High Energy Physics (Theory)
The doubly conformal dispersion relation
Maddalena Ferragatta and Balt C. van Rees
We provide a simple derivation of the conformal dispersion relation of Carmi and Caron-Huot which reconstructs a CFT four-point function from its double discontinuity. We exhibit a hidden conformal
symmetry which explains the appearance of the "magic variable" x as a simple cross-ratio, built from four physical cross-ratios. We also introduce a regulator in the double discontinuity operation and then prove that one subtraction suffices for all integrals to converge.
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Earth and Planetary Astrophysics
Recovering the Morning and Evening Limbs of WASP-94Ab from Its Limb-Averaged JWST Transmission Spectrum
Tyler R. Fairnington, Michael Radica, Michael Zhang et al. (+5 more)
Recent JWST observations have revealed that the morning and evening limbs of the hot Jupiter WASP-94Ab have very different transmission spectra. An analysis of these resolved limb spectra yielded a
metallicity more than an order of magnitude below that obtained from the limb-averaged spectrum, which calls into question the accuracy of traditional
retrievals for heterogenous
planets. Here we analyze the limb-averaged JWST NIRISS and NIRSpec transmission spectra of WASP-94Ab using both a standard one-temperature-profile (1-TP)
retrieval with patchy clouds, and a new two-temperature-profile (2-TP)
retrieval. The 2-TP
retrieval assumes a linear combination of two atmospheric components that share the same bulk elemental composition but have independent thermal structures, chemistries, and aerosol properties. This model is implemented in PLATON 7.0, a JAX-accelerated code that is over 100 times faster than its predecessor, which is key to making the
retrieval computationally tractable. The limb-averaged spectrum of WASP-94Ab favors the 2-TP model by a Bayes factor K=1.8x10^{5} and shifts the
metallicity downward to Zatm/Zsun = 11^{+9}_{-4} from 170^{+30}_{-24} obtained with the 1-TP model. The 2-TP
retrieval predicts two, equally weighted components that reproduce the limb-resolved spectra across both instruments without prior knowledge of them. This work demonstrates that compositional information survives limb averaging for WASP-94Ab, suggesting that 2-TP
retrievals can be used to identify limb-asymmetry and extend
metallicity studies beyond the small set of
planets amenable to limb-resolved spectroscopy.
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All authors Tyler R. Fairnington, Michael Radica, Michael Zhang, Eliza M.-R. Kempton, Jacob L. Bean, Eva-Maria Ahrer, Arjun B. Savel, Pascal S. D'Andrea
Superconductivity
Metallic Néel order stabilized by coupling between inequivalent Hubbard layers
Yi-Ming Wu, Jessica Yiqi Pan, Hong Yao et al. (+1 more)
Inspired by recent ARPES studies on multilayer ($n\geq3$ layers) cuprate
superconductors, we use the unrestricted Hartree-Fock approximation to explore the ground-state phase diagram of two coupled, inequivalently doped square-
lattice Hubbard layers. In the decoupled-layer limit, the lightly hole-doped ground state is typically an incommensurate
spin-stripe state. However, with sufficiently strong interlayer coupling, stripe order is destabilized relative to a commensurate Néel-ordered metal. The resulting state exhibits a reconstructed
Fermi surface with hole pockets centered at $(\pm\pi/2,\pm\pi/2)$ that are similar in character to those seen in experiments. Our results illustrate the qualitatively new physics that can arise from interlayer coupling in multilayer cuprates.
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All authors Yi-Ming Wu, Jessica Yiqi Pan, Hong Yao, Steven A. Kivelson
Astrophysics of Galaxies
ALMA Chemical Evolution (ACE) survey: The gas fundamental metallicity relation at cosmic noon
I. Langan, I. Shivaei, G. Popping et al. (+11 more)
Chemical enrichment shapes how
galaxies form and evolve. The gas-phase
metallicity is directly linked to the
stellar mass,
star formation rate, and cold gas of the interstellar medium. Thus, the cold gas fundamental
metallicity relation (GFMR) is a powerful tool for probing
galaxy evolution, bridging large-scale gas flows modulating the cold gas reservoir and small-scale metal enrichment tracing the cumulative impact of
star formation. Constraining all these properties for the same representative sample of
galaxies remains challenging yet essential. Using CO(3–2) band 3 observations from the Atacama Large Millimeter/submillimeter Array Chemical
Evolution (ACE) survey, we investigated the GFMR in a sample of 26 main-sequence (log(M_*, med)=9.96), subsolar-
metallicity (12+log(O/H)_med=8.44)
star-forming
galaxies (SFGs) at z~2. With 17/26 CO detections, including some of the lowest-
metallicity CO detections at
cosmic noon, we find that the
stellar mass remains the primary driver of the chemical
evolution in our sample (sigmaMZR~0.10). Whereas the molecular gas likely plays a secondary role (sigmaGFMR~0.11) similar to that of the
star formation rate (sigmaFMR~0.13). This likely reflects our sensitivity to only the CO-bright component of the molecular reservoir. Our results remain consistent with gas-regulator models and suggest the existence of efficient molecular
outflows, with an average mass loading factor of eta~4, regulating
star formation and chemical enrichment.
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All authors I. Langan, I. Shivaei, G. Popping, L. A. Boogaard, N. N. Geesink, M. Kaasinen, A. Pope, R. Popescu, M. Solimano, L. Arriscado, D. Narayanan, M. Parente, N. Reddy, R. L. Sanders
High Energy Astrophysical Phenomena
Little Red Dots As Super-Eddington Fountain Flows
Nicholas Kaaz, Eliot Quataert, Taya Govreen-Segal et al. (+1 more)
Little red dots (LRDs) may be powered by supermassive black holes (SMBHs) accreting above the Eddington limit. Spectroscopy of LRDs often shows absorption troughs blueshifted by $\sim100-300\,{\rm km\,s^{-1}}$, implying a slow wind. This is puzzling: super-Eddington disks drive much faster winds, $\gtrsim10^3-10^4\,{\rm km\,s^{-1}}$. We argue that LRDs are super-Eddington SMBHs viewed off-axis and engulfed in a slow wind that covers most sight-lines; the fast wind escapes near the poles. Trapped light puffs the inner disk into a quasi-spherical envelope that launches the slow wind. The wind may be “
photon-tired”, meaning the light only barely unbinds it. Such marginally unbound winds lead to fountain flows, where some gas escapes and the rest falls back. We model the envelope with idealized, spherically symmetric “marginally unbound” ($v\sim v_{\rm esc}$) and “
photon-tired” winds. We feed these profiles into the radiative transfer code Sirocco to study how the wind reprocesses the light from an accreting $10^6\,M_\odot$ SMBH. We describe most of the wind as a “Balmer cocoon” – a Compton-thick region in which depletion of Balmer continuum
photons ($h\nu >3.4\,{\rm eV}$) rather than Lyman continuum
photons ($h\nu > 13.6\,{\rm eV}$) keeps the gas ionized. The spectra span the range of LRD-like sources: “little blue dots” at lower
outflow rates ($\sim2.5\,M_\odot\,{\rm yr}^{-1}$); V-shaped LRDs with a Balmer break ($\sim5-10\,M_\odot\,{\rm yr}^{-1}$); and red LRDs with full breaks ($\sim15\,M_\odot\,{\rm yr}^{-1}$). Our Balmer line profiles show P~Cygni features atop broad, exponential wings, as is observed. The break is possible at lower wind densities than in LTE models because Lyman~$\alpha$ trapping sustains our $n=2$ hydrogen population and electron scattering enhances the optical depth. Our arguments are also applicable to winds from supermassive
stars or quasi-
stars.
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All authors Nicholas Kaaz, Eliot Quataert, Taya Govreen-Segal, Hanpu Liu
High Energy Physics (Theory)
Massive type 0A string theory and M-theory
Niccolò Cribiori, Andriana Makridou and Salvatore Raucci
We propose an M-theory origin for the two massive deformations of type 0A string theory by extending Hull's realization of massive type IIA in the context of a recent proposal for massless type 0A from M-theory. We introduce an M-theory setup that we call
quantum fibration, in which two independent integral monodromies yield the Romans masses, T-dual to the two Chern numbers of the
quantum fibration. A key ingredient is a formulation of the type 0B duality group in terms of a marked
elliptic curve. We discuss further implications of this description and some puzzles concerning the M-theory origin of branes and Chern–Simons terms.
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High Energy Physics (Phenomenology)
Entropy Dilution Mechanism and Dark Matter Isocurvature
Miha Nemevšek and Yue Zhang
We explore dark matter isocurvature perturbations in cosmological scenarios with
entropy dilution resulting from a late decaying massive state that temporarily dominates the universe before big-bang nucleosynthesis. The dilution mechanism features a non-standard scaling window of the radiation energy density, which allows for a new way to derive the
entropy dilution factor. On super-horizon scales, the same scaling window also governs the
evolution of isocurvature, and we present an analytic approach to solving the perturbation equations. We characterize various regimes where dark matter isocurvature survives and is subject to constraints from the
cosmic microwave background observations. For cosmologically viable scenarios, we find that dark matter is dominantly produced from its dilutor decay, and the isocurvature is suppressed by the
entropy dilution factor to the $4/3$ power. Our work demonstrates the complementarity between isocurvature and collisionless damping of dark matter as powerful probes of the
entropy dilution mechanism.
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High Energy Physics (Theory)
Discrete Gauging of 5d $\mathcal{N}=1$ $E_n$ SCFTs
Guillermo Arias-Tamargo, Mario De Marco, Craig Lawrie et al. (+2 more)
We study the gauging of discrete
symmetries of the 5d rank-one $E_n$ SCFTs that fix the Coulomb branch coordinate but act nontrivially on the
Higgs branch
chiral ring. Using generalized toric polygons and $(p,q)$-brane webs, we identify
symmetries of the
moduli space that extend to
symmetries of the full SCFT. In many cases they are non-anomalous, and we analyze the
moduli space of the gauged theories. We realize the resulting
Higgs branch quotients as Coulomb branches of wreathed
magnetic quivers and compute their
Hilbert series; the
flavor algebras extracted from moment maps agree with the fixed-point subalgebras of $\mathfrak{e}_n$. We also lift the discrete actions to the Seiberg–Witten geometry and recover the expected restriction on the mass deformations. For $\mathbb{Z}_2$-wreathings that exchange adjacent gauge nodes, we find that the monopole formula requires a flux-dependent sign and propose a corrected prescription. Finally, we
conjecture a higher-rank extension and verify it for the rank-two $E_6/\mathbb{Z}_2$
Higgs branch.
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All authors Guillermo Arias-Tamargo, Mario De Marco, Craig Lawrie, Shani Nadir Meynet, Alessandro Mininno
Strongly Correlated Electrons
Bootstrapping Disordered Quantum Systems
Yaprak Önder, Michael G. Scheer, Minjae Cho et al. (+1 more)
We present a bootstrap framework that yields rigorous two-sided bounds on ground-state observables of
quantum systems with quenched disorder. The key idea is to extend the operator
algebra to include classical disorder variables and to encode the disorder distribution through a set of moments. The method directly bounds disorder-averaged expectation values for finite or infinite
lattice systems and for arbitrary disorder distributions. In contrast to conventional approaches, we do not need to sample disorder realizations, which enables us to make thorough use of
symmetries that hold only on average rather than for each disorder realization. Additionally, we show that multi-replica operators can be used to access disorder fluctuations such as the variance of an observable. We apply the method to the one-dimensional random transverse-field Ising model (RTFIM) with discrete, uniform, and Gaussian disorder, obtaining tight bounds on the disorder-averaged ground-state energy density and short-range
spin-
spin correlators, as well as bounds on the disorder variance of the energy density. Additionally, we show that the difference between the upper and lower bounds on the disorder-averaged ground-state energy density, which we term the bootstrap gap, can be used to map out the phase diagram of the RTFIM. The bootstrap gap is small and flat within the paramagnetic and
ferromagnetic phases at weak disorder, grows upon entering the Griffiths regions, and peaks along the critical line.
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All authors Yaprak Önder, Michael G. Scheer, Minjae Cho, Eslam Khalaf
High Energy Physics (Theory)
A Type IIB Dualifold
Zihni Kaan Baykara and Cumrun Vafa
We present evidence that ten-dimensional type IIB string theory orbifolded by the $\mathbb{Z}_3$ duality
symmetry at the strong-coupling fixed point $\tau=\exp(2\pi i/3)$ defines a consistent theory. Motivated by its F-theory dual description and its duality with M-theory in nine dimensions and type IIA string theory in eight dimensions, we argue that the resulting theory is a ten-dimensional
chiral non-supersymmetric theory with a discrete gauge
symmetry whose bosonic part is the
automorphism group of the Narain
lattice $\Gamma^{2,2}(A_2)$ ($S_3 \times S_3 \times \mathbb{Z}_2$). We further identify the ten-dimensional tachyon fields with the corresponding Narain
moduli. Gauge anomalies cancel nontrivially through a topological Green-Schwarz mechanism involving a $\mathbb{Z}_3$-valued two-form gauge
symmetry: the ten-dimensional lift of the familiar zero-form orbifold
quantum symmetry in the eight-dimensional type IIA description.
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High Energy Physics (Phenomenology)
All-Order Helicity Selection Rules in Effective Field Theories
Luigi C. Bresciani and Nudzeim Selimovic
Using on-shell methods, we derive an all-order non-renormalization
theorem for general four-dimensional effective field theories, relying on Poincaré invariance and unitarity. Each operator $\mathcal O$ is assigned the weights $(w,\bar w)=(\ell-h,\ell+h)$, where $\ell$ and $h$ are the number of particles and total helicity of its minimal configuration. At $L$ loops, the mixing $\mathcal O_j\to\mathcal O_i$ vanishes when $\ell_j-\ell_i=L-1$ and either $w_i<w_j-2(L-1)$ or $\bar w_i<\bar w_j-2(L-1)$, in the absence of non-holomorphic Yukawa couplings. These zeros follow entirely from tree-level data and are scheme independent under finite renormalizations that preserve the operator-length selection rule. For operators of dimensions five through eight, we identify broad classes of previously unknown zeros at higher loop orders, with particular emphasis on two loops, where the
theorem provides direct checks on current calculations, as in the Standard Model Effective Field Theory.
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Astrophysics of Galaxies
Free-Free Radio Emission from Little Red Dots as a Probe of Ionized Gas
Takumi S. Tanaka, Kohei Inayoshi, Zu Yan et al. (+3 more)
Recent studies have hypothesized that little red dots (LRDs) are rapidly accreting black holes surrounded by dense gaseous environments. Both neutral and ionized gas play a key role in explaining many of the puzzling spectral features of LRDs, including the emission line profiles in the optical-infrared bands, although the physical conditions required for these gas components remain poorly constrained. We propose that free-free emission provides a robust, independent probe of ionized gas in LRDs. Free-free self-absorption produces a characteristic spectral turnover whose critical frequency and luminosity depend on the electron column density and the characteristic size of the ionized region, such that
radio observations simultaneously constrain both quantities. The spectral slope at frequencies below the turnover further probes the radial density distribution on spatial scales far below those achievable by current and future optical-infrared observatories. We also present predicted free-free spectral energy distributions for two representative LRDs in the local and high-
redshift universe and show that future
radio-to-millimeter observations with ALMA and ngVLA can probe the range of ionized-gas parameters inferred from current observations. Free-free emission therefore offers a unique way to probe the geometry and physical conditions of the ionized gas surrounding LRDs.
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All authors Takumi S. Tanaka, Kohei Inayoshi, Zu Yan, Tomokazu Kiyota, Yuichi Harikane, John D. Silverman
Quantum Physics · Cross-listed from cs.LG
Do Quantum Models Scale Like LLMs?
David S. Berman, Ying-Jer Kao, Roger G. Melko et al. (+1 more)
In this work, we study the neural scaling laws of RydbergGPT, an autoregressive
transformer model trained on
qubit projective measurement data gathered from interacting Rydberg atom arrays. The
quantum system is known to exhibit a finite-size remnant of a critical point as the
laser detuning parameter is varied. We find that near the critical point the
transformer loss as a function of training
dataset size is well described by a power-law with a loss floor correction. However, away from criticality the quality of the power-law description is substantially reduced. We then compare the statistical structure of both Rydberg measurements and natural-
language corpora using an
entropy-normalised, finite sample corrected mutual information "two-point" function. We find that near-critical statistics of the two point functions are closest to those observed in natural-
language, whilst other
qubit configurations far from the critical point have two-point functions that decay more rapidly. This supports the hypothesis that multi-scale dependence contributes to stable neural scaling, and that scaling behaviour should be viewed as a property of the model-data pair.
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All authors David S. Berman, Ying-Jer Kao, Roger G. Melko, Alexander G. Stapleton
High Energy Physics (Theory)
Calculating Axion-Matter Couplings in String Theory
Joshua N. Benabou, Naomi Gendler, Thomas R. Harvey et al. (+1 more)
In this work we calculate, for the first time, the dominant perturbative contributions to
axion–matter couplings explicitly in string theory. Concretely, we compute these couplings in Calabi–Yau compactifications of heterotic string theory where the vector bundle is a sum of line bundles. They are expressed as overlap integrals requiring the
Ricci-flat metric, the Hermitian Yang-Mills bundle metric, and the matter field harmonic forms. We compute these by solving the corresponding coupled differential equations with neural networks. Our results establish a characteristic hierarchy of four-dimensional couplings:
axions couple to
fermions as $\mathcal{L} \supset c_\psi\,\frac{\partial_\mu a}{f_a}\, \psi^\dagger \bar{\sigma}^\mu \psi$ with $c_\psi$ an $\mathcal{O}(1)$ function of Kähler
moduli for the model-dependent
axions, while the corresponding coupling for the model-independent
axion is suppressed by $\alpha_{\rm YM}$ at the ultraviolet matching scale. The model-dependent
axions thus couple to
fermions similarly as DFSZ-like four-dimensional
axions, whereas the model-independent
axion's couplings are loop-suppressed as in KSVZ-like constructions. The methods developed here apply directly to the large class of heterotic line bundle models with realistic spectra, and can be adapted to type II constructions.
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All authors Joshua N. Benabou, Naomi Gendler, Thomas R. Harvey, Jakob Moritz
Materials Science
Deformation-induced amorphous complexion transitions elevate strength and ductility
Masoud Ahmadi, Jin Qin, Gabrielle Tiphéne et al. (+6 more)
Grain boundary engineering is a major avenue for tailoring the mechanical behavior of polycrystalline materials. Grain boundary complexions, including amorphous intergranular films, are classically accessed through thermal driving forces and solute segregation. Here, we discover that plastic deformation can drive amorphous complexion transitions at room temperature in a chemically primed nanocrystalline binary CuZr
alloy. High-resolution and four-dimensional scanning transmission electron microscopy reveal that the amorphous complexions preferentially emerge at incoherent twin boundaries. Spatially-resolved electron pair distribution function analysis at the atomic scale, the local-order characterization of amorphous complexions, demonstrates short-range and medium-range order gradients from
crystal-templated interfaces to a metallic-glass-like core. We thus uncover a novel amorphous complexion transformation-induced plasticity mechanism that concurrently increases the yield strength, fracture strain, and tensile toughness about a factor of two relative to a designed reference material. Our findings establish mechanical deformation as a non-thermal pathway to trigger amorphous interfacial states for enhancing damage tolerance in nanostructured metals.
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All authors Masoud Ahmadi, Jin Qin, Gabrielle Tiphéne, Mohamed Charai, Alejandro Gómez-Pérez, Khalid Hoummada, Thomas Pardoen, Matteo Ghidelli, Hosni Idrissi
Atomic Physics
Integration of the NIST Spectroscopic Plate Archive into the Harvard Plate Stacks
Jacob Ward, Thom Burns, Lisa Bravata et al. (+2 more)
For many decades, the National Institute of Standards and Technology (NIST) Atomic Spectroscopy Group housed a growing collection of thousands of photographic glass plate negatives. With the closure of the NIST Atomic Spectroscopy Group in March 2025, the irreplaceable collection needed a new home. Staff from NIST were contacted by staff from the Harvard Plate Stacks at the Center for Astrophysics | Harvard & Smithsonian (CfA). The Harvard Plate Stacks is the largest collection of astronomical glass plates in the world, with over 500,000 glass plate negatives from the 1880s to the 1990s. Given the long-standing history of the Harvard Plate Stacks and the expertise of the staff, it was decided that the NIST archive would move to the CfA. We summarize the contents of this collection regarding the instruments used and the spectra measured, and we present the tools and procedures we use for digitizing the collection. This includes the use of calibrated flatbed scanners for digitizing the plates themselves, as well as the digitization of correlated lab notebooks with important metadata associated with the plates.
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All authors Jacob Ward, Thom Burns, Lisa Bravata, Gillian Nave, Adam Foster
General Relativity and Quantum Cosmology
Thermodynamic topology of magnetic GMGHS black holes: the $\overline {W}^{1-}$ subclass
Dejiang Yin, Qi-Qi Liang, Yu-Die Wan et al. (+1 more)
Thermodynamic
topology provides a topological classification of black hole states and their branch structures in thermodynamic parameter space. We investigate the thermodynamic
topology of the charged nonextremal
magnetic Gibbons–Maeda family in four-dimensional asymptotically flat Einstein–Maxwell–dilaton
gravity, with particular emphasis on its string-theory member at the dilaton coupling $a=1$, the Gibbons–Maeda–Garfinkle–Horowitz–Strominger (GMGHS) black hole. An analytic classification over the complete domain of regular outer horizons shows that the dilaton coupling separates the family into three limiting structures of the inverse Hawking temperature. At $a=1$, the GMGHS defect curve approaches a nonzero lower inverse temperature endpoint and contains a single unstable branch. In particular, the
magnetic GMGHS black hole provides an explicit realization of the previously proposed $\overline W^{1-}$ thermodynamic topological subclass within an asymptotically flat Einstein–Maxwell–dilaton solution. This result demonstrates that the global topological number $W$ alone does not completely characterize black hole thermodynamic
topology. The asymptotic behavior of the inverse Hawking temperature near the boundaries of the physical horizon domain provides an additional criterion for distinguishing thermodynamic topological subclasses with the same $W$.
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All authors Dejiang Yin, Qi-Qi Liang, Yu-Die Wan, Li-Yun Zhang
General Relativity and Quantum Cosmology
Slowly Rotating Wormholes in f(R,T) Gravity: Particle Dynamics and Weak-field Lensing
M. Sharif, Tayyab Naseer and Rida Batool
Among all gravitational solutions, traversable wormholes stand out as truly fascinating, yet within general relativity, they almost always demand exotic matter that necessarily violate null energy requirement. The inclusion of matter-geometry coupling in modified
gravity theories provides a viable platform where wormholes remain open which are supported by effective gravitational field. We therefore examine the structure and properties of slowly rotating traversable wormholes using the $f(R,T)$ framework. We formulate stationary wormhole models coupled with the anisotropic fluid and show that they are regular, horizon-free, approach a flat spacetime geometry at large distances, and satisfy the
flare-out requirement at the throat. Our results indicate that the required matter meets both the null and strong energy conditions, demonstrating that rotating wormholes do not necessarily require unconventional sources. We further study particle trajectories, frame dragging phenomena, and non-geodesic behavior resulting from matter-geometry coupling, alongside the weak-field and
lensing effects caused by the rotation. Our results establish the potential astrophysical viability of rotating wormholes in $f(R,T)$
gravity.
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Chemical Physics
RECOB: Reliable Benchmarking of Experimental Optimization in Chemistry and Materials Science
Zikai Xie, Jiaming Wan and Linjiang Chen
Optimization methods for experimental science are often evaluated on synthetic functions that are reproducible but omit important characteristics of real experiments. We introduce RECOB (REliable Chem Optimization
Benchmark, Github repository: \hyperlink{https://github.com/XieZikai/RECOB}{https://github.com/XieZikai/RECOB}), a black-box optimization
benchmark constructed exclusively from data generated through physical experiments in chemistry and materials science. The suite contains 14 single-objective and two multi-objective tasks spanning chemical reactions, material formulations, electrochemical systems, continuous-flow processes, and automated laboratories. Each task provides a machine-readable specification of its decision variables, feasible domain, physical constraints, objective direction, and experimental provenance. Continuously queryable learned oracles are screened using repeated holdout validation and prespecified admission criteria, while measured-table replay enables evaluation using the original experimental responses. Under a common paired evaluation protocol, we compare ten single-objective and eight multi-objective optimization methods. HEBO achieves the best aggregate single-objective rank, while qNEHVI leads the multi-objective comparison. Model-based methods generally outperform non-adaptive baselines, although their computational overhead varies substantially. We further assess
benchmark reliability using independent oracle retraining and measured-table replay. Aggregate optimizer rankings remain highly consistent across retrained oracles, while replay preserves the broad performance hierarchy using only physically measured responses. Together, these results show that RECOB can reproducibly distinguish optimizer performance as an experimentally grounded and reliability-tested
benchmark for black-box optimization in chemistry and materials science.
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Quantum Physics
Environment Alignment and Redundant Record Formation in Imperfect-CNOT Quantum Darwinism
Aleksander Lasek and Paweł Horodecki
Quantum Darwinism explains objective information through redundant environmental records. Earlier work established that imperfect records can be amplified and that environment self-
evolution can enhance or suppress their formation. We investigate how preparation, interaction angle, and field disorder combine in an imperfect-CNOT model with random Gaussian couplings and pure, noninteracting environment
qubits. We find that, without fields, a single
alignment parameter $\Lambda$ determines the preparation and interaction-angle dependence of conditional-state distinguishability. Increasing interaction imperfection or local field strength can improve or suppress recording. We explain this nonmonotonic response through the geometry of conditional branch separation. For the pure initial environments considered here, the $Z$ basis remains optimal for Holevo information, so field-assisted recording requires no change of the recorded system observable. Comparing uniform local field strengths with Gaussian-distributed strengths at equal root-mean-square strength shows how disorder broadens both beneficial and detrimental field effects. Exact expressions for fragment information and numerical simulations with up to 24 environment
qubits quantify the distinction between high mean information and reliable records across fragments and throughout a finite observation window. These results connect the geometry of local information acquisition to the fragment sizes needed for robust recording. The branch-distinguishability analysis itself requires only the conditional
evolution of each environment
qubit and extends to other interactions that preserve a system pointer basis.
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Computational Physics
How Does Distribution Shift Shape Pretraining Gains in Neural PDE Surrogates?
Pochinapeddi Sai Bhargav, Nithin Somasekharan, Rohit Sunil Kanchi et al. (+2 more)
Pretraining a neural PDE surrogate can reduce the amount of new CFD data needed when geometry or modeled physics changes. However, it remains unclear how different components of distribution shift affect this benefit. We pretrain a surrogate on 254,909 RANS solutions from one airfoil family and fine-tune it on a new family under two target settings with matched freestream ranges: the same Spalart-Allmaras (SA) modeling and SA with added $e^N$ transition modeling. At $N=1000$, the pretrained model matches the accuracy of a model trained from scratch on $3.25\times$ as many samples for the same-SA target, but $2.58\times$ as many for the transition-modeled target. By $N=5000$, this ordering reverses ($1.56\times$ versus $1.86\times$). At $N=1000$, sampling more distinct airfoils lowers error on both targets, but only for the same-SA target is the gain increase larger than the observed draw-to-draw variation ($3.3\times$ to $4.0\times$). These results show that pretraining value depends jointly on target-data budget, target-data coverage, and whether source and target differ in modeled physics.
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All authors Pochinapeddi Sai Bhargav, Nithin Somasekharan, Rohit Sunil Kanchi, Sicheng He, Shaowu Pan
Strongly Correlated Electrons
A comparison between statistics and 't Hooft anomaly
Hanyu Xue
Anomalies of generalized
symmetries are closely related to the statistics of topological excitations. Truncating a
symmetry transformation to a finite region produces an operator that creates
symmetry defects on its boundary; we call this a
symmetry patch operator. Such operators resemble hopping operators that create topological excitations at the boundary of their support, but this
geometric similarity does not justify identifying the two. For finite Abelian groups in one spatial dimension, we prove that if the same family of local operators defines both valid hopping operators and compatible
symmetry patches, the type-III component of the anomaly is $-2$ times that of the statistics. We establish a one-to-one correspondence between statistics and anomaly by treating hopping operators as symmetric operators that commute with the global
symmetry, following the description of
symmetry through the
algebra of local symmetric operators. We explain this correspondence through gauging by coupling boundary matter to a Dijkgraaf-Witten gauge field in one higher spatial dimension. Hopping operators act on the gauge-invariant degrees of freedom. After fixing the background gauge field, the residual gauge transformations become the global
symmetry, and the gauge invariance of hopping operators becomes the requirement that they commute with this
symmetry.
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Astrophysics of Galaxies
A near-IR survey of luminous asymptotic giant branch stars in the satellites and stellar halo of M31
Jess M. Howell, Annette M. N. Ferguson, Olivia C. Jones et al. (+5 more)
We investigate the
dwarf spheroidal (dSph) satellites and
stellar halo of M31 using near-infrared imaging from the Wide-Field Camera on the UKIRT 3.8 m
telescope. Our homogeneous analysis covers the
stellar extents of 12 dSphs, as well as their surrounding
halo field populations. We identify carbon-rich (C) and oxygen-rich (M) thermally-pulsing AGB
stars (TP-AGBs) using colour-magnitude and colour-colour diagrams, which also allows for effective contaminant rejection. TP-AGB
stars are detected in eight of the 12 dSphs, indicating small intermediate-age populations in a substantial fraction of the sample; they are also found in considerable numbers throughout most of M31's
stellar halo. By combining 316 new detections with a revised classification of objects previously reported in the literature, we increase the TP-AGB candidate population in the dSphs from 82 to 359. We use the resulting dSph and
halo AGB samples to compute C/M ratios and infer
metallicities in the dSphs and adjacent
halo fields with non-zero AGB counts. A clear
metallicity gradient is observed in the M31
stellar halo out to ~150 kpc, consistent with that found using other tracers. Using literature
star formation histories from main-sequence turn-off photometry, we find a tight correlation between the number of C
stars in the dSphs and the
stellar mass formed in the last 0.5–3 Gyr. This study underscores the promise of AGB
stars as quantitative tracers of intermediate-age
star formation, particularly in intrinsically faint systems, and provides a catalogue of candidate TP-AGB
stars for follow-up.
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All authors Jess M. Howell, Annette M. N. Ferguson, Olivia C. Jones, Mike. J. Irwin, Maria-Rosa L. Cioni, Geraint F. Lewis, Nicolas. F. Martin, Alan. W. McConnachie
General Relativity and Quantum Cosmology · Cross-listed from math.AP
The linear instability of Kasner spacetimes
Oliver Petersen
We prove linear stability of Kasner spacetimes in the direction of the Big Bang, up to an explicit finite dimensional space of non-decaying self-similar solutions. The fastest growing solution is the linearization of Taub's explicit Bianchi II solution, describing a Kasner transition. All other non-decaying solutions are inhomogeneous analogues of this, and the linearized Kasner metric. The key novelty is a notion of quasinormal modes on Kasner spacetimes, similar to quasinormal modes on stationary black holes spacetimes. All quiescent (as opposed to oscillatory)
vacuum Big Bang spacetimes of dimension 4 are asymptotic to a Kasner spacetime from the perspective of a single observer at the Big Bang. They are expected to be highly unstable due to the oscillations conjectured by Belinski, Khalatnikov and Lifschitz. This paper provides a complete description of this instability on a linear level without
symmetry assumptions.
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High Energy Physics (Theory)
M2-brane matrix models and Fermi gas on affine ABCD quivers
Taro Kimura and Tomoki Nosaka
We study a new class of M2-brane
matrix models associated with affine BC and twisted affine AD quivers. These models exhibit the characteristic $N^{3/2}$ scaling of the free energy in the large $N$ limit. We establish a
Fermi gas formalism and demonstrate that their grand canonical sum is given by a Fredholm Pfaffian, which is in parallel with the affine D quiver
matrix models. The resulting
Fermi gas density
matrix shows a rational dependence on the canonical position/momentum operators in addition to the standard
hyperbolic dependence. This leads to unconventional sub-leading corrections, which obstruct the Airy function structure in the $1/N$ expansion of the free energy observed in the previously studied M2-brane
matrix models.
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Quantum Physics
Locally optimized variational evolution for quantum many-body systems
Carolin Wille, Maximilian Marvell, Lauren Stewart et al. (+4 more)
Quantum many-body dynamics is difficult to simulate because the global wavefunction develops extensive complexity, whereas local observables may retain only an intrinsic, system-size-independent complexity. This distinction is especially relevant in thermalizing systems, where local subsystems lose microscopic information and relax towards
equilibrium. We introduce a variational time-
evolution principle that exploits this separation by replacing global-state fidelity with a cost function defined on local reduced density
matrices. The resulting locally optimized
matrix-product-state (LOMPS)
algorithm retains coherent short-time dynamics while using the simplification generated by thermalization at later times, and admits closed-form equations of motion analogous to the time-dependent variational principle. The same principle yields a
quantum-classical
algorithm in which a
quantum processor evaluates the local cost and a noise-robust classical procedure performs the optimization. Proof-of-principle implementations on Quantinuum H2 and IBM Heron processors recover the characteristic local dynamics.
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All authors Carolin Wille, Maximilian Marvell, Lauren Stewart, Maximillian Murphy, Vinul Wimalaweera, Lesley Gover, Andrew G. Green
High Energy Physics (Phenomenology)
The axion mass in the post-inflationary scenario in a minimal scaling model
José Correia, Mark Hindmarsh, Joanes Lizarraga et al. (+3 more)
We calculate the dark matter
axion mass in the post-inflationary scenario in a minimal model with a set of classical field theory simulations on $12\,288^3$ grids. In the model, the Peccei-Quinn U(1)
symmetry is broken by a complex scalar field at a temperature $f_{\rm a} \sim 10^{11}$ GeV, creating a string network. The strings become the boundaries of domain walls at the QCD transition, which draw the strings together and annihilate them. The decay of the strings and domain walls leaves behind
axion radiation, with a comoving number density estimated to be $9.48(23)f_{\rm a}^2 H_*$, normalised to unit scale factor when the
axion mass is equal to the Hubble rate $H_*$. Using the most commonly quoted
lattice results for the topological susceptibility, the dark matter
axion mass in this minimal model is $17.46(84)\,\mu\text{eV}$. This corresponds to a
symmetry-breaking scale of $3.27(15) \times 10^{11}\, \text{GeV}$, and a haloscope resonant frequency of $4.22(20)\,\text{GHz}$. We argue that field theory simulations of non-minimal models where the strings have a
Higgs condensate or gauge flux, and are annihilated by domain walls, will give
axion mass predictions below about $40\,\mu\text{eV}$.
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All authors José Correia, Mark Hindmarsh, Joanes Lizarraga, Asier Lopez-Eiguren, Kari Rummukainen, Jon Urrestilla
Nuclear Theory
Parametric Neural Quantum States for Nuclear Physics
Yukari Yamauchi, Ryan Curry, Garrett B. King et al. (+3 more)
We introduce a new approach, based on neural
quantum states (NQSs), to rapidly compute
nuclear observables when couplings in
nuclear Hamiltonians are varied. A single interaction-dependent NQS, trained across a range of couplings in the
Hamiltonian, provides high-fidelity wavefunctions for that continuous range of interaction parameters. With access to the wavefunction for each set of couplings, any static observables can be computed efficiently without retraining the NQS. We apply this framework to two-body
nuclear scattering and the deuteron ground state with local interactions derived from
chiral effective field theory up to third order.
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All authors Yukari Yamauchi, Ryan Curry, Garrett B. King, Scott Lawrence, Rahul Somasundaram, Ingo Tews
Mathematical Physics
Disorder on the hyperbolic square lattice I: Anderson delocalization and absolutely continuous spectrum
Simon Becker and Izak Oltman
We study the Anderson model on
hyperbolic lattices. The graph is the Cartesian product of the Euclidean
lattice with the regular
hyperbolic square
lattice having five squares at each vertex. We prove the existence of absolutely continuous spectrum and the absence of singular spectrum on a deterministic set of positive measure at weak disorder, and for $0<\lambda\le2$ when the single-site density is bounded below on $[-1,1]$. Truncated Cauchy distributions and controlled perturbations give purely absolutely continuous spectrum on intervals.
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High Energy Astrophysical Phenomena
Systematic Effects of Hydrogen and Helium Atmosphere Mismatch on Radius Inference in PSR~J0740+6620-like Synthetic NICER Data
Isiah M. Holt, M. Coleman Miller, Alexander J. Dittmann et al. (+1 more)
Constraints on
neutron star radii provide insight into the properties of the cold, dense matter in their interiors. Previous studies using synthetic
Neutron star Interior Composition Explorer (NICER) pulse waveform data have demonstrated that radius inferences derived therefrom are robust against several classes of modeling systematics. Here we explore the consequences of assuming the wrong atmospheric composition, using synthetic data based on the $\sim 2.1~M_\odot$
pulsar PSR~J0740$+$6620. We find that the assumption of a hydrogen atmosphere when the synthetic data assumed a helium atmosphere, or vice versa, produces little bias in the inferred radius at the spot-to-background ratio of the actual PSR~J0740$+$6620 data. However, when we increase the spot-to-background ratio by a factor of $\sim20$ while keeping the total number of counts fixed at the observed $\sim 5.5\times 10^5$, we find that composition mismatch can produce significantly biased radius estimates while remaining hidden inside a fit with statistically acceptable residuals. Even in these cases, the
Bayesian evidence consistently identifies the correct atmospheric model. Our findings reinforce the importance of using the
Bayesian evidence for model comparison and goodness-of-fit tests.
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All authors Isiah M. Holt, M. Coleman Miller, Alexander J. Dittmann, Frederick K. Lamb