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Thursday 18 June

High Energy Physics (Phenomenology)

Warm fermionic dark matter from freeze-in at stronger coupling

We study warm fermionic dark matter (DM) in the framework of freeze-in at stronger coupling, in the minimal Higgs portal scenario. The reheating temperature is taken to be low, so that DM production from the Standard Model thermal bath is Boltzmann-suppressed and the DM stays out of equilibrium even for a sizeable coupling. This opens the possibility of observable signatures, in particular invisible Higgs decays. We compute the DM relic abundance including both the pre- and post-reheating contributions. We find that the fermionic DM production reaction is strongly velocity suppressed, requiring larger reheating temperatures than those obtained for scalar DM in order to reproduce the correct relic abundance. The resulting DM momentum distribution is strongly non-thermal and its shape is not captured by the common $\alpha\beta\gamma$-parametrization. We find that the Lyman-$\alpha$ constraint excludes DM masses below about $100 -180\,\mathrm{keV}$, depending on the reheating history.
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Astrophysics of Galaxies

Investigating the Spectral Properties of Dual Nuclei in Galaxy Mergers from the GOTHIC survey: Supermassive Black Hole Growth, metal enrichment and Dual AGN

Dual nuclei systems are galaxy merger remnants or closely merging galaxies that have two distinct stellar cores separated by ~ 10pc to 10kpc. They are important laboratories for probing the co-evolution of stellar populations, galaxy dynamics, and central black holes during the hierarchical assembly of galaxies. In this study, we present a spectroscopic analysis of a sample of dual nuclei from the GOTHIC survey, using the penalized pixel-fitting (pPXF) code. The sample consists of star forming nuclei pairs, dual active galactic nuclei (DAGN) and mixed pairs. Using the SDSS spectra, we extracted stellar kinematics, emission line fluxes, the star formation history, metallicity of the nuclei, and derived important properties such as the supermassive black hole (SMBH) masses, accretion rates and SMBH ratios. We compared different properties of the nuclei in the dual systems, such as stellar velocity dispersion, stellar masses, black hole masses, age and metallicity. Our results show that the SMBH masses are higher for BHs in galaxy mergers compared to single nuclei for a given stellar mass, thus revealing that SMBHs grow during the galaxy merging process and not only due to the merger of SMBHs. Our study provides new observational constraints on the dynamical and evolutionary states of dual-nuclei systems, offering a deeper understanding of the role these systems play in galaxy evolution and central black hole growth.
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All authors Prerana Biswas, Mousumi Das, Sudhanshu Barway, Françoise Combes, Anwesh Bhattacharya, Snehanshu Saha, C. P. Nehal

Astrophysics of Galaxies

The Lifecycle and Emission Properties of PAHs in Cosmological Hydrodynamic Galaxy Formation Simulations

We present the first cosmological model for the lifecycle and luminous properties of PAHs in galaxies as they evolve from z=6–>0. We model 40 zoom-in galaxies, coupled with an on-the-fly model for the evolution of dust grains in the ISM. We approximate PAHs as ultrasmall (a < 13 Angstrom) carbonaceous dust grains, and couple this model with single-photon excitation calculations to compute the emergent mid-infrared spectra. (1) If we assume that dust is large upon formation, then PAHs are naturally able to form in situ in the ISM via grain-grain shattering. Interstellar collision velocities increase in low density, diffuse gas in our model; as galaxies evolve, the increase in fractional mass of diffuse gas drives an increase in grain-grain collision velocities and a corresponding rise in the PAH mass fraction (qPAH) from ~5 x 10^{-4} at z~4 to ~10^{-2} at z~0. (2) Increased PAH production in the diffuse ISM results in an inverse relationship between qPAH and the molecular gas fraction. (3) The PAH light-to-mass ratio scales linearly with the radiation field intensity (LPAH/MPAH ~ G_0) but anti-correlates with qPAH, because high-Sigma_SFR galaxies have a denser ISM that suppresses shattering. This means the physical qPAH and observed LPAH/LFIR do not evolve in lockstep. (4) The PAH-metallicity relationship (PZR) arises naturally in this framework: galaxies enrich and grow their diffuse ISM fraction simultaneously, linking rising metallicity to rising qPAH. Our models represent the first to reproduce the PZR observed across z=0-2. (5) The LPAH-SFR and LPAH-M_mol relations emerge from two effects: more massive galaxies have larger PAH reservoirs, and higher-SFR galaxies excite their PAHs more efficiently per unit mass. Taken together, these results suggest that grain-grain shattering in the diffuse ISM is the main driver behind the evolution of cosmic PAH abundances.
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All authors Desika Narayanan, Paul Torrey, Massimiliano Parente, Grant Donnelly, Dhruv Zimmerman, Alex Garcia, Helena Richie, J.-D. T. Smith, Brandon Hensley, Federico Marinacci, Jed McKinney, Alexandra Pope, Gergo Popping, Laura Sales, Karin Sandstrom, Ethan Savitch, Irene Shivaei, Justin Spilker, Corey Whitcomb

Strongly Correlated Electrons

Partition function zeros of quantum many-body systems: perturbative results

A systematic method to find the Yang-Lee partition function zeros of quantum many-body systems based on perturbation theory at finite temperatures was recently introduced in arXiv:2504.01880. This method identifies wave-vector and temperature-dependent complex virtual energies obtainable from the thermal electronic Greens function. The collection of virtual energies over all $\vec{k}$ yield the Yang-Lee zeroes. We apply this approach to the one-dimensional Hubbard model for different boundary conditions. We compare the results obtained by this method up to second-order in perturbation theory with the results found by exact diagonalization. We also propose a quantity that could be used for experimental detection of these zeros of a Hubbard ring. An example of the detection method is presented using exact diagonalization of the 8-site Hubbard ring.
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Statistical Mechanics

Tuning ergodicity breaking: Anomalous diffusion under asymptotic power-law forcing

In non-Markovian systems, distinct dynamical phases arise from the competition between internal memory and external forcing, encompassing thermalization, persistent ergodicity breaking, and runaway energy growth. This study shows that the scaling parameter $\eta$ governs the emergent phase diagram within a system described by the Generalized Langevin Equation, particularly when subjected to external drives with asymptotic power-law tails. Three universal regimes for diffusive processes are delineated by this parameter: thermalization ($\eta > 0$), non-ergodic saturation ($\eta = 0$), and a force-dominated runaway phase ($\eta < 0$). The fluctuation-dissipation theorem, within this framework, is shown to be independent of external force and determined by the integral of noise density of states. A selective breaking of ergodicity is revealed by this formulation; microscopic fluctuations are decoupled from the drive, yet the relaxation completely encodes it, which in turn controls the kinetic effective temperature. Direct Langevin simulations in the Markovian limit quantitatively confirm this classification, capturing the non-thermal plateau at the critical point.
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General Relativity and Quantum Cosmology

$\mathrm{ISIM}(2)$ gravitational gauge model via Soft Algebra formalism

This work presents a comprehensive account of a gravitational model based on the gauging of the $\mathrm{ISIM}(2)$ Lorentz subgroup parameters through the so-called soft algebra formalism. After presenting a closed form for $\mathfrak{sim}(2)$ and its inhomogeneous extension, we proceed to develop a complete torsionless gravitational model, culminating in an invariant action.
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Quantum Physics

Distribution Complexity of Electronic Structure Simulations on Quantum Supercomputers

Efficient simulation of strongly-interacting fermionic systems on quantum processing units (QPUs) is a challenging task due to nonlocal mode entanglement generation. However, it is not yet well understood how the structure of entanglement governs the hardness of large-scale quantum chemistry simulations or the scaling of distributing such workloads. Here, we introduce an algorithm for estimating the distribution complexity of hybrid quantum-classical simulation for electronic structure Hamiltonians over heterogeneous high-performance architectures. Our algorithm relies on efficient analytical evaluation of the low entanglement boundaries for the orbital rotations and dephasing-induced localization within tensor fragments, in a double-factorized representation. Our entanglement estimation scales as $O(N^3)$ for each fragment, where $N$ is the number of orbitals. When QPUs are communicating via a quantum network, the cost of distribution per fragment is reduced quadratically from $O(N^2)$ to $O(N)$. Similarly, for hybrid quantum-classical approaches, with access to only conventional HPC interconnects, the worst-case cost is reduced from $O(\exp(N^2))$ to $O(\exp(N))$. We show that emergent entanglement patterns are induced by the interplay between coherent Gaussian orbital rotations and disordered Coulomb interactions. We discuss the underlying physical mechanisms that govern distribution complexity and introduce model systems that are tunable based on the localizability of fragments and the overlap of interfragment rotations. We characterize three different regimes of hardness for distribution complexity and classical simulability. The framework introduced here enables novel and more efficient quantum-classical application workflows towards utility-scale quantum computing.
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All authors Jason Necaise, Namit Anand, Gaurav Gyawali, K. Grace Johnson, James D. Whitfield, Masoud Mohseni

Astrophysics of Galaxies

LEGGOS II: A Strong Lens Model and Source-Plane Projection of the Clumpy Star-Forming Galaxy SGASJ111020.0+645950.8 at z=2.48

Strong gravitational lensing by galaxy clusters combined with the resolution of JWST enables studies of star formation on ~10-100 pc scales in galaxies at z~2-4. As part of the LEnsing and Galaxy Growth: Observing Substructures survey (LEGGOS), we present an updated strong lensing model of the galaxy cluster SDSSJ1110+6459 (z=0.659), which lenses the clumpy star-forming galaxy SGASJ111020.0+645950.8 at z=2.481 into a highly magnified giant arc. Using JWST NIRCam imaging, NIRSpec spectroscopy, and archival HST data, we confirm and refine the identification of four multiply imaged background sources, including one newly identified system, and map over 20 luminous regions between each image of the primary arc. Spectroscopy confirms that several previously ambiguous edge "clumps" belong to the main arc at z=2.481. Despite the limited number of strongly lensed sources in the field, the resulting lens model has high precision, owing to the high density of JWST-resolved clump constraints that tightly probe the lensing potential near the giant arc. The model yields a projected lens mass of $M(<250~\mathrm{kpc}) = 1.21^{+0.09}_{-0.04} \times 10^{14}~M_\odot$, an Einstein radius of $\theta_\mathrm{E} = 10.8^{+0.3}_{-0.4}~\mathrm{arcsec}$, and a total effective magnification of $\mu_\mathrm{tot}=24.2^{+3.4}_{-1.2}$ for the giant arc. Across the arc, individual clump magnifications span $\mu_\mathrm{clump}\sim4-19$, with fractional magnification uncertainties of $\sigma_\mu/|\mu_{\rm best}|\sim0.03-0.09$. We report a $\sim2-8\times$ improvement in magnification precision over previous models. Ongoing and future analyses of this arc will enable robust measurements of star-forming structure, building on the lensing foundation established here for LEGGOS studies of galaxy growth and feedback during cosmic noon.
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All authors Pedram Abedi, Keren Sharon, Taylor A. Hutchison, Matthew B. Bayliss, Michael Florian, Gourav Khullar, Michael D. Gladders, Dylan Berry, Catherine Cerny, Håkon Dahle, Aleena Ebey, Juliana S.M. Karp, Keunho Kim, James W. Kulp, Guillaume Mahler, Jane R. Rigby, T. Emil Rivera-Thorsen, Amritaansh Srivastava, Brian Welch, Alex Ross, Julissa Sarmiento

Earth and Planetary Astrophysics

Planet-Planet Secular Migration Predicts a Stellar Obliquity-Period Anti-Correlation

Stellar obliquities provide a fossil record of hot Jupiter (HJ) migration. An emerging observational trend in single-star systems is that strongly misaligned HJs are largely confined to short orbital periods, while longer-period HJs are preferentially aligned. This pattern cannot be explained by tidal dissipation in the star and may instead preserve clues to the migration pathway. We show that secular high-eccentricity migration driven by a distant planetary companion naturally produces such an obliquity–period correlation. In our simulations, the shortest-period HJs tend to be produced by the von Zeipel–Lidov–Kozai mechanism driven by highly inclined companions, which results in a broad range of final stellar obliquities. The longest-period HJs, on the other hand, are produced over longer timescales by coplanar high-eccentricity migration, which preserves low obliquities. The transition between these two limits is not abrupt, with intermediate-period HJs displaying a moderate range of obliquities. According to this interpretation, we predict that the shortest-period HJs should have distant planetary companions with broadly distributed mutual inclinations, whereas the companions of longer-period HJs should reside in nearly coplanar orbits. Upcoming Gaia astrometric constraints will provide a key test of this picture.
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Astrophysics of Galaxies

LEGGOS III: Mapping Star Formation and Dust in Gravitationally Lensed Galaxies with $\textit{SUMAC}$, a UMAP and Clustering Framework

Strong gravitational lensing combined with JWST's spatio-spectral resolution enables resolved studies of star-forming regions in $z\sim$ 2-4 galaxies, but identifying and characterizing such regions in lensed integral-field and multi-band data remains a manual, observer-dependent process. We present $\texttt{SUMAC}$ (Software for the Uniform Manifold Approximation of Clumps), an unsupervised learning pipeline that segments JWST imaging and spectroscopy at the "spaxel" level by combining $\texttt{UMAP}$-based manifold embedding with $\texttt{HDBSCAN}$ density clustering applied to spectral energy distributions/spectra. We demonstrate the pipeline on JWST/NIRSpec PRISM IFS observations of the lensed galaxy SGAS111020.0+645950.8 at $z = 2.481$, recovering six physically distinct stellar/nebular populations. The cluster median SEDs separate cleanly on the presence and strength of H$\beta$+[OIII], H$\alpha$+[NII], $\beta_{NUV}$ slope, Balmer break strength, and the Balmer decrement, with bluer clusters tracing unobscured star-forming regions and progressively redder clusters tracing dusty star-forming regions.
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All authors Alex Ross, Gourav Khullar, Taylor Hutchison, Dylan Berry, Aritra Ghosh, T. Emil Rivera-Thorsen, Guillaume Mahler, Brian Welch, Pedram Abedi, Cole Panzer, Michael Florian, Julissa Sarmiento, the JWST LEGGOS Collaboration

Astrophysics of Galaxies

No hidden monsters: Probing recently-quenched galaxies for obscured AGN with JWST-PRIMER MIRI and NIRCam

We investigate the role of obscured active galactic nuclei (AGN) in recently quenched post-starburst galaxies (PSBs), using a sample of 65 photometrically selected PSBs in the PRIMER-UDS field at $1 < z < 2$. Combining JWST/MIRI 7.7 $\mu$m and 18 $\mu$m (F770W and F1800W) imaging with eight NIRCam and three HST/ACS bands, we probe hot dust emission to test for hidden AGN or dust-enshrouded star formation. We find strong differences between the low- and high-mass PSBs. Most high-mass PSBs ($ > 10^{10}\textrm{M}_\odot$) show no excess infrared emission (consistent with the quiescent population), indicating little or no dust-obscured activity, while low-mass PSBs display enhanced emission at 18 $\mu$m, which we attribute to residual star formation. AGN template modelling indicates that the absence of mid-IR excess in massive PSBs limits any dust-enshrouded AGN to Eddington ratios of $ < 1\%$. In addition, we show that the F770W–F1800W colour alone is a highly effective diagnostic for separating passive and star-forming galaxies, particularly at high stellar masses. Overall, our results provide further evidence for distinct quenching pathways within the PSB population, and confirm that massive PSBs show no evidence for excess AGN activity relative to older passive galaxies.
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All authors Guillaume Hewitt, Omar Almaini, David Maltby, Emma Chapman, Thomas de Lisle, Pallavi Patil, Kate Rowlands, Maya Skarbinski, Elizabeth Taylor, Vivienne Wild, Adam C. Carnall, James S. Dunlop, Norman Grogin, Anton M. Koekemoer, Derek J. McLeod, Pablo G. Pérez-González

High Energy Physics (Phenomenology)

Phenomenology of heavy-flavour jet angularities at hadron colliders

We compute resummed and matched predictions for jet angularities in hadronic Z+jet events, where the jet is initiated by a b-quark. The analysis is performed both with and without grooming the candidate jets using the SoftDrop algorithm. Mass effects are consistently included at both fixed-order and resummed levels. Our theoretical predictions also incorporate non-perturbative corrections from the underlying event and hadronization, implemented through parton-to-hadron transfer matrices extracted from dedicated Monte Carlo simulations with Sherpa. Finally, we compare results for b-jets with the ones from light-flavour jets, in order to quantify the impact of finite-mass effects.
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All authors Andrea Ghira, Lorenzo Mai, Simone Marzani, Daniel Reichelt, Steffen Schumann, Leon Stöcker

High Energy Physics (Experiment)

Measurement of mixing-induced CP violation in the decay $B^0 \to \pi^0 \pi^0$

Measurements of charge-parity (CP) violation in quark transitions provide stringent tests of the current theory and sensitive probes of particles or interactions beyond it. We report the first measurement of mixing-induced CP violation in $B^0\to\pi^0\pi^0$ decays. The measurement uses 190 million $\Upsilon(4S)\to B^{0}\overline{B}{}^0$ events collected with the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. A new approach that exploits the quantum entanglement of the $B^{0}\overline{B}{}^0$ pair enables a decay-time-dependent analysis without reconstructing the $B^0 \to \pi^0\pi^0$ decay position. We measure the mixing-induced CP-violating coefficient to be $S_{\pi^{0}\pi^{0}} = 0.61^{+0.75}_{-0.79}\,(\mathrm{stat}) \pm 0.11\,(\mathrm{syst})$, attaining a precision that would require a data set twenty times as large with a conventional analysis. We also measure the direct CP-violating coefficient to be $C_{\pi^{0}\pi^{0}} = 0.05 \pm 0.28\,(\mathrm{stat}) \pm 0.07\,(\mathrm{syst})$. These results substantially improve the constraints from $B \to \pi\pi$ decays on the CP-violating phase $\phi_2$ of the quark-mixing matrix using far less data than had previously been assumed necessary.
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All authors Belle II Collaboration: M. Abumusabh, I. Adachi, K. Adamczyk, A. Aggarwal, Y. Ahn, H. Aihara, M. Akdag, N. Akopov, S. Alghamdi, M. Alhakami, N. Althubiti, K. Amos, M. Angelsmark, N. Anh Ky, C. Antonioli, K. Arai, H. Atmacan, T. Aushev, V. Aushev, R. Ayad, V. Babu, H. Bae, N. K. Baghel, S. Bahinipati, P. Bambade, Sw. Banerjee, S. Bansal, M. Barrett, M. Bartl, J. Baudot, A. Beaubien, F. Becherer, J. Becker, G. F. Benfratello, J. V. Bennett, F. U. Bernlochner, V. Bertacchi, M. Bertemes, E. Bertholet, M. Bessner, S. Bettarini, V. Bhardwaj, B. Bhuyan, F. Bianchi, T. Bilka, D. Biswas, A. Bobrov, D. Bodrov, A. Bondar, G. Bonvicini, J. Borah, A. Boschetti, A. Bozek, M. Bračko, P. Branchini, N. Brenny, R. A. Briere, T. E. Browder, A. Budano, S. Bussino, F. Callet, Q. Campagna, M. Campajola, L. Cao, M. Carminati, G. Casarosa, C. Cecchi, M.-C. Chang, P. Cheema, C. Chen, L. Chen, B. G. Cheon, C. Cheshta, H. Chetri, K. Chilikin, K. Chirapatpimol, H.-E. Cho, K. Cho, S.-J. Cho, S.-K. Choi, S. Choudhury, S. Chutia, J. Cochran, J. A. Colorado-Caicedo, I. Consigny, L. Corona, H. Crotte Ledesma, S. Cuccuini, J. X. Cui, S. Das, E. De La Cruz-Burelo, S. A. De La Motte, G. de Marino, G. De Nardo, G. De Pietro, R. de Sangro, M. Destefanis, S. Dey, R. Dhayal, A. Di Canto, J. Dingfelder, Z. Doležal, X. Dong, M. Dorigo, K. Dugic, G. Dujany, P. Ecker, D. Epifanov, J. Eppelt, R. Farkas, P. Feichtinger, T. Ferber, T. Fillinger, C. Finck, G. Finocchiaro, F. Forti, A. Frey, B. G. Fulsom, A. Gabrielli, P. Gagneja, E. Ganiev, M. Garcia-Hernandez, R. Garg, G. Gaudino, V. Gaur, V. Gautam, A. Gaz, A. Gellrich, G. Ghevondyan, D. Ghosh, H. Ghumaryan, R. Giordano, A. Giri, P. Gironella Gironell, A. Glazov, B. Gobbo, R. Godang, O. Gogota, W. Gradl, E. Graziani, D. Greenwald, Y. Guan, K. Gudkova, I. Haide, Y. Han, K. Hara, K. Hayasaka, H. Hayashii, S. Hazra, C. Hearty, M. T. Hedges, A. Heidelbach, G. Heine, I. Heredia de la Cruz, M. Hernández Villanueva, T. Higuchi, M. Hoek, M. Hohmann, R. Hoppe, P. Horak, X. T. Hou, C.-L. Hsu, T. Humair, T. Iijima, K. Inami, N. Ipsita, A. Ishikawa, R. Itoh, M. Iwasaki, P. Jackson, D. Jacobi, W. W. Jacobs, D. E. Jaffe, E.-J. Jang, Q. P. Ji, S. Jia, Y. Jin, A. Johnson, K. K. Joo, H. Kakuno, D. Kalita, K. H. Kang, G. Karyan, F. Keil, C. Kiesling, C. Kim, D. Y. Kim, H. Kim, J.-Y. Kim, K.-H. Kim, H. Kindo, K. Kinoshita, P. Kodyš, T. Koga, S. Kohani, A. Korobov, S. Korpar, E. Kovalenko, R. Kowalewski, P. Križan, P. Krokovny, T. Kuhr, Y. Kulii, R. Kumar, K. Kumara, T. Kunigo, A. Kuzmin, Y.-J. Kwon, S. Lacaprara, T. Lam, J. S. Lange, T. S. Lau, R. Leboucher, H. Lee, M. J. Lee, P. Leo, P. M. Lewis, C. Li, L. K. Li, Q. M. Li, S. X. Li, W. Z. Li, Y. Li, Y. B. Li, Y. P. Liao, J. Libby, J. Lin, S. Lin, Z. Liptak, V. Lisovskyi, C. Liu, G. Liu, M. H. Liu, Q. Y. Liu, Z. Q. Liu, D. Liventsev, S. Longo, A. Lozar, T. Lueck, J. L. Ma, Y. Ma, M. Maggiora, S. P. Maharana, R. Maiti, G. Mancinelli, R. Manfredi, E. Manoni, M. Mantovano, D. Marcantonio, S. Marcello, M. Marfoli, C. Marinas, C. Martellini, A. Martens, T. Martinov, L. Massaccesi, M. Masuda, T. Matsuda, D. Matvienko, S. K. Maurya, M. Maushart, J. A. McKenna, Z. Mediankin Gruberová, R. Mehta, F. Meier, D. Meleshko, M. Merola, C. Miller, M. Mirra, K. Miyabayashi, H. Miyake, R. Mizuk, G. B. Mohanty, S. Moneta, A. L. Moreira de Carvalho, H.-G. Moser, N. Mudgal, Th. Muller, H. Murakami, R. Mussa, K. R. Nakamura, M. Nakao, H. Nakazawa, Y. Nakazawa, Z. Natkaniec, A. Natochii, M. Neu, M. Niiyama, S. Nishida, R. Nomaru, A. Novosel, S. Ogawa, R. Okubo, H. Ono, Y. Onuki, G. Pakhlova, S. Pardi, J. Park, K. Park, S.-H. Park, A. Passeri, S. Patra, T. K. Pedlar, R. Pestotnik, M. Piccolo, L. E. Piilonen, P. L. M. Podesta-Lerma, T. Podobnik, L. Polat, A. Prakash, V. Prasad, C. Praz, S. Prell, E. Prencipe, M. T. Prim, S. Privalov, I. Prudiiev, H. Purwar, P. Rados, S. Raiz, K. Ravindran, J. U. Rehman, M. Reif, S. Reiter, M. Remnev, L. Reuter, D. Ricalde Herrmann, I. Ripp-Baudot, G. Rizzo, S. H. Robertson, J. M. Roney, A. Rostomyan, N. Rout, G. Russo, S. Saha, Y. Sakai, L. Salutari, D. A. Sanders, S. Sandilya, L. Santelj, V. Savinov, B. Scavino, C. Schmitt, J. Schmitz, S. Schneider, K. Schoenning, C. Schwanda, Y. Seino, K. Senyo, J. Serrano, M. E. Sevior, C. Sfienti, W. Shan, X. D. Shi, T. Shillington, T. Shimasaki, J.-G. Shiu, D. Shtol, B. Shwartz, A. Sibidanov, F. Simon, J. B. Singh, J. Skorupa, A. Soffer, A. Sokolov, E. Solovieva, S. Spataro, K. Špenko, B. Spruck, M. Starič, P. Stavroulakis, S. Stefkova, R. Stroili, M. Sumihama, K. Sumisawa, M. Takahashi, M. Takizawa, U. Tamponi, K. Tanida, F. Testa, A. Thaller, D. V. Thanh, T. Tien Manh, O. Tittel, R. Tiwary, D. Tonelli, E. Torassa, K. Trabelsi, F. F. Trantou, I. Tsaklidis, M. Uchida, I. Ueda, T. Uglov, K. Unger, Y. Unno, K. Uno, S. Uno, P. Urquijo, Y. Ushiroda, S. E. Vahsen, R. van Tonder, K. E. Varvell, M. Veronesi, A. Vinokurova, V. S. Vismaya, L. Vitale, V. Vobbilisetti, R. Volpe, M. Wakai, S. Wallner, M.-Z. Wang, A. Warburton, M. Watanabe, S. Watanuki, C. Wessel, X. P. Xu, B. D. Yabsley, S. Yamada, W. Yan, W. P. Yan, J. Yelton, K. Yi, J. H. Yin, K. Yoshihara, C. Z. Yuan, J. Yuan, L. Yuan, Y. Yusa, L. Zani, F. Zeng, M. Zeyrek, B. Zhang, X. Zhao, V. Zhilich, J. S. Zhou, Q. D. Zhou, X. Y. Zhou, L. Zhu, R. Žlebčík

High Energy Physics (Theory)

$N=1$ Supersymmetry, Weil-Petersson Volume Recursion, and a Spectral Curve

The Stanford-Witten-Norbury generalization of Mirzakhani's volume recursion computes $V^{(2m)}_{g,n}(\{b_i\})$, the Weil-Petersson volumes of the moduli space of $N=1$ supersymmetric Riemann surfaces of genus $g$ with $n$ Neveu-Schwarz boundaries of geodesic lengths $b_i$ ($i{=}1,\ldots,n$), and $2m$ Ramond punctures. Recently, a spectral curve has been derived that allows their Laplace transforms $W^{(2m)}_{g,n}(\{{\hat z}_i\})$ to be computed using topological recursion. We prove that the Stanford-Witten-Norbury volume recursion is directly derivable from the spectral curve. An alternative volume recursion can also be derived from it. The difference comes from whether the Ramond information is in the initial data, or in the volume recursion's kernels. The latter invites a geometrical understanding.
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Cosmology and Nongalactic Astrophysics

Raising the reionization optical depth with inflationary CMB features

Within the highly successful $\Lambda$CDM paradigm established with cosmic microwave background (CMB) anisotropy measurements, the optical depth through reionization $\tau$ is the most uncertain due both to the difficulty in measuring large-angle polarization and the assumptions made in their interpretation. Currently, for the Planck primary data in the flat $\Lambda$CDM cosmology with slow-roll inflation and standard reionization, the one-sided 95% upper limit for $\tau$ is $\tau_{\rm max}=0.0696$. Yet when all current CMB measurements excluding large-angle polarization are combined with baryon acoustic oscillation (BAO) measurements, the one-sided 95% lower limit is an incompatible $\tau_{\rm min}=0.074$. If the long-standing low-power feature of the temperature measurements is interpreted as physically originating from inflation then $\tau$ inferred from large-angle polarization becomes larger. Marginalizing over templates of the low-power feature based on the generalized slow-roll formalism of inflation raises the Planck maximum to a more compatible $\tau_{\rm max}=0.075$ which further increases to $\tau_{\rm max} = 0.082$ with the inclusion of all CMB+BAO data. This marginalization does not assess the statistical significance of the low-power feature itself; rather, it shows that allowing a higher $\tau$ is a consequence of interpreting the anomaly as a physical feature instead of a statistical fluctuation.
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Cosmology and Nongalactic Astrophysics

Constraints on Horndeski gravity with phantom crossing

Gravity models in which the dark energy equation of state crosses $w=-1$, also known as the phantom divide, have received extensive interest due to recent analyses favouring this behaviour. We introduce a new subclass of Horndeski scalar-tensor models capable of generating phantom crossing, whilst remaining minimally coupled to matter: the Asymptotic Cubic Galileon (ACG) models. We show that ACG models can jointly fit the expansion history inferred from observations of the Planck cosmic microwave background, baryon acoustic oscillation measurements from the Dark Energy Spectroscopic Instrument, and distance-ladder supernovae measurements from the Dark Energy Survey. We then demonstrate that requiring a positive galaxy-ISW cross-correlation, together with physically viable screening behaviour, substantially restricts the viable ACG parameter space. Model comparison metrics, including $\chi^{2}$ and Bayesian evidence, favour both ACG and $w_{0}w_{a}$CDM models over $\Lambda$CDM, with ACG providing a fit of comparable quality to $w_{0}w_{a}$CDM. Crucially, ACG models ground the observationally preferred $w_{0}w_{a}$CDM behaviour in a robust Lagrangian formulation. This enables interpretation beyond mere phenomenological fits, and motivates further tests of these models on nonlinear scales.
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All authors Krishna Naidoo, James Hallam, Tessa Baker, Sergi Sirera

Astrophysics of Galaxies

The explosive growth of the Messier 74 galaxy. A galaxy doubling its size in less than a Gigayear

Galaxy formation models predict that galaxies grow inside-out, becoming larger over time. While observations broadly support this paradigm, the nature and timescales of this growth remain poorly constrained. We report the discovery of an extremely faint and young (~600 Myr) stellar component in the outer regions of the nearby galaxy Messier 74 (M74). Using deep optical imaging from the TST telescope at the Teide Observatory, reaching surface brightness limits of ~30-31.5 mag arcsec^-2 in the g, r and i bands, we detect stellar emission extending well beyond the previously known disc radius of ~14 kpc. This newly identified component reaches galactocentric distances of ~30 kpc, effectively doubling the known size of the stellar disc and matching the extent of the HI disc. The revised size of M74 places it in the upper envelope of the mass-size relations. The young age of the outer stellar population suggests a recent episode of disc growth, potentially occurring on timescales shorter than ~1 Gyr. We discuss a possible scenario in which a past flyby interaction with UGC 1176 may have triggered this extended star formation. Further studies of galaxies with similar deep imaging will be key to determining whether such rapid outer disc growth is common or exceptional.
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All authors Ignacio Ruiz Cejudo, Ignacio Trujillo, Sergio Guerra Arencibia, Miguel R. Alarcon, Miquel Serra-Ricart, Ouldouz Kaboud

High Energy Physics (Phenomenology)

Minimal Proton-Mass Dark Matter

We present a minimal dark matter scenario: a single complex scalar carrying baryon and lepton number, with no new exact stabilizing symmetry. Its leading interaction is a dimension-7 semileptonic portal that, below confinement, generates a low-energy Yukawa coupling with the proton and electron. Requiring absolute stability of both the proton and dark matter forces the dark matter mass into a narrow window around the proton mass, which may be anthropically selected. Despite its minimal field content, the model can be probed by many observables: proton burning in stars, hydrogen decay, brown dwarfs and neutron star heating, and nucleon decay-like signatures in direct detection. UV-dominated freeze-in produces the observed relic abundance. This framework provides a unique testable example of dark matter arising from a minimal extension of the Standard Model.
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All authors Majed Khalaf, Eric Kuflik, Alessandro Lenoci, Hitoshi Murayama, Edoardo Vitagliano

Lattice Field Theory

Neural Wavefunctions in Quantum Field Theory I: Asymptotic Freedom

We present a variational approach to quantum field theory based on wavefunctions parameterized by neural networks. While variational methods have a celebrated history across many fields, their application to quantum field theory has been limited by well-known challenges. We show that neural-network wavefunctions, combined with modern machine-learning techniques, enable competitive variational calculations in nontrivial field theories. As a demonstration, we reproduce the essential features of the two-dimensional nonlinear $\sigma$-model: asymptotic freedom, dynamical mass generation and the model's step-scaling function.
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All authors Paulo F. Bedaque, Hersh Kumar, Suryansh Rajawat, Gregory Ridgway

High Energy Physics (Theory)

Complexity Inequalities for Quantum Subsystems

Motivated by the role of the holographic entropy cone in constraining the entanglement structure of states with classical gravitational duals, we investigate combinations of subsystem complexities associated with reduced density matrices in multipartite quantum systems. Focusing on subsystems composed of three disjoint regions, we introduce two quantities: a tripartite complexity, inspired by the tripartite information, and a complexity gap, designed to characterize emergent complexity in the full quantum state beyond that of its constituents. We study the sign structure of these quantities in three selected approaches to subsystem complexity. In holography, we employ the complexity=volume proposal in AdS spacetimes; for Gaussian many-body states, we use Fisher-Rao subsystem complexity; and we further develop a Krylov-space inspired, effective framework for reduced density matrices, which we test in few-qubit systems and coherent-state dynamics. Across all three approaches, we find that the tripartite complexity is not sign-definite in general. By contrast, the complexity gap exhibits a definite sign in every example we analyze, although the sign itself depends on the underlying notion of subsystem complexity. Our results suggest that the complexity gap could be a natural candidate building block for a prospective hierarchy of subsystem complexity inequalities.
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Earth and Planetary Astrophysics

Dynamical Tides during High-Eccentricity Migration produces the Hot Jupiter Pile-up, Neptune Ridge, and Neptune Desert

The period distribution of hot gaseous exoplanets depends strongly on mass. Clustering between the orbital periods of $\sim$3 to $\sim$5-6 days is seen for sub-Saturns ("Neptune ridge") and Jovians ("hot Jupiter pile-up"), contrasting with a sharp deficit interior to 3 days for sub-Saturns, not seen for Jovians ("Neptune desert"). During high-eccentricity migration, tidally-excited fundamental-modes (f-modes) act as a reservoir for orbital energy, and can take gaseous planets formed beyond several AU and place them at short separations. However, how f-modes relinquish their energy into the planet interior is unknown. Here, we show how f-modes can not only circularize orbits – causing clustering near the Neptune ridge and hot-Jupiter pile-up – but can also shock and unbind mass, leaving sub-Saturn cores in the Neptune desert. Our hydrodynamical simulations demonstrate that close approaches tidally excite f-modes, whose super-sonic velocities shock gaseous envelopes. Atmospheres cool by radiative diffusion or winds when shocks penetrate shallow versus deep depths. Planetary structural and orbital evolution is followed over many periastron passages using an iterative map: shocks that diffusively cool circularize and bunch orbits near the hot Jupiter pile-up and Neptune ridge, while shocks that drive outflows unbind envelopes and place gas giant cores in the Neptune desert. Sub-Saturns that dwell in the desert are predicted to arrive with large spin-orbit misalignments after producing luminous flares.
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All authors J. J. Zanazzi, Morgan MacLeod, Marta L. Bryan, Suvrath Mahadevan

High Energy Physics (Phenomenology)

Leggett-Garg Inequality Violation in Muon $g-2$ Experiments

We present the first study of Leggett-Garg inequality violation in polarized muon spin precession. We formulate a procedure to reconstruct temporal correlators of the longitudinal muon polarization from measured time-dependent muon decay spectra and apply it to publicly available Fermilab Muon $g-2$ data corresponding to approximately $10$ billion muon decays. Using a simplified model of the detector acceptance and efficiency, the Leggett-Garg inequality is found to be violated with a single-bin significance of $5.5\sigma$, while combining neighboring bins further increases the significance. While our analysis is limited by systematic uncertainties associated with the detector modeling, a dedicated experimental analysis could reduce these uncertainties toward the statistical level, $\mathcal{O}(10^{-3})$, potentially enabling one of the most precise measurements of temporal quantum correlations.
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Astrophysics of Galaxies

Gas-induced gravitational-wave dephasing and accretion periodicities of live post-Newtonian massive black hole binaries: warm disk

We perform 3D hydrodynamical simulations of an equal-mass quasi-circular live $10^6~{\rm M}_\odot$ massive black hole binary (MBHB) embedded in a prograde, locally isothermal circumbinary disk (CBD) with $0.1$ aspect ratio. The binary evolves under the effect of gaseous torques and $2.5$ post-Newtonian dynamics. This approach allows us to track the influence of the CBD on a gravitational-wave (GW) driven MBHB inspiral all the way down to merger from $53$ Schwarzschild radii ($r_s$) over $1.5$ years. Comparing the GW inspiral rate with the viscous inflow, we find the binary to decouple from the CBD just $\approx2$ days before merger. We measure gas torques (gravitational and accretion) with and without concurrent GW emission, finding that their sums agree to within $\lesssim5\%$ down to $25~r_s$. We then measure a gas-induced phase-shift in the GW signal of $\approx9.0\times10^{-4}$ rad that accumulates over a year until $40~r_s$ and saturates afterward, which should be LISA-detectable at redshift $z{\lesssim0.2}$. We further characterize the mass accretion rate modulations. We recover the periodicity associated with the “lump" at the inner cavity edge. The periodicities at the binary orbital period and at half of it are shifted to lower frequencies. We measure the former, due to relativistic apsidal precession, in an inspiraling binary for the first time, and newly identify the latter as due to the precession of the eccentric cavity. Our results have implications for multi-messenger astronomy, since observation of accretion rate modulation by LSST/Roman surveys and phase-shift by LISA will provide crucial information on the complex environment surrounding MBHBs.
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Materials Science

Boosting lattice polarization Mixing the perspectives of geometry optimization and cell-augmentation

Topologically polarized mechanical metamaterials enjoy a special built-in asymmetry that manifests as a preferred localization of edge states on selected edges. While this property has been shown for a few ideal Maxwell lattices, we currently lack systematic criteria to design families of structural systems exhibiting polarization. Here, we propose a framework to design polarized structural configurations enabled by topology optimization (TO), using both band and mode morphological properties as drivers of the optimization algorithm. Through the lens of TO, we are able to tap into a vast design space, unlocking geometric freedom far beyond what is achievable with canonical lattice architectures. At the same time, we elucidate important criteria that need to be satisfied, beyond the optimization outcome, to ensure robustness of the achieved polarization against perturbations of the edge morphology. These results provide the inspiration to loop back into the realm of ideal lattices in search of new configurations characterized by extreme polarization. The peculiar shape and connectivity of the TO-generated lattice offer a blueprint for identifying a new family of Maxwell trusses based on augmented kagome geometry. We demonstrate the achievement of strong polarization signatures up to a three-count edge state mismatch. For all the cases studied, we show agreement between theory, simulations, and experiments, which include laser vibrometry wave measurements on a waterjet-cut specimen and static tests on a 3D-printed prototype.
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All authors Pegah Azizi, Rahul Dev Kundu, Xiaojia Shelly Zhang, Stefano Gonella

Instrumentation and Detectors

Deep-Ocean Application-Specific Neutrino Experiment

This report introduces the concept, prototype design, projected costs, and scientific goals of a mobile experiment for detecting geoneutrinos originating from uranium and thorium decay chains in the Earth's mantle. This will constrain the planet's radiogenic heat production and unearth its geochemical makeup. This design of a deep-ocean mobile neutrino experiment, which is not mirrored by any active or planned experiments, supports physics and geoscience's goal of multi-modal data on the Earth's internal composition and structure. Based on geoscientific studies, this design is expected to achieve a 50–100-fold reduction in crustal background compared to similarly sized continental detectors, thereby enabling direct measurements of mantle geoneutrinos. The multiple stereoscopic projections enabled by the detector's unique mobility can map spatial variations in heat-producing elements within the mantle. Beyond discussing the design, we report on our collaboration's most recent hardware developments in the active prototyping of this detector. We briefly highlight the potential multiuse and interdisciplinary nature of this detector.
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All authors Takumi Araki, Simran Chauhan, Lyla Choi, Brian C. Crow, Max A. A. Dornfest, John Graham, Misaki Hosoya, John G. Learned, Viacheslav A. Li, William F. McDonough, Takeru Ohno, Takanobu Ono, Taichi Sakai, Jackson Seligman, Nathan Sibert, Shang-Wen Stradleigh, David Vartanyan, Hiroko Watanabe, Zhihao Xu, Jeffrey G. Yepez

General Relativity and Quantum Cosmology

The Cosmological Constant Problem: An Accessible Introduction

We present a pedagogical introduction to the cosmological constant problem that requires only basic knowledge of quantum field theory and general relativity. A massive real scalar field is used to illustrate how the quantum vacuum energy density and pressure can be calculated both in flat spacetime and in an expanding universe. Detailed computations are provided for dimensional, cutoff, and adiabatic regularizations. No attempt is made to address quantum gravitational effects, and the expanding-universe background is treated classically. We point out that although the commonly cited discrepancy of 120 orders of magnitude between theory and observation is based on an estimate that does not account for regularization and renormalization, fundamental principles of quantum field theory nevertheless lead to a huge mismatch. In addition to this large discrepancy, we emphasize that there are also conceptual challenges related to cosmic expansion, such as the choice between comoving and physical scales in certain contexts and the non-uniqueness of vacuum.
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General Relativity and Quantum Cosmology

Selective enhancement of quantum decay channels

In the decay of quantum particles under field theoretic consideration, the decay rate is typically a convolution of the density of modes the primary field is allowed to decay into and the allowed probability density for the field to decay into such modes. In free space, though many such processes show high amplitude of such transitions towards the infrared sector, the depletion of allowed mode density in that regime arrests the efficacy of such decays at low energies. Therefore in free space, in order to enhance the decay rate, one needs the transition probability density to be rich enough towards the high energy sector where mode density support is also high enough to make the rate sufficiently large. In this work we argue that in the controlled boundary condition environment e.g. in a cavity, the mode functions of product field receive significant support towards their infrared sector, boosting the probability (and hence rates) of low energy processes. The cavity geometry offers sweet spots in terms of resonant geometry around which the interaction of a primary field with product fields receives dramatic enhancement, significantly enlarging its decay rates. Therefore, a judicious selection of cavity geometry serves as a potential substitute to studying interesting processes at high energy. The results have direct relevance for the study of QED processes and implications for the study of exotic new physics are also discussed.
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General Relativity and Quantum Cosmology

Study of Cosmic Acceleration of the Universe in the Presence of Bulk Viscous Matter

Over the past century, both theoretical advancements and experimental observations have established General Relativity (GR) as the most successful framework for describing gravitational phenomena. However, observations from multiple cosmological probes over the last two decades have provided compelling evidence for the accelerated expansion of the Universe. The rapid progress in observational astronomy and precision cosmology has highlighted several challenges that motivate the search for extensions or alternatives to General Relativity. In this thesis, we investigate alternative formulations of gravity based on non-Riemannian geometry, with particular emphasis on (f(Q)) gravity in the presence of bulk viscosity. We first explore the existence of exact cosmological solutions for viscous fluid models within the framework of (f(Q)) gravity and constrain the free parameters of these solutions using observational datasets. The resulting constrained models are then employed to study the evolutionary history of cosmic expansion. Our analysis demonstrates that the proposed viscous (f(Q)) gravity models can successfully account for the observed late-time acceleration of the Universe. Furthermore, we examine several classes of nonlinear viscous (f(Q)) gravity models through both dynamical systems and observational analyses. Particular attention is given to the cosmological viability of these models and their ability to reproduce the different evolutionary epochs of the Universe, ranging from matter-dominated eras to accelerated expansion phases.
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Chemical Physics

A large-scale foundation model enables simulation-to-real adaptation for nuclear magnetic resonance-based molecular structure analysis

Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful tool for molecular structure analysis, and spectral artificial intelligence offers great potential for its rapid and automated interpretation. However, the scarcity of experimental NMR datasets has constrained deep learning in this domain to narrow, task-specific applications that lack broad generalization. Here, we introduce UltraNMR, a large-scale foundation model for NMR that leverages the intrinsic properties of NMR spectra to learn generalizable spectral representations. We collected 158 million paired simulated $^{1}$H and $^{13}$C NMR spectra to train UltraNMR, employing multiple domain-specific pre-training objectives. UltraNMR captures both intra-spectral and inter-spectral dependencies, enabling seamless simulation-to-real adaptation. We demonstrate that adapting UltraNMR to a range of molecular structure analysis tasks on experimental NMR spectra consistently yields state-of-the-art performance and clearly outperforms UltraNMR variants trained directly on downstream data without simulation pre-training. We also construct a large-scale NMR spectral vector library by encoding simulated NMR spectra using UltraNMR, covering 94 million unique molecules and enabling effective structure-aware retrieval. In real-world applications, UltraNMR facilitates the structural elucidation of two previously unknown natural products from Chinese herbal medicines recorded in the Chinese Pharmacopoeia. These results suggest that large-scale simulation pre-training can effectively bridge the simulation-to-real gap, enabling robust and generalizable molecular structure analysis of real-world NMR spectra.
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All authors Chen Yang, Zheng Fang, Hanyu Sun, Fanjie Xu, Hongxin Xiang, Hanyu Gao, Xiangxiang Zeng, Yuqiang Li, Xiaojian Wang, Jun Xia

Chemical Physics

Empowering Polymeric Materials Discovery by Artificial Intelligence

Polymeric materials underpin modern technologies spanning energy storage, microelectronics, healthcare and sustainable manufacturing. Yet their rational design remains exceptionally challenging because material performance emerges from complex interactions among molecular composition, chain architecture, processing history and hierarchical structural evolution across multiple length and time scales. Consequently, polymer research has long relied on labor-intensive experimentation and fragmented modeling approaches, limiting both mechanistic understanding and innovation efficiency. Recent advances in data infrastructure, machine learning, large artificial intelligence (AI) models and laboratory automation are beginning to reshape this landscape. Rather than functioning as isolated tools, polymer databases, predictive models, AI agents and automated laboratories are increasingly converging into interconnected discovery ecosystems. As a result, the central challenge is shifting from improving predictive accuracy alone to enabling reliable decision-making, adaptive learning and seamless integration across computation, experimentation and scientific reasoning. We argue that polymer science is entering an era of autonomous discovery, in which data, simulation, reasoning and experimentation operate within self-improving feedback loops that continuously generate hypotheses, design materials, execute experiments and refine predictive models. By unifying molecular design, process optimization, experimental validation and industrial translation, such autonomous ecosystems establish a more predictive, reproducible and scalable paradigm for polymer innovation, fundamentally transforming how polymer research is conducted.
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All authors Chenyao Ma, Linda Zhang, Yuheng Chen, Wei Du, Shangwen Fang, Zihao Jiang, Chuanyu Liu, Xinyu Ma, Rui Su, Gang Wang, Muyao Yu, Dong Zhong, Jie Zhu, Weibo Gong, Huan Gu, Limin Li, Chen Shen, Rui Wu, Zhenghao Wu, Kan Xu, Min Zhou, Donglin He, Xiayun Huang, Shan Jiang, Pengfei Ou, Jiayu Peng, Yuwei Zhang, Jie Zhao, Di Zhang, Piao Ma, Zhenghao Li, Hao Li