selection complements other approaches to identifying candidate YSOs in the Vela-Carina region. The resulting catalog provides a well-defined MIR-excess sample with homogeneous multiband photometry, SED characterization, distances, and variability diagnostics, forming a foundation for future spectroscopic and time-domain studies.
Read the full abstract ▾
All authors R. M. Torres, R. K. Saito, V. Fermiano, P. Esteves, B. W. Borges, D. Quispe, D. Minniti
Materials Science · Cross-listed from cs.LG
An open benchmark for machine learning-based polymer property prediction
Robert W. Learsch, Nicholas Liesen, Daniel S. Levine et al. (+2 more)
Polymer property prediction lacks open, standardized
benchmarks that enable rigorous comparison of machine-learning methods, with existing resources covering only a narrow fraction of
polymer architectures, such as homopolymers. We introduce
Polymer Benchmark 2026 (PolyBench26), an open
dataset comprising nearly 250,000
polymer-property datapoints across eight physical properties, including data from experimental measurements, density functional theory, and molecular dynamics. The
benchmark supports four evaluation tasks across homopolymers and alternating, random, and block copolymers: in-distribution property prediction,
dataset-size scaling, repeat-unit complexity, and transfer to held-out
polymer architectures. We compare
language model, graph-based, and descriptor-based approaches and find graph-based models provide the lowest errors in property prediction, retain their advantage across the evaluated training-set sizes, and remain robust to increasing repeat-unit complexity. PolyBench26 provides a reproducible foundation for developing models for the increasingly complex
polymer design space. The PolyBench26
benchmark is available open-source at https://github.com/rlearsch/PolymerBenchmark2026.
Read the full abstract ▾
All authors Robert W. Learsch, Nicholas Liesen, Daniel S. Levine, Anna M. Hiszpanski, Evan R. Antoniuk
Instrumentation and Methods for Astrophysics
Laboratory Evidence that Methanol-Rich Ice Mantles Lower Methyl Formate Binding Energies
Rachel E. Gross, Jeroen Terwisscha van Scheltinga, L. Ilsedore Cleeves et al. (+5 more)
Complex organic molecules are widely detected in
star-forming regions and are important precursors to prebiotic species. Because these molecules are thought to form primarily within icy grain mantles, their desorption is assumed to be regulated by the sublimation of the surrounding H$_2$O ice
matrix. However, observations increasingly reveal gas-phase abundances of methyl formate (MF) at temperatures well below the sublimation temperature of water ice (T ~ 100K), challenging this view. To investigate how ice composition and phase influence MF desorption, we present laboratory temperature-programmed desorption measurements of MF from four astrophysically relevant substrates: amorphous and crystalline H$_2$O and CH$_3$OH. Desorption kinetics were analyzed using pre-exponential factors derived from transition-state theory with leading-edge analysis and non-negative least-squares inversion to recover binding-energy distributions. We find that MF binds more weakly to CH$_3$OH ice than to H$_2$O-rich substrates, with representative binding energies of ~6247K for amorphous H$_2$O, ~6213K for crystalline H$_2$O, and ~5469K for amorphous CH$_3$OH. MF deposited on crystalline CH$_3$OH exhibits coverage-independent leading edges consistent with multilayer or island desorption, yielding an effective binding energy of 5333K. Enhanced surface mobility and reduced trapping efficiency on methanol ice, combined with weaker MF binding, provide a natural explanation for the early appearance of gas-phase MF observed in
star-forming environments, with characteristic desorption temperatures of ~85K on CH$_3$OH and ~95-100K on H$_2$O. Together, these effects support a two-step thermal desorption pathway in which MF associated with CH$_3$OH-rich ice can be released prior to bulk H$_2$O sublimation.
Read the full abstract ▾
All authors Rachel E. Gross, Jeroen Terwisscha van Scheltinga, L. Ilsedore Cleeves, Catherine A. Dukes, Robin T. Garrod, Alexia Simon, Shane Sawyer, Adam Woodson