Astrophysics of Galaxies
The progenitor galaxies of the intracluster light
Rebecca J. Mayes, Facundo A. Gómez and Antonela Monachesi
Intracluster Light (ICL) is a diffuse stellar component of
galaxy groups and clusters, bound to the structure's potential rather than to individual
galaxies and primarily formed through the stripping and mergers of intermediate-mass
galaxies. Its formation and
evolution is strongly linked to the central
galaxies of groups and clusters, typically the Brightest Cluster
Galaxies (BCGs) in clusters. To determine the properties of the progenitor
galaxies of the ICL of clusters and groups at
redshift z = 0 and compare them with the progenitors of their BCGs. We select 127 clusters and groups in the hydrodynamic Illustris-TNG100 simulation above a mass of 10^{13}~$M_{\odot}$. We divide the ICL from the BCG by applying a surface brightness cut at the Holmberg radius of 26.5 mag/arcsec^{-2}, where
star particles within this radius are defined as attached to the BCG, and outside, the ICL. We then determine the masses and contributions of progenitor
galaxies of the ICL and BCG. We find that the number of ICL progenitors increases with structure mass, and that the ICL has more progenitors than the BCG. The ICL has a larger percentage of material from low-mass
galaxies. Quenched
galaxies contributed a large fraction of the ICL, and this fraction increases with
galaxy mass. The mean mass radial gradient of ex-situ material in structures for the ICL and the BCG+ICL is generally negative and increases with structure mass, indicating that material from more massive progenitors is found towards the centres of clusters. The mean mass radial gradient is significantly impacted by structure formation history. ICL progenitor properties are impacted by structure history and are therefore highly individual to each system. At a given structure mass, there is diversity in the properties of the progenitors that formed the ICL. Although the BCG and the ICL co-evolve, the BCG has fewer, more massive progenitors.
Read the full abstract ▾
Optics
Photoluminescence study of Vanadium in 4H- and 6H- Silicon Carbide
Ibrahim Boulares, Anne R. Evans, Jeremy L. Smith et al. (+1 more)
Point defects with optically addressable
spin states are a key building block for
quantum networks, but few solid-state emitters combine a
spin-
photon interface with emission in the low-loss telecommunications band. Vanadium (V4+) defects in silicon carbide (SiC) meet this requirement, emitting zero-
phonon lines (ZPLs) throughout the telecom O-band in both the 4H- and 6H-SiC polytypes while retaining an addressable electron and nuclear
spin system [1,2]. Although the orbital and
spin structure of these defects has been characterized in detail, the polarization selection rules have not been fully mapped experimentally. Here we present polarization-dependent photoluminescence (PL) measurements of vanadium ZPLs in 4H- and 6H-SiC at cryogenic temperature, of two scattering geometries: edge and face-on (emission wavevector perpendicular and parallel to the
crystal c-axis, respectively). Emission from two of the four {\alpha} sites, ({\alpha}2 and {\alpha}3) and the 6H-SiC {\gamma} sites, are polarized parallel to the c-axis ({\sigma}-polarized), whereas emission from {\alpha}1 and {\alpha}4 are polarized perpendicular to the c-axis ({\pi}-polarized). Additionally, we report preliminary, lower signal measurements of the e̱ta} sites.
Read the full abstract ▾
All authors Ibrahim Boulares, Anne R. Evans, Jeremy L. Smith, Brenda VanMil
Cosmology and Nongalactic Astrophysics
Debiasing Local Cluster Infall Reveals $\boldsymbol{H_0}$: Application to the Virgo Cluster
Bastien Carreres, David Benisty, Jenny Wagner et al. (+3 more)
Galaxy recession velocities are commonly used to measure the Hubble constant, $H_0$, with peculiar velocities treated as random noise. Around massive clusters, however, these motions can be predicted by the gravitational potential of the central
halo, allowing them to be modeled rather than averaged over. Past analyses relied on analytic approximations for the distance-infall-velocity relation, whose accuracy has not been tested using realistic cosmological simulations. We use
halos from the IllustrisTNG simulation to quantify the bias and precision of several commonly used Hubble-flow models. We find that widely used fitting functions systematically underestimate $H_0$, whereas the full analytical solution reduces but does not eliminate these biases. We develop a simulation-based method to infer $H_0$ and apply it to TRGB distance samples around the Virgo Cluster. We find $H_0=74.4\pm 2.9$ and $73.4\pm 3.9$ km s$^{-1}$ Mpc$^{-1}$ (stat) for the minor and the major infall models, respectively. Correcting for the bias calibrated on TNG
halos, these measurements raise the value of $H_0$ to $81.6 \pm 7.8$ and $87.3 \pm 8.8$ km s$^{-1}$ Mpc$^{-1}$ (stat+sys), where the minor infall model has the smallest bias from the Virgo mocks. We show that statistical errors are dominated by the residual velocity scatter around the infall model, while systematic errors are dominated by the transformation to the structure's comoving frame and
halo population variance. These results establish a framework for interpreting cluster infall measurements and explain trends in previous $H_0$ inferences.
Read the full abstract ▾
All authors Bastien Carreres, David Benisty, Jenny Wagner, Avery Erlenbach, Dan Scolnic, Adam Riess
Chemical Physics · Cross-listed from cs.LG
NEMORA: Neural Equivariant Multipole Operators for Long-Range Atomistic Learning
Jay L. Kaplan, Samuel Varner, Rebecca Willett et al. (+1 more)
Equivariant graph neural networks have emerged as foundational architectures for machine-learned interatomic potentials, approaching
quantum-chemical accuracy at a fraction of the computational cost. These models describe local atomic environments accurately, but finite spatial cutoffs truncate long-range information flow, and stacking message-passing layers can lead to over-smoothing and over-squashing. Existing long-range extensions either prescribe a fixed analytical propagation kernel, restrict long-range communication to scalars or degree-preserving channels, are only approximately equivariant, or incur super-linear computational cost. Combining learnable long-range equivariant transport with multiscale many-body expressivity and efficient scaling for larger systems remains a central challenge. We introduce Neural Equivariant Multipole Operators (NEMORA), a neural equivariant extension of the Fast Multipole Method (FMM) for learning long-range tensorial representations. NEMORA generalizes the FMM's analytical multipole expansion and translation operators to learned equivariant counterparts on an adaptive spatial hierarchy. Its operators couple angular degrees and form many-body interactions across length scales, retaining the FMM's hierarchical organization and analytical radial factors as physical inductive biases while learning data-dependent long-range couplings. NEMORA evaluates in linear time and
memory complexity, allowing it to treat larger systems than other long-range methods reaching hundreds of thousands of atoms, and it augments both
symmetry-constrained and unconstrained short-range backbones. On non-local
benchmarks, it reduces force and energy errors relative to the short-range backbones by over an order of magnitude and up to three orders of magnitude, respectively, which is better than or competitive with existing long-range extensions in accuracy.
Read the full abstract ▾
All authors Jay L. Kaplan, Samuel Varner, Rebecca Willett, Juan J. de Pablo
Quantum Physics
Scaling Quantum Optimization to the Thousand-Qubit Scale with Distributed Quantum Sampling
Amana Liaqat, Ahmed Darwish, Stephen DiAdamo et al. (+6 more)
The Minimum Birkhoff Decomposition (MBD) seeks a sparse weighted sum of matchings and is a challenging optimization problem with applications in network scheduling and energy trading. We scale a
quantum-assisted decomposition method by combining single-layer QAOA sampling with Extended Fully-Corrective Frank-Wolfe (E-FCFW) optimization, spectral graph partitioning, and greedy feasibility repair. We demonstrate the pipeline on the 1,354-node PEGASE bus test case (representing a 1,354-bus transmission grid with 1,710 transmission lines), whose 1,710 edges define a native 1,710-variable matching optimization problem requiring 1,710
qubits in the unpartitioned encoding. Partitioning enables distributed execution on IBM superconducting
quantum processors. The best reported hardware result uses a 50-
qubit partition bound, while reducing partitions to 20
qubits degrades convergence in the partition-size comparison. Larger partitions are more demanding for
matrix product state (MPS) simulation, and bond-dimension tests show that truncating
quantum correlations reduces candidate quality. The results therefore motivate retaining a substantive
quantum sampling task within each partition as the overall problem scales. On the PEGASE-1354
benchmark, repaired QAOA samples achieve lower residual decomposition error than both simulated annealing and uniform random sampling baselines, while spatial
circuit packing reduces hardware execution time by approximately a factor of three. These results demonstrate that combining spectral partitioning, spatial
circuit packing, and classical feasibility repair provides an executable path for deploying gate-based
quantum sampling on thousand-variable constrained optimization problems on current hardware.
Read the full abstract ▾
All authors Amana Liaqat, Ahmed Darwish, Stephen DiAdamo, Dan Holme, Kieran McDowall, Emre Sahin, Naeimeh Mohseni, Giorgio Cortiana, Corey O'Meara
High Energy Physics (Phenomenology)
Hot and dense QED at N$^3$LO: infrared sector
Tyler Gorda and Swastik Majumder
We determine the infrared-sensitive contribution to the pressure of hot and dense massless
quantum electrodynamics (QED) at $O({e}^6)$ in the electric charge $e$, obtaining a representation valid across the crossover between the thermally dominated and degenerate regimes. This contribution arises from a hard-thermal-loop (HTL) resummed soft
photon dressed by either the one-loop power correction or the two-loop next-to-leading-order
photon self-energy. After separating the static and nonstatic sectors, we obtain the static contribution in closed form and perform the nonstatic Matsubara sum analytically in terms of the digamma function, reducing the remaining finite coefficient to a one-dimensional numerical integral. The finite-temperature HTL counterterm cancels the factorization divergence before expansion; at strictly zero temperature $T$, this divergence instead cancels against the hard four-loop contribution. At vanishing chemical potential, the static sector reproduces the complete known $O\left(e^5\right)$ pressure. Taking the cold limit of the dimensionally regulated, unsubtracted nonstatic contribution reproduces the correct cold mixed result. Crucially, at any fixed $T>0$, the nonstatic result remains analytic in $e^2$. The zero-temperature $O(e^6\ln e)$ term in QED arises only in the nonuniform limit ${T}/{m_{\rm{E}}}\to0$ where $m_{\rm{E}}$ is the electric screening mass, demonstrating that the weak-coupling and zero-temperature limits do not commute.
Read the full abstract ▾
High Energy Physics (Theory)
Reconstruction of Black Hole Islands from Hawking Radiation via the Algebraic Petz Map
Niloofar Vardian
The island proposal guarantees a
unitary Page curve for evaporating black holes, implying that operators deep behind the horizon must be fully reconstructable from asymptotic Hawking radiation. However, because the interior is causally disconnected and highly dynamical, standard
entanglement wedge reconstruction methods, relying on global isometries or continuous modular flow, fail to provide this mapping. We resolve this by constructing a protocol for island reconstruction using the algebraic Petz map. By using modular theory, we reflect island operators into the accessible complement, transport them to the boundary, and map them into the radiation
algebra. Furthermore, we demonstrate that this purely algebraic derivation naturally yields the structure of Papadodimas-Raju mirror operators. This framework provides a rigorous operational dictionary for the island formula, proving that information trapped inside a black hole can be decoded.
Read the full abstract ▾
Instrumentation and Methods for Astrophysics
Microwave Loss in Low-Temperature ICPCVD Silicon Nitride: Dependence on Precursor Ratio and RF Substrate Bias
H. Athreya, J. Cornelison, M. Mikhailov et al. (+5 more)
Low-loss dielectric films are an important component of superconducting
circuits with applications ranging from
quantum information to superconducting detectors for astrophysics. In millimeter-wave detector
circuits, dielectric loss can be the limiting factor on efficiency and resonator performance. Some advantageous detector fabrication architectures require dielectric deposition at temperatures substantially lower than those conventionally used to achieve low dielectric loss. In this work, we characterize silicon nitride (SiN$_x$) films deposited by inductively coupled
plasma chemical vapor deposition (ICPCVD) at $150\,^{\circ}\mathrm{C}$ for use in temperature-constrained superconducting detector fabrication. We measure the dielectric loss tangent of these films at $\sim 4-7$ GHz using superconducting niobium microstrip resonators and extract the loss by fitting the temperature-dependent resonant frequency to a two-level-system model. We vary the N$_2$/SiH$_4$ precursor-flow ratio between dielectric depositions and find a clear trend of decreasing loss with decreasing N$_2$/SiH$_4$. We additionally find that applying an RF substrate bias during deposition reduces the loss compared to films deposited without bias. These results identify precursor ratio and substrate bias as practical process parameters for improving low-temperature SiN$_x$ for superconducting detector
circuits.
Read the full abstract ▾
All authors H. Athreya, J. Cornelison, M. Mikhailov, R.J.H. van der Kolk, C. Chang, T. Cecil, M. N. Ali, J. A. Zebrowski
Strongly Correlated Electrons
Gustavo M. Yoshitome, Pedro R. S. Gomes and Guilherme Delfino
We develop a constructive framework for characterizing modulated
symmetries and their gauging in $d$-dimensional
lattice systems. The modulation profiles are organized as a finite-dimensional representation of the space group acting on a finite Abelian internal
symmetry group. Since the corresponding automorphism group is finite, the nontrivial spatial action factors through a finite quotient of the space group, leading to periodic modulation patterns and providing a classification framework for discrete Abelian modulated
symmetries. The
symmetry-allowed local interactions are systematically obtained from a kernel construction, which also yields an
algebra of open operators. Upon gauging, its elements are transmuted into extended Wilson and boundary operators while retaining their algebraic relations. In the deconfined regime, the resulting
algebra realizes a mixed 't Hooft anomaly, providing a microscopic route to Abelian crystalline
symmetry-enriched topological phases (SETs). These SETs do not mix electric and
magnetic sectors, which transform in mutually contragredient representations, thereby preserving their braiding pairing. We illustrate the framework through explicit examples and show that several models present in the literature fit naturally within our construction.
Read the full abstract ▾
Quantum Physics
Engineering Quantum Interactions: From Effective Models to Validated Physical Predictions
Sinara S. Dourado, Ciro Micheletti Diniz, Gabriel P. L. M. Fernandes et al. (+3 more)
Effective models make complex
quantum dynamics tractable by retaining only the states, processes, and timescales relevant to a given physical question. Their predictive power, however, depends on treating the retained
manifold, initial state, observables, micromotion, dissipative channels, and eliminated degrees of freedom consistently. We develop a unified framework for constructing and validating effective descriptions using projection methods, Schrieffer–Wolff transformations, Magnus expansions, adiabatic elimination, small rotations, time coarse graining, and Floquet theory. The
quantum Rabi model and its dispersive limits serve as recurring
benchmarks for identifying control parameters, virtual processes, spectral corrections, observable dressing, and breakdown. Higher-order resonances and applications to collective light–matter coupling, Raman processes,
spin-chain buses, lossy mediators, and driven
lattices illustrate how effective interactions can be interpreted and designed. A physical prediction is organized into three order-consistent steps: encoding into the retained description,
evolution under the effective dynamics, and reconstruction of the physical observable. This viewpoint exposes failures caused by leakage, small denominators, neglected micromotion, inconsistent observables,
memory effects, or incorrectly transformed dissipation, while linking derivation, physical interpretation, and mechanism-guided discovery. Companion notebooks provide QuTiP implementations, convergence tests, and microscopic-to-effective comparisons.
Read the full abstract ▾
All authors Sinara S. Dourado, Ciro Micheletti Diniz, Gabriel P. L. M. Fernandes, Rogério J. de Assis, G. D. de Moraes Neto, Celso J. Villas-Boas
Quantum Physics
Quantum-Enhanced Inference of Conditional Future Probabilities with Reduced Memory Cost
Jianjun Chen, Akshat Gupta, Chengran Yang et al. (+4 more)
Many potential future events have devastating consequences, from the onset of earthquakes to financial black swan events. Accurate predictions of their probability of occurrence are vital. Yet as the
stochastic systems underlying such events become increasingly complex, these probabilities can depend on ever-growing amounts of past data, which require ever more
memory to track. The accuracy of our estimates is ultimately limited by both computational and
memory constraints; the former to reduce sampling error, the latter to avoid sampling bias. Traditional
quantum algorithms – such as amplitude estimation – address only the former, and become untenable especially in near-future
quantum devices where
quantum memory is a premium. Here, we offer
quantum-algorithmic means to reduce systematic bias while maintaining a quadratic speed-up. Our results thus advance the timeline for the practical deployment of
quantum technologies, and illustrate their additional benefits when simulating processes of growing complexity.
Read the full abstract ▾
All authors Jianjun Chen, Akshat Gupta, Chengran Yang, Ariel Neufeld, Jayne Thompson, Thomas J. Elliott, Mile Gu
Astrophysics of Galaxies
Pushing Variability Searches to Extreme Dwarf Galaxies with the Vera C. Rubin Observatory Data Preview 2
Fan Zou, W. N. Brandt, Elena Gallo et al. (+15 more)
Galaxies with stellar masses $M_\star<10^8~M_\odot$, hereafter referred to as extreme dwarf
galaxies (EDGs), represent one of the least explored regimes in the search for accreting intermediate-mass black holes. Using the recent Vera C. Rubin Observatory Data Preview 2 (DP2; covering 2025-04-25 to 2026-01-06), we present the first systematic search for variability among EDGs in the ELAIS-S1 field, the most extensively observed LSST Deep-Drilling Field in DP2. Applying single-band and cross-band variability statistics to difference-imaging light curves for $6.2\times10^4$ EDGs with archival multiwavelength characterizations, we identify seven variable EDG candidates, all brighter than $i$-band magnitude of 24 and located within $z<0.3$. The two brightest candidates are previously known AGNs, three have light curves more consistent with
supernovae, and two do not have a clear nature. The sample corresponds to an apparent EDG variable fraction of $6.8_{-2.1}^{+3.1}\times10^{-4}$ at $i$-band magnitudes brighter than 24 and is expected to consist primarily of AGNs and
supernovae. Compared to a magnitude-matched massive-
galaxy sample with the same variability selection applied, the EDG variable fraction is comparable or at most lower by up to a factor of three. This proof-of-concept study demonstrates that Rubin will identify a statistically meaningful sample of variable EDG candidates, opening a new regime for black-hole demographics. Spectroscopic follow-up will nevertheless be required to secure
redshifts and confirm individual candidates.
Read the full abstract ▾
All authors Fan Zou, W. N. Brandt, Elena Gallo, Franz E. Bauer, Angela Bongiorno, Colin J. Burke, Alister W. Graham, Hengxiao Guo, Lorena Hernández-García, Marcin Marculewicz, Dieu D. Nguyen, Swayamtrupta Panda, Alessandro Peca, Bindu Rani, Claudio Ricci, Ohad Shemmer, Wei Leong Tee, Zhibo Yu
Cosmology and Nongalactic Astrophysics
Primordial black holes
V.I. Dokuchaev, Yu.N. Eroshenko, V.V. Nikulin et al. (+3 more)
Primordial black holes, whose formation in the early Universe was first hypothesized by Ya.B.~Zel'dovich and I.D.~Novikov in 1966 (the text of this pioneering article is provided in Appendix II to this review), have attracted increasing
attention in recent years. Modern astronomical data across the electromagnetic spectrum, together with observations of gravitational waves and
cosmic neutrinos, have revealed a number of unique astrophysical phenomena that may be related to primordial black holes formed in the pre-stellar cosmological epoch. This review describes various models of primordial black hole formation, as well as methods for testing these models with astronomical and astrophysical observations. In particular, we discuss in detail the formation of primordial black holes and their clusters through the collapse of closed domain walls and through effects associated with extra spatial dimensions of the Universe.
Read the full abstract ▾
All authors V.I. Dokuchaev, Yu.N. Eroshenko, V.V. Nikulin, K.A. Postnov, S.G. Rubin, V.D. Stasenko
High Energy Physics (Theory)
Fourier analysis of compact oscillons
Pawel Klimas, Leandro Roza Livramento and João Saldanha Streibel
We present a new derivation of the exact compact oscillon in the signum-Gordon model using
Fourier methods. This approach decomposes the oscillon into an infinite, uniformly convergent series of discrete modes consisting of a fundamental frequency and its odd higher harmonics, in contrast to standard analytic potentials, where the corresponding infinite perturbative series fails to converge. Crucially, our oscillon evades the non-existence
theorem for spatially localized, small-amplitude periodic states. We investigate the accuracy of truncating the
Fourier series and find that the primary mode alone provides a remarkably accurate approximation of the exact solution, with agreement improving significantly when the first two non-vanishing harmonic modes are included. Furthermore, we generalize this framework to a swaying compact oscillon with a periodically moving boundary. We show that describing such an oscillon requires even-order modes, whose coupling with the odd source terms induces a dynamic modulation that generates the swaying motion, even though the spatial
Fourier profiles themselves are time-independent.
Read the full abstract ▾
High Energy Physics (Theory)
Polynomial and Eigenspace Factorisations for the One-loop Dilatation Operator at Finite $N$
Adrian Padellaro, Sanjaye Ramgoolam and Ryo Suzuki
We study gauge-invariant two-
matrix polynomials of degree $L$, corresponding to the states in the $su(2)$ sector of $\mathcal{N}=4$ super Yang-Mills theory with gauge group $U(N)$ or $SU(N)$ at finite $N$. For the $U(N)$ theory, the state space has the structure of an
algebra $\mathcal{A}_N(L)$, which is a direct sum of permutation centraliser
algebras, i.e. sub-
algebras of the group
algebra $\mathbb{C}[S_L]$ of $S_L$. For $N \ge L$, $\mathcal{A}_N (L) = \mathcal{A} (L)$ is independent of $N$, and the one-loop dilatation operator acts on $\mathcal{A}(L)$ with $N$ as a parameter. For $N < L$, $\mathcal{A}_N (L)$ is a subspace of $\mathcal{A}(L)$ defined using a finite-$N$ cutoff on Young diagrams with $L$ boxes. We establish two results on the eigenspaces of the one-loop dilatation operator. Our first main result is that the characteristic
polynomial of the one-loop dilatation operator on $\mathcal{A}_N(L)$ divides the characteristic
polynomial from $\mathcal{A}(L)$, continued to $N < L$. Our second result is that each eigenstate of the one-loop dilatation operator in the $SU(N)$ theory generates an infinite tower of eigenstates in the $U(N)$ theory, through the multiplication of single-letter traces. These towers define an eigenspace factorisation of the $U(N)$ theory labelled by the number of such traces. Further, we
conjecture that the space of $SU(N)$-invariant
polynomials in two traceless
matrices at finite $N$ is isomorphic to the intersection of $\mathcal{A}_N(L)$ with the subspace of $\mathbb{C}[S_L]$ spanned by derangements. This intersection
conjecture is supported by dimension counting. Finally, we propose a one-loop dilatation operator on the intersection, thus providing a direct permutation framework for the $SU(N)$ spectral problem at finite $N$. The computed spectra based on the proposal agree with the prediction from the eigenspace factorisation in the $U(N)$ theory.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Feedback-Conditional 3D Reconstruction of Cosmic Baryons with Flow Matching
Maryam Hussaini, Aizhan Akhmetzhanova, Carolina Cuesta-Lazaro et al. (+1 more)
The complex relationship between
galaxies and diffuse gas at large scales depends strongly on astrophysical feedback and cosmology. The dispersion measure (DM) of Fast
Radio Bursts (FRBs) is a column of
cosmic baryon density and is dominated by the intergalactic medium, which is not necessarily captured by traditional
halo model prescriptions. We introduce a generative model to reconstruct 3D gas density fields from
galaxy surveys, including
redshift space distortions. The probabilistic model is trained on the CAMELS50 simulation suite (IllustrisTNG) and learns to predict the posterior distribution of gas fields conditioned on stellar mass-weighted
galaxy density, cosmological parameters, the minimum stellar mass threshold for the
galaxy sample, and the baryon suppression power spectrum as a measure of baryonic feedback. Our method uses the 3D gas reconstruction to estimate per-sightline FRB DMs and their posteriors. We validate the model on test boxes by showing agreement between predicted and true DM across individual lines of sight and the overall DM distribution. The model generalizes to a box size $\sim$\,4$^3$ times larger in volume than the training boxes and can cover the volumes spanned by cosmological FRB sightlines. The model's 3D gas density predictions vary with input power spectrum and feedback scenarios, offering an inference path to constrain feedback models from FRBs and other probes such as X-rays, the SZ effect, and weak
lensing.
Read the full abstract ▾
All authors Maryam Hussaini, Aizhan Akhmetzhanova, Carolina Cuesta-Lazaro, Liam Connor
Solar and Stellar Astrophysics
Population II Post-AGB Stars. I. Methodology, Initial Results, and the First Luminosity Function
S. Jean Feeser, Robin Ciardullo, Michael H. Siegel et al. (+2 more)
Post-asymptotic giant branch (PAGB)
stars share many advantages with the tip of the red giant branch (TRGB) for Population II distance measurements, including minimal internal reddening, easy identification, a solid theoretical foundation, and an expected weak
metallicity dependence. At visual wavelengths PAGB
stars are the brightest members in old populations, appearing up to $\sim2$ mag brighter than the TRGB and $\sim4$ mag brighter than RR Lyrae
stars. Stellar
evolution theory predicts that these objects occupy a narrow luminosity strip across the top of the Hertzsprung-Russell diagram, making them excellent standard candles. Observations in Galactic globular clusters (GCs) support this prediction, but a comprehensive survey is required to define their luminosity function and test for systematic errors. In this work, we construct a multi-wavelength catalog, spanning the ultraviolet (UV) to infrared (IR), for PAGB
stars in 39 Galactic GCs. We validate cluster membership with Gaia astrometry, identify 21 objects across 16 GCs using ground-based uBVI and space-based UV photometry, and perform
Bayesian spectral energy distribution (SED) fitting with stellar atmosphere models to estimate their effective temperatures, luminosities, and radii. We find that PAGB
stars occupy a narrow luminosity range centered at $\log(L_{\mathrm{bol}}/L_{\odot})=3.25\pm0.03$, with dispersion $\sigma=0.12$ dex, supporting their use as reliable Population II distance indicators. Comparisons with theoretical tracks show excellent agreement with evolutionary models. We confirm that PAGB
stars occur preferentially in metal-poor clusters with blue horizontal branches. Our results demonstrate that PAGB
stars provide a powerful probe of late stellar
evolution and a promising Population II standard candle.
Read the full abstract ▾
All authors S. Jean Feeser, Robin Ciardullo, Michael H. Siegel, C. J. Hapich, Akshat S. Chaturvedi
Mathematical Physics
Finite- and long-range spin-wave free-energy asymptotics for the two-dimensional quantum Heisenberg ferromagnet
Andreas Klippel
For the two-dimensional
quantum Heisenberg ferromagnet with asymptotically radial power-law exchange, we prove the leading low-temperature free energy at every fixed
spin, uniformly on the weak-field scale. We obtain fractional and logarithmically corrected laws associated with the dispersions predicted in [16, 17].
Quantum Monte Carlo simulations support the associated anomalous
magnon dispersions for
spin one-half [20]. For kernels with finite second moment, we also extend the nearest-neighbour
theorem [14], generalizing Takahashi's quadratic law [21] and its weak-field dependence [11].
Read the full abstract ▾
High Energy Physics (Theory)
The hidden sunrise in the energy-energy correlator
Matthew D. Schwartz and Xiaoyuan Zhang
The energy-energy correlator (EEC) is one of a handful of
collider observables that can be computed analytically to high orders. As an energy-weighted cross-section, it exposes features of
quantum field theory that scattering amplitudes do not, and it can be compared directly to data. As with scattering amplitudes, the analytic expressions require special functions beyond polylogarithms. In Henn et al., the EEC was computed to next-to-next-to-leading order (NNLO) for $\mathcal{N}=4$ super Yang-Mills (SYM) theory, and the result is expressed in terms of both harmonic polylogarithms (HPLs) and one two-fold integral, which contains elliptic curves. In this work, we report a complete result including the remaining elliptic sector, which is closely related to the sunrise Feynman integrals. We find the $j$-invariants of the EEC and the sunrise agree identically under a Möbius map, and thus the elliptic sector in the EEC lives on the $\Gamma_1(6)$ modular curve of the sunrise integral. We then express the answer in terms of iterated Eisenstein integrals, which can be evaluated to high precision quickly. The analytic form also allows a first study of the EEC Landau bootstrap, and the understanding of its function space in $\mathcal{N}=4$ SYM offers a concrete handle on the elliptic sector of the EEC in QCD. Many of the technical results in this paper were completed with AI under human supervision.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Hydrodynamic Anomalous Hall Effect in a Two-Dimensional Dirac Fluid
A. Levchenko and D. A. Pesin
In ultraclean conductors, electron-electron collisions can make transport hydrodynamic. In a Berry-curved band, these collisions can also produce two-particle coordinate shifts, which contribute to the anomalous Hall current in the presence of a transport electric field. We develop a kinetic theory of this contribution for a two-dimensional massive Dirac Fermi
liquid with weak contact interactions and weak short-range disorder. The computed response is independent of interaction strength at leading Born order. Its contribution to the anomalous Hall conductivity is comparable to the thermal correction to the intrinsic anomalous Hall conductivity. The existence of the momentum zero mode of the electron-electron collision integral leads to a nontrivial frequency dependence of the anomalous Hall response considered in this work. In particular, the limits of vanishing frequency (dc) and vanishing disorder do not commute. In the dc limit, the momentum response to the transport field grows inversely with the momentum relaxation rate. This allows arbitrarily weak, energy-dependent impurity scattering to produce a finite correction by coupling conserved momentum to the modes relaxed by electron-electron scattering. This correction disappears when the clean limit is taken before the zero-frequency limit. As a result, the interaction-induced Hall response retains information about the mechanism of momentum relaxation even as the overall disorder strength tends to zero.
Read the full abstract ▾
Optics
Propagation-Invariant Transmission Eigenmodes in Weakly Scattering Media
J.C Osorio-Tascon and P. A. Quinto-Su
Propagation-invariant beams (PIBs) with annular angular spectra preserve their transverse intensity structure over extended propagation distances. Here, we investigate whether scattering invariant modes (SIMs) can simultaneously exhibit scattering and propagation invariance. We measure free-space and sample transmission
matrices (TMs) in an orthonormal annular basis for weak, moderate, and strong scattering media and identify localized SIMs (LSIMs) whose angular spectra remain predominantly confined to one or a few neighboring rings. Under weak scattering, 75 of the 128 SIMs considered for annular localization satisfy this criterion, with LSIMs exhibiting Bessel-like propagation. Under moderate scattering, 25 LSIMs are recovered after filtering low-intensity spectral components, whereas none are found under strong scattering. Although increasing modal crosstalk progressively suppresses annular localization and nondiffracting behavior, SIMs retain higher transverse-intensity correlation over propagation than the Gaussian-like and Bessel beams in the moderate and strong regimes. These results show that annular localization enables SIMs to acquire propagation invariance when scattering is weak, whereas the enhanced propagation robustness of SIMs can persist even after this localization is lost.
Read the full abstract ▾
Quantum Physics
Single-shot magic state factories for quantum LDPC codes
Varun Menon, Rohan Mehta, Andi Gu et al. (+8 more)
Quantum low-density parity-check (qLDPC) codes can substantially reduce the
qubit overhead of fault-tolerant
quantum computation, but any useful architecture based on such codes also requires an efficient mechanism to implement non-Clifford gates in a fault-tolerant manner. We introduce a space-time-efficient magic state factory for high-rate qLDPC codes by combining the transversal non-Clifford gates of recently developed tricycle codes with single-shot four-dimensional balanced product quadcycle codes. The key ingredient is an efficient "escape" mechanism that teleports postselected logical magic states from tricycle codes to larger distance quadcycle codes. Under a standard
circuit-level noise model at physical error rate $10^{-3}$, our factories produce $\mathrm{CCZ}$ states at logical error rates as low as $10^{-9}$ with 10-40 times lower space-time cost than state-of-the-art magic state generation methods. The resulting states are directly encoded in high-rate blocks suitable for computation. We identify the quadcycle codes by an AI-assisted search and show that they can serve as excellent
memories capable of single-shot error correction. Finally, we present a concrete implementation of the entire factory with highly efficient atom transport on reconfigurable neutral-atom
quantum computers. Together, these results provide an end-to-end, practical protocol for producing and utilizing high-fidelity magic states within a high-rate qLDPC architecture, with the lowest space-time cost to date.
Read the full abstract ▾
All authors Varun Menon, Rohan Mehta, Andi Gu, Andrei C. Diaconu, Daniel Bochen Tan, Xiao Xiao, Michael J. Gullans, Qian Xu, Hengyun Zhou, Mikhail D. Lukin, J. Pablo Bonilla Ataides
High Energy Physics (Phenomenology)
pyAmpliCol: fast tree-level matrix elements
Rikkert Frederix, Valentin Hirschi, Lucien Huber et al. (+3 more)
Tree-level
matrix elements sit at the heart of
collider event generation, but their cost rises rapidly just where additional resolved radiation becomes most important. We present pyAmpliCol, a public generator aimed at extending the practical reach of colour-resolved
matrix elements to higher multiplicities. It builds on the colour-ordered, off-shell-current strategy of AmpliCol, providing fast access to individual leading-colour flows while retaining the option of next-to-leading or exact full colour. The latter introduces its own high-multiplicity bottleneck: the dense interference of factorially many colour orderings. pyAmpliCol addresses this contraction with a fast
Fourier transform on the symmetric group, preserving the exact colour result while avoiding the direct pairwise sum. Representative full-colour
benchmarks demonstrate substantial speedups over the reference calculations considered here. It supports Standard Model processes and a broad class of UFO models, selected or summed helicities, vectorised evaluation and controllable numerical precision. It further provides colour- and
spin-correlated Born quantities and tree-level colour connections at arbitrary perturbative order, opening the same framework to local subtraction and other higher-order applications. Together, these capabilities connect high-multiplicity
matrix elements to their use in event generation, merging, parton showers and precision calculations within a single generator.
Read the full abstract ▾
All authors Rikkert Frederix, Valentin Hirschi, Lucien Huber, Shahriar Iravanian, Ben Ruijl, Timea Vitos
High Energy Astrophysical Phenomena
Descalarization bursts from Galactic supramassive neutron stars: a kHz continuous-wave target
José Carlos Olvera M., Daniela D. Doneva, Pablo Cerdá-Durán et al. (+2 more)
In massive scalar-tensor
gravity, a scalarized
neutron star must shed its scalar hair as it collapses into a black hole. Using 3D simulations of a realistic rotating progenitor we show that dispersion stretches the emitted burst into a quasi-monochromatic signal in the kHz frequency range lasting $>10^4$ yr and amenable to continuous-wave methods. We find that detecting these signals in directed searches of
supernova remnants without a central
pulsar requires sensitivity depths of 233–762 $\rm{Hz^{-1/2}}$ with the A+-ET-CE detector network. We estimate up to $\sim3$ of these signals in transit at any observational epoch.
Read the full abstract ▾
All authors José Carlos Olvera M., Daniela D. Doneva, Pablo Cerdá-Durán, José A. Font, Stoytcho S. Yazadjiev
Astrophysics of Galaxies
First uGMRT Constraints on Rotation Measure in the Radio-Quiet Seyfert Galaxy NGC 4235
Salmoli Ghosh, Preeti Kharb and Janhavi Baghel
We present a multi-frequency polarimetric study of the
radio-quiet Seyfert
galaxy NGC 4235 using the upgraded Giant Metrewave
Radio Telescope (uGMRT), aimed at constraining the Faraday rotation properties of its kpc-scale
radio emission. This marks the first-ever analysis of polarization across two frequency bands of the uGMRT and the first constraints on rotation measure (RM) at lower frequencies for a weak
radio source (17.1$\pm$1.7 mJy at 1.3 GHz, 27.7$\pm$2.8 mJy at 663 MHz). We detect linearly polarized
radio emission associated with the `core' and the extended lobes of NGC 4235. Broadband polarimetric analysis yields an RM value of {$\sim200$ rad m$^{-2}$} in the `core', indicating Faraday rotation by magnetized
plasma external to the synchrotron-emitting regions. Using these RM constraints, we estimate an average electron density of the Faraday-rotating medium of $\sim$3$\times10^{-2}$ cm$^{-3}$ for a characteristic perturbation scale of $\sim$0.3 parsec within an assumed magnetized region of size $\sim$1.3 kpc, consistent with a diffuse magnetized sheath or AGN-driven wind. These results extend classical Faraday rotation diagnostics to the low-power,
radio-quiet AGN regime and demonstrate the potential of uGMRT broadband polarimetry for probing magnetized environments in and around such AGN.
Read the full abstract ▾
Materials Science
Resolving the interfacial mechanical landscape of monolayer NbSe2 grown by confined epitaxy
Ye Wang
Confined epitaxy has recently emerged as a novel methodology for controlled growth of high-quality monolayer two-dimensional (2D) materials. However, mechanistic understanding remains limited to analysing
nucleus adsorption and
diffusion barriers. Here, I discover that van der Waals (vdW) confinement not only affects the specific adsorption and
diffusion of
nuclei on confined substrates but also induces strong coupling to atomic forces at the interface. Using artificial intelligence (AI) assisted density functional theory (DFT) calculations, I study how vdW confinement couples to the atomic motion of monolayer NbSe2 grown between c-plane sapphire and hexagonal boron nitride (h-BN). The calculated force-electronic landscape yields large mechanical forces of +0.070 and -0.04 eV per Angstrom on Nb and Se, respectively, giving rise to a unit-
cell interfacial interaction energy up to 2.4 eV, comparable to reported adsorption and
diffusion energies on similar substrates. The results indicate that interfacial mechanics may explain the success of confined epitaxy. The findings suggest that tuning interfacial mechanics, and related vdW mechanochemistry, could be a promising route to high-throughput, high-quality materials synthesis.
Read the full abstract ▾
High Energy Physics (Theory)
Surface defects in $\mathcal{N}=4$ Super Yang-Mills: exact results and holographic bootstrap
Lorenzo Bianchi, Davide Bonomi, Maddalena Ferragatta et al. (+1 more)
We study two-point functions of chiral primary operators in $\mathcal{N}=4$ Super Yang-Mills in the presence of a half-BPS surface defect. Such a defect preserves only the diagonal combination of transverse rotations and of a global U(1) R-
symmetry, so that the correlator depends on one additional cross-ratio and splits into sectors of definite angular charge. We solve the superconformal Ward identities and construct the bulk and defect superconformal blocks in all sectors, including the charged ones, which have no analogue for defects preserving transverse rotations. The solution contains a holomorphic sector, which we fix non-perturbatively by mapping it to a chiral
algebra correlator. We extend this map to defects breaking transverse rotations, where it requires a redefinition of the modes of the two-dimensional current
algebra, and use it to fix the charged sectors as well. We then use the defect dispersion relation to reconstruct the full correlator of the dimension-two chiral primary at leading order at large N and strong coupling. In the charged sectors long multiplets are absent and the answer is conjecturally exact in both N and the coupling; expanding it at weak coupling, we find perfect agreement with known results. From these correlators we extract infinitely many new pieces of defect CFT data. Finally, we reproduce the strong-coupling answer by an independent Witten diagram bootstrap on the rotation-invariant locus.
Read the full abstract ▾
All authors Lorenzo Bianchi, Davide Bonomi, Maddalena Ferragatta, Valentina Forini
Astrophysics of Galaxies
NGC 4936: abundant multi-phase medium in the central weak X-ray cool core and optically dark H I clouds in the group
Prathamesh Tamhane, Ming Sun, Hao Chen et al. (+6 more)
We present a multiwavelength analysis of NGC 4936, the central
galaxy of a weak cool-core group hosting an unusually large cold/warm gas reservoir. NGC 4936 contains $\sim2\times10^8$ M$_\odot$ of molecular gas in a rotating disk of radius $\sim1$ kpc, but no detected H I, with a $3\sigma$ upper limit of $1.13\times10^7$ M$_\odot$ within $\sim2.5$ kpc. The resulting $H_2$/H I mass ratio $>17$ is consistent with a predominantly molecular medium in the high-pressure environments of central
galaxies. SOAR imaging and MUSE spectroscopy reveal ionised gas extending to $\sim15$ kpc in a complex filamentary morphology that broadly follows the molecular gas kinematics while extending well beyond the CO disk. Dust filaments similarly extend to $\sim14$ kpc and appear to interact with a companion
galaxy located only $\sim2.5$ kpc away in projection. NGC 4936 has a
star formation rate of $0.29$ M$_\odot$ yr$^{-1}$, and its AGN shows sub-mm and X-ray variability. We favour atmospheric condensation as the primary origin of the molecular gas, although externally acquired gas may contribute. Our recalculated thermodynamic profiles reach $t_{\rm cool}/t_{\rm ff}\sim25$ in the innermost region, placing the system near the threshold for multiphase condensation. The ongoing interaction may perturb the atmosphere and promote condensation while shaping the morphology and kinematics of the multiphase medium, rather than directly supplying most of the central cold gas. We additionally detect 20 H I structures in the surrounding group environment, with masses of $\sim10^7$–$10^8$ M$_\odot$, including several with no obvious optical counterparts.
Read the full abstract ▾
All authors Prathamesh Tamhane, Ming Sun, Hao Chen, Thomas Connor, Megan Donahue, Mark Voit, Mpati Ramatsoku, Kokoro Hosogi, Tim Edge
Astrophysics of Galaxies
Prevalence of radio Active Galactic Nuclei in galaxy groups since z=3.5 in the COSMOS-Web field
F. Ubertosi, I. Delvecchio, I. Prandoni et al. (+30 more)
Radio active galactic
nuclei (AGN) are key tracers of kinetic feedback from supermassive black holes. Although the dependence of their triggering on host stellar mass is well known, the impact of the large-scale environment across
cosmic time is poorly understood. We investigate the role of the environment in triggering
radio AGN activity, while also studying the dependence on stellar mass ($10\leq\log M_{\ast}\,{\rm [M_{\odot}]}\leq11.4$),
radio luminosity ($22\leq\log L_{1.4}\,{\rm [W\,Hz^{-1}]}\leq26$), and
redshift ($0.1\leq z \leq 3.5$). We combine the VLA-COSMOS 3 GHz Large Project with the COSMOS-Web
galaxy and group catalogs, selecting
radio-excess AGN and building
radio luminosity functions (RLF) and
radio AGN fractions separately for sources in
galaxy groups (124
radio AGN) and in the field (405
radio AGN), out of the total of 20203
galaxies and 1678
galaxy groups. We fit the RLF to derive the
cosmic evolution of
radio AGN in different environments, and we provide a new parametric description of the
radio AGN fractions as a function of environment, $M_{\ast}$, $L_{1.4}$, and z. Besides confirming the known positive correlation of
radio AGN fraction with host $M_{\ast}$ in both groups and in the field, more importantly we find that the activation of a
radio AGN in groups is enhanced relative to the field by a factor of 3–30 in space density and of 2 in
radio AGN fraction at fixed stellar mass; the enhancement is also a function of $M_{\ast}$, $L_{1.4}$, and z. Furthermore, in all z bins, the
radio AGN fractions peak within $r \leq 0.2R_{200}$. Overall, dense environments enhance
radio AGN triggering out to at least z=3.5. We suggest the existence of a possible transition in the dominant triggering mechanism of
radio AGN activity around z~1.5, potentially related to the intragroup medium in the core of groups at lower z and to merger and structure growth at earlier
cosmic times.
Read the full abstract ▾
All authors F. Ubertosi, I. Delvecchio, I. Prandoni, G. Toni, G. Zamorani, E. Daddi, M. Gitti, M. Sargent, A. Traina, C. Spingola, F. Vito, L. Moscardini, G. Gozaliasl, D. Kakkad, W. Wang, S. Sanjaripour, Z. Ghaffari, M. N. Isla Llave, R. M. Samir, G. Peluso, M. Maturi, V. Smolcic, C. Casey, J. Kartaltepe, H. J. McCracken, J. Rhodes, B. Robertson, M. Franco, D. Liu, M. Shuntov, H. Akins, O. Ilbert, A. A. Khostovan
High Energy Physics (Phenomenology)
The Silence of the Dipoles: Accidental Symmetries in Lepton Flavor
Andrea Di Lecce, Majid Ekhterachian, Marko Pesut et al. (+1 more)
Upcoming experiments are set to dramatically improve the search for charged lepton flavor violation, with the sensitivity to the rates of $\mu\to eee$ decay and $\mu N\to eN$ conversion expected to improve by four orders of magnitude in the near future. We study how these measurements reshape our understanding of fundamental interactions and their implications for the
Higgs hierarchy problem. We consider the framework of Strongly Interacting Light
Higgs with partial compositeness. In generic models of partial compositeness, the existing constraints from $\mu\to e\gamma$ and the electric dipole moment (EDM) of the electron require the scale of
Higgs compositeness to be above $\sim\mathcal{O}(100)$ TeV. These mass scales lie beyond the direct reach of the LHC and envisioned future
colliders and are comparable to, or higher than, those accessible to future $\mu\to3e$ and $\mu N\to eN$ searches. We show, however, that models where the strongly coupled sector has an accidental $U(3)\times\mathrm{CP}$ or $U(2)\times U(1) \times\mathrm{CP}$
symmetry, broken by the elementary–composite mixings, can substantially relax these constraints. In the $U(3)$ case, these
symmetries (1) lead to an accidental
alignment of the Yukawa and dipole couplings at leading order, suppressing $\mu\to e\gamma$ and the electron EDM, allowing the compositeness scale to lie in the few-TeV range; (2) are probed by the upcoming $\mu\to eee$ and $\mu N\to eN$ experiments; and (3) provide a direct target for current and future
collider experiments. In the $U(2)\times U(1)$ case, $\mu\to e\gamma$ and the electron EDM remain important constraints, while upcoming searches for $\mu\to eee$, $\mu N\to eN$ and flavor-violating $\tau$ decays provide complementary probes. We discuss how these accidental
symmetries can arise in the infrared compatibly with the dynamical generation of flavor hierarchies in the ultraviolet.
Read the full abstract ▾
All authors Andrea Di Lecce, Majid Ekhterachian, Marko Pesut, Stefan Stelzl