High Energy Physics (Phenomenology)
Non-Perturbative Modulus Decay and Multi-Component Dark Matter
Gordon Kane, Leia Price, Luis Rufino et al. (+2 more)
Non-thermal cosmological histories rest on the assumption that scalars displaced during inflation undergo coherent oscillations, dominate the energy density of the universe before Big Bang Nucleosynthesis, and decay perturbatively through gravitationally suppressed interactions. In addition, usually a single dark matter component is assumed. This early matter-dominated era is the basis for the usual predictions of non-thermal WIMP production,
axion dark matter,
entropy generation, and dark radiation. This paper examines whether this picture is dynamically robust against non-perturbative decay of the modulus condensate. In this work, we study non-perturbative particle production from oscillating
moduli using the effective field theory appropriate to $G_2$ compactifications. We find that non-perturbative production of Wino-like
fermions is strongly suppressed in the relevant parameter regime. In contrast, a modulus-dependent
axion kinetic term admits narrow instability bands with growth rates that can exceed the Hubble rate. A linear Floquet analysis alone, however, cannot determine whether these bands significantly deplete the modulus condensate, since
cosmic expansion, backreaction, rescattering, and higher-order operators in the effective theory can become important. As a result, the conventional modulus-dominated cosmology remains robust against Wino and gauge-field preheating, while the
axion channel provides a potentially important modification that requires nonlinear study. If sufficiently efficient,
axion production can alter the division of dark matter between Winos and
axions and enhance the dark-radiation abundance.
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All authors Gordon Kane, Leia Price, Luis Rufino, Scott Watson, Fred Adams
Solar and Stellar Astrophysics
Super-Chandrasekhar white dwarfs by the evolution of magnetized main-sequence stars: New mass-limits from STARS simulation
Zenia Zuraiq, Banibrata Mukhopadhyay, Achal Kumar et al. (+4 more)
We explore the time
evolution of the magnetized main-sequence
stars (MSs) to magnetized non-rotating white
dwarfs (WDs) with a series of models, capturing modified Hertzsprung-Russell diagram. We use the Cambridge
Stellar evolution code,
STARS, with modifications by introducing
magnetic effects and cooling. We investigate the possible existence of stable, magnetized, massive, super-Chandrasekhar, approximately spherical WDs, away from Chandrasekhar's mass-radius curve. These we refer to as B-WDs. They are inferred from the observations of peculiar over-luminous type Ia
supernovae, e.g. SN2003fg. We show that the classical effects of
magnetic fields significantly impact MSs and their time
evolution to WDs. Moreover, the
magnetic field could be decisive in explaining the unusually large radius observed in some sub-Chandrasekhar WDs, e.g. SDSS J123204.19+522548.2, along with the finite temperature effect. We further investigate the stability of magnetized WDs, both below and above the Chandrasekhar limit and confirm the possibility of super-Chandrasekhar B-WDs with new mass limits that depend on the
magnetic field geometry, mass
accretion from a companion and cooling rates. Therefore, while the "Chandrasekhar limit" may be sacrosanct, its value severely depends on the underlying physics, here the
magnetic field.
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All authors Zenia Zuraiq, Banibrata Mukhopadhyay, Achal Kumar, Arnab Sarkar, Alexander J. Hackett, Projjwal Banerjee, Christopher A. Tout
Astrophysics of Galaxies
Low-power jet-ISM coupling and disk-plane perturbations in the edge-on Seyfert galaxy NGC 4388
M. Ceci, G. Venturi, C. Marconcini et al. (+26 more)
Active
galactic nuclei (AGN) may regulate
galaxy evolution through radiatively driven winds and collimated jets, but their relative impact and coupling to the interstellar medium (ISM) remain uncertain. We investigate the ionized gas in the nearby ($D\sim$ 17 Mpc) Seyfert 2
galaxy NGC 4388, hosting a
galaxy-scale ($\sim$1.6 kpc), low-power ($\sim1.4~\times~10^{42}~erg~s^{-1}$) bipolar
radio jet projected roughly perpendicular to its edge-on disk. We analyze optical integral-field spectroscopic observations from the Wide Field Mode with adaptive optics of VLT/MUSE, complemented by VLA
radio data tracing the jet. We map ionized-gas emission, kinematics, excitation, and
dust attenuation. We reconstruct the de-projected 3D
outflow geometry and velocity field using the MOKA3D kinematic model, and estimate its mass and energetics. The ionized gas shows a rotating disk and a kpc-scale biconical
outflow. We measure a total ionized
outflow mass of $\sim10^6~M_\odot$, a mass
outflow rate of $\sim0.2~M_\odot$~yr$^{-1}$, and a kinetic power of $\sim3\times10^{40}~erg~s^{-1}$, which gives a coupling efficiency of $\sim1\%$ relative to both the jet kinetic and the radiation-driven
nuclear wind power, indicating that either mechanism could drive the
outflow. We detect an extended ($\sim$2 kpc) enhancement of the gas velocity dispersion along the
galaxy disk plane, oriented perpendicular to the
outflow and jet axes. These regions show optical line ratios consistent with shock excitation. The spatial correspondence with ALMA CO(2-1) emission is marginal, while enhanced
stellar velocity dispersion prevents an exclusive jet interpretation. We report the first observational evidence that even a low-power
radio jet oriented nearly perpendicular to the
galaxy disk can efficiently couple with the ISM, suggesting that jet-induced perturbations are an important AGN feedback channel regardless of jet orientation.
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All authors M. Ceci, G. Venturi, C. Marconcini, M. V. Zanchettin, G. Cresci, M. Tartėnas, K. Zubovas, E. Treister, E. Amenta, E. Bertola, F. Belfiore, C. Bracci, E. Cataldi, Q. D'Amato, A. Feltre, M. Ginolfi, I. Lamperti, F. Mannucci, A. Marconi, A. Marasco, M. Meenakshi, M. Mingozzi, B. Moreschini, D. Mukherjee, E. Nardini, M. Perna, F. Ricci, M. Scialpi, L. Ulivi
Nuclear Theory
Probing the nucleon axial form factor via the $\vec{e}^{\,+} + {}^2\text{H} \rightarrow \bar{\nu}_e + p + p$ reaction below the pion-production threshold
A. M. Ankowski, J. Golak, E. Pérez del Rio et al. (+7 more)
The nucleon axial form factor $F_A(Q^2)$ is a primary source of systematic uncertainty in charged-current quasielastic interactions, of critical importance for long-baseline
neutrino-oscillation studies. Its low-$Q^2$ behavior is particularly problematic to pin down in
neutrino measurements. To address this limitation, we investigate the weak process of polarized positron capture on the deuteron, $\vec{e}^{\,+} + {}^2\text{H} \rightarrow \bar{\nu}_e + p + p$. Employing a relativistic momentum-space formalism, we present predictions for the total cross section. Focusing on the kinematic regime free from pion-production backgrounds, we analyze various differential cross sections and their sensitivity to the $F_A(Q^2)$ variation. Our results demonstrate that thanks to the positron upgrade, Jefferson Lab will gain a unique position to make inroads into determining the low-$Q^2$ behavior of the axial form factor.
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All authors A. M. Ankowski, J. Golak, E. Pérez del Rio, S. Sharma, R. Skibiński, K. Topolnicki, H. Witała, W. N. Polyzou, H. Kamada, D. Dutta
Astrophysics of Galaxies
Galaxy-SMBH co-evolution in 2,435 DESI disk galaxies and merger-free BH growth in bulgeless disks
Sophie M. Jewell, Rebecca J. Smethurst, Chris J. Lintott et al. (+8 more)
We analyse black hole scaling relations for disk-dominated
galaxies, and present evidence for secularly driven
galaxy-black hole co-
evolution. We do this observationally by looking at “bulgeless”
galaxies, where the lack of a
stellar bulge suggests a quiet merger history. We first compose a sample of 2,435 disk-dominated
galaxies hosting optical broad line active
galactic nuclei (AGN) from DESI data, and find a $M_{\mathrm{BH}}$–$M_{*}$ scaling relation of $\log(M_{\mathrm{BH}})= - 3.7^{+0.3}_{-0.3} + 1.00^{+0.03}_{-0.03} \log(M_*)$. From these, we identify 546 bulgeless
galaxies hosting AGN, a factor of $\gtrsim 5$ larger than pre-existing samples, and find they follow the same $M_{\mathrm{BH}}$–$M_{*}$ relation as the general disk
galaxy sample. Comparing the bulgeless
galaxies to those with some bulge component, we find good agreement in the $M_{\mathrm{BH}}$–$M_{*}$ relation (within $3 \sigma$), but disagreement in the $M_{\mathrm{BH}}$–$M_{*, \mathrm{bulge}}$ relation (at $>7 \sigma$). This is the opposite of what is expected from merger-driven co-
evolution, suggesting secular growth is significant in establishing observed $M_{\mathrm{BH}}$–$M_{*}$ scaling relations. Furthermore, in a control sample of early-type
galaxies we find tentative evidence of increased AGN luminosity compared to the bulgeless sample, but no statistical difference in black hole mass. This suggests the assumed merger-dominated evolutionary history of early-type
galaxies does not lead to significantly increased long-term BH growth. These results support numerous recent observational and theoretical studies which suggest secular processes fuel significant supermassive black hole growth and
galaxy-black hole co-
evolution.
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All authors Sophie M. Jewell, Rebecca J. Smethurst, Chris J. Lintott, Brooke D. Simmons, Ricarda S. Beckmann, Izzy L. Garland, Tobias Géron, Benne W. Holwerda, Karen L. Masters, Ragadeepika Pucha, Ashley Spindler
Astrophysics of Galaxies
Direct imaging of sub-parsec binary SMBHs in the central galaxy of the NGC 5044 group
Francesco Ubertosi, Gerrit Schellenberger, Ewan O'Sullivan et al. (+7 more)
Binary active
galactic nuclei (AGN) consist of two supermassive black holes (SMBHs) hosted in a single
galaxy that are simultaneously accreting gas. These systems are key to understanding hierarchical
galaxy evolution and represent
prime targets for low-frequency gravitational wave (GW) experiments. However, binary AGN remain extremely rare: only a handful are confirmed at separations of a few hundred parsecs, and just one pc-scale binary - in an elliptical
galaxy at the center of a
galaxy cluster - has been securely and visually identified. Direct imaging of sub-parsec binary AGN, the final stage before the GW regime, has so far been missing. Here we report on Very Long Baseline Array (VLBA) observations of NGC 5044, the central
galaxy of the X-ray brightest
galaxy group. This
galaxy is known to exhibit pc-scale
radio jets nearly orthogonal to two older AGN outbursts. The 4.9, 8.4, 15.2, and 23.6 GHz VLBA images reveal two compact, flat-spectrum, and variable
radio cores separated by just 0.38 parsec at the heart of the
galaxy, forming the tightest directly imaged binary AGN known by an order of magnitude. This discovery suggests that the older outbursts may have been powered by jets from the secondary core, without invoking any reorientation of the primary jet axis. More broadly, comparison with other systems points to massive, cluster-central elliptical
galaxies being promising targets to search for binary SMBHs.
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All authors Francesco Ubertosi, Gerrit Schellenberger, Ewan O'Sullivan, Laurence P. David, William Forman, Simona Giacintucci, Christine Jones, Kamlesh Rajpurohit, Tiziana Venturi, Jan Vrtilek
Solar and Stellar Astrophysics
A Quantitative Method to Investigate the Spectral Class Time Evolution of Novae
Maria Kopsacheili, Martín Guerrero and Diego Alejandro Vasquez Torres
Novae are spectroscopically classified as Fe II or He/N according to the dominance of Fe II, or He and N emission lines in their pre-nebular spectra, while spectra exhibiting both are classified as hybrid. Evidence suggests that these spectral classes represent spectral
evolution. We investigate this scenario using a large spectroscopic
dataset and introduce a quantitative coefficient, $\kappa$, to characterise the relative strength of Fe II and He/N emission. The coefficient is defined as the ratio of the flux of the Fe II ($\lambda5169$) line to the mean flux of five He and N emission lines, with $\kappa>1$ indicating Fe II-dominated spectra and $\kappa<1$ indicating He/N-dominated spectra. We apply this method to 26 novae using spectra from the Astronomical Ring for Amateur Spectroscopy (ARAS) Database and compare the
evolution of $\kappa$ with optical light curves. Fifteen of the 24 classical novae and one of the two recurrent novae exhibit at least one transition between Fe II- and He/N-dominated phases, while temporal trends suggest this fraction could approach 90% with complete spectroscopic coverage. The $\kappa$ coefficient closely tracks the optical light curves and repeatedly crosses unity in novae exhibiting jitters, revealing non-monotonic spectral
evolution linked to brightness fluctuations. These results support the interpretation of Fe II, He/N, and hybrid spectra as evolutionary stages rather than distinct nova types and establish $\kappa$ as a quantitative tool for tracing nova spectral
evolution while reducing biases from incomplete spectroscopic coverage.
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Astrophysics of Galaxies
Dual Signatures of Bursty Star Formation in High-Redshift UV Luminosity Functions
Guochao Sun, Claude-André Faucher-Giguère, Steven R. Furlanetto et al. (+1 more)
The UV luminosity function (UVLF) encodes key information about
galaxy formation. The slowly evolving bright-end UVLFs at $z\gtrsim10$ have made UV variability from bursty
star formation a promising explanation, but the impact of such variability need not be restricted to the bright end. Motivated by ultra-deep measurements of the $z\simeq7$ UVLF, we investigate whether UV variability can provide a unified interpretation of the low-mass
star formation efficiency (SFE) at $z\simeq7$ and the abundance of UV-bright
galaxies at $z\gtrsim12$. Using abundance matching, we show that a steep faint-end UVLF at $z\simeq7$ admits a range of interpretations. For modest, mass-independent UV variability, the inferred median SFE starts flattening below $M_{\rm h} \sim10^{10.5} M_{\odot}$. If UV variability instead grows with decreasing
halo mass—a possibility motivated by simulations and observations—the inferred median SFE is steeper and lower by a factor of about three at $\sim10^9 M_{\odot}$, consistent with stronger feedback suppression in low-mass
halos. Calibrated to the common target $z\simeq7$ UVLF, these two scenarios diverge strongly when extrapolated to $12\lesssim z\lesssim17$ under
redshift-independent UV variability and SFE prescriptions. Strongly mass-dependent $M_\mathrm{UV}$ scatter links the steep $z\simeq7$ faint-end slope and high $z\gtrsim12$ bright-end abundance as dual signatures of burstiness in similarly low-mass
halos. Stronger variability makes bright
galaxies contribute a larger fraction of the UV luminosity density, whereas weaker variability favors faint sources, despite their similar predicted reionization histories. At fixed $M_\mathrm{UV}$, UV variability broadens the
halo mass distribution and lowers the clustering bias, which provides a useful diagnostic of burstiness for JWST and Roman.
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All authors Guochao Sun, Claude-André Faucher-Giguère, Steven R. Furlanetto, Adam Lidz
High Energy Physics (Phenomenology)
Gravitational Waves from Long Strings and Loops
Christos Litos, Sarunas Verner, Wei Xue et al. (+1 more)
We compute the gravitational wave spectrum produced by a global
cosmic string network in the scaling regime. The spectrum naturally divides at the string correlation length into infrared and ultraviolet parts. In the infrared, we derive the spectrum analytically from the unequal-time correlator of the string stress-energy tensor within the unconnected segment model, which we generalize for the first time to string loops. The loop contribution can be comparable to that of long strings, depending on the loop
evolution parameters. In the ultraviolet, where structure below the correlation length dominates the source, we develop a data-driven method that connects this correlator formalism to the instantaneous radiation power spectrum measured in existing
lattice simulations. The predicted spectrum rises with frequency as $\Omega_{\rm GW}\propto k$ and $k^{3}$ in the infrared, and flattens into a plateau with a mild logarithmic tilt in the ultraviolet. The turnover frequency between the two is set by the mass of the Goldstone
boson, the
axion. Confronting the predicted spectrum with current data and projected sensitivities, we map out current constraints and future probes in the plane of the
symmetry-breaking scale~$f_a$ and the
axion mass~$m_a$.
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All authors Christos Litos, Sarunas Verner, Wei Xue, Fengwei Yang
Instrumentation and Methods for Astrophysics
Probing Millisecond Optical Timescales with Continuous-Readout Mode Observations from ZTF
Shar Daniels, Federica Bianco, Igor Andreoni et al. (+6 more)
The subminute-timescale phase space is an underexplored regime of the optical sky. Sub-second optical observations are difficult to accomplish with traditional CCD exposure-readout cycles, and alternative technologies like EMCCDs and CMOS have historically limited surveys to targeted observation. Continuous-readout mode enables millisecond-timescale observations on traditional cameras by leaving the shutter open during readout, enabling high-cadence observations on all-sky surveys. We present the first results from continuous-readout mode data from the Zwicky Transient Facility. We developed a deep-learning-based data analysis pipeline and report results on 141 square degrees, or 1128
star-hours, of data, sampled at 300x/second. Our Convolutional Neural Network can retrieve optical transients of duration 9.7-29.2 milliseconds with a precision of 66% and recall of 78% for brightness changes of 10% and greater, and our subsequent light curve-based analysis has an efficiency of >94.6%. We retrieve a total of ~300,000 candidates on sources of magnitude G_{RP} < 12, of which 100 are above SNR=1.55 and were visually inspected. After accounting for noise and filtering contaminants both known and unique to this mode of observation, these 100 candidates were eliminated as being astrophysical in nature, leading to upper limits on the observed rate of ~10-ms transient events associated with point sources as well as specifically with white
dwarfs and
quasars. This first survey-scale characterization of the bright millisecond optical transient and variable sky establishes the rarity of short-timescale variability in the optical regime.
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All authors Shar Daniels, Federica Bianco, Igor Andreoni, Ashish Mahabal, Rich Dekany, Gregory Dobler, Matthew Graham, Roger Smith, Rujula Yete
Astrophysics of Galaxies
Star Formation and Nebular Attenuation from Pa$\alpha$, Br$\alpha$, and Br$\beta$ in Massive Dust-obscured Galaxies at Cosmic Noon using JWST
Virginia Vanicek, Jed McKinney, Alexandra Pope et al. (+14 more)
Near-infrared hydrogen recombination lines can provide robust
star-formation rates if the effects of
dust attenuation continue to diminish towards longer wavelengths. To quantify near-infrared attenuation and ultimately measure accurate
star-formation rates (SFRs) at the height of
cosmic star-formation, we present Pa$\alpha$, Br$\alpha$, and Br$\beta$ detections in $27$ luminous infrared
galaxies at $z\sim 1-2$, including pure
star-forming
galaxies as well as
dust-obscure Active
Galactic Nuclei (AGN). Using combined spectra from the JWST MIRI (Mid-Infrared Instrument) LRS (Low Resolution Spectrometer) and the Spitzer Space
Telescope IRS we quantify the
star formation rates of our sample using a sub-sample of 13
galaxies detected in Pa$\alpha$ emission ($1.87\, \mu$m), 14
galaxies detected in Br$\alpha$ ($4.05\, \mu$m), and 12
galaxies detected in Br$\beta$ ($2.63\, \mu$m). By combining multiple near-infrared recombination lines in individual
galaxies we calculate nebular attenuation, finding $A_\lambda\sim3$ mag at $\sim2\,\mu$m and $A_\lambda\sim1$ mag at $\sim4\,\mu$m. Nebular lines trace the SFR on $\sim 10$ Myr timescales, which we compare to the total infrared luminosity ($L_{\rm IR}$) which probes the
star formation over the last $\sim 100$ Myr. SFRs measured from $L_{\rm IR}$ using common conversions are systematically higher than the SFRs derived from attenuation-corrected nebular line measurements by a factor of $\sim2.5$. This could be indicative of a declining or static
star formation history with a past burst or systematic effects on $\rm SFR_{{\rm IR}}$ such as
dust heating from evolved
stellar populations, and/or an active
galactic nucleus.
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All authors Virginia Vanicek, Jed McKinney, Alexandra Pope, Anna Sajina, Stacey Alberts, Meredith Stone, Lee Armus, Sinclaire M. Manning, Olivia Cooper, Tanio DÍaz-Santos, Miriam Eleazer, Caitlin Casey, Thomas S.-Y. Lai, Steven Finkelstein, Leonid Sajkov, Allison Kirkpatrick, Anthony Taylor
Astrophysics of Galaxies
Linking X-ray emission to galaxy populations in GAMA groups
Selene Levis, Hernán Muriel, Valeria Coenda et al. (+3 more)
We study how the presence of a detectable hot intragroup medium affects
galaxy colour and
star-formation properties, and how these trends depend on dynamical stage within the group. We analysed
galaxies in GAMA groups with and without X-ray detection (XG and NXG) at 0.1 <= z <= 0.2, using samples with similar
halo-mass distributions, compared with a field control sample.
Galaxies were classified as red, green, or blue by UV-optical colour, and group
galaxies further classified into dynamical classes based on projected phase-space position and host
halo mass. We examined
galaxy populations as a function of orbital class,
star-formation activity,
nuclear activity, and cluster-centric distance. The
galaxy population is systematically more evolved in XG than NXG, with lower blue and
star-forming fractions and higher red and passive fractions. The green fraction is stable across environments and orbital classes, though high-mass recent arrivals show a mild excess of green systems while retaining relatively high
star-forming and low passive fractions, suggesting an intermediate quenching stage. The active
galactic nucleus fraction shows no environmental dependence, while the post-starburst fraction increases strongly in XG, reaching nearly 20 percent, consistent with enhanced rapid quenching.
Galaxy properties show stronger radial segregation in XG than NXG, with colour fractions differing from field values even at R/R200 ~ 3, consistent with preprocessing. Despite similar
halo-mass distributions, the systematic differences between XG and NXG show that
halo mass alone does not determine
galaxy properties. A detectable hot intragroup medium is associated with enhanced environmental processing, stronger quenching, and more frequent rapid transitions, highlighting the role of the intragroup medium's thermodynamical state, beyond
halo mass, in shaping
galaxy evolution at group scales.
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All authors Selene Levis, Hernán Muriel, Valeria Coenda, Andrea Biviano, Héctor J. Martínez, Martín de los Rios
High Energy Astrophysical Phenomena
GRB 220706A: a gamma-ray burst with a month-long engine and a luminous supernova
Benjamin P. Gompertz, Nusrin Habeeb, Dheeraj R. Pasham et al. (+30 more)
While the progenitors of many long gamma-ray bursts (GRBs) are well established as the core collapse of very massive, envelope-stripped, rapidly-rotating
stars, it has been suggested that bursts at the extremely long end of the duration distribution may be a separate population of `ultra-long' GRBs. With durations of thousands of seconds or more, these bursts are difficult to reconcile with the engine timescales expected from the compact Wolf-Rayet
stars that are typically assumed to produce more `standard' long GRBs. Here, we present observations of GRB~220706A, where X-ray follow-up reveals flaring episodes that last until $\approx 51$ days after trigger. At the measured
redshift of $z = 0.8577$, this corresponds to 27 days in the GRB rest frame, and represents the latest central engine activity ever observed in a GRB by a margin of $\approx 21$ rest-frame days. We also identify a likely
supernova (SN) which, when accounting for the inferred optical extinction of $0.9 \leq A_V \leq 3.6$ mag (constrained by indirect arguments), has a peak absolute magnitude of $M_r \leq -20.25$, resembling the energetic SN\,2011kl found accompanying ultra-long GRB\,111209A, and consistent with super-luminous SNe. We discuss the implications GRB~220706A has for ultra-long GRB progenitor models and possible powering mechanisms for the extremely late central engine activity.
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All authors Benjamin P. Gompertz, Nusrin Habeeb, Dheeraj R. Pasham, Antonio de Ugarte Postigo, Daniele B. Malesani, Phil A. Evans, Kim L. Page, Ben Rayson, J. Feliciano Agui Fernandez, Michael Bremer, Andrew J. Levan, Genevieve Schroeder, Nial R. Tanvir, Christina C. Thone, Eric Burns, Valerio D'Elia, Massimiliano De Pasquale, Dimple, Dieter Hartmann, Pall Jakobsson, Sylvio Klose, Antonio Martin-Carrillo, Matt Nicholl, Ana M. Nicuesa Guelbenzu, David O'Neill, Giovanna Pugliese, Arne Rau, Andrea Rossi, Jesper Sollerman, Rhaana Starling, Darach Watson, Isabelle Worssam, Makenzie E. Wortley
Quantum Physics
Gibbs resampling transitions and structured fast-measurement protocols
Daan Timmers, Benedikt Placke and Siddharth A. Parameswaran
Quantum Gibbs sampling
algorithms generalize classical Markov chain Monte Carlo (cMCMC) methods, and prepare thermal states on
quantum computers by implementing local dissipative
evolution for a mixing time $t_{\rm mix}$. Since
quantum measurements disrupt the prepared state, the rate of extracting unbiased information from the system depends on the recovery of the underlying thermal correlations. The corresponding ”Gibbs resampling” time $t_{\rm res}$ is distinct both from $t_{\rm mix}$ and from the autocorrelation time relevant to cMCMC sampling. We study this problem in effective classical models that emulate disruptive
quantum measurements of local observables on extensive subsystems. When such subsystems are chosen randomly, in models with non-local order parameters we uncover a ”resampling transition” as a function of the fraction of sites $p$ that are measured, from $t_{\rm res}\propto \log L$ for small $p$ to $t_{\rm res}\propto {\rm poly} L$ for large $p$, in systems of linear size $L$. We argue that this transition is generically absent in systems with local order parameters, and relate this dichotomy to one between the coarsening of initial states that break 1- and 0-form
symmetries under Glauber dynamics. Finally, we devise a structured fast-measurement protocol that evades slow resampling even with non-local order parameters, while leaving only a vanishing fraction of all sites unmeasured.
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Astrophysics of Galaxies
Multi-tracer constraints on quasar outflows. Acceleration from BLR to galactic scales
M. Brazzini, M. Bischetti, S. Hagen et al. (+14 more)
Black hole-driven
outflows are a fundamental component of the Active
Galactic Nuclei (AGN) paradigm, and may play a major role in regulating the
evolution of both supermassive black holes and their host
galaxies. Yet, their physical properties remain challenging to constrain, due to their multi-phase and multi-scale nature which demands a combined approach of different complementary observational tracers. In this work, we investigate AGN-driven ionized
outflows from
nuclear to
galaxy scale within individual
quasars, with the aim of establishing whether and how these phenomena are physically connected. We assemble a luminosity-matched sample of 148
quasars with bolometric luminosities higher than 10^47 erg/s, spanning the
redshift range z~2-6.5. We perform a homogeneous analysis of CIV emission and broad absorption line (BAL) profiles to derive
outflow properties on different spatial scales. We find statistically significant correlations between emission- and absorption-based
outflow diagnostics, including the minimum and maximum BAL velocities, vmin,BAL and vmax,BAL, and the v98 of CIV emission lines. These correlations are tighter in high
redshift quasars. We also find evidence for an
evolution of
outflow properties across
cosmic time, with high-
redshift quasars exhibiting systematically larger CIV line shifts and broader profiles, and faster BAL
outflows. According to our
outflow toy model, these correlations suggest a scenario in which a clumpy BAL wind is composed of expelled and accelerated broad-line region gas clouds.
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All authors M. Brazzini, M. Bischetti, S. Hagen, V. D'Odorico, N. Arav, G. Becker, G. Cupani, F. Fiore, M. Ghosh, E. Piconcelli, F. Salvestrini, M. Sharma, A. Travascio, A. Tortosa, G. Vietri, L. Zappacosta, C. Feruglio
High Energy Physics (Phenomenology)
Resonant Gravitational Production of Chiral Dark Photons
Leah Jenks, Marc Kamionkowski and Edward W. Kolb
Vector fields with a
chiral, parity-odd coupling to a pseudoscalar field are known to undergo resonant amplification. In this work, we study this phenomenon in the context of cosmological gravitational particle production during early-universe inflation. We consider a massive vector (dark
photon) field with a parity-odd coupling to the inflaton. There are two regimes of production, delineated by the relative size of the coupling and the dark
photon mass, arising from a tachyonic instability, and a parametric resonance, respectively. As a result of the coupling, the transverse modes, subdominant in both the minimally and nonminimally coupled theories, can dominate the total late-time abundance. The viable parameter space for dark-
photon dark matter is thus widened. Furthermore, in the tachyonic case, the production is dominated by a single helicity mode, leading to a population of
chiral dark
photons that can lead to potential parity-violating observational signatures. We further explore the dependence of the production on the reheating history, and find that information about reheating is encoded in the number density spectrum.
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High Energy Physics (Theory)
Microcanonical Operator Spectrum, BPS Chaos and Free Probability Theory
Alexandre Belin, Yichao Fu and Federico La Rocca
Matrix elements of simple operators are central to thermalization in chaotic
quantum many-body systems. Their moments are often described statistically through the Eigenstate Thermalization Hypothesis. In this paper, we study a more refined characterization of these
matrix elements: the eigenspectrum of simple operators once projected to microcanonical energy windows. The spectrum encodes all moments of the
matrix elements at once, and is particularly relevant when the spectrum of the
Hamiltonian is degenerate. Assuming that the eigenbasis of the simple operator is Haar-randomly oriented with respect to that of the
Hamiltonian, we prove that the spectrum of an operator projected to a small microcanonical window obeys Gaussian random
matrix statistics. We do this directly by studying the probability distribution inherited from the random orientation, as well as using tools from Free Probability Theory. We discuss the implications for BPS chaos and more generally for eigenstate thermalization.
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High Energy Astrophysical Phenomena
Geometrically Thin Sub-Eddington AGN Accretion Disks show a suppressed Lyman Edge
Ish Kaul, Yan-Fei Jiang, Omer Blaes et al. (+1 more)
The observed ultraviolet continua of active
galactic nuclei (AGN) generally lack a strong intrinsic HI Lyman edge predicted by classical optically thick
accretion disk atmosphere models. We revisit this long-standing problem using our previous sub-Eddington ($L/L_{\rm Edd}\sim 0.03$) geometrically thin 3D
accretion disk simulation evolved with gray angle-dependent radiation magnetohydrodynamics (MHD) around a $10^8M_{\odot}$ black hole. This disk is
magnetic pressure dominated, and has surface densities more than two orders of magnitude below the corresponding radiation-pressure-supported $\alpha$-disk prediction. By restarting the simulation with multiple frequency groups, we compute the emergent continuum directly from the frequency-dependent radiation fluxes and find no sharp HI Lyman edge at 13.6 eV. This suppressed Lyman edge is mainly caused by the low densities in a
magnetic pressure supported disk where the Lyman opacity jump is far weaker than in standard disk models. These results indicate that
magnetic pressure support may provide a possible solution to reconciling optically thick AGN disks with the smooth observed continuum emission around the Lyman edge. However, in this simulation, a substantial fraction of the emission near 13.6 eV is expected to originate at smaller radii closer to the central black hole, which is outside our simulation domain. More detailed predictions of the spectrum will require an extension to the inner disk, non-LTE radiation transfer, higher frequency resolution and a survey across a broader range of
accretion rates.
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All authors Ish Kaul, Yan-Fei Jiang, Omer Blaes, Lizhong Zhang
Strongly Correlated Electrons
Bootstrap certification of string order in quantum spin chains
Sagnik Banerjee, Haoyu Guo and Debanjan Chowdhury
The many-body bootstrap certifies ground-state properties by minimizing energy over correlators constrained only by positivity, without any variational wavefunction. Its cost, however, grows exponentially with the size of the operators involved, placing the long-range string correlators that diagnose topological phases out of reach. We overcome this by treating string operators as primary objects: bare and endpoint-dressed strings satisfy a closed operator
algebra with one another and with local words, yielding a semidefinite program whose cost grows only polynomially with string length. A single computation then yields estimates of string correlators of all lengths. Rigorous two-sided bounds are obtained for each target string once the ground-state energy is pinned within a window. When benchmarked against density-
matrix renormalization group computations on the cluster Ising and
spin$-1$ Heisenberg chains, the method certifies the nonlocal string order of the cluster and Haldane phases directly from the
Hamiltonian. Our rigorous certification of string order parameters reveal that the sharpness of the bounds is set by which operators enter the calculation, not by their length alone. By exploiting algebraic closure of strings and local words, our framework lifts spatially extended observables into polynomially tractable bootstrap variables, opening up a route to wavefunction-free certification of nonlocal order in
quantum many-body systems.
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Physics and Society · Cross-listed from stat.AP
Projected Effects of Naloxone and Buprenorphine Scale-Up on Opioid Overdose Mortality in Six Pennsylvania Counties
Abdulrahman A. Ahmed, M. Amin Rahimian, Qiushi Chen et al. (+1 more)
Opioid overdose deaths remain a severe public health crisis in the US, with heterogeneous burden across counties that differ in epidemic trajectory, baseline resources, and local context. While harm reduction through naloxone distribution and buprenorphine treatment are both evidence-based strategies, limited information on county-level effects hinders the ability of policymakers to prioritize resources across counties. We developed a simulation model of opioid use disorder (OUD), calibrated separately to six Pennsylvania counties spanning large urban (Allegheny, Philadelphia), intermediate-sized (Erie, Dauphin), and rural (Clearfield, Columbia) settings. We projected county-specific overdose mortality trajectories under three levels of increase in buprenorphine dispensing and naloxone distribution (10%, 20%, and 30% above each county's baseline), over a five-year horizon from 2025 to 2029. A 30% increase in naloxone distribution above projected county baseline levels was projected to reduce 2029 overdose deaths by approximately 70% (95% uncertainty interval, UI: 55-81%) in Allegheny County, 11% (95% UI: 4-17%) in Erie County, and 28% (95% UI: 2-64%) in Clearfield County. The relative projected benefits of naloxone and buprenorphine varied by county; buprenorphine produced larger reductions in Erie and Dauphin. The same proportional increase in naloxone distribution produced substantially different projected mortality reductions across the six Pennsylvania counties. County-level context is important for informing harm reduction and treatment prioritization at the county level.
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All authors Abdulrahman A. Ahmed, M. Amin Rahimian, Qiushi Chen, Praveen Kumar
General Relativity and Quantum Cosmology · Cross-listed from math.DG
The suboptimal Penrose inequality for charged initial data sets
Eunice Ng
Given a complete, 3-dimensional, asymptotically flat initial data set for the Einstein-Maxwell equations with vanishing
magnetic field, we show that there exists a small universal constant $\mathcal{C}$ such that $m\geq\mathcal{C}(\sqrt{\mathcal{A}/(16\pi)}+\mathcal{Q}^2\sqrt{\pi/\mathcal{A}}\,)$. An analogous statement holds for asymptotically hyperboloidal initial data sets with the ADM mass replaced by
hyperbolic energy. Under the additional assumption of axisymmetry, the inequality may be further strengthened to include angular momentum. These results extend the Penrose-type inequalities recently obtained by Allen-Bryden-Kazaras-Khuri to the charged setting.
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Physics Education
AI-Assisted Assessment of Experimental Physics Laboratory Reports: Potential, Limitations, and Support for Teaching Practice
Marcos Abreu, Cecilia Stari and Arturo C. Marti
The incorporation of AI into the assessment of physics laboratory reports offers opportunities to support the review of student work and the provision of feedback. This article revisits an experience involving the use of ChatGPT models to analyze laboratory reports and examines the conditions that influence their usefulness in teaching practice. The analysis considers the
evolution of AI models, document-processing procedures, and different modes of interaction, with particular
attention to the effective availability of evidence contained in student reports. The findings indicate that differences between AI-generated and teacher assessments may be related not only to model capabilities but also to difficulties in retrieving and interpreting equations, graphs, tables, units, and other visual elements. The possibilities of systematic processing of sets of reports and conversational review of cases requiring more focused analysis are also examined. Based on these observations, a working strategy is proposed in which AI serves as a complementary resource for organizing assessment, supporting feedback, and identifying recurring difficulties in student work. The analysis highlights the importance of document-processing conditions and evidence availability, as well as the teacher's role in interpreting AI-generated information and making evaluative and pedagogical decisions.
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Accelerator Physics
Persistent homology of Hamiltonian orbits with applications to beam physics: Euler-Betti classification and topological chaos indicators
D. Iglesias Tinoco and B. Erdélyi
Estimating the dynamic aperture of circular particle accelerators typically requires expensive long-term tracking. Using classical homology, we construct a two-dimensional theoretical classification of regular and chaotic orbits and use persistent homology for its numerical implementation on short orbit segments. In four dimensions, we introduce topological chaos indicators based on persistent homology and use normal-form theory to apply the classification to two
symplectic-plane projections. The methods reproduce the expected organization of regular and chaotic motion in several canonical
Hamiltonian systems. Applied to symplectified one-turn maps of a nonlinear
lattice model of the Integrable Optics Test Accelerator, the results obtained from the first 200 turns identify the central connected stability region and its surrounding transition to chaos. They are consistent with the short-term dynamic aperture of the electron configuration obtained from $10^4$ turns and the long-term dynamic aperture of the
proton configuration obtained from $10^8$ turns. For the configurations studied, persistent homology of short orbit segments predicts the dynamic aperture obtained by substantially longer tracking, potentially reducing the need for exhaustive simulations in studies of existing accelerators and the design of future facilities. The methods could also complement classical chaos indicators and modern approaches based on artificial intelligence.
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Materials Science · Cross-listed from eess.IV
AutoRASOR: Autonomous Rapid Scanning Electron Microscope Operator
Kevin Zhang, Mohammad Taha, Rafael Espinosa Castañeda et al. (+7 more)
Scanning Electron Microscopy (SEM) is a foundational technique for characterizing material microstructure, which dictates many fundamental physical and chemical properties. With the rise of Self-Driving Labs (SDLs), samples are now synthesized in large batches, demanding equally high-throughput, autonomous characterization. Existing automated electron microscopy pipelines are task-specific: they detect pre-defined features, optimize known properties, or require prior knowledge of the sample, restricting each pipeline to the material system it was built for. We introduce AutoRASOR, a task-agnostic autonomous SEM pipeline that captures the multi-scale morphology of an unknown sample without domain-specific pre-training, fine-tuning, or human prompting. AutoRASOR embeds micrographs in real time with a
vision foundation model (VFM), DINOv3, and selects regions of interest (ROIs) through two complementary policies: Latent Farthest Point Sampling (LFPS) and active learning on morphological ambiguity, which is the conditional variance of unresolved fine-scale features given lower magnification appearance. Active learning on ambiguity consistently captures more diverse and rare morphologies than random ROI selection, while LFPS reliably recovers the specimen's morphological distribution within a limited capture budget, tested both on real SEM micrographs and synthetic phase-field images. By shifting autonomous characterization from pre-defined, task-specific targeting of features to morphological survey, AutoRASOR generates information-rich multi-scale
datasets for diverse downstream tasks. Without the need for domain-specific pre-training or prior material assumptions, this framework can be deployed out-of-the-box to characterize novel materials produced by SDLs.
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All authors Kevin Zhang, Mohammad Taha, Rafael Espinosa Castañeda, Yutong Liu, Yin Zhu, Lotan Portal, Robert A. Mcleod, Vahid Attari, Jane Y. Howe, Jason Hattrick-Simpers
Mathematical Physics · Cross-listed from math.CA
Rectifiability of the straight visible boundary and the limits of segment-based Hardy criteria
H. Abbas and A.Azzouz
Weighted Hardy inequalities on a domain $\Omega\subset\R^n$ can be deduced from lower Hausdorff-content bounds on suitable visible parts of the boundary, and it is natural to look for visible sets described by straight segments, which are easier to verify than the curve-based visual boundary of Koskela and Lehrbäck. We show that this approach is subject to an intrinsic obstruction. If a boundary point $\xi$ is seen from $x\in\Omega$ along a segment satisfying a uniform thickness condition, then $\Omega$ contains a truncated cone with vertex $\xi$; consequently the quantitatively straight visible boundary $\partial^{\mathrm{str}}_{x,\alpha}\Omega\cap B(x,C_0d_\Omega(x))$ is a finite union of Lipschitz graphs, is $(n-1)$-rectifiable, and carries no $\lambda$-Hausdorff content for any $\lambda>n-1$. Since content conditions with $\lambda\le n-1$ already imply the $(p,\beta)$-Hardy inequality for $\beta<p-n+\lambda$ without any visibility assumption, segment-based criteria are either unsatisfiable or redundant: they never reach the regime $\beta\ge p-1$ in which visibility is genuinely needed. We show that the exponent $n-1$ is attained, so that the rectifiability
theorem is sharp; we exhibit a boundary point lying in the visual boundary of Koskela and Lehrbäck but in no $\partial^{\mathrm{str}}_{x,\alpha}\Omega$; and we observe that raw straight visibility, without the thickness condition, escapes the obstruction, is sufficient for $\lambda\le n-1$, and remains open for $\lambda>n-1$.
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High Energy Physics (Phenomenology)
Coherent deeply virtual Compton scattering on helium-4 beyond the leading twist approximation
V.Martínez-Fernández, B.Pire, P.Sznajder et al. (+1 more)
Coherent hard exclusive reactions on light
nuclei offer access to their
quark and
gluon structure and provide a framework for three-dimensional
nuclear tomography. We analyze deeply virtual Compton scattering on a helium-4 target, including leading-twist contributions as well as kinematical twist-3 and twist-4 effects. We present numerical estimates of cross sections and asymmetries for kinematic regimes relevant to JLab experiments. We emphasize the importance of next to leading order (NLO) and kinematical twist 3 and 4 contributions to interpret data in the JLab kinematics. We deduce a first tomographic image of
quarks and
gluons in the helium-4
nucleus.
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All authors V.Martínez-Fernández, B.Pire, P.Sznajder, J.Wagner
Fluid Dynamics
An experimental and numerical study of the circular hydraulic jump
Arnab Kumar Mallik, Hrvoje Jasak, D. Ian Wilson et al. (+2 more)
This paper describes experiments and numerical simulations on the normal impact of a round
liquid jet onto a horizontal surface, such as when water from a tap hits the bottom of a kitchen sink. In this case the
liquid impacting on the surface spreads as a fast-flowing thin film and, at some distance from the point of impact, the thickness of the flow abruptly increases and the speed of the flow is reduced. In the experiments studied here the flow is axisymmetric about the axis of the jet, and the abrupt change in depth occurs at a given radius and is known as a circular hydraulic jump (CHJ). We present new experiments in which we measure the thickness of the
liquid film inside and beyond the jump and use these measurements to estimate the governing parameters, the Weber, Froude and Reynolds numbers that determine the influence of surface tension,
gravity and viscosity, respectively. We also carry out numerical simulations of the flow that show excellent agreement with the experiments and provide independent estimates of these dimensionless parameters. We find that, on the scale of a kitchen sink, and for water at high Reynolds number and low Bond number, at the jump the Weber number is of order unity while the Froude number is large, implying that the jump is controlled by surface tension. We also define a critical dimensionless jet flow rate at which this control no longer holds and
gravity plays a significant role.
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All authors Arnab Kumar Mallik, Hrvoje Jasak, D. Ian Wilson, P. F. Linden, Rajesh K. Bhagat
Superconductivity
Raman scattering in cuprate oxychlorides high-temperature superconductors single-crystals
Chafic Fawaz, Yingzheng Gao, Luca Laveder et al. (+13 more)
We investigate the Raman response of sodium-doped cuprate oxychloride Na$\_x$Ca$\_{2-x}$CuO$\_2$Cl$\_2$ high-temperature
superconductors across their entire phase diagram, from the
antiferromagnetic to the superconducting region. In addition to the expected Raman-active
phonon modes, we detect several additional modes that can be interpreted as being excited via a resonance process enabled by strong electron–
phonon coupling. To verify the resonance effect, the Raman response at different incident
photon energies was measured. At high energies, there is a well-defined $B\_{1g}$ mode in the
antiferromagnetic phase, which can be interpreted as a bimagnon We follow its temperature and doping dependence, providing information on the multimagnon excitation in these cuprates, which can be theoretically linked to the exchange interaction.
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All authors Chafic Fawaz, Yingzheng Gao, Luca Laveder, Lorenzo Menon, Owen Moulding, Rolf Heid, Blair W Lebert, Christophe Bellin, Keevin Beneut, David Santos-Cottin, Ikuya Yamada, Yuichi Okazaki, Hajime Yamamoto, Masaki Azuma, M.-A. Méasson, Matteo d'Astuto
General Relativity and Quantum Cosmology
Sourced Gravitational Radiation in Parity-Violating Tetrad Gravity
G.G.L. Nashed
We study linear gravitational modes, sourced far-zone fields, and quadratic energy balance in a four-parameter tetrad theory of
gravity. The theory contains three parity-even torsion invariants and a parity-odd coupling $v^\mu a_\mu$, where $v_\mu$ and $a_\mu$ are the vector and axial torsion components. Linearizing around Minkowski spacetime and applying a scalar–vector–tensor decomposition, we find two tensor, two scalar, and four vector degrees of freedom in the generic nondegenerate parity-violating region. The tensor and scalar modes propagate at the speed of light, while the two vector branches have coupling-dependent propagation speeds. We derive their kinetic
eigenvalues, characteristic speeds, and flux normalizations. An exact trace identity shows that the vector
Hamiltonian is not positive definite in the generic branch, even when the kinetic
eigenvalues are positive and the propagation speeds are real. We also derive the response to a general compact canonical source and obtain explicit source-to-amplitude relations for all eight linear polarizations. The field $V_\mu=\partial^\nu B_{\nu\mu}$ is used to illustrate intrinsic-
spin multipoles. {We further prove that the quadratic Noether current equals the second-order Møller current for the chosen first-derivative tetrad Lagrangian and derive the corresponding mode-resolved energy and momentum fluxes.} The vector contribution remains a formal signed response because of the unbounded
Hamiltonian. The stationary limit reproduces the results of Ref.~\cite{ShirafujiNashed1997}, and a representative parameter scan illustrates vector-mode splitting and kinetic degeneracy.
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Materials Science · Cross-listed from cs.SD
Causal limits and optimal allocation for passive frequency-selective hearing protection
Geonhwi Hwang, Jaewoo Lee, Hyunjun Kim et al. (+1 more)
Passive Helmholtz-resonator earplugs aim to attenuate hazardous noise while keeping
speech audible; the air volume of an ear-sized shell is finite, and we treat it as the resource a design spends. For a vented bore transparent at zero frequency and loaded by reactive side branches, causality fixes a conserved integral of transmission loss. We derive it in device variables, add viscous and flanking constraints, and allocate the budget by hazard-weighted water-filling with a continuous
speech-cost price. The audio-band budget B_ad = (20/ln10) pi^2 V / 2cS is set by the ratio of total cavity volume V to bore area S; occluding plugs are exempt. The f^2 price signal favours frequencies well above the source peak. Replacing strict transparency by a
speech-cost price gives an exchange rate of about 1.3 dB of protection per decibel of
speech cost under the present model, with the budget setting where it saturates. Across three form factors, low-frequency-selective designs stay near a decibel while hazard-matched mid/high-frequency designs reach twelve. The binding variables are bore area and
speech allowance, not resonator count.
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All authors Geonhwi Hwang, Jaewoo Lee, Hyunjun Kim, Hyeonwoo Na