Quantum Physics
Algebraic structure of Tiger codes
Clément Poirson, Anthony Leverrier and Christophe Vuillot
Tiger codes form a family of multimode bosonic
quantum codes that unify several previously known constructions, including cat, paircat, and the two-mode binomial code. In this work, we give a rigorous algebraic treatment of these codes. Starting from a kernel definition of the codespace, we prove that the annihilation-type constraints admit a finite generating set, construct an explicit orthonormal basis, and show that the logical structure of the code is governed by the homology of an underlying chain complex, as expected in the original work on Tiger codes of Xu et al. We then develop a
Fourier transform over the codespace to prove that the span of phase-rotated projected coherent states is dense therein, and to yield dual $X$- and $Z$-type descriptions of the code. We further extend the framework to non-linear number constraints, encompassing codes such as the four-legged cat or the repetition cat code. Finally, we investigate the implementation of logical operations. We first generalise the construction of logical Pauli operators proposed by Xu et al. to arbitrary logical spaces, and then construct non-Clifford gates using physical
polynomial phase rotations of the form $e^{iP(\hat{\boldsymbol{n}})}$. We derive criteria on the real
polynomial $P$ which, for positive single-logical-
qubit Tiger codes satisfying an additional sign assumption, such as the paircat code, characterise the
polynomials $P$ that preserve the codespace by decomposing them into a family of univariate
polynomials. Through this decomposition, we relate the degrees of the resulting components to the induced logical action in the Clifford hierarchy. These results establish Tiger codes as a mathematically robust framework for describing a broad class of bosonic encodings.
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Fluid Dynamics
Modeling and Stabilization of Transport-Dominated Flows
Christopher Agesen, Sam Bradford, Abhijnan Dikshit et al. (+7 more)
This report explores and compares numerical stabilization methods for transport-dominated flows arising in atmospheric modeling. The Streamline-Upwind (SU) and Streamline-Upwind Petrov-Galerkin (SUPG) stabilization formulations are implemented in Julia's ClimaCore.jl package and Python's Firedrake package for a test problem with slotted-cylinder initial conditions. These methods are compared for their ability to mitigate spurious oscillations while preserving sharp features against existing hyperdiffusion and quasi-monotone limiter methods, alongside various combinations. For this
benchmark, quasi-monotone limiters were most effective at minimizing un-physical extrema, at the expense of diffusing the overall structure. The SUPG method was not found to improve upon the no stabilization case, for this test case in the computed error metrics. However, it performs best at preserving sharp feature and overall structure, among tested stabilized runs. Theoretical properties of SUPG are analyzed, and an asymptotics-based SUPG
algorithm is proposed as future work.
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All authors Christopher Agesen, Sam Bradford, Abhijnan Dikshit, Anshi Gupta, Bhavana Morankar, Jack Murphy, Nanda N. Raghunathan, Karnav Raval, Lane H. Rogers, Valeria Barra
Instrumentation and Methods for Astrophysics
Optical design of VIPER: a high-resolution multimode fiber-fed VIPA spectrograph for characterizing exoplanet atmospheric escape
Matthew C. H. Leung, David Charbonneau, Andrew Szentgyorgyi et al. (+1 more)
We present the optical design of VIPER: a high-resolution, multimode fiber-fed, narrowband, cross-dispersed, seeing-limited spectrograph based on a Virtually Imaged Phased Array (VIPA), a spectral disperser that provides higher dispersion and a more compact form factor than conventional diffraction gratings. VIPER is specifically designed to probe
exoplanet atmospheric escape through the helium 1083 nm triplet line, with a resolving power of 300,000 over a 10 nm wavelength range. VIPER is intended for operation at the 1.5 m Tillinghast
Telescope at the Fred Lawrence Whipple Observatory (FLWO) on Mount Hopkins, Arizona, USA, and is matched to this
telescope's 100 $\mu$m circular-core multimode optical fiber feed at f/6. VIPER's optical design is specifically optimized for high throughput, which, in a VIPA spectrograph, is more challenging with a multimode fiber feed than a single-mode fiber feed because of the larger etendue. To address this challenge, our design implements a novel use of a cylindrical beam expander and pupil slicer. We validate our design using analytic calculations and simulations in Zemax OpticStudio non-sequential mode. Our results demonstrate the feasibility of multimode fiber-fed VIPA spectrographs as compact, high-throughput alternatives to conventional grating-based spectrographs for
exoplanet science and other astronomical applications.
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All authors Matthew C. H. Leung, David Charbonneau, Andrew Szentgyorgyi, Colby Jurgenson
High Energy Physics (Phenomenology)
Baryon-number-violating nucleon decays into a dark photon particle
Jin-Han Liang, Yi Liao, Xiao-Dong Ma et al. (+1 more)
Baryon-number-violating (BNV) nucleon decays into a light new particle represent an exciting yet experimentally unexplored frontier. In this work, we systematically study nucleon decays into a dark
photon using a low-energy effective field theory extended with a dark
photon $X$, referred to as $X$LEFT. We first construct a complete set of leading-order BNV $X$LEFT operators and then perform a systematic matching onto the
chiral perturbation theory for operators involving light $u,d,s$
quarks that dominantly contribute to nucleon decays. Within the
chiral framework, we derive general expressions for the decay widths of both two- and three-body nucleon decays and analyze the momentum distributions in the latter. Finally, we thoroughly reinterpret the existing experimental data on conventional two-body modes (into a
lepton and a
meson) to set lower bounds on partial lifetimes of the corresponding three-body modes involving an additional dark
photon. These bounds allow us to further set stringent constraints on the $X$LEFT operators and other correlated decay modes. Our results provide a toolkit for future experimental and theoretical studies of these exotic nucleon decays.
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All authors Jin-Han Liang, Yi Liao, Xiao-Dong Ma, Xiang Zhao
High Energy Physics (Theory)
Entanglement in Presence of Topological Interfaces and Dualities
Christian Northe, Riccardo Poletti and Paolo Rossi
Entanglement through interfaces has attracted considerable
attention in 2d conformal field theory (CFT). However, it is known that field-theoretic predictions based on the existing framework are in general incompatible with numerical results [1-4]. A new framework for
entanglement through topological defects was recently proposed in [5]. It provides a general description of
entanglement through topological defects and successfully reproduces the numerical results for the Ising model in all tested cases and regimes. The key insight is that the relevant
quantum correlations are encoded in twisted states, allowing for the construction of the full reduced density
matrix (RDM). In this work we pursue two objectives. First, we provide new examples by studying defects in the free
boson CFT. Second, we extend the framework to topological interfaces connecting two, possibly distinct, CFTs. Of particular interest are interfaces relating dual theories. We show that the reduced density
matrix for a duality interface is the projection of the
vacuum reduced density
matrix onto a single
symmetry sector, closely paralleling the framework of
symmetry resolution. Unlike
symmetry resolution, however, the projection is imposed by the physical interface itself, demonstrating that duality interfaces reflect
quantum correlations back into the entangling interval. We establish this mechanism for diagonal and non-diagonal rational CFTs as well as the free
boson CFT. Relative
entropy allows us to quantify the distinguishability of the duality interface RDM from the
vacuum RDM.
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High Energy Physics (Theory)
TransPlanckian Censorship on Dark Dimension Inflation
Luis A. Anchordoqui, Ignatios Antoniadis and Jules Cunat
It was proposed that extra dimensions can acquire large size by higher dimensional inflation connecting two large hierarchies in particle physics and cosmology, namely the weakness of the actual gravitational force to the largeness of the observable Universe, in terms of one fundamental scale. This proposal is consistent with the observed approximate scale invariant power spectrum of
primordial density perturbations only for one or two extra dimensions of around the micron size. While a cosmological history connecting the period of higher dimensional inflation to the beginning of the standard cosmology has recently been studied, we investigate here the TransPlanckian Censorship
Conjecture in that context and show that it drastically constrains the parameter space of the model.
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Quantum Physics
Highly indistinguishable photons from a tin-vacancy spin qubit in diamond
Dennis Herrmann, Robert Morsch-Golsong, Tobias Bauer et al. (+9 more)
Quantum networks promise secure communication, distributed sensing and modular
quantum computing by interconnecting distant
quantum nodes through photonic links. Extending such networks beyond metropolitan distances requires
quantum repeaters to overcome the exponential attenuation of
photons in optical fiber. Across all architectures, a key requirement is the indistinguishability of single
photons, which directly impacts the fidelity of photonic operations based on two-
photon interference, such as Bell-state measurements and fusion gates. Here, we demonstrate generation of highly indistinguishable single
photons from a coherently excited tin-vacancy center in diamond, achieving raw Hong-Ou-Mandel interference visibilities exceeding 0.95. By separating intrinsic emitter properties from technical imperfections, we show that decoherence plays a negligible role and that the remaining limitations are predominantly technical in nature, arriving at an intrinsic indistinguishability of up to 0.999. We further show that
quantum frequency conversion to the telecom C-band preserves the
photon indistinguishability. In combination with the long-lived electron and
nuclear spin coherence times, these results establish tin-vacancy centers in diamond as a competitive platform for long-distance
quantum networks and photonic
quantum information processing. We further substantiate this potential through Monte Carlo simulations of a
quantum-repeater link, demonstrating that the SnV-center platform surpasses the bound set by direct transmission.
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All authors Dennis Herrmann, Robert Morsch-Golsong, Tobias Bauer, Marlon Schäfer, David Lindler, Linus Ehre, Peter van Loock, Matthew Markham, Nicola Palmer, Soumen Mandal, Oliver Williams, Christoph Becher
Atomic Physics
Long-range magnetic interaction within quantum electrodynamics formalism
D. Solovyev, T. Zalialiutdinov, A. Anikin et al. (+6 more)
Within the framework of
quantum electrodynamics, the interaction between two atoms at large distances is analyzed. Using the S-
matrix formalism, an expression for the
magnetic interaction potential is derived, which agrees with the well-known result of classical electrodynamics. However,
quantum electrodynamics goes beyond this conventional result and allows one to treat a wide range of problems related to the structure of atomic energy levels. In particular, it is shown that the asymptotic behavior of the interaction potential can deviate from the classical prediction, depending on the atomic states involved. As an example, dispersion coefficients are calculated for the s-states of hydrogen atoms, where the long-range potential reduces to a
spin-
spin interaction. The results obtained open up the possibility of a straightforward comparative analysis of long-range interaction potentials between atoms of matter and antimatter. The applicability of this approach is demonstrated for the hydrogen-antihydrogen system.
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All authors D. Solovyev, T. Zalialiutdinov, A. Anikin, A. Bobylev, P. Kvasov, J. J. Lopez-Rodriguez, A. Moshkin, D. Zinenko, D. Glazov
Quantum Physics
A route to damage tolerance exceeding $10\%$ in shuttling-equipped quantum processors
Quinten Eggerickx and Simon C. Benjamin
This is a short study of an approach offering high tolerance to damage (i.e. defects or 'drop outs') in solid state fault-tolerant
quantum computing. Our method is primarily aimed at
semiconductor electron
spin-
qubit systems, which have been shown to support fast and high-fidelity shuttling along pre-defined paths. We adapt the recent CAbLECAR method of Chadwick and Chong: stabilisers are performed by ancillas which each follow a bespoke pre-programmed path. We consider the simple surface code but we damage the physical
lattice, and rely on route-solving software to find efficient pathways under constraints enforcing stabiliser commutation and hook error avoidance. Solutions are then converted to detector error models for Stim and logical error rates are obtained. We express our results by gauging the logical performance against that of a pristine
lattice, using the notion of a reduced equivalent surface-code distance; for reasonable underlying error rates we find that $10\%$ damage leaves roughly half of the pristine equivalent distance ($d_\text{equiv}\approx0.48\,d_\text{pristine}$ in the large-array limit, rising to $\approx0.60$ for our smallest array). This suggests that one can tolerate substantial damage by building oversized arrays. We note that investigating damage tolerance of other qLDPC codes is a straightforward generalisation, and potentially one could adapt to damage emerging at runtime.
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Earth and Planetary Astrophysics
JWST NIRCam Reveals the Largest Known M-dwarf Debris Disk Around TWA 10 and New Scattered-Light Observations of the TWA 25 Debris Disk
Katie A. Crotts, Aarynn L. Carter, Beth Biller et al. (+26 more)
We present JWST NIRCam observations of two M-
dwarf systems located in the TW Hydra association, TWA 10 and TWA 25. Both systems harbor detected debris disks in the F200W and F444W filters. Whereas the TWA 25 disk has been previously imaged, these observations represent the discovery and first images of the TWA 10 disk. In addition to
planet searches within these systems, we also conduct an analysis of each debris disk, where the TWA 10 debris disk is characterized for the first time. We find that the TWA 10 debris disk is very large, with a radius of $\sim$191 au, significantly greater than other known M-
dwarf debris disks. The TWA 25 disk hosts a sharp inner
dust surface density power-law and a moderate brightness asymmetry present at 2 $\mu$m, suggesting potential sculpting from inner
planets and potentially enhanced collisional activity. Finally, we find one potential companion candidate within the TWA 10 system and two within the TWA 25 system, although the measured F200W-F444W color suggests that these candidates are likely background objects. Both systems do not have measured IR-excesses in their SEDs, where radiative-transfer modeling suggests that these disks (and potentially more M-
dwarf disks) were likely missed by previous disk detection surveys due to having low luminosity fractions.
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All authors Katie A. Crotts, Aarynn L. Carter, Beth Biller, Mark Booth, Rachel Bowens-Rubin, Raphaël Bendahan-West, Rodrigo Ferrer-Chavez, Kellen Lawson, Briley L. Lewis, Sebastian Marino, Tim Pearce, Marshall Perrin, Giovanni M. Strampelli, Clémence Fontanive, Aiza Kenzhebekova, Patricia Luppe, Isabel Rebollido, Ben J. Sutlieff, Ellis Bogat, Evelyn L. Bruinsma, Christine H. Chen, Julien H. Girard, Kielan Hoch, Andrew D. James, Rohan Kane, Jarron Leisenring, Emily Rickman, Andy Skemer, Klaus Subbotina Stephenson
Cosmology and Nongalactic Astrophysics
Selection effects in correlated observations with application to distance-ladder observations
Will J. Percival
For over a century, following the work of Eddington, Kapteyn, Malmquist and others, astronomers have wrestled with selection biases when making inferences from samples of objects. Typically, selection is performed on the same observations used to make the measurements of interest. However, selecting objects using one observable while analyzing another can also lead to a selection bias when the observables are correlated. Within a
Bayesian framework, unmodelled selection effects correspond to a misspecified generative model. We derive the likelihood for truncated selection in correlated observables and demonstrate its usefulness by searching for residual selection effects of this form in recent distance ladder measurements of the Hubble constant H0. We specifically look for the form of bias in Cepheid selection where the correction depends on the photometric uncertainties, which the data can constrain while simultaneously measuring H0. We find mild evidence for non-zero residual selection corrections for Cepheids within calibrator
galaxies at a significance of 1.3sigma to 2.3sigma depending on the distance-prior adopted, but find that allowing for them does potentially have an appreciable effect on H0. Including a single extra parameter to model the unknown cut-off in Cepheid selection in SN Ia host
galaxies lowers the recovered H0 by -1.4km/s/Mpc. Including further selection corrections for the SN Ia samples decreases the recovered H0 by -0.2km/s/Mpc, while using an equal-volume distance prior rather than one uniform in distance modulus reduces H0 by -1.0km/s/Mpc. When included together, these effects substantially reduce the inferred tension with CMB measurements.
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Solar and Stellar Astrophysics
Alexandre C. M. Correia
Spin-orbit misalignment is increasingly observed in binary
stars, but its origin remains uncertain. We study the secular
spin dynamics of
stellar binaries and derive the associated Cassini states. We isolate a
spin-
spin resonance that arises when the two
stellar spin-precession frequencies become commensurate. This resonance can excite the obliquity of the secondary to high values even when the primary is only weakly tilted.
Magnetic braking favors the formation of high-obliquity states, whereas
tidal dissipation may suppress them.
Spin-
spin coupling may thus help explain the observed diversity of obliquities in young
stellar binaries.
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Fluid Dynamics
PRIMS: Physics-guided Representation for Fluid Identification in Multimodal Sensing
Hai-Long Nguyen, Trung Thanh Nguyen, Lars Holm et al. (+2 more)
Accurate on-device fluid identification is essential for microfluidic applications, yet maintaining reliability under varying flow, pressure, and temperature remains a key challenge. Existing learning-based methods often treat sensor signals as domain-agnostic features, neglecting the underlying physical relationships that govern fluid behavior, thereby limiting generalization and interpretability. To address this, we propose PRIMS, a physics-aware
multimodal Transformer that integrates physical knowledge into representation learning and
attention mechanisms through three dedicated modules: (1) Physics-based
Token Vectorization transforms raw Coriolis and pressure sensor signals into physically meaningful
token embeddings; (2) Physical Component Synthesizer models viscosity-related dependencies among flow, pressure, and density; and (3) Physics-guided Fusion captures cross-physical correlations through
attention-based integration. By
embedding these physics-based relationships directly into the model architecture, PRIMS bridges analytical fluid mechanics and deep learning, enabling interpretable, data-efficient, and resilient fluid classification. Evaluations on a five-fluid
benchmark under dynamic flow, pressure, and temperature conditions show that PRIMS achieves 98.92% average F1-score with only 0.46 million parameters, a 14 times reduction compared to state-of-the-art
Transformer-based methods. PRIMS also consistently outperforms prior SOTA models under out-of-distribution shifts to unseen temperature ranges and unseen flow-rate ranges, indicating strong robustness to operating conditions not observed during training. These findings suggest that designing architectures that explicitly mirror governing physical relationships can make them learn transferable, environment-independent representations, improving real-world reliability for microfluidic sensing.
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All authors Hai-Long Nguyen, Trung Thanh Nguyen, Lars Holm, Dennis Alveringh, Duc Viet Le
High Energy Physics (Phenomenology)
Hot and dense medium effects on the $B_s^*$ and $B^*$ multiplets
K. Azizi, N. Er and J.Y. Süngü
We present an extensive analysis of the in-medium masses and decay constants of the $B_s^*(5415)$ and $B^*(5325)$ multiplets, including both particles and antiparticles, using QCD sum rules at finite temperature and density. The OPE incorporates the full temperature- and density-dependent contributions from the
quark,
gluon, and mixed condensates. Computing the strange ($B_s^{*0}$, $\bar{B}_s^{*0}$), charged ($B^{*\pm}$), and neutral ($B^{*0}$, $\bar{B}^{*0}$) doublet properties allows us to study the effects of
flavor symmetry breaking, strangeness, and heavy-
quark decoupling on the beauty vector
mesons in the medium. Our results indicate that the mass is remarkably resistant to the medium across the entire multiplet: no state loses more than $\sim 13\%$ of its
vacuum value, even at $T = T_c$ and $n = 5n_0$, the extreme conditions explored here. The decay constant is far more sensitive, losing up to $\sim 78\%$ at the same point.
Baryon density clearly dominates the medium response, while temperature plays a secondary role until the system approaches the deconfinement crossover. At zero density, every state loses almost the same fraction of its mass and decay constant: mass shifts lie between $-(0.5$-$1.1)\%$ and decay-constant shifts between $-(3.9$-$5.3)\%$, regardless of charge or
flavor, so temperature alone does not distinguish a particle from its antiparticle. At finite
baryon density, a clear particle-antiparticle asymmetry emerges: at $T = 0$ and $n = 5n_0$, the $\bar{B}^{*0}$ mass decreases by $12.9\%$, whereas the $B^{*0}$ mass shifts by only $6.1\%$, a gap of nearly seven percentage points driven entirely by the vector self-energy. This provides a theoretical basis for the future heavy-ion collision program at RHIC, LHC, FAIR, and NICA.
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High Energy Astrophysical Phenomena
Winds Versus Jets in Active Galactic Nuclei
David Garofalo, Chandra B. Singh, Atticus Magerko et al. (+3 more)
The well-established anti-correlation between disk winds and relativistic jets in X-ray binaries is often interpreted in a scale-invariant black hole
accretion context. If so, active
galactic nuclei (AGN) should exhibit a direct mass-scaled analog. We test this prediction across FRII
radio quasars,
radio-quiet
quasars, and jetted and non-jetted Narrow Line Seyfert 1
galaxies (NLS1) in spirals, among others. They exclude simple scale invariance. The highest-velocity winds occur exclusively in
radio-quiet
quasars, while powerful FRII
quasars host systematically weaker winds despite equally large black hole masses. Jetted NLS1s show strong wind suppression consistent with X-ray binary behavior, whereas FRII
quasars occupy a distinct regime in which jets and winds coexist. Black hole mass and
spin magnitude alone cannot account for this dichotomy. We argue that the angular momentum direction of the disk relative to that of the black hole (aligned versus anti-aligned or co-rotation versus counter-rotation) is the critical parameter: secularly fueled spiral systems and most post-merger systems favor co-rotation, which is associated with compact ISCO radii, high radiative efficiency, strong winds, and jet suppression, while the counter-rotating subset of merger-influenced ellipticals can sustain powerful jets alongside moderate winds. Moreover, while spiral AGN and merger-driven
radio-quiet
quasars experience similar strong jet/wind anti-correlation, they cannot be treated as strict scaled analogs of X-ray binaries, which undergo rapid state transitions involving
magnetic flux redistribution absent in AGN. At least two distinct wind-jet regimes therefore operate across the mass scale. We identify the details of this behavior across AGN subclasses.
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All authors David Garofalo, Chandra B. Singh, Atticus Magerko, Marco Botello, Sophia Soto, Max North
Computational Physics
Hyperspatial Sampling: Circumventing Free-Energy Barriers via Replica Exchange with Extra Dimensions
Henrik Christiansen, Matheus Ferraz, Takashi Maruyama et al. (+1 more)
Simulating systems with rugged free-energy landscapes remains a central challenge in computational physics and chemistry. We introduce hyperspatial replica exchange (HS-REX), an enhanced sampling method in which the physical system is artificially extended by additional spatial dimensions. In higher dimensions, free-energy barriers can be circumvented through paths that are geometrically inaccessible in the original space. Restricting the penalty to only solute atoms dramatically reduces the number of replicas required for solvated systems compared to standard temperature replica exchange, a feature especially relevant for biological applications. As proof of concept, we demonstrate the method on a double-well model system and on alanine dipeptide in explicit water as
benchmark system. In the latter case, HS-REX achieves enhanced conformational sampling of not only the slow backbone dihedral angles, but also both
chiral configurations of the molecule, which are sterically inaccessible to standard sampling in three dimensions. This demonstrates enhanced ergodic sampling over conventional temperature replica exchange.
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All authors Henrik Christiansen, Matheus Ferraz, Takashi Maruyama, Francesco Alesiani
Cosmology and Nongalactic Astrophysics
Dark matter-baryons elastic coupling
David Figueruelo and Florencia Anabella Teppa Pannia
We consider a cosmological model where dark matter and
baryons interact via a pure momentum transfer. We present the foundations of the interaction and derive its main equations. In this framework, only the Euler equations for the two interacting components differ from those in the standard scenario. We also explain how this interaction relates with the common Tight-Coupling Approximation schemes typically used in many Boltzmann solver. After that, we implement the model in CLASS and CAMB Boltzmann solvers, which relay on those Tight-Coupling Approximation schemes and in SymBoltz, which is free from any approximation scheme. We demonstrate full consistency among all the implementations in the difference codes. We demonstrate how this type of interactions are useful regarding the $\sigma_8$ tension by producing a reduced clustering on smaller scales. Using
cosmic microwave background,
baryon acoustic oscillations,
supernovae type Ia data and low-
redshift constraints from Sunyaev-Zeldovich cluster counts and from DES year 6 results, we show the interacting scenario is mildly preferred when those low-
redshift datasets are included.
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General Relativity and Quantum Cosmology
Les Houches lectures on Spinfoam Path Integrals
Oleksandra Hrytseniak, Etera R. Livine and Valentine Maris
In these lecture notes for the Les Houches School on Loop
Quantum Gravity 2025, which took place in September 2025, we give a pedagogical review of the basics of the spinfoam framework for a
quantum gravity path integral. While
spin network states in loop
quantum gravity describe the
quantum geometry of the 3d space as dynamical networks of entangled quanta of volumes, spinfoams define transition amplitudes for those
spin networks using the reformulation of general relativity as an "almost-topological" field theory and tools from
quantum BF theory and topological state-sums. The lectures were a short format of three times one hour and a half, only allowing to cover the basics and offer a glimpse of more advanced lines of research. We introduce
spin foam path integrals for increasing spacetime dimensions starting with 2d BF theory, then build up to 3d
quantum gravity with the Ponzano-Regge state-sum and the Turaev-Viro invariant, and finally the quantization of general relativity in four dimensions.
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Instrumentation and Methods for Astrophysics
HRMOS: a very high-resolution, multi-object spectrograph for the ESO VLT
Andrea Bianco, Sofia Randich, Emma Fernandez Alvar et al. (+7 more)
HRMOS (High-Resolution Multi-Object Spectrograph) is a proposed new instrument for the ESO Very Large
Telescope (VLT) developed in the context of the ESO VLT Beyond 2030 call. It is designed to fill a unique and currently unoccupied region in the observational landscape: the combination of very high spectral resolution (R=80,000) with multi-object capability (50-60 simultaneous targets), a radial-velocity (RV) precision of 10m/s, and coverage of three key spectral windows (385-421nm, 480-522nm, 623-677nm). Scientifically, HRMOS will address a rich portfolio of high-priority astrophysical questions spanning from f
giant exoplanet formation, to nucleocosmochronology and constraints on cosmological parameter, to probing hierarchical
galaxy assembly outside the Milky Way. The instrument is based on a modular approach and it consists in four primary subsystems, the Front End with a hybrid fiber-positioning and atmospheric dispersion correction (ADC) architecture, the Fiber Link with double-scrambling and the image slicers, three spectrographs based on volume phase
holographic (VPH) gratings covering the three spectral ranges and a Calibration Unit.
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All authors Andrea Bianco, Sofia Randich, Emma Fernandez Alvar, Oscar Gonzalez, Sergio Sousa, Thomas Bensby, Letizia Caito, Enrico Giro, Laura Magrini, Marco Riva
Instrumentation and Detectors
A Kalman Filter Based Approach to NV Diamond Data Fusion For Improved Temperature Sensing
Shraddha Rajpal, Qiaochu Guo, Brendon A. McCullian et al. (+2 more)
Nitrogen-vacancy (NV) centers in diamond have been demonstrated to enable highly sensitive temperature measurements using multiple modalities. Standalone optically detected
magnetic resonance (ODMR) provides robust temperature estimates, albeit with high latency, whereas all-optical measurements provide millisecond resolution but suffer from poorer long-term accuracy. In this work, we demonstrate a hot-start Kalman filtering approach that fuses the two modalities, leading to a 57% improvement in accuracy. The fused estimate achieves higher long-term accuracy with lower latency, demonstrating a viable route toward implementing self-correcting, high-precision NV-diamond temperature sensing schemes.
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All authors Shraddha Rajpal, Qiaochu Guo, Brendon A. McCullian, Tyrus Berry, Zeeshan Ahmed
Accelerator Physics
Electromagnetic Simulations
Thomas Flisgen
This contribution reviews fundamental concepts of electromagnetic simulations for RF structures used in particle accelerators. The necessity of numerical methods for electromagnetic simulations is discussed, and the fundamental steps involved in performing such simulations are presented. Spatial discretization is reviewed in a very general way to obtain semi-discrete equations. These semi-discrete equations are employed to revisit time-domain and frequency-domain approaches. Special
attention is devoted to the computation of network
matrices (e.g. scattering
matrices) of structures with large quality factors as this topic is highly relevant in the context of
radio-frequency for accelerators. This leads to a very short recapitulation of model-order reduction methods. The various sources of error inherent in electromagnetic simulations are examined. Finally, recommendations for the careful validation and assessment of simulation results are presented.
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Earth and Planetary Astrophysics
A closer look at the WISPIT 2 host star. Evidence for a spectroscopic binary
Cade J. Bürgy, Myriam Benisty, Hala Alqubelat et al. (+2 more)
While hundreds of protoplanetary discs have been studied in great detail, the detection of protoplanets still embedded in their native discs remains rare. WISPIT 2 is only the second laboratory allowing for direct study of
planet formation while in progress. The recently discovered system hosts two
giant protoplanets in a multi-ringed disc. Here, we aim at characterising the WISPIT 2 host
star spectroscopically to determine its
stellar properties,
accretion rate, and inner disc diagnostics, providing a more complete picture of the system. We present optical and near-infrared spectroscopic observations obtained with the ESO VLT/X-Shooter and 2.2 m/FEROS instruments. We model the
stellar spectrum to determine the spectral type and effective temperature, analyse the emission lines to estimate the
accretion rate, and search for evidence of a close
stellar companion using radial velocity measurements. Our observations reveal that WISPIT 2 is a spectroscopic binary. The binary has a period of $4.8\pm 0.1$ days, which corresponds to a semi-major axis of $0.072$ au or $15.54 R_\odot$, assuming co-planarity with the disc and a circular orbit. The binary system consists of a $\sim 0.97 M_{\odot}$ primary of spectral type K3 ($T_{\rm eff} \sim 4700K$), and a $\sim 0.33M_\odot$ secondary (mass ratio $\sim$0.34). We detect weak H$\alpha$ emission, implying an
accretion rate of $\sim 2 \times 10^{-11}\,M_{\odot}\,\mathrm{yr}^{-1}$. However, this value is below the chromospheric level, suggesting little to no ongoing
accretion onto the young
stars. This discovery makes the WISPIT 2 disc the first circumbinary system with directly imaged protoplanets, establishing this system as a unique
benchmark for studying
planet formation and disc
evolution around binary
stars.
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All authors Cade J. Bürgy, Myriam Benisty, Hala Alqubelat, Carlo F. Manara, Stefano Facchini
High Energy Astrophysical Phenomena
4th TDAMM Workshop White Paper
Daniel Kocevski, Raffaella Margutti, Michael Coughlin et al. (+46 more)
Time-Domain and Multi-Messenger Astrophysics (TDAMM) is entering a new era in which the rate and diversity of transient discoveries will grow rapidly across electromagnetic, gravitational-wave,
neutrino, and
cosmic-ray facilities. The scientific return from these investments will increasingly depend not on discovery alone, but on the ability to identify, prioritize, and coordinate follow-up observations across a heterogeneous and globally distributed network of observatories. This white paper summarizes the outcomes of the Fourth TDAMM Workshop and assesses the near-term discovery landscape, the infrastructure and tools that support coordinated observations, and the technical, policy, and capability gaps that may limit future progress. The workshop identified three principal challenges: insufficiently scalable and interoperable alert and coordination infrastructure, policies that impede rapid multi-facility observations and rare-event science, and the potential loss of critical high-energy, rapid-response, and spectroscopic capabilities. The white paper identifies the need for sustained support for alert distribution, brokers, standardized observatory metadata, cross-facility coordination platforms, and unified follow-up repositories; expanded joint observing opportunities and funding mechanisms for coordinated analysis; and strategic investment in future TDAMM facilities. The white paper also present a framework for community observing plans that would establish pre-coordinated responses to rare, high-impact events, supported by transparent governance, immediate public data release, and regular community revision. Science overviews and detailed observing strategies are provided for gamma-ray bursts,
tidal disruption events, X-ray binaries, novae,
supernovae, magnetars, compact binary mergers, and high-energy
neutrino sources.
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All authors Daniel Kocevski, Raffaella Margutti, Michael Coughlin, Christopher Fryer, Kate Alexander, Igor Lorenzo Andreoni, Jean-Luc Atteia, Elias Aydi, Matthew Baring, Joe Bright, Eric Burns, Brad Cenko, Sanjana Curtis, Fabio DeColle, Courey Elliott, Corinne Fletcher, Anna Franckowiak, Carla Fr"ohlich, Adam Goldstein, Alec Habig, Erica Hammerstein, Anna Y. Q. Ho, D. Andrew Howell, Chin-Ping Hu, Xiaoshan Huang, Michelle Hui, Brian Humensky, Jamie Kennea, Ali Kheirandish, Ryan Lau, M. Coleman Miller, Brenna Mockler, Michela Negro, Jan-Uwe Ness, Brendan O'Connor, Kim Page, Tyler Pritchard, Judith Racusin, David Radice, Christopher Roberts, Dave Russell, Dave Sand, Peter Shawhan, Rachel Street, Alexander van der Horst, Justin Vandenbroucke, Zorawar Wadiasingh, Yuhan Yao, George Younes
High Energy Physics (Phenomenology)
Non-Markovian heavy-quark equilibration and equilibrium correlation function in a thermal medium
Monisha Nair, Juan Torres-Rincon and Santosh K. Das
We compute the charm-
quark current-current correlation function within the Langevin framework and extract the heavy-
quark diffusion coefficient using the Green–Kubo formula. The formalism is further extended to evaluate the correlation function using a generalized Langevin equation that incorporates
memory effects via an exponentially decaying
memory kernel. We find that while
memory effects qualitatively modify the transient structure of the current correlations, the value of the transport coefficient remains unchanged in the non-relativistic limit. In addition, we investigate heavy-
quark thermalization in the presence of
memory and compare the non-
equilibrium solution of a generalized Fokker–Planck equation with the one obtained from the generalized Langevin equation in the non-relativistic limit. We also consider the relativistic version of the correlated noise case and observe that
memory effects can give rise to a damped, oscillatory equilibration of the heavy
quark in a non-Markovian bath.
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Fluid Dynamics
Neural Differential Equations for Oscillatory Flows in Aeroelasticity Applied to Transonic Buffet
Michael Candon, Pier Marzocca and Earl Dowell
Self-excited aerodynamic flows arise across a broad range of systems and can drive nonlinear fluid-structure interactions and aeroelastic instabilities that are challenging and computationally expensive to predict. This paper presents a physics-guided neural differential equation (DE) reduced order model (ROM) combining a nonlinear fluid oscillator, a finite-
memory multi-input Volterra series, and a compact neural network correction. The multi-input aerodynamic formulation is generalized to m structural modes, capturing direct and nonlinear cross-modal coupling. The model is identified from a single prescribed-motion CFD simulation with simultaneous excitation of all retained structural modes, and is then coupled with the structural equations of motion for efficient aeroelastic prediction. Applied to transonic buffet over the ONERA OAT15A airfoil, the time-marching ROM predicts aeroelastic stability, frequency lock-in, and limit cycle amplitudes in good agreement with full-order reference solutions. The ROM is used to provide substantial new insight into buffet-induced aeroelastic instabilities involving more than one structural mode.
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General Relativity and Quantum Cosmology
Light deflection in general static and spherically symmetric spacetime with a homogeneous plasma
Guanming Li, Zhongze Li and Junji Jia
We developed in this work a perturbative technique to compute the deflection angle of light rays in general static and spherically symmetric spacetimes with a homogeneous non-
magnetic plasma. The deflection angle is expressed as a power series of $M/b$ with $M$ and $b$ being the spacetime mass and the impact parameter of the ray. The series coefficients are
polynomials of the asymptotic expansion coefficients of the metric functions and the reciprocal of the asymptotic refractive index. When the
plasma is dilute, the deflection angle can also be expressed as a dual series of $M/b$ and the frequency ratio between the electron
plasma frequency and the asymptotic
photon frequency. The series result reveals that for general SSS spacetime, the
plasma at the leading order always enhances the deflection angle and therefore increases the apparent angles of the gravitational
lensing images. These series results of the deflection angle are then shown to have excellent agreement with those obtained using numerical integration. The general formula of the deflection angle is then applied to the Reissner-Nordström, charged Horndeski and charged Galileon spacetimes. The effect of the
plasma and characteristic parameter of the spacetimes on the deflection angles in these spacetimes was briefly discussed. In the appendix, the deflection angles in previously attempted spacetimes are re-computed and compared with the literature.
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Quantum Physics
Explicit block-encodings for biharmonic boundary-value problems
Chuwen Ma and Zihao Tang
The biharmonic equation is a prototypical fourth-order partial differential equation whose high-dimensional discretization suffers from rapidly growing degrees of freedom and severe ill-conditioning. We develop QSVT–VTAA
quantum linear-system
algorithms by constructing explicit block-encodings tailored to periodic, simply supported, and Dirichlet–Neumann boundary conditions. For periodic and simply supported problems,
Fourier and sine-transform diagonalizations yield augmented Poisson systems with the condition-number scaling of a second-order operator. For Dirichlet–Neumann problems, we introduce a second-order boundary-corrected finite-difference discretization, establish mesh-independent stability, and construct an explicit block-encoding of the resulting nonsymmetric
matrix. We also formulate a coupled-Laplace system with additional boundary unknowns and characterize its complexity in terms of the condition number of the complete augmented
matrix. The analysis covers discretization error, block-encoding normalization, gate complexity, and solution extraction under an amplitude-input and
quantum-state-output model. Numerical experiments validate the proposed discretizations and the corresponding linear solves.
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High Energy Physics (Phenomenology)
Simultaneous extraction of top quark mass, strong coupling, effective mixing angle, and proton PDFs using inclusive DIS and proton-proton collision data
Mikel Mendizabal Morentin, Katerina Lipka, Giovanni Limatola et al. (+4 more)
We present the first simultaneous determination of the
proton parton distribution functions (PDFs) together with the strong coupling, the top
quark pole mass, and the effective weak mixing angle. The analysis is performed at next-to-next-to-leading order in QCD using the xFitter framework, based on inclusive deep-inelastic scattering measurements at HERA and precise measurements of jet, electroweak
boson, and top
quark-antiquark pair production in
proton-
proton collisions at the LHC. Non-relativistic QCD effects in top
quark-antiquark pair production are considered at next-to-leading order, and combined with next-to-leading logarithmic soft-
gluon resummation. Simultaneously with PDFs and Standard Model (SM) parameters, relevant top
quark SM effective-field-theory (SMEFT) operators are constrained. The precision of the obtained SM parameters is competitive with the state-of-the art individual extractions and accounts for the correlations among those parameters and PDFs. This work paves the way for future global interpretation of the LHC data in terms of QCD, SM and SMEFT.
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All authors Mikel Mendizabal Morentin, Katerina Lipka, Giovanni Limatola, Efstathios Agrafiotis, Oleksandr Zenaiev, XiaoMin Shen, Sven Olaf Moch
Instrumentation and Methods for Astrophysics
ANDES, the high-resolution spectrograph for the ELT: design and performance analysis of the YJH spectrograph
Vinooja Thurairethinam, David Lee, James Stevenson et al. (+29 more)
The ArmazoNes high Dispersion Echelle Spectrograph (ANDES) is a powerful second-generation high-resolution spectroscopic instrument for the Extremely Large
Telescope (ELT). The UBV, RIZ, and YJH modules comprise fibre-fed spectrographs of the ANDES baseline design and will offer continuous wavelength coverage of 0.35-1.8 $\mu$m, with the addition of a K-band channel providing coverage up to 2.4 $\mu$m. Coupled with a spectral resolution of $\sim$100,000, ANDES must deliver the required wavelength calibration stability of 1 m/s over 24 hours, with a goal of 0.02 m/s across 10 years. These requirements establish the framework for the infrared module of ANDES, the YJH Spectrograph, leading to what will likely be the largest cryogenic, ultra-stable, high-resolution spectrograph ever built, and will offer the unique ability to observe in both seeing- and diffraction-limited modes interchangeably. We present the current design and performance analysis of the ANDES YJH Spectrograph, outlining the engineering challenges encountered alongside the corresponding strategies adopted to navigate them. In particular, we detail the technology development of the primary dispersing element, an echelle grating mosaic that will span over a metre in length.
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All authors Vinooja Thurairethinam, David Lee, James Stevenson, Étienne Artigau, Frédérique Baron, Ciarán Breen, Bella Boyd, Denis Brousseau, David Buscher, Neil J. Cook, René Doyon, Martin Fisher, Bradley Frank, Vincent Geers, Rory Gillespie, Oscar Gonzalez, Éamonn J. Harvey, Wei Li, Roberto Maiolino, Lison Malo, Thomas Marquart, David Montgomery, Alan O'Brien, Ernesto Oliva, Jonathan St-Antoine, Jay Stephan, Simon Thibault, Philippe Vallée, Chris Waring, Sandi Wilson, Junyi Zhou, Paolo Di Marcantonio
Mathematical Physics · Cross-listed from math.PR
Super-Brownian limits and the $k$-point function for high-dimensional percolation
Arthur Blanc-Renaudie and Tom Hutchcroft
We prove that there exist positive constants $A$ and $V$ such that the high-dimensional critical percolation $k$-point function is given by \[ T_{p_c}(x_1,x_2,\ldots,x_{k}) \sim V^{k-2} A^{2k-3} \sum_{T\in \mathsf{Tr}(k)} \sum_{\substack{\Phi:V(T)\to \mathbb{Z}^d \\ \Phi(i)=x_i \forall 1\leq i \leq k}} \prod_{\substack{u,v\in V(T)\\u\sim v}}G(\Phi(u),\Phi(v)) \] as $\min_{i\neq j}\|x_i-x_j\|\to \infty$, where $\mathsf{Tr}(k)$ is a set of isomorphism class representatives of trees with $k$ labelled leaves $\{1,\ldots,k\}$ and unlabelled internal vertices all of which have degree $3$ and $G$ is the
lattice Green's function. This verifies a
conjecture of Aizenman and Newman (1984) subject to the usual perturbative conditions needed for convergence of the lace expansion. It follows from this
theorem that the law of the cluster of the origin, considered as the counting measure on its range, converges under rescaling to the canonical measure of the integrated super-Brownian excursion. By computing the asymptotics of various more complicated variations on the $k$-point function, we also prove the stronger result that the cluster converges as an embedded metric-measure space to the continuum random tree equipped with its Brownian
embedding into $\mathbb{R}^d$. This convergence holds simultaneously with respect to the chemical distance, pivotal distance, and resistance distance on the cluster, which we prove are asymptotic to constant multiples of each other. This resolves
conjectures of Hara and Slade (1998) and van der Hofstad and Slade (2003). As a corollary of our results we prove that there exists a positive constant $C$ such that $\mathbb{P}_{p_c}(0\leftrightarrow \mathbb{Z}^d \setminus [-r,r]^d)\sim C r^{-2}$, answering a question of Heydenreich and van der Hofstad (2017).
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