Mathematical Physics · Cross-listed from math.PR
Non-colliding space-time inhomogeneous Markov chains
Theodoros Assiotis and Miles Foster Nyamundanda
We establish the explicit leading order asymptotics, with a quantitative error bound, of tail probabilities of collision times for a class of integrable space-time inhomogeneous Markov chains, in discrete and continuous time. The corresponding process conditioned not to intersect arises in interacting particle systems with local push-block interactions thereby confirming a recent prediction. The generic discrete nature of the spatial inhomogeneities rules out powerful coupling-with-Brownian-motion techniques, so our proof strategy proceeds instead via a novel steepest-descent analysis combined with a Karlin–McGregor
semigroup expansion in terms of dominant-index contributions.
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Materials Science
Investigation on the temperature dependence of substrate-induced in-plane uniaxial magnetic anisotropy in Ni thin films grown on 128{\deg} Y-cut LiNbO3
Kalani Perera, Morton Greenslit, Luke Doucette et al. (+2 more)
We report the temperature dependence of the substrate-induced
magnetic anisotropy in continuous Ni thin films deposited at room temperature using magnetron sputtering on a 128{\deg} Y-cut LiNbO3 substrate. Ultrathin films exhibit a pronounced temperature dependence in magnetization, with as-grown films showing isotropic behavior and an unconventional hysteresis branch crossing at relatively low temperatures, whereas no branch crossing is observed in annealed films over the investigated temperature range, indicating suppression of the underlying mechanism. Temperature-dependent magnetization measurements show that post-deposition annealing establishes uniaxial anisotropy with well-defined easy and hard axes, whose strength evolves with temperature due to the nature of residual strain governed by both
lattice mismatch and coefficient of thermal expansion (CTE) mismatch between the Ni film and the 128{\deg} Y-cut substrate, independent of film thickness for both 5 nm and 100 nm films. The emergence of this anisotropy following annealing indicates enhanced magnetoelastic coupling at the film-substrate interface, as the
magnetic response begins to follow the anisotropic strain imposed by
lattice mismatch and CTE mismatch.
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All authors Kalani Perera, Morton Greenslit, Luke Doucette, Mauricio Pereira da Cunha, Nicholas S Bingham
Quantum Physics
Particle-preserving fermionic shadows with mode-independent sample complexity
Maxwell West, M. Cerezo and Martin Larocca
We consider the problem of learning expectation values of particle-preserving operators with respect to an unknown $\eta$-particle $n$-mode fermionic state via classical shadows. Our main application is to estimating overlaps with arbitrary Slater determinant states: While it is known that such overlaps can, in the average case, be learnt to a fixed additive precision with a constant number of samples, the best-known worst case bound is $\mathcal{O}(\sqrt n \log n)$; here we improve this to $\mathcal{O}(\eta\log\eta)$, achieving a mode-independent sample cost. Our procedure is also computationally efficient, requiring only classical post-processing which for a generic dense orbital runs in time $\mathcal{O}(n\eta^2)$. For the task of estimating the expectation value of a general particle-preserving quadratic fermionic observable $h$, we prove a sample complexity bound of $\mathcal{O}(\eta \|h_0\|_2^2)$, where $h_0$ is the traceless component of $h$; the associated classical post-processing scales as $\mathcal{O}(n^2\eta )$. Finally, we discuss implementation of the required randomization: in a first-quantized encoding, approximate
unitary designs give
circuit depths polylogarithmic in the number of modes, contrasting with linear-depth requirements for nearest-neighbor second-quantized matchgate implementations. On the technical side, our proof reduces the extremal shadow variance to harmonic analysis on the AIII symmetric space $U(n)/(U(\eta)\times U(n-\eta))$ and evaluates the resulting integral using techniques from the theories of Jacobi ensembles and orthogonal
polynomials, in a calculation which may be of independent interest.
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Plasma Physics
Ion firehose and ion cyclotron instability with subtracted-Kappa distributions
Luiz F. Ziebell, Rudi Gaelzer and Danny Summers
In the present paper we discuss numerical solutions of the dispersion relation for electromagnetic waves propagating along the lines of an ambient
magnetic field, considering parameters representative of space
plasma environments, and considering the ion population described by a subtracted-Kappa distribution. We consider situations in which the ion thermal anisotropy is such that $T_{i\perp}<T_{i\parallel}$, and investigate the effect of some parameters associated to the subtracted-Kappa distribution on the ion firehose instability. We also consider situations in which $T_{i\perp}>T_{i\parallel}$, and investigate the effects of the same parameters on the ion-cyclotron instability. For both forms of instability, we also investigate the effect of the thermal anisotropy of the electron distribution, and the effect of the occurrence of a drift velocity in the electron distribution function. Among the results obtained, we show that the increase of the loss-cone feature in a bi-kappa distribution leads to a decrease of the growth rates of the firehose instability, and to an increase of the growth rates of the ion-cyclotron instability.
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Earth and Planetary Astrophysics
Improving exoplanet mass characterisation with Bayesian model selection using the Learned Harmonic Mean Estimator
Ross S. Dobson, Vincent Van Eylen, Ioanna Manolopoulou et al. (+1 more)
Radial velocity (RV) analyses require modelling choices (such as eccentricity treatment, noise model, velocity trends, and number of
planets) that can significantly affect derived planetary masses. Current practice often relies on information criteria to compare and select models, but these have known limitations: they lack the built-in Occam's razor of
Bayesian model comparison, and they do not incorporate prior information. Computing the
Bayesian evidence needed for Bayes factor model comparison has traditionally required dedicated
algorithms such as nested sampling. The learned harmonic mean
estimator (LHME) offers an alternative, estimating the
Bayesian evidence directly from MCMC posterior samples, with less computational cost and with no modification to the fitting procedure. We present the first application of the LHME to RV model selection, fitting 18 model variants – comparing circular and eccentric orbits, white noise and Gaussian Process noise models, and long-term velocity trends – to six single-
planet systems, and 72 variants to a seventh system for an $N$ versus $N+1$
planet model comparison. We find that no single model is universally preferred, reinforcing the need for model comparison to select the most appropriate model for a system, thereby ensuring robust mass characterisation. The LHME, implemented in the open-source harmonic package, makes rigorous
Bayesian model comparison accessible to existing MCMC-based RV workflows, and we encourage its wider use for other model comparisons in astrophysics.
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All authors Ross S. Dobson, Vincent Van Eylen, Ioanna Manolopoulou, Kendall Sullivan
Quantum Physics
Quantum computer architecture with ions in tweezer arrays
Benjamin F. Schiffer, Christopher Monroe, Peter Zoller et al. (+1 more)
We propose a
quantum computer architecture based on ions confined in optical tweezer arrays, combining the long coherence times of trapped-ion
qubits with the reconfigurability and parallel operation enabled by tweezer platforms. Selected ions are transported to local interaction zones, where excitation to an auxiliary state with a displaced optical potential generates a controllable effective electric dipole. We develop and analyze entangling-gate mechanisms mediated by the Coulomb interaction between such effective dipoles, and show that they enable precise, temperature-robust closure of the center-of-mass and relative motional trajectories, leaving no residual
entanglement between the
qubits and the motion. We further outline a concrete implementation with barium ions based on state-selective polarizability, and study the suppression of cross-talk during parallel gate execution, with relevance to transversal gates in
quantum error correction. Our results thereby establish a realistic route toward scalable ion-tweezer
quantum processors.
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All authors Benjamin F. Schiffer, Christopher Monroe, Peter Zoller, J. Ignacio Cirac
General Relativity and Quantum Cosmology
Shortest-Path Multiplicity Heterogeneity as a Graph Diagnostic for Radial Organization in Sampled Geometries
Ariadna Uxue Palomino Ylla
Shortest-path counts describe how many minimal routes connect a pair of graph vertices, complementing distance alone. We study their heterogeneity within graph-distance shells using C_log(p, r_g), the cube root of the third absolute central moment of log shortest-path multiplicities. This permutation-invariant statistic measures variation across shell targets and does not encode direction by itself. In a Flamm–Schwarzschild case study, its radial profile differs from that of a matched-flat control. The binned statistic has a Pearson correlation of approximately 0.912 with a logarithmic Schwarzschild reference profile, indicating radial-reference agreement rather than reconstruction of continuum
curvature. Comparisons across sample sizes and neighbor parameters further describe behavior under the tested graph constructions. Preserved summaries and plotting records support the numerical evidence, although original graph realizations and the definitive execution state were not recovered. These results motivate multiplicity heterogeneity as a graph diagnostic for radial organization, with interpretation conditional on sampling, connectivity and boundary effects.
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Solar and Stellar Astrophysics
MUSE Imaging Spectroscopy of the Fullerene Planetary Nebula Tc 1
J. R. Walsh, M. J. Barlow, A. Monreal-Ibero et al. (+6 more)
The planetary nebula Tc 1 (PN G345.2 -08.8), one of the rare group of
Galactic PNe showing fullerene emission in the infrared, was observed with MUSE wide field mode with adaptive optics, wavelength range 4750-9300A. Extinction, electron temperature (T_e) and density (N_e) images are presented from collisionally excited and recombination line ratios. The nebula has a high surface brightness 12 arcsec core, an elliptical ring of major axis 2.8 arcsec around the central
star and some low ionization
knots, and an extended
halo 55 arcsec in size; between the core and
halo is an annulus with intermediate properties, including higher T_e and lower N_e than in the core. The image of optical extinction from H Balmer line ratios is highly structured, and shows an annulus, adjacent to the core, of low extinction, lower than the line-of-sight interstellar extinction. Instrumental effects to account for this anomalously low extinction area are investigated and intrinsic effects from the scattering properties of nebular
dust; neither can entirely explain the low-extinction region and the most likely cause is a local non-standard
dust reddening law. This low extinction region also shows an anomalously high He I 7281/6678A line ratio, possibly caused by a contaminating line, but none were conclusively identified. The spectrum of the central
star was extracted and fitted by a 31000K model atmosphere and is of type O7.5I(f). Over extended regions an enhancement of the detected continuum above the nebular continuum was found, as also seen in some other PNe observed with MUSE. The annulus of low extinction occurs outside the region of strongest fullerene emission, in the zone where N_e declines and T_e rises. A change in
dust properties linked to conditions in this transition region between the higher density core nebula and lower density
halo is deduced. (Abridged)
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All authors J. R. Walsh, M. J. Barlow, A. Monreal-Ibero, J. Cami, E. Peeters, R. Wesson, J. Bernard-Salas, N. L. J. Cox, G. F. J. Watt
Cosmology and Nongalactic Astrophysics
Methodological Frontiers in 21-cm Intensity Mapping: the Treatment of Systematics and Foreground Contamination
Marta Spinelli, Matilde Barberi-Squarotti, José Luis Bernal et al. (+29 more)
The distribution of neutral hydrogen (HI) in the post-reionization universe traces the
cosmic large-scale structure and therefore serves as a powerful cosmological probe. An efficient way to measure its distribution over wide sky areas and
redshift ranges is through single-dish intensity mapping, which exploits the autocorrelation signal of each dish in a
telescope array while scanning the same sky patch. Thanks to its broad frequency coverage and technical capabilities, SKA-Mid will enable measurements of the integrated 21 cm emission from HI up to
redshift $z\sim3$, making single-dish intensity mapping a key observable for probing dark matter and dark energy. Isolating the faint 21 cm cosmological signal without introducing biases is, however, challenging. The 21 cm signal is several orders of magnitude weaker than the astrophysical foregrounds, and its analysis is further affected by instrumental systematics. Overcoming these difficulties requires detailed modelling together with continuous improvements and innovations in data-analysis techniques. Over the past decade, the international community has developed and tested new methods to address current observational challenges and prepare for forthcoming SKA-Mid observations. This chapter reviews recent advances in map-making and component-separation techniques, with particular emphasis on
telescope-specific systematics such as beam response and correlated noise. We focus on results obtained in controlled simulation environments, providing a valuable framework for assessing the strengths and limitations of different approaches. Developing robust
algorithms capable of accurately handling instrumental effects and sky-model uncertainties is a crucial step toward fully exploiting the cosmological potential of HI intensity-mapping surveys in the SKA Observatory era.
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All authors Marta Spinelli, Matilde Barberi-Squarotti, José Luis Bernal, Somnath Bharadwaj, Victor Bonjean, Philip Bull, Carmelita Carbone, Isabella P. Carucci, Stefano Camera, Suman Chatterjee, Tianyue Chen, Zhaoting Chen, Samir Choudhuri, Devin Crichton, Steven Cunnington, Bianca De Caro, Khandakar Md Asif Elahi, Jose Fonseca, Athanasia Gkogkou, Abhik Ghosh, Keith Grainge, Wenkai Hu, Melis O. Irfan, Yichao Li, Siyambonga Matshawule, Geoff Murphy, Simon Prunet, Mario G. Santos, Jean-Luc Starck, Jingying Wang, Laura Wolz, Zheng Zhang
High Energy Physics (Theory)
Characteristic Lightcone Sources in SO(1,3) Yang-Mills Theory
Kaushlendra Kumar
The SO(1,3)-symmetric reduction of Yang-Mills theory on Minkowski space yields a stress-energy tensor that is smooth on the timelike and spacelike Lorentz orbits but diverges on the lightcone that separates the two regions. We ask what consistent source this singularity represents. A natural cure is a real shift of the singular denominator. This does not regularize the source but instead moves the singular support onto a hyperboloid off the cone, where the corresponding source cannot remain both conserved and traceless. Our analysis shows that the displaced support cannot retain both properties, whereas a completion on the lightcone can. The matching condition fixes this completion up to one parameter $\chi$, which has a causal interpretation as the relative weight of the future and past cones. On regular constant-time slices, the completed source carries zero total four-momentum, so its physical content is a residual causal charge inferred from its
curvature response.
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Chemical Physics
Modular molecular toolkit for photochemical energy conversion in a self-assembling nanocontainer
David Kaftan, David Bina, Guy Michel Wolf et al. (+8 more)
Production of useful chemicals using photoelectrochemical biohybrid devices offers an environmentally friendly alternative to existing energetically demanding processes. These devices exploit light-driven charge separation, e.g. by a photosystem, and require efficient electron transfer to a tailored redox enzyme cascade. Here we demonstrate that electron transfer efficiency can be increased by confining the photosystem with the redox
protein inside a self-assembling, virus-based nanocontainer. The photosynthetic system from the phototrophic bacterium Cereibacter sphaeroides and cytochrome c were conjugated to a bacteriophage P22 scaffolding
protein and co-incorporated into the 50 nm diameter virus shell in vitro. The porous shell confined the macromolecular components for efficient electron transfer while allowing free exchange of small electron mediators. Sustainable and accelerated light-driven electron transfer between the encapsulated components was confirmed by optical spectroscopy. This self-assembly system presents a versatile platform for developing nanoreactors that combine photosystems with complex redox pathways.
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All authors David Kaftan, David Bina, Guy Michel Wolf, Martin Baroch, Jakub Kodel, Juraj Dian, Filip Dycka, J. Thomas Beatty, Heiko Lokstein, Jakub Psencik, Roman Tuma
General Relativity and Quantum Cosmology
Endpoint Control of Thermodynamic Topological Classes for Fixed Charge \texorpdfstring{$d$}{d}-dimensional Reissner–Nordström Black Holes in a Cavity
Rongrong Zhai
We study thermodynamic topological classes of $d$-dimensional Reissner–Nordström (RN) black holes in a cavity at fixed charge. Starting from the reduced Euclidean action, we use the quasilocal energy,
entropy, and on-shell inverse temperature to construct the off-shell vector field. The central question is which boundary thermodynamic quantities, rather than which local branch formulas, determine the refined thermodynamic topological class. A finite cavity gives two charge dependent classes: neutral black holes belong to $W^{0-}$, whereas charged black holes belong to $W^{1+}$. If the cavity radius is sent to infinity at fixed physical charge, the endpoint thermodynamic quantities change, giving $W^{1-}$ for the neutral case and $W^{0+}$ for the charged case. Thus the electric charge and the outer boundary, rather than the spacetime dimension in the explicit four- and five-dimensional examples, determine the refined topological class within this RN cavity family. The result identifies the cavity wall as part of the endpoint thermodynamic input entering the boundary degree, not merely as a thermodynamic regulator.
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Quantum Physics
A hardware-safety-gated system for LLM-written native ARTIQ control code on a trapped-ion platform
Duanyang Wang, Lu Qi, Yuanheng Xie et al. (+2 more)
Large-
language-model (LLM)
agents can write and run experimental control code. This allows laboratory work to be conducted autonomously. However, this autonomy raises a safety problem that prior work has not addressed. Unchecked code can damage the apparatus, and there is no formal, per-operation boundary between human authorization/supervision, and
agent decisions. We present a control system that places an LLM
agent in the loop of a trapped-ion experiment while enforcing such a boundary. The
agent controls the existing Advanced Real-Time Infrastructure for
Quantum physics (ARTIQ) stack through tools provided by a Model Context Protocol (MCP) server. No tool call reaches the hardware unless it carries an authorization
token bound to its exact contents.
Tokens are issued in one of two ways: automatically, by running the
agent's proposed script in an isolated hardware simulation (dax.sim) and checking every operation against preset per-device bounds, or manually by a human operator for sensitive actions. Within this boundary the
agent develops its own experiments, rather than only calling pre-built routines. We deploy the system on a co-trapped $^{40}$Ca$^{+}$/$^{40}$CaOH$^{+}$
crystal, where the
agent autonomously builds a full calibration stack and, with targeted operator guidance, closes a cross-instrument
magnetic-field-stabilization loop. On a separate, independent $^{171}$Yb$^{+}$ platform, we confirm interface-level portability. We systematically test
token-authorization mechanism with
adversarial scripts that attempt to bypass it, mapping the precise boundary of its protection and prioritizing where to strengthen it next. Analyzing where the
agent still requires human guidance, we find that its limits lie in metacognitive control, namely recognizing when a problem must be re-framed, rather than in domain knowledge.
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All authors Duanyang Wang, Lu Qi, Yuanheng Xie, Norbert M. Linke, Kenneth R. Brown
Instrumentation and Methods for Astrophysics
Time-Domain Synthesis of Gravitational-Wave Detector Glitches using Class-Conditional Derivative Generative Adversarial Networks
Tom Dooney, Mees de Boer, Harsh Narola et al. (+4 more)
Gravitational-wave detectors such as LIGO, Virgo, and KAGRA are highly sensitive instruments susceptible to many noise sources. Short-duration transient noise events, known as glitches, pose a particular challenge for data analysis pipelines, as they can mimic or obscure astrophysical signals. We present GlitchGAN, a class-conditional generative model built on the Conditional Derivative GAN (cDVGAN) architecture, capable of synthesizing seven glitch types from LIGO's third observing run (O3) directly in the time domain. GlitchGAN generalizes effectively, learning to reproduce a diverse glitch space consistent with high-quality DeepExtractor reconstructions, and can generate hybrid glitch morphologies by interpolating across its class-conditioning vector. It generates 1000 glitches in under 22 seconds on a CPU, suitable for detector simulations, mock data challenges, and pipeline validation. Synthetic glitches are validated using the
Gravity Spy classifier and UMAP
embeddings, both showing strong agreement with real data. To probe residual distributional differences, we train a separate holdout GlitchGAN model and use a downstream CNN to distinguish held-out real glitches from synthetic ones: detectability is high in a clean representation but drops substantially once both populations are injected into realistic detector noise, the condition under which they would typically be used. Despite this, GlitchGAN-generated glitches remain practically useful: augmenting real training sets with synthetic samples matches simple duplication of real data when data is abundant, and increasingly outperforms it as real data becomes scarce. Finally, we highlight a limitation of magnitude-only spectrograms: magnitude Q-transform classifiers can confidently misclassify physically unrealistic glitches from less robust models, underscoring the need for validation methods that preserve phase information.
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All authors Tom Dooney, Mees de Boer, Harsh Narola, Melissa Lopez, Stefano Bromuri, Daniel Stanley Tan, Chris Van Den Broeck
High Energy Astrophysical Phenomena
A search for Fast Radio Bursts from globular clusters in M49 with FAST
Simon C.-C. Ho, Chris Flynn, Matthew Bailes et al. (+7 more)
The origins of fast
radio bursts (FRBs) remain uncertain, although magnetars are a leading progenitor candidate. Because magnetars are thought to form primarily through core-collapse
supernovae in young
stellar populations, the discovery of FRB 20200120E in a globular cluster (GC) in the nearby
galaxy M81 was unexpected given the ancient
stellar populations of GCs. Expanding the sample of FRBs localised to nearby
galaxies is therefore essential for testing FRB formation channels in old
stellar environments. M49 (NGC 4472) is a nearby (~17 Mpc),
radio-quiet
giant elliptical
galaxy in the Virgo cluster hosting about 7000 GCs, making it an ideal target for GC FRB searches. We conducted a 9-hour SnapShotCal observation of M49 using the Five-hundred-meter Aperture Spherical
Telescope (FAST) 19-beam receiver, covering approximately 4230 GCs (2.1 hr per GC), and performed a comprehensive single-pulse search over a dispersion measure range of 0-5000 pc cm^-3. No unambiguous astrophysical FRBs were detected. The most significant trigger reached a post-processed signal-to-noise ratio of 8.6 sigma at a dispersion measure of 412.2 pc cm^-3, but is statistically consistent with thermal noise after accounting for the false-alarm rate. We derive a beam-averaged peak flux-density sensitivity of about 16.5 mJy (corresponding to a fluence limit of about 16.5 mJy ms for a 1 ms burst) and place an upper limit on the FRB occurrence rate of 4.7 x 10^-4 FRB GC^-1 hr^-1. Our non-detection constrains only bright bursts above this fluence threshold during the observing window.
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All authors Simon C.-C. Ho, Chris Flynn, Matthew Bailes, Emma Carli, Lei Zhang, Manisha Caleb, Kenneth C. Freeman, Tetsuya Hashimoto, Tomotsugu Goto, James O. Chibueze
Quantum Physics
A 0.651-approximation to quantum Max Cut via Rydberg atoms
Tomás Crosta, Matthieu Saubanere and Felix Huber
Quantum Max Cut, also known as the anti-
ferromagnetic Heisenberg
Hamiltonian, is a QMA-complete problem which serves as a
benchmark for approximation
algorithms in
quantum physics. Here we develop a hybrid approximation
algorithm to
quantum Max Cut, which uses the natural
quantum dynamics of Rydberg atom systems in combination with semidefinite programming and randomized rounding. It achieves a conditional approximation ratio of $0.651$, compared to the best-known ratio of $0.614$ that relies on semidefinite programming alone. The
algorithm is robust in the sense that the advantage persists even if the annealing procedure of the Rydberg atom system obtains a state whose energy is only $89\%$ of its true ground state energy. Our approach opens a new route for hybrid
quantum-classical
algorithms that combine
quantum with classical optimization methods.
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High Energy Physics (Theory)
Causality and the Equivalence Principle for Higher Energy Scattering
Yu-tin Huang and Lukas W. Lindwasser
Recently, it was proposed that the leading high-energy behavior of scattering amplitudes is universal, independent of charge, thereby extending the equivalence principle beyond the graviton pole. In this Letter, we derive a sharper causality constraint on such behavior by studying the Regge limit of colored scattering. Parameterizing a trajectory by $s^{\alpha(t)}$ with $\alpha(0)=2-\delta$, we analyze the Shapiro/Wigner–Smith time-delays in the irreducible scattering channels. We show that any non-singlet trajectory with $\delta< 1/2$ produces a growing sign-indefinite time-delay (with $\delta=1/2$ a marginal, dimension-dependent case), which becomes dominant in the Regge
diffusion region in the weak-
gravity regime. The essential point is that, while the eikonal phase is naturally organized in $t$-channel irreducible representations, the physical time-delays are its
eigenvalues in the $s$-channel. A non-singlet exchange therefore recouples into the physical channels with both signs, inevitably producing a negative time-delay in at least one channel.
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Earth and Planetary Astrophysics
Cross-correlation transmission spectroscopy of ultra-hot Jupiters WASP-189b, HAT-P-57b, KELT-17b, and KELT-21b with GIANO-B
P. Meni-Gallardo, J. Orell-Miquel, Gareb Fernández-Rodríguez et al. (+6 more)
Since the discovery of the first
exoplanet, significant efforts have been made to characterise their atmospheres. Ultra-hot Jupiters (UHJs) are of particular interest due to their extended and hot atmospheres. Although previous studies have focused on the detection of atomic species at optical wavelengths, near-infrared (NIR) observations offer the potential to detect molecules. In our study, we applied the cross-correlation technique to NIR transmission spectra from \giano. The analysis focuses on the search for H$_2$O, CO, CO$_2$, CH$_4$, HCN, and FeH molecular signals in the atmospheres of four UHJs: HAT-P-57 b, KELT-17 b, KELT-21 b, and WASP-189 b. For the first time, we report results on the NIR transmission spectra of KELT-17b, KELT-21b, and WASP-189b. We report a tentative detection ($3.8\sigma$) of H$_2$O in HAT-P-57 b and a detection ($5.3\sigma$) of FeH in KELT-17~b, which is the third FeH detection ever in a UHJ and with the lowest
equilibrium temperature. No molecular signals were found in KELT-21b and WASP-189b, or for other molecules in HAT-P-57b and KELT-17b. The cross-correlation results for HAT-P-57 b, KELT-17 b, KELT-21 b, and WASP-189 b in transmission align with the species detected in the UHJ population. This work underscores the need for further observations to confirm and expand the transmission study of UHJs in the NIR, and the capabilities of high-resolution spectrographs on 4-m-class
telescopes.
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All authors P. Meni-Gallardo, J. Orell-Miquel, Gareb Fernández-Rodríguez, H. Parviainen, M. Basilicata, E. Pallé, M. Stangret, I. Carleo, P. Giacobbe
Soft Condensed Matter
Light selects non-equilibrium states of phase-separated droplets
Zi Lin, Thomas Beneyton, Suzanne Lafon et al. (+5 more)
Driving phase-separated droplets out of
equilibrium can oppose coarsening and trigger division. Selecting and sustaining these distinct states remains an important experimental challenge. Here, we use reversible photoswitching to tune molecular driving in DNA-azobenzene coacervates confined in microfluidic droplets without chemical fuel depletion or waste accumulation. Single-wavelength illumination sustaining bidirectional molecular switching arrests droplet coarsening at a finite size. Dual-wavelength illumination with wavelength-dependent penetration depths generates spatially asymmetric molecular driving within uniformly illuminated droplets, producing persistent interfacial instabilities. Under low-salt conditions, droplets divide and undergo recurrent growth-division cycles. Kinetic and thermodynamic measurements reveal how flux balance, phase stability and droplet size govern these distinct non-
equilibrium states. These findings establish optically controlled molecular driving as a route to selecting sustained non-
equilibrium droplet dynamics.
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All authors Zi Lin, Thomas Beneyton, Suzanne Lafon, Edison Rafael Jimenez Granda, Liangfei Tian, Alexandre Baron, Jean-Christophe Baret, Nicolas Martin
Optics
Plasmonic coated scatterers for tunable coherent perfect absorption
Ali Ghorashi, Ali H. Alhulaymi and A. Douglas Stone
We derive, in closed-form, the surface conductivity required for coated subwavelength-scale spherical and cylindrical scatterers to perfectly absorb incident coherent light of fixed angular momentum. To address the challenge of synthesizing an incident wave of a fixed angular momentum, we analyze two geometries where this physics can be accessed from the far-field: a single coated sphere suspended above a good conducting surface, and an array of dipole-coupled coated cylindrical scatterers. We show that the required complex surface conductivities necessary for coherent perfect absorption over a large bandwidth in the terahertz may be easily achieved in moderately doped
graphene.
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High Energy Physics (Theory)
The gauge invariance of non-perturbative vertex prescriptions
M.E. Carrington, A.R. Frey and B.A. Meggison
We study the gauge invariance of different continuum methods to include non-perturbative effects in gauge theories. We work with three dimensional
quantum electrodynamics and implement vertices using two different methods: a set of coupled Schwinger-Dyson (SD) integral equations, and the self-consistent equations obtained from the 3-particle irreducible (3PI) effective action. We work in Landau gauge and assess the extent to which results are gauge invariant by checking how well the Ward identity is satisfied. Our results show that there is a fairly significant violation of the Ward identity at large coupling, although the 3PI effective theory is slightly better than the SD vertex. We also compare the results of both calculations with the commonly used Ball-Chiu ansatz and show that the agreement of the ansatz with both non-perturbative vertices is fairly good at small coupling but deviates more significantly at large coupling. We compare results for the two point functions of the theory and discuss the possible implications for phase transitions.
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Quantum Physics
Quantum group codes for non-Clifford logic: enhanced decoding, addressability and parallelizability
Jean Gasnier and Virgile Guémard
We introduce a framework based on classical quasi group codes to define a class of
quantum CSS codes, called
quantum group codes, supporting transversal multi-control-$Z$ gates which are both addressable and parallelizable, thus allowing to efficiently implement
circuits composed of non-Clifford gates at the logical level. Building on this, we use a lifting procedure of classical AG codes established from class field theory to construct good
quantum group codes with improved decoding complexity and logical multi-control-$Z$ gate parallelizability. More precisely, on input a good
quantum AG code over the alphabet $\mathbb F_q$ with transversal $\mathsf{C}^m\mathsf Z$ gate, we apply this lifting procedure to its underlying classical AG code and obtain a
quantum group code over the alphabet $\mathbb F_{q^2}$ supporting a transversal $\mathsf{C}^m\mathsf Z$ gate as well as addressable and parallelizable $\mathsf{C}^{m-1}\mathsf Z$ gates. In addition, this
quantum code admits a quasi-quadratic time decoder with a linear decoding radius. This is to be compared with the previous
quantum AG codes which have a cubic-time decoder. Hence, our work implies a decrease of the time complexity of state-of-the-art magic-state
distillation protocols by an almost linear factor.
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Soft Condensed Matter
Organic Semiconductor Alignment via Confinement in Vapor-Guided Droplets
Robert Malinowski, Alessandro Rossi, Lewis M. Cowen et al. (+8 more)
Organic
semiconductors are lightweight, solution-processable materials with strong potential for printed and flexible electronics, from deformable displays to wearable sensors. Despite significant advances in materials synthesis and manufacturing, controlling molecular and mesoscale
alignment during deposition remains a central challenge, as film morphology critically governs charge transport and device performance. Here, we demonstrate that flows developing within the intrinsically confined volume of microliter vapor-guided droplets can be harnessed to produce highly aligned organic
semiconductor films. As droplets move in response to an external vapor source, internal flows align organic semiconducting nanowires within the droplet prior to deposition, yielding films with pronounced directional order. Organic field-effect transistors fabricated with this approach exhibit approximately 40% enhancement in saturation current relative to
spin-coated controls. Beyond improved device performance, the contactless and compact nature of our method enables the deposition and
alignment of organic
semiconductors on curved and flexible surfaces. More broadly, vapor-guided droplets offer a scalable framework for the confinement-induced
alignment of functional soft materials, with potential for integration into existing additive manufacturing platforms for flexible electronics and beyond.
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All authors Robert Malinowski, Alessandro Rossi, Lewis M. Cowen, Peter A. Gilhooly-Finn, Michael A. Parkes, Ming-Hao Chang, Yu-Cheng Chiu, Ioannis Papakonstantinou, Matthew O. Blunt, Bob C. Schroeder, Giorgio Volpe
Strongly Correlated Electrons
Finite temperature precursors of Mottness in the Fermi Hubbard model
Sayantan Roy, Abhisek Samanta and Nandini Trivedi
We investigate finite-temperature precursors of Mottness in the repulsive Hubbard model above the
spin-ordering temperature, using numerically exact determinant
quantum Monte Carlo. We show that the finite-temperature crossover is accompanied by a pronounced suppression of charge fluctuations, despite the presence of a gapless single-particle spectra, demonstrating that Mottness first emerges via two-particle response in an anomalous metallic regime, before appearing in single-particle spectral functions. We further show that a gap formation in the density of states occurs through momentum-resolved redistribution of spectral weight across the Brillouin zone, that begins at the onset of anomalous metallic regime, rather than through gap formation in single-particle spectral functions at individual momenta. Upon doping, the anomalous-metallic regime generates transport and spectroscopic signatures characteristic of doped Mott
insulators. This shows that the transport and spectroscopic anomalies of the doped Hubbard model do not require the presence of a fully formed Mott
insulator at half-filling, but instead originate from the strong charge-response renormalization and spectral-weight redistribution that develop within the precursor anomalous metallic regime at half-filling.
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Earth and Planetary Astrophysics
Evidence for possible N2 basal flow beneath Pluto northern Sputnik Planitia
S. Alan Stern, Orkan Umurhan, Gary D. Clow et al. (+4 more)
Sputnik Planitia (SP) on Pluto is a large, predominantly N2 ice-filled basin with a surface area of one million square kilometers; it is among the most spectacular surface features on the
planet. The northern extent of SP displays a variety of geomorphological features that can be interpreted as evidence for convective flows in the basin-filling ice sheet. The complete lack of detected craters in SP argues that these processes are ongoing. The convection
cells in northern SP also display sharp, darkened boundaries that are bordered by more diffuse, less darkened zones. We hypothesize that these patterns may be explained as evidence of the flow of
liquid molecular nitrogen sourced from beneath the glacier. This hypothesis suggests that basal melt of the ice sheet occurs, that this melt reaches the surface before it freezes in transit upward through colder ice, and that the melt has sufficient time before it freezes during flow across the ice surface to fill topographic lows. Here we discuss the evidence on which we base these interpretations, constrain the required physical conditions to create them, and briefly discuss some of their implications.
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All authors S. Alan Stern, Orkan Umurhan, Gary D. Clow, Robert S. Anderson, Alan Howard, Kelsi N. Singer, the New Horizons Team
Astrophysics of Galaxies
HALO II: Constraining Hubble constant $H_{0}$ through continuum delay fitting of Fairall 9
Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal et al. (+28 more)
The Hubble tension remains one of the most significant unresolved problems in modern cosmology. A key question is whether it may arise from underestimated systematic uncertainties in the different measurement techniques. In this context, new independent methods are of exceptional importance. We therefore pursue a novel approach to determining the Hubble constant, $H_{0}$ based on continuum time delay and spectral energy distribution (SED) modeling in active
galactic nuclei (AGNs). Unlike conventional techniques, this method is entirely independent of the
cosmic distance ladder and does not require cross-calibration against other distance indicators. As a result, it enables a direct determination of $H_{0}$, free from the arbitrary normalizations that often affect indirect measurements. We conducted a dedicated monitoring campaign of the Seyfert
galaxy Fairall 9 and further developed the H0RIZON-AGN model to interpret the resulting observations. The model incorporates the effects of radiation reprocessing in the surrounding cold
accretion disk, enabling a more realistic description of the observed continuum delays. Through the simultaneous modeling of the continuum lag-spectrum and the broadband SED of Fairall 9, we derived a Hubble constant of $H_{0}=72.4_{-3.7}^{+3.4} \, \rm km \, s^{-1} \, Mpc^{-1}$. Achieving a measurement precision of approximately 5% from a single source demonstrates the considerable potential of this method for independent determinations of the Hubble constant. Our determination of $H_{0}$ is broadly consistent, within the current uncertainties, with both early- and late-Universe measurements. Future applications of the method to larger
datasets, particularly those provided by the Vera Rubin Observatory, are expected to reduce the uncertainty to below 1%, thereby establishing this approach as a powerful independent probe of the Hubble tension.
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All authors Amit Kumar Mandal, Francisco Pozo Nuñez, Vikram Kumar Jaiswal, Mohammad Hassan Naddaf, Bożena Czerny, Swayamtrupta Panda, Paulina Karczmarek, Grzegorz Pietrzyński, Shivangi Pandey, R. Edelson, B. M. Peterson, Michal Zajaček, Alberto Floris, Mary Loli Martínez-Aldama, Michal Dovčiak, Vladimir Karas, Weronika Narloch, Mirosław Kicia, Marek Górski, Mikołaj Kałuszyński, Gergely Hajdu, Piotr Wielgórski, Bartłomiej Zgirski, Cezary Gałan, Wojciech Pych, Radosław Smolec, Ricardo Salinas, Henryka Netzel-Iłkiewicz, Karolina Bąkowska, Wolfgang Gieren, Pierre Kervella
High Energy Astrophysical Phenomena
Stellar black hole binaries from two common envelope evolution phases in triple stellar systems
Lotem Unger and Noam Soker
We propose a triple-
star evolutionary channel involving two common envelope
evolution (CEE) phases to form close binary black hole (BBH) systems with an average positive effective inspiral
spin $\chi_{\rm eff}$ and a tail of systems having $\chi_{\rm eff}<0$, as observed by gravitational wave detectors. $\chi_{\rm eff}$ is the mass-weighted
spin of the two merging BHs, and a positive (negative) value indicates an effective
spin along (opposite) the orbital angular momentum. The first BH progenitor engulfs a low-mass
star during the post-main-sequence
evolution. The tertiary
star spirals in and
spins up the core, which forms the first BH at the first core-collapse
supernova (CCSN) explosion. Its
spin is along the orbital angular momentum of the inner binary, which can be highly inclined to the outer binary angular momentum. The secondary
star later engulfs the BH in a second CEE phase and explodes as a CCSN to form the second BH with a
spin that is more aligned with the orbital angular momentum of the two BHs. We use empirically calibrated initial distributions of triple-
star systems consisting of two massive
stars and impose a hierarchical stability criterion. We compare the predicted ratio of merging BBHs to CCSN explosion rates and find it is up to a factor of 2 larger than the observed rate. This channel can significantly contribute to the population of observed merging BBHs and can explain their qualitative
spin distribution.
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Statistical Mechanics
An integrable approach to macroscopic fluctuation theory for the multispecies SSEP
Luigi Cantini
We study the macroscopic fluctuation theory (MFT) of a multispecies generalization of the symmetric simple exclusion process (mSSEP) on the infinite line, in which particles of $N+1$ species – including, possibly, a vacancy species – exchange positions at unit rate. Working with the full, redundant set of coarse-grained densities $\bfrho=\{\rho_0,\dots,\rho_N\}$ keeps the relabelling
symmetry of the model manifest throughout. We first extend the argument of Derrida and Gerschenfeld to the multispecies setting, showing that the cumulant generating function of the multispecies current between two regions of an arbitrary graph depends on the boundary densities $ \bfrho_L,\bfrho_R$ and on the fugacities $\bflambda$ only through a single scalar variable $\omega$. We then formulate the MFT saddle-point equations for the mSSEP on the infinite line and show that they define an integrable system: they are of Landau–Lifshitz type, and a Zakharov–Takhtajan gauge transformation recasts them in AKNS form. Solving the resulting linear scattering problem by the inverse scattering method, we recover the cumulant generating function $F(\omega)$ for the multispecies current, as well as the initial and final density profiles conditioned on a prescribed current fluctuation. In particular, we show that $F(\omega)$ coincides with the function obtained by Derrida and Gerschenfeld for the single-species SSEP, now derived for an arbitrary number of species directly from the integrable structure of the multispecies MFT equations.
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Solar and Stellar Astrophysics
Chemical Complexity in the Early Stages of Star Formation in the SKAO Era
Eleonora Bianchi, Mathilde Bouvier, Claudio Codella et al. (+44 more)
About 350 molecules have been identified in the interstellar medium (ISM), including complex molecules relevant to prebiotic chemistry. A remarkable level of molecular diversity has been observed from the earliest stages of
star formation, providing the initial chemical inventory inherited by planetary systems.
Radio observations have played a pivotal role in these discoveries, starting with the identification of the first polyatomic molecule, $\text{NH}_3$ (Cheung et al. 1968). (Sub-)millimeter observations have revealed complex organic molecules of prebiotic relevance, including formamide ($\text{NH}_2\text{CHO}$), glycolaldehyde ($\text{CH}_2\text{OHCHO}$), and even urea ($(\text{NH}_2)_2\text{CO}$), and hydroxylamine ($\text{NH}_2\text{OH}$), which are possible precursors of RNA nucleotides (Ceccarelli et al. 2023; Jiménez-Serra et al. 2020). However, in dense protostellar regions,
dust opacity hampers the detection of molecular emission. Additionally, large molecules and those containing heavy atoms, which have rotational transitions at lower frequencies, often remain inaccessible to current instruments. The Square Kilometre Array Observatory (SKAO) will provide an unprecedented combination of sensitivity and angular resolution at
radio wavelengths. This will allow for the detection of prebiotic species and offer new insights into the chemical pathways that shape emerging planetary systems (Jiménez-Serra et al. 2022). This chapter details the scientific questions and advancements that the SKAO, and more specifically, SKA-Mid equipped with the Band 5 receivers, will pursue in the field of astrochemistry, focusing on the chemical complexity in both high-mass and
solar-type
star-forming regions.
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All authors Eleonora Bianchi, Mathilde Bouvier, Claudio Codella, Laura Colzi, Audrey Coutens, Marta De Simone, Joan Enrique Romero, Gisela Esplugues, Francesco Fontani, Antonio Garufi, Lisa Giani, Arshia Maria Jacob, Izaskun Jiménez-Serra, Marco Padovani, Linda Podio, Albert Rimola, Pablo Rivière Marichalar, Giovanni Sabatini, Andrea Socci, Riccardo Giovanni Urso, Tyler L. Bourke, Gemma Busquet, Paola Caselli, Cecilia Ceccarelli, Tomoya Hirota, John D. Ilee, Valerio Lattanzi, Manuela Lippi, Ana López-Sepulcre, Pierre Marchand, Liton Majumdar, Sabyasachi Pal, Maria Elisabetta Palumbo, Jaime E. Pineda, Manoj Puravankara, Elena Redaelli, Victor M. Rivilla, Basmah Riaz, Álvaro Sánchez-Monge, Silvia Spezzano, Leonardo Testi, Himanshu Tyagi, Claudia Toci, Alessio Traficante, Grazia Umana, Charlotte Vastel, Susanne Wampfler
Quantum Physics
From Approximate Floquet Engineering to Full Floquet Theory: Coherent Control of Chiral Spin Systems in Spintronics
Andrea Simion, Claudiu Filip and Coriolan Tiusan
Coherent control of interacting
spin systems under time-periodic driving is a central challenge in
spin-based
quantum technologies. Here we demonstrate the applicability of a full Floquet-space formalism, adapted from
Nuclear Magnetic Resonance (NMR) methodologies, to model the dynamics of driven coupled electron
spins in the presence of a static
magnetic field B0 and a transverse oscillating field B1. The framework explicitly includes isotropic exchange coupling J and the
chiral Dzyaloshinskii-Moriya antisymmetric exchange interaction (DMI), and its numerical convergence is systematically validated with respect to
Fourier-space truncation. In the non-interacting limit, the expected driven-
spin dynamics is recovered, with the oscillation periodicity governed by B1. Exchange coupling alone does not modify the collective
spin expectation values under the chosen initial condition, consistent with
symmetry considerations. In contrast, increasing DMI generates a finite Sy component, suppresses Sz, and produces tilted, elliptical Bloch-sphere trajectories, reflecting the emergence of
chiral spin-
spin correlations. These effects are pronounced for open boundary conditions, while remaining nearly negligible in the periodic boundary case. When exchange coupling and DMI coexist, the dynamics becomes strongly perturbed and multi-frequency in nature. Together, these results demonstrate that full Floquet-space modeling provides a robust and predictive framework for analyzing and engineering coherent dynamics in driven interacting
spin systems beyond simple coherent-rotation regimes.
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