High Energy Physics (Theory)
Spread Complexity for Local Operator Quenches with Conserved Momentum
Ali Fatemiabhari
We study a family of locally excited states in two-dimensional conformal field theories in different setups, defined on the plane, on the cylinder, or at finite temperature. These states are constructed by assigning independent
chiral and anti-
chiral regulators to a local primary operator, leading to excitations carrying net momentum. We analytically calculate the first few Lanczos coefficients and the early time behaviour of the spread complexity associated with these states. Then, using numerical methods, we obtain the coefficients reaching larger Krylov indices and find the associated spread complexity for a longer range of time
evolution. We also compare the rate of change of the resulting spread complexity with the proposed
holographic dual quantity, related to the proper momentum of an infalling particle in the dual bulk, but we observe a mismatch.
Read the full abstract ▾
High Energy Physics (Theory)
Quantum vacuum interaction between semitransparent plates in a Pöschl-Teller background: an exact relative TGTG formula
Jose M. Muñoz-Castañeda, Inés Cavero-Peláez and Gonzalo Sancho-Garrido
We derive an exact background-dressed TGTG formula for the one-loop
quantum vacuum inter- action between two semitransparent Dirac-delta plates in the one-
soliton Pöchl-Teller background. The interaction is defined through a relative determinant in which the two isolated one-plate contributions are subtracted in the same background. As a result, the energy depends on the individual plate positions as well as on their separation. For repulsive plates, the normalizable zero mode does not induce an infrared divergence in the relative interaction energy. We also extend the construction to planar plates and analyze the corresponding position-dependent interaction forces.
Read the full abstract ▾
Atomic Physics
Systematic errors from scalar slowing-down models in transient SERF magnetometry
Marek Kopciuch, Harini Raghavan and Morgan W. Mitchell
Reduced Bloch models of
spin-exchange-relaxation-free (SERF) magnetometers commonly describe the coupled electron–
nuclear spin dynamics using a single
nuclear slowing-down factor. We show that this scalar description becomes inaccurate when the polarization magnitude changes appreciably. We derive an effective Bloch equation with separate longitudinal and transverse slowing-down factors, $q_\parallel(P)$ and $q_\perp(P)$, governing changes in polarization magnitude and direction. For $^{87}\mathrm{Rb}$ under representative SERF conditions and undergoing free-induction decay (FID), comparison with master-equation simulations shows that the dynamic scalar model produces a
magnetic-field estimation bias of up to $4.2\%$ at high initial polarization, while fixing the slowing-down factor at a reference value increases the error to $10.1\%$. Lowering the polarization suppresses this bias but also reduces the
magnetic-field information contained in the FID signal. We further show that the anisotropic response modifies noncollinear optical pumping and introduces an additional nonlinear contribution to the harmonic response under periodic driving. The resulting model retains the simplicity of a three-component Bloch description while improving the quantitative accuracy of transient and driven SERF magnetometry.
Read the full abstract ▾
Networking
AirLog: Store-Level Indoor Life Logging Made Easy
Zihui Yun, Jiaying Du, Yue Yu et al. (+4 more)
This paper presents AirLog, a smartphone-based life journaling system that automatically reconstructs users' store visits in shopping malls and summarizes them into human-readable journals. Unlike conventional indoor localization systems, AirLog avoids labor-intensive
radio-map construction and dedicated wireless localization infrastructure and
algorithm calibrations. Instead, it repurposes two cues already available in commercial spaces: semantic information exposed by ambient Wi-Fi SSIDs and indoor directory images. AirLog converts directory images into spatial maps and fuses Wi-Fi semantic anchors with inertial dead reckoning to recover store-level trajectories, which are then summarized into journals by an LLM. Such store-level life logs can support applications such as personal
memory recall, activity reflection, and automated diary generation without requiring users to manually record where they have been. We implement AirLog on commodity smartphones and evaluate it on both a large-scale public
dataset and a self-collected
dataset. The results demonstrate that AirLog substantially improves store-level region recovery, semantic matching, trajectory reconstruction, and journal quality over existing baselines. A human evaluation further shows that the generated journals are coherent and faithful to users' visits.
Read the full abstract ▾
All authors Zihui Yun, Jiaying Du, Yue Yu, Zhewei Liu, Zhen Xiang, Longfei Shangguan, Zhenlin An
Quantum Physics
Indefinite causal order with output-signalling instruments
Ricardo Silveira, Patrick Andriolo, Davide Poderini et al. (+2 more)
Quantum processes can exhibit indefinite causal order, allowing coherent superpositions of distinct orderings of events. Whether such processes generate genuinely noncausal statistics, however, depends not only on their global causal structure but also on the local operations available to the parties. Here, we restrict communication to the classical outcomes of local operations, yielding a causal polytope with new causal inequalities that can be violated using measure-and-reprepare,
entanglement-breaking instruments requiring no coherent transmission through the laboratories. Using a semidefinite-programming framework, we bound the achievable violations and reveal noncausal correlations that satisfy all conventional input-signalling inequalities, demonstrating that restricting the information available for communication can uncover forms of indefinite causal order inaccessible under less restrictive operational assumptions.
Read the full abstract ▾
All authors Ricardo Silveira, Patrick Andriolo, Davide Poderini, Dmitry Melnikov, Rafael Chaves
High Energy Physics (Phenomenology)
Prompting Particle Physics: Tokenized Multi-modal Foundation Models for Combinatorially Many Tasks
Nilotpal Kakati, Daniel Murnane, Baran Hashemi et al. (+5 more)
Reconstruction and simulation at a
collider experiment are long chains of specialised
algorithms, each tuned to a single step. We explore how one model can serve many of those steps at once, while still producing the intermediate objects (tracks, calorimeter
cells, clusters, particles and jets) that make the chain interpretable. To do so, we represent every object in a jet in a single shared
token vocabulary and train one model to map any subset of these modalities to any other. A task is then only a choice of which modalities to provide and which to request: particle flow, detector simulation and charged energy subtraction are all directions through the same set of weights. We train over all modality combinations, with a decoder emitting
tokens either autoregressively or in parallel. With tokenisation, both architectures train stably with little tuning. In evaluations, both models produce realistic reconstruction and simulation objects, with the autoregressive model particularly faithful to output from Geant4. The autoregressive model also outperforms a state-of-the-art particle flow
algorithm on many typical jet reconstruction metrics.
Read the full abstract ▾
All authors Nilotpal Kakati, Daniel Murnane, Baran Hashemi, Samuel Klein, Jeffrey Krupa, Eilam Gross, Lukas Heinrich, Michael Kagan
Group Theory
Infinitely many finite simple groups of Lie type are not generated invariably by two elements of prime order
Robert M. Guralnick, John Shareshian and Russ Woodroofe
We show that there are infinitely many k for which Sp_{2k}(2) is not generated invariably by two elements of
prime order.
Soft Condensed Matter
Mechanical Clustering of Cells via the ExtraCellular Matrix
Ran Glinowiecki, Shahar Goren, Oren Tchaicheeyan et al. (+4 more)
Tissues are composites of living
cells and extracellular
matrix (ECM), that jointly determine their unique mechanical behavior. Here, we experimentally demonstrate that contractile
cells remodel the ECM by generating long-range bands of aligned and densified fibers that mechanically couple
cells into multicellular clusters. Using a finite-element model, we quantify the collective mechanical interactions mediated by these ECM bands for various volume fractions of
cells. The model incorporates contractile particles that mimic
cell-active forces within a nonlinear biological gel, inducing stiffening internally rather than through external loading. We find that even a small volume fraction of contractile particles (approximately 10%), much below what is expected for percolation of sphere contacts, leads to internal stiffening, mediated by the high-concentrated stress bands between
cells and is strongly dependent on the nonlinear mechanical response of the ECM. Percolation analysis of the band network reveals sharp transitions at a critical particle volume fraction, that aligns with the onset of internal stiffening. These results demonstrate that long-range interaction between contractile
cells through the deformation of the medium has the potential to globally shape the structure and mechanics of the bulk gel, leading to a functional structure with modified properties. These modified macroscopic changes can define organizing principles in tissue patterning and morphogenesis.
Read the full abstract ▾
All authors Ran Glinowiecki, Shahar Goren, Oren Tchaicheeyan, Bar Ergaz, Robin L. B. Selinger, Yair Shokef, Ayelet Lesman
Earth and Planetary Astrophysics
Variable X-ray flux may explain variable helium escape from the habitable-zone exoplanet LHS 1140b
Collin Cherubim, Tim Cunningham and Jason A. Dittmann
A central goal in
exoplanet science is to understand the conditions under which potentially habitable worlds retain atmospheres. This question is of special interest for worlds orbiting M
stars, whose habitable-zone
planets are more readily observable, but which also emit prolonged high-energy radiation that can erode planetary atmospheres. For one such world, LHS 1140b, a rocky
planet orbiting in the habitable zone of an inactive
star, time-variable helium absorption has been observed as the
planet transited in front of its host
star, consistent with atmospheric escape. We present X-ray/ultraviolet flux observations with the XMM-Newton space
telescope, which serve to test whether the observed helium absorption variability can be explained by
stellar XUV flux variability. We detect X-ray flux variability with an amplitude of $F_\mathrm{max}/F_\mathrm{min} = 8.5^{+9.4}_{-4.4}$ within the 18-hour observing window. We do not detect variability in the UV or visible flux. The integrated X-ray flux is fully consistent with the X-ray flux measured in 2018, suggesting stable XUV flux over years-long timescales. We find that the 2018 observation was not sensitive to the level of variability observed in 2026. We explore several models that fit both
datasets and conclude that short-term XUV variability and/or small
flares are more likely to explain the helium variability than long-term XUV variability. Simultaneous observations of the
planet-transit in the near-infrared and
stellar activity indicators like XUV flux are critical to confirm the link between the observed helium signal variability and the observed X-ray variability.
Read the full abstract ▾
Mathematical Physics
Locality of KMS states for infinite fermionic lattice systems
Lennart Becker
We study how thermal
equilibrium states of infinite fermionic
lattices respond to perturbations of the
Hamiltonian. Our main result concerns extensive perturbations of a chosen KMS state. We show that exponential decay of correlations and exponential local indistinguishability under the extensive perturbation yield stretched-exponential decay of correlations for the perturbed state. Neither the initial nor the perturbed state is required to be unique, allowing stability to be studied in the presence of phase coexistence. Our approach uses
Quantum Belief Propagation (QBP), which we establish directly on the underlying $C^*$-
algebra. Combining QBP with Lieb–Robinson bounds, we show implications between decay of correlations, the principle that local perturbations perturb locally, and local indistinguishability, closing the cycle for perturbations of the tracial state under the stated decay, support and uniformity assumptions. For extensive perturbations under uniform clustering conditions, we also obtain a differentiable path of local
equilibrium expectations and bound their change linearly in the interaction norm of the perturbation.
Read the full abstract ▾
Artificial Intelligence
LLM Judge Validation Under Sparse Overlap: From Inference to Design
Junxuan Li, Arko Mukherjee and Soumyabrata Pal
Validating an LLM-as-a-judge requires estimating its agreement with humans, yet annotation budgets rarely allow every item to be multiply labeled. We prove that this overlap sparsity is the first-order determinant of wrong deployment decisions: at 5% pairwise overlap, wrong-decision rates reach 25% and the probability of selecting the wrong best judge among ten candidates is 65%. The two actionable levers are overlap quantity and allocation. For quantity, we derive a minimum-overlap formula showing $\rho \geq 0.25$ suffices for non-borderline judges while borderline cases remain fundamentally hard. For allocation, a zero-cost stratified scheme halves false-rejection rates relative to random sampling when strata are informative. We validate on 10 LLM judges across four evaluation
matrices spanning visual assessment, causal
reasoning, and summarization.
Read the full abstract ▾
Analysis of PDEs
Eigenfunction asymptotics and nodal domain estimates for dumbbell domains
Thomas Beck, Yaiza Canzani and Jeremy L. Marzuola
We study the nodal structure of Neumann eigenfunctions on planar dumbbell domains as the width of the neck joining two fixed end domains tends to zero. Under simplicity and non-degeneracy assumptions, we show that sufficiently thin necks force an increasing number of nodal domains as the limiting
eigenvalue grows. At the bottom of the spectrum this forcing can attain Courant's upper bound: in particular, the third Neumann eigenfunction has exactly three nodal domains and is Courant sharp. At the same time, nodal deficiency of an eigenfunction on an end domain can persist on the full dumbbell, giving eigenfunctions that are not Courant sharp. The main analytic difficulty is that the singular limit may vanish on one or both end domains even though these regions contribute nodal domains for every positive neck width. We overcome this by deriving refined asymptotics for the first nonzero profiles on the vanishing regions, expressed through Neumann Green's functions with poles at the neck attachment points and obtained by a two-dimensional matched asymptotic analysis with logarithmic terms.
Read the full abstract ▾
Robotics
PHIRL: Aligning Learned Rewards with Task Progress for Inverse Reinforcement Learning
Hang Yu, James Staley, Cheng Xi Tsou et al. (+8 more)
Human demonstrations provide dense policy-level information but sometimes lack local precision. Human feedback presents accurate local critiques, but offers sparse evaluations rather than direct policy guidance. We propose Progress-Heuristicized Inverse Reinforcement Learning (PHIRL), a data-efficient framework that learns robust reward functions by jointly leveraging demonstrations and feedback. Specifically, we use progress, a feedback modality that describes cumulative task completion. PHIRL iteratively infers a reward function from demonstrations via inverse reinforcement learning, calculates the learned rewards over the progress-annotated demonstrations, and aligns the rewards with progress annotations over four dimensions. We evaluate PHIRL on real and simulated
robot tasks, with additional exploration using a fine-tuned
vision-
language model to provide progress feedback. Results demonstrate that PHIRL significantly outperforms the baselines, achieving substantially higher environmental return rewards and task success with only twenty percent of demonstrations annotated. Analysis of reward-hacking scenarios demonstrates that PHIRL learned reward functions are reliable against exploitation.
Read the full abstract ▾
All authors Hang Yu, James Staley, Cheng Xi Tsou, Xiujin Liu, Wenchang Gao, Jindan Huang, Shijie Fang, Zhegong Shangguan, Angelo Cangelosi, Reuben Aronson, Elaine Short
Systems and Control
An Exact Lyapunov Characterization of Regional Rate Performance for Rational Stability
Declan S. Jagt and Matthew M. Peet
Rational stability is a quantitative stability notion for nonlinear ordinary differential equations (ODEs), under which convergence is characterized by a rationally-in-time decaying bound on solutions. Although Lyapunov characterizations of rational stability have been proposed, no existing condition has been shown to exactly characterize rational rate performance. The paper resolves this issue by providing an exact converse Lyapunov characterization of regional rational stability with prescribed rate performance. To test the resulting converse Lyapunov conditions numerically, a tiered set of convex relaxations is proposed which can be enforced using Sum-of-Squares (SOS) programming. A conjectured conservatism scaling factor in rate performance is associated with each tier and validated numerically. The first proposed tier appears to be novel and is shown to outperform classical SOS-based approaches. Numerical examples are used to validate the results and compute nested regions of state-space on which prescribed levels of performance can be guaranteed.
Read the full abstract ▾
Quantum Physics
Quantum Fisher Information as the Speed Limit for Multipartite Entanglement
Zain H. Saleem, Da-Wei Luo, Anjala M. Babu et al. (+3 more)
We derive a universal upper bound on the speed of multipartite
entanglement generation. For arbitrary differentiable pure multipartite states undergoing parameter-dependent
evolution, we prove that the rate of change of generalized concurrence is bounded by the square root of the
quantum Fisher information (QFI). The proof follows directly from the symmetric logarithmic derivative formalism, revealing the bound as a consequence of
quantum estimation theory, while a complementary Schmidt-spectrum analysis identifies the conditions for saturation and yields a tighter bound for rank-two bipartitions. We illustrate these results in interacting many-body
spin models and investigate their behavior across the
quantum phase transition of the transverse-field Ising model. At the critical point, we find that the QFI can be strongly enhanced while the generalized concurrence is nearly stationary and its sensitivity to the coupling is suppressed. This demonstrates that the enhanced parameter sensitivity associated with
quantum criticality need not arise from rapid changes in the magnitude of multipartite
entanglement.
Read the full abstract ▾
All authors Zain H. Saleem, Da-Wei Luo, Anjala M. Babu, Ting Yu, Stephen K. Gray, Anil Shaji
Cosmology and Nongalactic Astrophysics
Observational Evidence of Velocity Anisotropy Assembly Bias in Galaxy Clusters
Facundo Rodriguez, Andrea Biviano, Ravi K. Sheth et al. (+2 more)
Cosmological simulations show that
halo clustering depends on secondary internal properties beyond mass, an effect known as assembly bias. In particular, numerical models have shown that internal velocity anisotropy ($\beta$) is the
halo property most tightly linked to secondary
halo bias: at fixed mass,
haloes with isotropic velocity profiles are more strongly clustered, whereas
haloes in which radial motions dominate are more weakly clustered. Despite this robust theoretical prediction, direct observational detection of velocity anisotropy assembly bias has remained elusive. Here we present observational evidence for this effect using a sample of massive
galaxy clusters from the eROSITA and DESI surveys. We measure the internal orbital anisotropy $\beta$ for 91 clusters via Jeans dynamical modelling with MAMPOSSt, considering three anisotropy profile models to ensure robustness. We divided the sample into two subpopulations: isotropic and radially anisotropic, verifying that they show no significant differences in
halo mass. To quantify their large-scale clustering, we measured the projected cross-correlation function with We report evidence of velocity anisotropy assembly bias: clusters with isotropic internal kinematics exhibit stronger clustering than radially dominated ones, a segregation that is unlikely to be attributable to residual differences in cluster mass. This trend shows varying significance across three anisotropy profiles, from a mild tendency to a highly pronounced signal. Furthermore, the assembly bias remains distinct when restricting the sample to clusters consistently classified across all three models.
Read the full abstract ▾
All authors Facundo Rodriguez, Andrea Biviano, Ravi K. Sheth, Antonio D. Montero-Dorta, Manuel Merchán
Distributed Computing
IceCube Takes Flight with Pelican - A First Experience
David Schultz and Maclean Mansfield-Parisi
The IceCube
Neutrino Observatory has removed GridFTP and x.509 certificate authentication for data transfers, migrating to the Pelican Platform, the Open Science Data Federation, and WLGC
tokens. While this is a common solution on the computing infrastructure we use, we required several customizations to work with our existing data storage structure and make it easier for scientists to use. We wrote a custom WLCG
token issuer to support our POSIX filesystem with custom user and group permissions across the entire filesystem. We also made several modifications to HTCondor to ease job submission using
tokens, including a custom credmon. After an initially bumpy transition due to several now-resolved Pelican issues, the Pelican-based system has already proven superior to GridFTP in several ways.
Read the full abstract ▾
High Energy Physics (Phenomenology)
Milky Way White Dwarfs as Inelastic Dark Matter Detectors
Javier F. Acevedo
We show that white
dwarfs in the
Galactic Center are a sensitive probe of inelastic dark matter (IDM) annihilation. IDM particles traversing a white
dwarf may become gravitationally captured without fully settling in its interior if their energy drops below the kinematic threshold for inelastic scattering. In this regime, a fraction of the incoming particles remains bound on long-lived orbits that extend beyond the white
dwarf's volume, enabling annihilation to partially proceed outside of the object. Some of the annihilation products subsequently escape, rather than being absorbed by the
stellar material, producing a potentially detectable signal. We estimate the collective gamma-ray flux from the external annihilation sourced by these systems, as a function of the IDM parameters, and compare it to H.E.S.S. observations within the central degree of the
galaxy. From this comparison, we derive tentative limits on the IDM scattering cross-section at the TeV mass scale, under largely conservative assumptions for the IDM density in this region. As a concrete application, we map these results into specific parameter constraints for dark
photon-mediated and higgsino models with mass splittings at the MeV scale.
Read the full abstract ▾
Game Theory
Fair and Efficient Allocations: Decision Problems in the Gap of Polynomial Hierarchy
Xiaolin Bu and Biaoshuai Tao
We consider the fair division problem with indivisible goods and study the following decision problem: given a fair division instance, does there exist an allocation that is envy-free and efficient? We consider two efficiency criteria: Pareto-optimality and social welfare optimality. We provide a complete landscape on the computational complexity of this decision problem, with the number of
agents ranging from $2$ to $\infty$, both additive valuations and general valuations, and the more restricted class of $k$-ary valuation functions (where an item's marginal value is restricted to $\{0,1,\ldots,k-1\}$ for some constant $k\geq2$). One interesting observation is that many versions of the above-mentioned decision problems fall into the “gap” between the first and the second levels of the
polynomial hierarchy. Specifically, assuming the
polynomial hierarchy does not collapse to the first level (i.e., assuming $\text{NP}\neq\text{coNP}$), these problems are in $(\Sigma_2^{\text{p}}\cap\Pi_2^{\text{p}})\setminus(\text{NP}\cup\text{coNP})$. In particular, we provide a fine-grained complexity analysis across different parameter regimes, including the number of
agents and the choice of valuation models. Depending on different parameters, many problems admit different complexity classifications, ranging from the intermediate classes $\Theta_2^{\text{p}}$ and $\Delta_2^{\text{p}}$ between the two levels to $\Sigma_2^{\text{p}}$-completeness. Finally, De Keijzer et al. show the $\Sigma_2^{\text{p}}$-completeness of the decision problem when considering Pareto-optimality as the efficiency criterion with additive valuations. Our main results extend this result to more restricted settings, such as instances with a constant number of
agents or $3$-ary valuation functions, which resolves the open problem given by Bouveret and Lang.
Read the full abstract ▾
Machine Learning
Averaged Mirror Descent and Dual Gradient Methods: Convergent Algorithms for Entropic Gromov-Wasserstein Problems
Joanna Marks, Gabriel Rioux and Riccardo Passeggeri
The Gromov-Wasserstein (GW) distance measures the discrepancy between metric measure (mm) spaces and identifies optimal
alignments between them based solely on their intrinsic structure. Since it identifies isomorphic mm spaces, it provides a natural notion of distance for heterogeneous
datasets which may admit isomorphic representations. In order to accelerate computation of GW distances, many practitioners employ entropic regularization to obtain an Entropic GW (EGW) problem. The most popular EGW solver is the Mirror Descent (MD)
algorithm, which reduces EGW computations to an iterative process where an entropic optimal transport (EOT) problem is solved at each iteration. Despite its widespread use, the convergence of MD for this problem has only been established for restricted classes of costs. On the other hand, a recently proposed dual gradient method is available for general costs, but requires a choice of step size which depends on the regularization parameter. To address these two issues, we introduce Averaged Mirror Descent (AMD), which averages consecutive MD steps, and prove its convergence for arbitrary costs. Then, we establish that the dual gradient method with a fixed step size also converges for arbitrary costs at the cost of a more complicated iteration. In both cases, we also account for inexact iterations which are inescapable in practice. We compare the empirical performance of these methods across various settings and, in particular, show that AMD and the dual gradient method both converge on an example where classical MD fails.
Read the full abstract ▾
Computation and Language
Omni-IO Skills: Harnessing Your Agent Omni-Native
Yanlin Li, Mingyang Hao, Shengqiong Wu et al. (+3 more)
General-purpose
agents can plan, reason, and act over long horizons, yet their production capabilities remain fragmented across text, images, audio,
video, documents, 3D assets, and code. Extending a foundation model to additional modalities ties capability growth to costly model updates, while assembling specialist models and tools leaves unresolved how procedures, dependencies, intermediate assets, and cross-turn revisions should be coordinated. We present Omni-IO Skills, a plug-and-play
Agent Harness that makes existing
agents omni-native through hierarchical Skills, a standardized
multimodal execution interface, dependency-aware orchestration, and a persistent Asset Registry. Multi-asset workflows are represented as Declare Execution Graphs, which schedule independent operations concurrently and register successful outputs for downstream and cross-turn reuse across replaceable execution backends. Its 27 Skills cover 38 representative tasks spanning seven artifact modalities and four capability families: understanding, generation,
reasoning, and
retrieval. On UniM-90, the harness raises the input-support rates of GPT-5.6 Sol and Claude Sonnet 5 from 40.00% and 38.89% to 100%, while increasing relative Semantic–Quality Coupled Score from 26.99 to 74.94 and from 27.82 to 77.78, respectively; Strict Structure Score reaches 100.00 and 99.78. These results establish harness-level capability composition as a practical route to broad, evolvable Omni systems without changing the host
agent's
reasoning core.
Read the full abstract ▾
All authors Yanlin Li, Mingyang Hao, Shengqiong Wu, Hao Fei, Mong-Li Lee, Wynne Hsu
Strongly Correlated Electrons
Read-Rezayi fractional Chern insulators in modulated Bernal graphene
Ruth Mora-Soto, André Grossi Fonseca, Raul Perea-Causin et al. (+3 more)
Fibonacci anyons provide a universal platform for topological
quantum computation, and emerge as low-energy excitations in the $\mathbb{Z}_3$ Read-Rezayi phase in the fractional
quantum Hall effect. However, realistic microscopic realizations of this phase in the absence of a
magnetic field have remained elusive. We study a model of periodically modulated Bernal
bilayer graphene with gate-screened Coulomb interactions. Using the recently developed target-phase optimization method in conjunction with band-projected exact diagonalization, we identify at filling $\nu=3/5$ a region of parameter space whose ground state is consistent with a Read-Rezayi fractional Chern
insulator. The partially filled band from which it arises is a part of a two-band complex which mimics
geometric aspects of the lowest and first Landau levels, with the ground state at $\nu=1/2$ consistent with the Moore-Read state. Our results suggest that modulated Bernal
graphene can realize delicate non-Abelian fractional
quantum Hall states at zero
magnetic field, while demonstrating target-phase optimization as a practical route to discovering such phases in realistic, high-dimensional microscopic models.
Read the full abstract ▾
All authors Ruth Mora-Soto, André Grossi Fonseca, Raul Perea-Causin, Hui Liu, Emil J. Bergholtz, Marin Soljačić
High Energy Physics (Theory)
Nonlinear electroweak sphaleron clouds around Kerr black holes
Carlos Herdeiro, Jutta Kunz, Hendrik Mennenga et al. (+1 more)
Kerr black holes and electroweak sphalerons are remarkable solutions of two pillars of modern physics: General Relativity and the Standard Model of particle physics, respectively. In this work, we investigate their interplay by constructing nonlinear sphaleron clouds around Schwarzschild and Kerr black holes in the probe limit. We first revisit static and spinning (multi-)sphalerons in flat spacetime, using the measured electroweak parameters. We then explore the domain of existence and physical properties of the corresponding black-hole configurations, revealing a rich branch structure. Remarkably, the sphaleron clouds retain a finite mass gap and do not approach linear clouds within the families studied, distinguishing them from the familiar clouds associated with the onset of superradiant instabilities. We also obtain a closed-form leading-order
Higgs solution on an exact Yang-Mills configuration in a Schwarzschild background.
Read the full abstract ▾
All authors Carlos Herdeiro, Jutta Kunz, Hendrik Mennenga, Eugen Radu
Solar and Stellar Astrophysics
Probing the Nature of the Circumstellar Material Surrounding SN 2024ggi: A Search for Precursor Emission and Constraints from Radio Observations
Tobias Géron, James K. Leung, Maria R. Drout et al. (+8 more)
We present an analysis of the pre-explosion optical light curve and post-explosion
radio observations of the nearby
supernova (SN) 2024ggi, a Type II SN discovered in NGC 3621 at a distance of ~7.2 Mpc. Early spectra confirmed that SN 2024ggi showed “IIn-like” features, suggesting the presence of dense circumstellar material (CSM). We searched for precursor emission in the light curve up to 8 years pre-explosion from ATLAS using ATClean, which cleaned the light curve and effectively convolved it with rolling Gaussians of several timescales. No significant evidence for precursor variability was found. We find 80% detection thresholds on the absolute magnitude of -11.28 mag and -8.98 mag for outbursts with timescales of 2 and 300 days, respectively. Our
radio observations taken with the Australia
Telescope Compact Array (ATCA) are consistent with a wind-like CSM density profile, with an inferred mass-loss rate of ${\sim} 8 \times 10^{-5} M_\odot$ yr$^{-1}$, assuming $v_{\rm wind} = 50$ km s$^{-1}$. However, including CSM density estimates from the literature implies a two-component structure in the overall CSM density profile, with a denser inner structure at smaller radii ($\lesssim 6\times10^{14}$ cm) and an extended wind-like profile at larger radii. We conclude that the dense CSM around SN 2024ggi is likely not deposited there by eruptive outbursts. Instead, we favor a scenario with a lower but more stable mass-loss rate, such as pulsation-driven superwinds, a model with extended chromospheres, or a combination of both.
Read the full abstract ▾
All authors Tobias Géron, James K. Leung, Maria R. Drout, Rami Z. E. Alsaberi, W. V. Jacobson-Galán, Charles D. Kilpatrick, A. Rest, S. Rest, Stuart D. Ryder, Toshikazu Shigeyama, Yuki Takei
Probability
Stationary activated random walk: regularity, heavy tails, and remixing
Tobias Johnson, Matthew Junge and Josh Meisel
We study the stationary state of driven-dissipative activated random walk on an interval of length $n$ and prove that subintervals down to size $\log n$ have particle density near the critical value. We then deduce that the avalanche area is heavy-tailed and that the process forgets an initial stationary state after $o(n)$ steps. We
conjecture that the density fluctuations, avalanche area, and remixing time from stationarity are governed by the same critical exponent.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Correlated Signatures of Plasma Lensing in Fast Radio Bursts
Paz Beniamini and Pawan Kumar
Plasma lensing has been proposed to explain narrow spectra, multiple burst copies, frequency drifts, interference fringes, and polarization changes in fast
radio bursts (FRBs). Because many of these features are not unique to
lensing, a convincing identification requires several correlated observables to be reproduced by one lens model. We derive such relations for a one-dimensional Gaussian
plasma lens near a fold caustic. We distinguish the phase separation of the merging images from their observable group-delay difference and identify three regimes: resolved burst copies, overlapping images with negligible mutual coherence, and coherent spectral interference. We connect the magnification, image delay, spectral-envelope width, fringe spacing, differential dispersion, time-frequency caustic
curvature, and the brightness and ordering of the third image. We derive separate finite-source constraints from large fold magnification and from fringe visibility, and relate the wave-optics magnification scale to the
plasma column of the lens. High-contrast fringes simultaneously constrain the source size and the mutual coherence of the two image fields, which constrains the intrinsic coherence of the FRB radiation once the observed spectrum and instrumental bandpass are accounted for. We also derive the conditions for differential Faraday rotation in magnetized lenses. Finally, we show that clean
lensing by a volume-filling turbulent screen requires fine tuning between rare strong fluctuations and caustic confusion, suggesting that sparse sheets, filaments, interfaces, or shocked clumps are more promising
lensing structures.
Read the full abstract ▾
Quantum Physics
A Universal Budget for Entanglement and Nonlocal Non-Stabilizerness
Salvatore Marco Giampaolo
Entanglement and nonlocal non-stabilizerness are distinct
quantum resources encoded in the Schmidt spectrum of a bipartite pure state. For
qubit systems, we establish a universal quadratic constraint on their simultaneous allocation, governed by the minimum number of logical
qubits required on each side to encode the occupied Schmidt support. Additional spectral constraints reveal a strong asymmetry in their allocation with the
Entanglement that can exhaust the logical capacity, whereas the maximal nonlocal non-stabilizerness grows only logarithmically with it. For a tensor-network cut crossed by a single separating virtual edge, the logical capacity is determined by the occupied bond dimension. We further derive a one-sided certificate for the resources of the untruncated state from a retained Schmidt spectrum and its discarded weight. For small discarded weight, the resulting corrections are linear in that weight. These results connect a universal resource budget to resource-aware control of tensor-network truncations.
Read the full abstract ▾
Robotics
Humanoid Badminton: Learning Dynamic Racket Skills from Limited Human Motion Data
Jingzhi Cui, Zhexiong Wang, Bangjie Xu et al. (+9 more)
High-speed racket sports provide a demanding testbed for
humanoid robots, requiring time-critical decisions, precise striking, and dynamic whole-body coordination. In badminton, fast-changing shuttle trajectories require timely contact decisions, while successful returns demand precise racket pose and velocity within a brief contact window and across a broad three-dimensional striking workspace. Human motion data provide valuable priors for such athletic skills, but usable badminton references are limited and imperfect. Direct tracking provides insufficient executable variation for diverse shuttle conditions, while purely task-driven optimization may produce unnatural motion. We therefore present a three-stage hierarchical reinforcement learning framework for dynamic
humanoid badminton. First, task-randomized motion augmentation expands sparse annotated hitting events into executable target-conditioned stroke variations, forming a continuous latent skill space. Second, a high-level planner outputs continuous latent skill codes to compose these skills online according to the observed shuttle state. Third, a context-conditioned
adversarial regularizer encourages more natural planner-level skill usage while preserving return performance. In real-world deployment, our system sustains multi-skill rallies with human players, including forehand, backhand, and highly dynamic jump returns. This is the first real-world
humanoid racket-sport system to demonstrate multi-skill human–
robot rallies including highly dynamic jump returns.
Read the full abstract ▾
All authors Jingzhi Cui, Zhexiong Wang, Bangjie Xu, Pengyu Zhao, Youyuan Li, Zhi Su, Peng Ren, Mengdi Xu, Chao Yu, Yi Wu, Luyang Wang, Zhongyu Li
Strongly Correlated Electrons
André Grossi Fonseca, Aidan Reddy, Ahmed Abouelkomsan et al. (+2 more)
Evidence for
chiral superconductivity has recently been observed in several van der Waals systems including rhombohedral multilayer
graphene and twisted
bilayer MoTe$_2$. In the latter, superconductivity emerges at carrier densities near a fractional Chern
insulator. This raises the question of what kinds of
superconductors may emerge in a system of electrons in a topological band with strong repulsive interactions. Here, we adapt the target-phase optimization method to search for
chiral superconductors in a minimal model of interacting electrons in a Chern band. We construct a differentiable loss function for
superconductors from the sign oscillation of the pair-binding energy and combine gradient-based optimization with a rigorous screening procedure to identify and characterize
superconductors. Applying this framework within exact diagonalization to spinless electrons in periodically modulated Landau levels with screened Coulomb interactions, we uncover a broad family of
chiral superconducting phases. At filling $\nu=2/3$, we recover the previously identified $f-\mathrm{i} f$ hole
superconductors and find additional $p\pm \mathrm{i} p$ and $f+\mathrm{i} f$
superconductors of both electrons and holes, occurring near and far from the limit of ideal
quantum geometry. At $\nu=1/2$, we identify $p- \mathrm{i} p$ electron and $f-\mathrm{i} f$ hole
superconductors and find, for the first time, a direct transition between
chiral superconductors and composite
Fermi liquids. Our results reveal that
chiral superconductivity in Chern bands comprises a diverse landscape of competing pairing instabilities and establish target-phase optimization as a general strategy for searching for
quantum phases in complex interacting systems.
Read the full abstract ▾
All authors André Grossi Fonseca, Aidan Reddy, Ahmed Abouelkomsan, Liang Fu, Marin Soljačić
Astrophysics of Galaxies
Quantifying the decline in CO(2-1) intensity around PHANGS-HST star clusters: Constraints on molecular gas dispersal, stellar feedback, and cluster formation efficiency
Hao He, Adam K. Leroy, Erik Rosolowsky et al. (+36 more)
We combine the largest survey of
star clusters in nearby
galaxies to-date, PHANGS-HST, with maps of molecular gas maps from PHANGS-ALMA to constrain the efficiency of cluster formation and the typical timescales over which clusters become dis-associated from their natal molecular gas. We analyse 29,233 clusters in 36
galaxies using CO maps at 150 pc resolution. For each
star cluster with
stellar mass $\geq 10^{3.5}$ M$_\odot$, we measure the radial profiles of CO(2-1) integrated intensity and obtain local background-subtracted CO intensity, $I_{\rm CO}^{\rm bkgsub}$, at cluster centre. We group the clusters by age and mass to quantify the dependence of $I_{\rm CO}^{\rm bkgsub}$ and corresponding molecular gas mass, $M_{\rm mol}$, on these cluster properties. To account for the cluster mass ($M_{\rm SC}$) dependence, we also calculate the normalised mass ratio of $(M_{\rm mol}/M_{\rm SC})$. We find that CO intensity varies systematically with cluster age and mass. Clusters that are spatially associated with H$\alpha$ emission exhibit the highest $I_{\rm CO}^{\rm bkgsub}$ of 7.4 K km s$^{-1}$, corresponding to a $M_{\rm mol}/M_{\rm SC}$ ratio of 82 and implying a cluster formation efficiency ($\epsilon_{\rm obs}$) of $\sim 1.2\%$. Young clusters without associated H$\alpha$ emission show lower and age-dependent $I_{\rm CO}^{\rm bkgsub}$ and $M_{\rm mol}/M_{\rm SC}$, decreasing from 1.3 K km s$^{-1}$ and 15 for clusters with age 1-3 Myr, to a level $\approx$ 0 for clusters older than 9–10 Myr. Clusters older than 10 Myr show no statistical excess of CO intensity. We use the clusters with H$\alpha$ association as initial conditions to model the impact of cluster drift and demonstrate that this is unlikely to drive the observed cluster-gas spatial disassociation on short timescales of 4-6 Myr. Instead, early
stellar feedback seems likely to be the main driver.
Read the full abstract ▾
All authors Hao He, Adam K. Leroy, Erik Rosolowsky, Janice Lee, Brad Whitmore, David Thilker, Daniel A. Dale, Frank Bigiel, Annie Hughes, Jiayi Sun, Gagandeep Anand, Ashley T. Barnes, Zein Bazzi, Médéric Boquien, Rupali Chandar, Dario Colombo, Sinan Deger, Simthembile Dlamini, Hamid Hassani, Stephan Hannon, Ralf S. Klessen, Simon C.O. Glover, Kathryn Grasha, Ivan Grasimov, Remy Indebetouw, Kirsten Larson, Lukas Neumann, Elias K. Oakes, Hsi-An Pan, Miguel Querejeta, Lise Ramambason, M. Jimena Rodríguez, Sumit K. Sarbadhicary, Eva Schinnerer, Qiushi Tian, Leonardo Úbeda, Antonio Usero, Thomas G. Williams, Jianwen Zhou