Papers

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Physics

Sunday 21 June

Materials Science

First-Principles Investigation of Ammonia Adsorption and N-H Activation on W-B Nanoclusters

Anastasiia V. Iosimovska, Mikhail M. Lukanov, Christian Tantardini et al. (+3 more)

Tungsten-boride nanoclusters are nanoscale systems of potential catalytic interest, but their structural stability and reactivity remain poorly understood. We combine evolutionary structure prediction with density functional theory to investigate W$_m$B$_n$ nanoclusters containing up to 43 atoms. The calculated stability descriptors reveal a strongly non-monotonic landscape, with several compositions locally favoured relative to neighbouring stoichiometries within the explored isolated-cluster model. Molecular NH$_3$ adsorption was examined at W-top and accessible B-top sites, with adsorption energies ranging from $-1.78$ to $-0.54$ eV on W sites and from $-1.54$ to $+0.62$ eV on B sites. H adsorption at W-top and B-top sites spans $-1.47$ to $+0.67$ eV, indicating pronounced composition- and site-dependence. CI-NEB calculations show that the first N-H bond-cleavage barrier is strongly pathway-dependent. These results characterize the initial activation of NH$_3$ on W-B nanoclusters and provide an atomistic basis for further investigation of the complete ammonia-decomposition mechanism.

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All authors Anastasiia V. Iosimovska, Mikhail M. Lukanov, Christian Tantardini, Alexander S. Novikov, Viktor S. Baidyshev, Alexander G. Kvashnin

Cosmology and Nongalactic Astrophysics

Fast Radio Burst Cosmology: Hubble Tension and Dark Energy

Fayin Wang, Xuandong Jia, Daohong Gao et al. (+1 more)

Fast radio bursts (FRBs) are luminous, millisecond-duration extragalactic radio transients that have emerged as a powerful, complementary cosmological probe for investigating the late-time cosmic evolution, offering unique advantages over conventional probes such as Type Ia supernovae, baryon acoustic oscillations, and cosmic microwave background radiation. This review systematically summarizes the cosmological applications of FRBs, focusing on their critical roles in measuring the Hubble constant ($H_0$) and constraining dark energy properties. Benefiting from the precise dispersion measure (DM) - redshift relation of localized FRBs, the integrated electron density of the intergalactic medium (IGM) along the line of sight can be tightly modeled, enabling independent and low-redshift measurements of the cosmic expansion rate. Current FRB samples consisting of localized and non-localized events provide competitive $H_0$ constraints, offering an independent method to measure $H_0$. FRBs also serve as effective tracers to constrain dark energy equation-of-state parameters. We comprehensively discuss key limiting factors for FRB cosmological precision, including uncertainties in Galactic and host galaxy electron density models, and IGM inhomogeneities. With the rapid growth of high-precision FRB surveys and localized FRB samples, FRBs are promising to provide stringent constraints on late-time cosmic acceleration, dark energy evolution and cosmic baryons.

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All authors Fayin Wang, Xuandong Jia, Daohong Gao, Zigao Dai

High Energy Astrophysical Phenomena

Fermi bubbles detected in $\sim$100 TeV neutrinos

Uri Keshet and Ilya Gurwich

The Fermi bubbles have been identified as a collimated bipolar outflow emanating from the Milky-Way center, tracing strong forward shocks which extend $\sim10$ kpc from the Galactic disk, originating from a $\sim10^{56\pm1}$ erg outburst. These shocks are sufficiently strong, extended, and energetic to produce a detectable flux of $\gtrsim 10$ TeV neutrinos, especially in their denser north and east, but early IceCube data were insufficient for identifying the signal. We find that IceCube high-energy starting events (HESE 12-year) correlate with the $\textit{Fermi}$-LAT sky map outside the Galactic plane ($>3\sigma$). Testing for neutrinos coincident with the bubble shells, localized using $\textit{eROSITA}$ data, we detect ($>4\sigma$) both bubbles at high ($|b|>30^{\circ}$) latitudes, with a local excess mainly in their X-ray bright eastern shells ($>5\sigma$). The signal matches the anticipated secondaries of relativistic ions carrying $\sim 10^{54.5}$ erg (with factor $\sim3$ uncertainty) in each bubble, shock-accelerated to $>$PeV energies. The results verify the strength of the shocks, suggesting an ion acceleration efficiency of order $\sim10\%$. We also present preliminary evidence for neutrinos from the even larger shells of the eROSITA bubbles, which encapsulate their younger Fermi-bubble counterparts, carrying a similar energy and confined by shocks nearly as strong.

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High Energy Physics (Theory)

Eight loop form factors, amplitudes and patterns in planar $\mathcal{N}=4$ super-Yang-Mills theory

Lance J. Dixon and Zhenjie Li

The simplest nontrivial amplitude in planar $\mathcal{N}=4$ super-Yang-Mills theory is six-gluon scattering in the maximally-helicity-violating configuration. It has been computed to 8 loops with the help of antipodal duality, which relates it to the three-point form factor of a protected operator, the chiral stress tensor super-multiplet, represented also as ${\rm tr} \phi^2$. In this talk, we describe the computation to 8 loops of another three-point form factor, for the operator ${\rm tr}\phi^3$. This form factor lives in the same restricted space of polylogarithms as the ${\rm tr}\phi^2$ form factor. We also report on all-order patterns for sequences of coefficients in the symbols of these polylogarithmic results, for the leading discontinuity of the ${\rm tr}\phi^3$ form factor.

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Quantum Physics

Vibe Calibration: Autonomous Bring-up of a 112-Qubit Superconducting Quantum Processor by a Skill-Orchestrating Language Agent

Huikai Xu, Jiaxiu Han, Shigang Ou et al. (+11 more)

Superconducting quantum computing is one of the most mature solid-state platforms for quantum computation, with processors exceeding one hundred qubits. Yet further scaling toward fault-tolerant quantum computing is increasingly constrained by calibration complexity. Conventional scripts are brittle to anomalous signals, and expert judgment is bounded by cognitive bandwidth and serial operation time, failing to keep pace with system scale. Here we report Vibe Calibration, an autonomous calibration system orchestrated by large language model agents, which distills expert tacit knowledge into reusable Skills. Each Skill is organized as a decision tree that packages parameterized measurement commands, quantitative acceptance criteria, and audit records, enabling autonomous execution and self-healing. We capture this knowledge through a three-phase human-in-the-loop distillation process and fine-tune a large language model on validated trajectories. On a 112-qubit processor with frequency-tunable transmons, the system autonomously completes calibration of 108 out of 112 qubits in 4.7 hours, achieving a 4–5$\times$ speedup over manual calibration of the full 112 qubits. A cross-validated comparison with expert manual calibration on a 16-qubit subset shows agreement on 14 out of 16 qubits. More importantly, the model demonstrates transferable calibration workflows across devices. While low-level control scripts require minor interface adaptation for different hardware platforms, the core decision logic and task orchestration generalize to new processors, demonstrating a reusable laboratory interface rather than a memorized script.This work demonstrates, for the first time, fully autonomous calibration of a hundred-qubit superconducting processor through reusable and auditable Skills, removing a critical barrier to scalable quantum hardware operation.

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All authors Huikai Xu, Jiaxiu Han, Shigang Ou, Cheng Ye, Zisong Shen, Jing Gao, Yijia Wang, Tianrui Che, Yu Song, Weiyang Liu, Lei Wang, Lin-Feng Zhang, Pan Zhang, Hai-Feng Yu

High Energy Physics (Experiment)

Search for the charged lepton flavor violating decay $\eta \to e^{\pm}\mu^{\mp}$

M. Ablikim, M. N. Achasov, P. Adlarson et al. (+709 more)

Based on $(10.087 \pm 0.044) \times 10^{9}~J/\psi$ events collected at the center-of-mass energy $\sqrt{s} = 3.097$~GeV with the BESIII detector, we search for the charged lepton flavor violating decay $\eta \to e^{\pm}\mu^{\mp}$ through the process $J/\psi \to \gamma \eta'$ with $\eta' \to \pi^{+} \pi^{-} \eta$. No signal is observed, and an upper limit on the branching fraction is determined to be $\mathcal{B}(\eta \to e^{\pm}\mu^{\mp}) < 6.8 \times 10^{-7}$ at the 90% confidence level. This result improves the previous best limit by one order of magnitude.

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All authors M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. H. An, Y. Bai, O. Bakina, H. R. Bao, X. L. Bao, M. Barbagiovanni, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, D. Cabiati, H. Cai, M. H. Cai, X. Cai, A. Calcaterra, G. F. Cao, N. Cao, S. A. Cetin, X. Y. Chai, J. F. Chang, T. T. Chang, G. R. Che, Y. Z. Che, C. H. Chen, G. Chen, H. S. Chen, H. Y. Chen, M. L. Chen, S. J. Chen, S. M. Chen, T. Chen, W. Chen, X. R. Chen, X. T. Chen, X. Y. Chen, Y. B. Chen, Y. Q. Chen, Z. K. Chen, J. Cheng, L. N. Cheng, S. K. Choi, X. Chu, G. Cibinetto, F. Cossio, J. Cottee-Meldrum, H. L. Dai, J. P. Dai, X. C. Dai, A. Dbeyssi, R. E. de, D. Dedovich, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De, E. Di, X. X. Ding, Y. Ding, Y. X. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. Dong, Z. J. Dong, M. C. Du, S. X. Du, X. L. Du, Y. Q. Du, Y. Y. Duan, Z. H. Duan, P. Egorov, G. F. Fan, J. J. Fan, Y. H. Fan, J. Fang, S. S. Fang, W. X. Fang, Y. Q. Fang, L. Fava, F. Feldbauer, G. Felici, C. Q. Feng, J. H. Feng, L. Feng, Q. X. Feng, Y. T. Feng, M. Fritsch, C. D. Fu, J. L. Fu, Y. W. Fu, H. Gao, Y. Gao, Y. N. Gao, Y. Y. Gao, Z. Gao, S. Garbolino, I. Garzia, L. Ge, P. T. Ge, Z. W. Ge, C. Geng, E. M. Gersabeck, A. Gilman, K. Goetzen, J. Gollub, J. B. Gong, J. D. Gong, L. Gong, W. X. Gong, W. Gradl, S. Gramigna, M. Greco, M. D. Gu, M. H. Gu, C. Y. Guan, A. Q. Guo, H. Guo, J. N. Guo, L. B. Guo, M. J. Guo, R. P. Guo, X. Guo, Y. P. Guo, Z. Guo, A. Guskov, J. Gutierrez, J. Y. Han, T. T. Han, X. Han, F. Hanisch, K. D. Hao, X. Q. Hao, F. A. Harris, C. Z. He, K. K. He, K. L. He, F. H. Heinsius, C. H. Heinz, Y. K. Heng, C. Herold, P. C. Hong, G. Y. Hou, X. T. Hou, Y. R. Hou, Z. L. Hou, H. M. Hu, J. F. Hu, Q. P. Hu, S. L. Hu, T. Hu, Y. Hu, Y. X. Hu, Z. M. Hu, G. S. Huang, K. X. Huang, L. Q. Huang, P. Huang, X. T. Huang, Y. P. Huang, Y. S. Huang, T. Hussain, N. H, N. in, J. Jackson, Q. Ji, Q. P. Ji, W. Ji, X. B. Ji, X. L. Ji, Y. Y. Ji, L. K. Jia, X. Q. Jia, D. Jiang, H. B. Jiang, S. J. Jiang, X. S. Jiang, Y. Jiang, J. B. Jiao, J. K. Jiao, Z. Jiao, L. C. L, S. Jin, Y. Jin, M. Q. Jing, X. M. Jing, T. Johansson, S. Kabana, X. L. Kang, X. S. Kang, B. C. Ke, V. Khachatryan, A. Khoukaz, O. B. Kolcu, B. Kopf, L. Kr, L. Kr, Y. Y. Kuang, M. Kuessner, X. Kui, N. Kumar, A. Kupsc, W. K, Q. Lan, W. N. Lan, T. T. Lei, M. Lellmann, T. Lenz, C. Li, C. H. Li, C. K. Li, D. M. Li, F. Li, G. Li, H. B. Li, H. J. Li, H. L. Li, H. N. Li, H. P. Li, J. N. Li, J. S. Li, J. W. Li, K. Li, K. L. Li, L. J. Li, M. H. Li, M. R. Li, M. T. Li, P. L. Li, P. R. Li, Q. M. Li, Q. X. Li, R. Li, S. Li, S. X. Li, S. Y. Li, T. Li, T. Y. Li, W. D. Li, W. G. Li, X. Li, X. H. Li, X. K. Li, X. L. Li, X. Y. Li, X. Z. Li, Y. Li, Y. B. Li, Y. C. Li, Y. G. Li, Y. P. Li, Z. H. Li, Z. J. Li, Z. L. Li, Z. X. Li, Z. Y. Li, C. Liang, H. Liang, Y. F. Liang, Y. T. Liang, Z. Z. Liang, G. R. Liao, L. B. Liao, M. H. Liao, Y. P. Liao, J. Libby, A. Limphirat, C. C. Lin, C. X. Lin, D. X. Lin, T. Lin, B. J. Liu, B. X. Liu, C. Liu, C. X. Liu, F. Liu, F. H. Liu, G. M. Liu, H. Liu, H. B. Liu, H. M. Liu, J. B. Liu, J. J. Liu, K. Liu, K. Y. Liu, L. Liu, L. C. Liu, M. H. Liu, P. L. Liu, Q. Liu, S. B. Liu, T. Liu, W. M. Liu, W. T. Liu, X. Liu, X. K. Liu, X. L. Liu, X. P. Liu, X. Y. Liu, Y. Liu, Y. B. Liu, Z. A. Liu, Z. D. Liu, Z. L. Liu, Z. Q. Liu, Z. X. Liu, Z. Y. Liu, X. C. Lou, H. J. Lu, J. G. Lu, X. L. Lu, Y. Lu, Y. H. Lu, Y. P. Lu, Z. H. Lu, C. L. Luo, J. R. Luo, J. S. Luo, M. X. Luo, T. Luo, X. L. Luo, Z. Y. Lv, X. R. Lyu, Y. F. Lyu, Y. H. Lyu, F. C. Ma, H. L. Ma, J. L. Ma, L. L. Ma, L. R. Ma, Q. M. Ma, R. Q. Ma, R. Y. Ma, T. Ma, X. T. Ma, X. Y. Ma, Y. M. Ma, F. E. Maas, I. MacKay, M. Maggiora, S. Maity, S. Malde, Q. A. Malik, H. X. Mao, Y. J. Mao, Z. P. Mao, S. Marcello, A. Marshall, F. M. Melendi, Y. H. Meng, Z. X. Meng, G. Mezzadri, H. Miao, T. J. Min, R. E. Mitchell, X. H. Mo, B. Moses, N. Yu, J. Muskalla, Y. Nefedov, F. Nerling, H. Neuwirth, Z. Ning, S. Nisar, Q. L. Niu, W. D. Niu, Y. Niu, C. Normand, S. L. Olsen, Q. Ouyang, S. Pacetti, Y. Pan, A. Pathak, Y. P. Pei, M. Pelizaeus, G. L. Peng, H. P. Peng, X. J. Peng, Y. Y. Peng, K. Peters, K. Petridis, J. L. Ping, R. G. Ping, S. Plura, V. Prasad, L. P, F. Z. Qi, H. R. Qi, M. Qi, S. Qian, W. B. Qian, C. F. Qiao, J. H. Qiao, J. J. Qin, J. L. Qin, L. Q. Qin, L. Y. Qin, P. B. Qin, X. P. Qin, X. S. Qin, Z. H. Qin, J. F. Qiu, Z. H. Qu, J. Rademacker, K. Ravindran, C. F. Redmer, A. Rivetti, M. Rolo, G. Rong, S. S. Rong, F. Rosini, M. Q. Ruan, N. Salone, A. Sarantsev, Y. Schelhaas, M. Schernau, K. Schoenning, M. Scodeggio, W. Shan, X. Y. Shan, Z. J. Shang, J. F. Shangguan, L. G. Shao, M. Shao, C. P. Shen, H. F. Shen, W. H. Shen, X. Y. Shen, B. A. Shi, Y. Shi, H. Shi, J. L. Shi, J. Y. Shi, M. H. Shi, S. Y. Shi, X. Shi, H. L. Song, J. J. Song, M. H. Song, T. Z. Song, W. M. Song, Y. X. Song, S. Sosio, S. Spataro, S. Stansilaus, F. Stieler, M. Stolte, S. S, G. B. Sun, G. X. Sun, H. Sun, H. K. Sun, J. F. Sun, K. Sun, L. Sun, R. Sun, S. S. Sun, T. Sun, W. Y. Sun, Y. C. Sun, Y. H. Sun, Y. J. Sun, Y. Z. Sun, Z. Q. Sun, Z. T. Sun, H. Tabaharizato, C. J. Tang, G. Y. Tang, J. Tang, J. J. Tang, L. F. Tang, Y. A. Tang, Z. H. Tang, L. Y. Tao, M. Tat, J. X. Teng, J. Y. Tian, W. H. Tian, Y. Tian, Z. F. Tian, I. Uman, E. van, B. Wang, C. Wang, D. Y. Wang, F. K. Wang, H. J. Wang, H. R. Wang, J. Wang, J. J. Wang, J. P. Wang, K. Wang, L. L. Wang, L. W. Wang, M. Wang, N. Y. Wang, S. Wang, T. Wang, W. Wang, W. P. Wang, X. F. Wang, X. L. Wang, X. N. Wang, Y. Wang, Y. D. Wang, Y. F. Wang, Y. H. Wang, Y. J. Wang, Y. L. Wang, Y. N. Wang, Z. Wang, Z. L. Wang, Z. Q. Wang, Z. Y. Wang, D. Wei, D. H. Wei, D. J. Wei, H. R. Wei, F. Weidner, H. R. Wen, S. P. Wen, U. Wiedner, G. Wilkinson, M. Wolke, J. F. Wu, L. H. Wu, L. J. Wu, S. G. Wu, S. M. Wu, X. W. Wu, Z. Wu, H. L. Xia, L. Xia, B. H. Xiang, D. Xiao, G. Y. Xiao, H. Xiao, Y. L. Xiao, Z. J. Xiao, C. Xie, K. J. Xie, Y. Xie, Y. G. Xie, Y. H. Xie, Z. P. Xie, T. Y. Xing, D. B. Xiong, G. F. Xu, H. Y. Xu, Q. J. Xu, Q. N. Xu, T. D. Xu, X. P. Xu, Y. Xu, Y. C. Xu, Z. S. Xu, F. Yan, L. Yan, W. B. Yan, W. C. Yan, W. H. Yan, W. P. Yan, X. Q. Yan, Y. Y. Yan, H. J. Yang, H. L. Yang, H. X. Yang, J. H. Yang, R. J. Yang, X. Y. Yang, Y. Yang, Y. G. Yang, Y. H. Yang, Y. M. Yang, Y. Q. Yang, Y. Z. Yang, Z. Y. Yang, W. J. Yao, Z. P. Yao, M. Ye, M. H. Ye, Z. J. Ye, Z. Y. You, B. X. Yu, C. X. Yu, G. Yu, J. S. Yu, L. W. Yu, T. Yu, X. D. Yu, Y. C. Yu, C. Z. Yuan, H. Yuan, J. Yuan, L. Yuan, M. K. Yuan, S. H. Yuan, Y. Yuan, C. X. Yue, A. A. Zafar, F. R. Zeng, S. H. Zeng, X. Zeng, Y. J. Zeng, Y. C. Zhai, Y. H. Zhan, B. L. Zhang, B. X. Zhang, D. H. Zhang, G. Y. Zhang, H. Zhang, H. C. Zhang, H. H. Zhang, H. Q. Zhang, H. R. Zhang, H. Y. Zhang, J. Zhang, J. J. Zhang, J. L. Zhang, J. Q. Zhang, J. S. Zhang, J. W. Zhang, J. X. Zhang, J. Y. Zhang, J. Z. Zhang, L. M. Zhang, N. Zhang, P. Zhang, Q. Zhang, Q. Y. Zhang, Q. Z. Zhang, R. Y. Zhang, S. H. Zhang, S. N. Zhang, X. M. Zhang, X. Y. Zhang, Y. T. Zhang, Y. H. Zhang, Y. P. Zhang, Z. Zhang, Z. D. Zhang, Z. H. Zhang, Z. L. Zhang, Z. X. Zhang, Z. Y. Zhang, G. Zhao, P. Zhao, J. Y. Zhao, J. Z. Zhao, L. Zhao, M. G. Zhao, R. P. Zhao, S. J. Zhao, Y. B. Zhao, Y. L. Zhao, Y. P. Zhao, Y. X. Zhao, Z. G. Zhao, A. Zhemchugov, B. Zheng, B. M. Zheng, J. P. Zheng, W. J. Zheng, W. Q. Zheng, X. R. Zheng, Y. H. Zheng, B. Zhong, C. Zhong, X. Zhong, H. Zhou, J. Q. Zhou, S. Zhou, X. Zhou, X. K. Zhou, X. R. Zhou, X. Y. Zhou, Y. X. Zhou, Y. Z. Zhou, A. N. Zhu, J. Zhu, K. Zhu, K. J. Zhu, K. S. Zhu, L. X. Zhu, S. H. Zhu, T. J. Zhu, W. D. Zhu, W. J. Zhu, W. Z. Zhu, Y. C. Zhu, Z. A. Zhu, X. Y. Zhuang, M. Zhuge, J. H. Zou, J. Zu

Optics

Nonlinear differential imaging via vectorial parametric interaction

Zhuohang Wei, Kun Huang and Heping Zeng

Optical image differentiation is a key operation for edge extraction in imaging and machine vision, yet most existing implementations rely on momentum-domain filtering elements and are typically developed within a scalar-wave framework. Here we demonstrate a nonlinear vectorial mechanism for optical image differentiation based on parametric wave mixing. By solving the full vector wave equation with a nonlinear polarization source term, we show analytically that frequency conversion intrinsically generates cross-polarized field components that correspond to spatial derivatives of the incident field. Exploiting the polarization-selective phase-matching conditions of second-order nonlinear crystals, particularly uniaxial crystals, we propose filter-free imaging schemes that simultaneously perform spatial differentiation and wavelength conversion. This nonlinear vector differentiation platform enables compact, wavelength-agile, and edge-enhanced imaging, offering new opportunities for mid-infrared imaging and all-optical signal processing.

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Optics

Single-photon time-stretch computational ghost spectroscopy

Zhibin Zhao, Kun Huang, Ben Sun et al. (+4 more)

Time-stretch spectroscopy is powerful for capturing transient spectral phenomena but remains fundamentally limited by detector bandwidth or timing jitter, especially under photon-starved conditions. Here, we devise and implement single-photon time-stretch computational ghost spectroscopy, which integrates dispersive wavelength-to-time mapping with programmable temporal encoding and correlation-based reconstruction to overcome these detection limitations. Specifically, temporally stretched ultrashort pulses are modulated by predefined encoding patterns and detected by a low-bandwidth detector, allowing reconstruction of near-infrared spectra with 450 resolvable channels across 1530-1590 nm without direct high-speed waveform acquisition. By further incorporating compressive sensing, accurate spectral recovery is achieved at sub-Nyquist sampling rates, substantially reducing acquisition requirements to facilitate high-speed operation at 210 kHz. In the single-photon regime, computational ghost reconstruction effectively suppresses the intrinsic detector timing jitter, yielding high-fidelity spectra at illumination fluxes down to 0.01 photons/pulse. By jointly enabling broadband coverage, high spectral resolution, high acquisition speed, and single-photon sensitivity, this approach establishes a computation-enhanced paradigm for time-stretch spectroscopy and provides a versatile platform for ultrafast and photon-efficient spectroscopic applications.

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All authors Zhibin Zhao, Kun Huang, Ben Sun, Beibei Dong, Wen Zhang, Jianan Fang, Heping Zeng

Optics

Alignment-Free Nanometric Optical Metrology Enabled by Structured Light

Yu Wang, Benquan Wang, Eng Aik Chan et al. (+7 more)

Advances in the semiconductor industry are driven by the development of increasingly compact devices featuring intricate etched geometries, the characterization of which essentially requires ultraprecise, label-free, and real-time metrology. However, non-destructive and alignment-free optical metrology of sub-wavelength structures with nanometric resolution remains a major challenge. Here, we demonstrate a novel single-shot, label-free, and alignment-free optical metrology approach for determining the 1D position of sub-wavelength nanostructures, achieving lambda/110 (7.2 nm) precision. The high precision benefits from utilizing structured illuminations of Laguerre-Gaussian (LG) or Hermite-Gaussian (HG) beams, and the AI analyzing method can retrieve the information when such structured light interacts with sub-wavelength objects. Instead of relying on phase singularities in superoscillatory microscopy, our approach leverages spatially distributed phase jumps in HG and LG beams interacting with the nanostructures, providing an alignment-robust solution to the challenges in optical metrology. Such an alignment-free, non-destructive, and high-precision metrology technique enables real-time machine vision, semiconductor inspection, and advanced manufacturing.

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All authors Yu Wang, Benquan Wang, Eng Aik Chan, Songze Li, Zhenyu Guo, Xi Xie, Masako Kishida, Che-Chin Chen, Yijie Shen, Jun-Yu Ou

Earth and Planetary Astrophysics

Autonomous Orbit Determination Analysis of a Conceptual Cislunar Navigation Constellation based on Inter-Satellite Range Measurement

Haohan Li, Yuxuan Miao, Xiyun Hou et al. (+5 more)

With the community's increasing interest in the cislunar space, building a navigation constellation servicing the whole cislunar space has become a pressing need. Previous studies mainly focus on constellations using orbits close to the Moon, which limits the servicing volume of the constellation. In this work, a four-satellite constellation using one L3 orbit, one L4 orbit, one L5 orbit and an orbit close to the Moon is proposed. The orbit determination accuracy is an important factor to be considered when designing parameters of the constellation. In this study, the mode of autonomous orbit determination (AOD) based on inter-satellite range data is considered. With such a model, the out-of-plane design parameters are identified as the main parameters influencing the AOD accuracy. For the AOD based on short arcs, we find that the increase of the out-of-plane amplitude can improve the AOD accuracy, and the out-of-plane initial phases have a more complex influence. A novel relative planarity factor (RPF) $P_\text{r}$, which has negative correlation with the AOD accuracy, is proposed as the metric to evaluate the variation of AOD performance. Using $P_\text{r}$, we demonstrate that the coplanarity of the constellation can significantly reduce the AOD accuracy. For the long arc AOD, the influence of different parameters is insignificant.

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All authors Haohan Li, Yuxuan Miao, Xiyun Hou, Bosheng Li, Jinjun Zheng, Hao Yu, Kanglian Zhao, Huan Yan

Mesoscale and Nanoscale Physics

Second-order dc conductivity in the velocity-gauge Keldysh formalism: gauge-invariant decomposition into nonlinear Drude, Berry-curvature-dipole, and quantum-metric responses

Junya Shibata

We derive a gauge-invariant clean-limit decomposition of the second-order dc nonlinear conductivity in multiband tight-binding systems within the velocity-gauge Keldysh Green's function formalism. In the constant-relaxation-time approximation, the dc response separates into four contributions with distinct lifetime $\tau$ scalings and physical origins: the nonlinear Drude term $\sigma^{\mathrm{ND}}_{ijk}\propto\tau^{2}$, the Berry-curvature-dipole term $\sigma^{\mathrm{BCD}}_{ijk}\propto\tau$, the intraband quantum-metric-dipole term $\sigma^{\mathrm{intra\text{-}QMD}}_{ijk}\propto\tau^{0}$, and the interband quantum-metric-dipole term $\sigma^{\mathrm{inter\text{-}QMD}}_{ijk}\propto\tau^{0}$. The intraband term is a Fermi-surface dipole of the ordinary band quantum metric, while the interband term is written, in the present representation, as a Fermi-sea-type response involving a band-normalized quantum metric. Working entirely within the velocity-gauge Keldysh–Kubo framework, we show that all connection-dependent commutator terms generated in the band-basis expansion cancel exactly between the covariant-quantum-connection sector $\sigma^{\mathcal{C}}_{ijk}$ and the three-Berry-connection sector $\sigma^{\mathcal{T}}_{ijk}$, making the role of the Peierls contact velocity vertices $V_{ij}$ and $V_{ijk}$ explicit; a complementary projector-based derivation appears in Ulrich et al., Phys. Rev. B 113, L201107 (2026), and our Fermi-surface dc-limit expression agrees with that reference after accounting for index and convention differences. As a diagnostic illustration, we introduce a real two-band model in which the Berry curvature and hence the BCD response vanish identically while the intraband quantum-metric dipole remains finite, establishing a practical route to quantum-metric dc responses not reducible to the Berry-curvature-dipole mechanism.

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High Energy Astrophysical Phenomena

EMU discovery of Thunder: a bow-shock PWN powered by PSR J1631-4722 escaping Nimbus SNR (G336.7+0.5)

S. Lazarević, C. Maitra, A. Ahmad et al. (+21 more)

We report the discovery of a bow-shock pulsar wind nebula (PWN), dubbed Thunder, powered by the radio pulsar PSR J1631-4722 and projected within the Galactic supernova remnant (SNR) G336.7+0.5 (Nimbus). The system was first identified in observations from the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey and further characterised using MeerKAT Galactic Plane Survey data together with follow-up observations at 5.5 and 9 GHz obtained with the Australia Telescope Compact Array (ATCA). Assuming a distance of 7 kpc, the radio images resolve an elongated ~80 arcsec (2.7 pc) cometary nebula, indicative of a high velocity pulsar. An X-ray counterpart extending ~50 arcsec (1.7 pc) is detected in archival XMM-Newton data. The flat radio spectrum ($\alpha$ = -0.27 $\pm$ 0.05) and hard X-ray photon index ($\Gamma$ = 1.6 $\pm$ 0.4) indicate synchrotron emission from relativistic particles injected in the pulsar wind. Polarisation analysis reveals a highly ordered magnetic field aligned with the nebular flow, with fractional polarisation reaching up to 30% in the tail. An equipartition estimate gives a PWN magnetic-field strength of Beq $\approx$ 54-140 $\mu$G. Pulsar timing over a ~2.2 yr baseline reveals strong timing noise and a small spin glitch with amplitude $\Delta{\nu}/{\nu}$ = 1.10$\times$10$^{-8}$. The SNR shows no clear diffuse X-ray counterpart. The morphology and multiwavelength properties of the Nimbus-Thunder system, along with evolutionary models, constrain the system's age to approximately 30-45 kyr, placing the remnant in the late Sedov phase, approaching the transition to the radiative stage.

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All authors S. Lazarević, C. Maitra, A. Ahmad, R. Z. E. Alsaberi, S. Dai, D. Leahy, M. D. Filipović, P. G. Edwards, O. Kargaltsev, M. Abdelmaguid, J. D. Gelfand, J. West, S. Hutschenreuter, R. Brose, R. Kothes, V. Velović, C. Burger-Scheidlin, B. D. Ball, G. Graham, A. M. Hopkins, G. P. Rowell, S. F. Rahman, Z. J. Smeaton, S. Taziaux

Atmospheric and Oceanic Physics

Emergence of Chaos in the Tropical Atmosphere: Study of the Weak Temperature Gradient System

Stéphane Vannitsem and Jonathan Demaeyer

The atmospheric tropical belt is believed to be more predictable than the extratropics. This question is revisited here by exploring the emergence of chaos in reduced-order model versions of the vorticity equation under the weak temperature gradient hypothesis, which provides a good description of the large-scale tropical atmosphere. The analysis reveals that under fairly realistic divergence forcing amplitudes, chaos may emerge, sometimes with Lyapunov time scales of less than a day. This result contrasts with the idea of a predictable tropical atmosphere, and opens important questions on the effective origin of predictability in the Tropics.

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Materials Science

Lattice-renormalized geometric frustration drives fast ionic transport

Jianmin Yang and Lin Xie

Fast ionic transport is commonly understood from two complementary perspectives: soft lattices that facilitate ion migration, and frustrated ionic sublattices that host multiple nearly degenerate configurations. Here, we show that the host lattice and ionic geometric frustration are fundamentally coupled, and together shape a lattice-renormalized free-energy landscape that unifies these two perspectives. Starting from a coupled ion-lattice Hamiltonian and eliminating the adiabatic lattice response, we derive a configuration-dependent free-energy renormalization that takes a quadratic form of the ionic configurational forces weighted by the inverse stiffness of the host lattice. In a coarse-grained representation, this renormalization decomposes into local lattice relaxation and non-local interference between lattice-response fields. These two contributions reshape local ionic configurations and their correlations, thereby redistributing the configurational statistical weights underlying collective ionic transport. Atomistic simulations of cubic Li$_7$La$_3$Zr$_2$O$_{12}$ and AgCrSe$_2$ substantiate this physical picture, from microscopic configurational rearrangements to macroscopic diffusion dynamics. This framework therefore recasts fast ionic transport as a lattice-renormalized geometric frustration problem, in which lattice softness, ionic frustration, and collective diffusion all arise from the same underlying landscape.

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Quantum Physics

Probabilistic Storage and Retrieval of Quantum Superchannels for "Retrospective" Intervention

Wataru Yokojima, Jisho Miyazaki and Mio Murao

Storing an unknown quantum computation in a quantum state and retrieving it at a desired later time is a challenging task, hindered by the no-programming theorem of quantum computations. In the previous studies on the task of probabilistic storage-and-retrieval (pSAR) of quantum channels, the maximum probability of exactly retrieving a single unknown unitary channel from a quantum state in which the unknown unitary has been encoded via multiple calls to the unknown unitary channel is derived. In this work, we consider a higher-order version of pSAR, the probabilistic storage-and-retrieval of definite-causal unitary superchannels, which are physically modeled by sequences of unitary channels with open slots where arbitrary channels can be inserted between the unitary channels for intervention. This task requires activating the "retrospective” intervention functionality on the superchannel, beyond its normal intervention functionality. We propose two protocols: partial teleportation, which is supported by our numerical results for the small queries, and staircase backstitch, which achieves unit success probability asymptotically as the number of queries increases. We also derive a universal inversion protocol for unitary superchannels.

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Nuclear Theory

Full Configuration Interaction Quantum Monte Carlo for Accurate $\textit{Ab Initio}$ Nuclear Structure Calculations

Rongzhe Hu, Furong Xu, Baishan Hu et al. (+1 more)

We introduce novel full configuration interaction quantum Monte Carlo (FCIQMC) as an accurate many-body solver for $\textit{ab initio}$ nuclear structure calculations. This stochastic approach directly samples the exact wave function in the full configuration space, enabling high-fidelity treatment of high-order many-body correlations in strongly interacting nuclear systems. Using interactions from chiral effective field theory, we have computed ground-state energies and charge radii of $^4$He, $^8$Be, $^{12}$C and $^{16}$O with sub-percent-level many-body uncertainties. These results establish FCIQMC as a stochastic full-configuration-space solver capable of treating systems beyond the reach of the conventional no-core shell model, and as an accurate benchmark for truncated many-body expansion methods.

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All authors Rongzhe Hu, Furong Xu, Baishan Hu, Ali Alavi

Quantum Physics

Lattice-quantile estimation of {\pi} and convex-region integrals from coined two-dimensional quantum walks

Jen-Yu Chang, En-Jui Kuo, Chih-Yu Chen et al. (+1 more)

Monte Carlo integration is fundamentally limited by the M^(-1/2) rate that the Cramer-Rao bound imposes on any sample-mean estimator of an expectation value, regardless of how the samples are drawn. Coined discrete-time quantum walks (DTQWs) are known to spread ballistically - their position variance scales as T^2 against the diffusive T of classical random walks - yet this faster spreading has not been exploited for numerical integration. We show that coupling the ballistic scaling of a 2D DTQW to the Hardy-Huxley asymptotic for Gauss circle lattice counts produces estimators whose dominant error is a deterministic number-theoretic residual controlled by walk depth T, not a statistical fluctuation controlled by sample count M. The construction replaces the empirical mean of a sample-mean estimator with the ratio N(R-hat)/R-hat^2 of a lattice count to the square of a radial position quantile, a structural change that sidesteps the Cramer-Rao barrier. A single batch of measurements then propagates through classically precomputed multipliers to cover an entire family of integrals simultaneously. We develop the framework for convex smooth domains via Kraetzel's lattice asymptotic and for smooth integrals with convex or annular super-level sets via Cavalieri's principle, and provide a parameter-free identity for the bias floor (validated to within 1.5x across all tested depths). Every experiment is benchmarked against the classical random walk with the identical estimator to isolate the quantum contribution; the framework is oracle-free in the QAE sense (no controlled unitary encoding the integrand is required) and structurally distinct from quantum amplitude estimation and Szegedy-walk approaches. These ratios compare measurement counts at fixed precision and do not include quantum circuit execution cost.

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All authors Jen-Yu Chang, En-Jui Kuo, Chih-Yu Chen, Tsung-Wei Huang

Quantum Physics

No Reference-Free Generalization in Quantum Machine Learning

Jeongho Bang

Quantum machine learning is often motivated by the exponentially large state space of quantum systems, but this promise leaves a basic generalization problem unresolved: how can a learner assign different meanings to unseen quantum directions when the training data provide no preferred basis, measurement frame, or other orienting structure? We address this identifiability problem by formulating supervised learning without an external quantum reference frame, so that predictions cannot depend on an arbitrary choice of Hilbert-space coordinates. This requirement forces the learned classifier to preserve every unitary symmetry left unbroken by the training data. We prove that whenever the training states fail to span the full Hilbert space, all pure states orthogonal to their span must receive the same prediction – even when those states are mutually orthogonal and perfectly distinguishable once an appropriate measurement is supplied. The limitation is therefore not caused by state discrimination, optimization, or computational power, but by missing reference information. We further establish a robust version under weak symmetry breaking and show that learning generic unstructured concepts on multiqubit systems requires exponentially many independently oriented training directions. Numerical illustrations visualize the resulting prediction collapse and its controlled relaxation. Our results identify feature maps, measurement bases, Hamiltonians, locality, symmetry priors, architectures, and sufficiently diverse training states as operational resources for generalization. The central implication is that Hilbert-space dimension alone is not a learnable feature space: successful QML must specify the physical structure that gives unseen quantum directions semantic meaning.

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Mathematical Physics

Singular barriers and quartic integrability breaking in the TTW system

Adrian M. Escobar Ruiz, Miguel E. Gómez Quintanar, Lidia Jiménez-Lara et al. (+1 more)

We study the competition between resonance-induced integrability breaking and centrifugal confinement in a symmetric quartic deformation of the classical $k=1$ Tremblay–Turbiner–Winternitz (TTW) system, $H=\frac{1}{2}\left(P_X^2+P_Y^2\right)+X^2+Y^2 +\frac{\gamma}{X^2}+\frac{\gamma}{Y^2}+\kappa X^2Y^2.$ The inverse-square terms are the centrifugal remnants of an $SO(2)\times SO(2)$ reduction of a four-dimensional oscillator, while the $X^2Y^2$ interaction couples the reduced radial modes and connects the Smorodinsky–Winternitz and Contopoulos limits. For $\gamma>0$, the axes are impenetrable and split configuration space into invariant sectors. For sufficiently small nonzero $\kappa$, resonant averaging constructs a phase-locked periodic orbit on each energy surface $H=h>4\sqrt{\gamma}$ whose fixed-energy reduced Poincaré map has no unit characteristic multiplier. Poincaré's criterion therefore excludes a second independent $C^1$ first integral in any invariant neighbourhood of this orbit. At finite coupling, Poincaré sections and finite-time Lyapunov maps show the breakup of invariant curves and the growth of chaotic layers. Comparison with the barrier-free limit separates two effects: the quartic interaction breaks integrability, whereas the singular barriers reduce phase-space connectivity and chaotic transport without restoring it.

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All authors Adrian M. Escobar Ruiz, Miguel E. Gómez Quintanar, Lidia Jiménez-Lara, Jaume Llibre

Lattice Field Theory

Multi-particle states investigation with tensor renormalization group method

Fathiyya Izzatun Az-zahra, Shinji Takeda and Takeshi Yamazaki

We investigate multi-particle states of the (1+1)d Ising Model using a spectroscopy scheme based on transfer matrix and tensor renormalization group method. The scheme begins with computing the energy spectrum of the system from the transfer matrix estimated by the coarse-grained tensor network. The quantum number and momentum of these energy eigenstates are not a priori known, thus we identify them using matrix elements of an interpolating operator that is numerically computed with an impurity tensor network. Furthermore, by observing the dependence of the energy as a function of system size, we identify the number of particles of the eigenstates and obtain one-, two-, and three-particle states for a specific quantum number and momentum. From the two-particle state sector, we compute the scattering phase shift using Lüscher's formula and wave function approach, and observe their consistency with theoretical prediction. Using the information of the two-particle scattering phase shift, we investigate the degeneracy of the two-particle states, the theoretical prediction of the three-particle finite volume energy and also the degeneracy in the three-particle states.

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Quantum Physics

Making Quantum Networks Work: Routing, Calibration, and Programmable Quantum Repeaters

Vinay Kumar

The quantum internet enables distribution of quantum states across distant nodes, supporting secure communication, distributed computing, and quantum sensing. Unlike classical networks, it is constrained by the no cloning theorem, probabilistic entanglement generation, decoherence, and hardware drift, making classical abstractions inadequate. Scalable quantum networking therefore requires new architectures, protocols, and optimisation methods that explicitly account for these limitations. This thesis studies the architecture, routing, and operation of quantum networks under realistic constraints, focusing on bipartite entanglement distribution over quantum repeater networks. Key metrics include end to end fidelity, throughput, scalability, and fairness. At the network layer, routing strategies are developed beyond assumptions of homogeneous nodes and full network knowledge. Routing under heterogeneous repeater efficiencies shows how partial knowledge of node quality improves fidelity and reduces path blocking. A grey box routing approach is then introduced, where path selection relies only on topology and end to end estimates, achieving robustness and fairness without detailed link information. At the link layer, calibration and hardware drift are addressed through a calibration aware model separating activation and calibration phases. For linear repeater chains, an optimal calibration schedule is derived to balance operation time and calibration overhead. This is extended to general topologies with shared links, where a greedy orchestration heuristic is proposed. Finally, the thesis connects network protocols with hardware via an instruction set architecture for programmable quantum repeater nodes based on NV centers, enabling coherent programmability and linking physical operations to higher layer protocols.

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Nuclear Theory

Multistage dynamical modeling of heavy-ion collisions

Lipei Du

Relativistic heavy-ion collisions create deconfined QCD matter whose properties must be inferred from final-state observables through dynamical modeling. This contribution discusses recent progress and open issues in multistage simulations, with emphasis on the connection between bulk evolution, conserved charges, strangeness, and heavy flavor. At RHIC Beam Energy Scan energies, the breaking of longitudinal boost invariance makes charge stopping and rapidity-dependent observables essential for constraining the finite-density medium. Strange hadrons are sensitive to the local chemical environment and conserved-charge correlations, while heavy flavor probes microscopic transport and hadronization. Combining these observables within multi-sector inference frameworks provides a path toward more robust constraints on the equation of state and transport properties of QCD matter.

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Cosmology and Nongalactic Astrophysics

Revisiting cosmic anisotropy with the Pantheon+ compilation

Yong Zhou and Dong Zhao

We investigate cosmic anisotropy within the updated Pantheon+ sample using both the dipole fitting (DF) and hemisphere comparison (HC) methods. With the DF method, the dipole signal within the full sample is statistically weak. However, the low-$z$ subsample yields a dipole signal of $A_{\mathrm{D}} = 0.952^{+0.454}_{-0.403} \times 10^{-3}$ at $\sim 2\sigma$ significance, pointing towards $(l,b) = (149.77^\circ, -12.20^\circ)$. This signal is predominantly driven by a combined subset of surveys 5, 56, 63, and 150, which is characterized by an amplitude of $A_{\mathrm{D}} = 1.730_{-0.715}^{+0.554} \times 10^{-3}$ towards $(l,b) = (153.05^\circ, -1.25^\circ)$. For the HC method, the full sample yields a maximum anisotropy level of $\mathrm{AL}_{\mathrm{max}} = 0.289 \pm 0.052$ oriented towards $(l,b) = (127.97^\circ, 17.90^\circ)$ with a $1.56\sigma$ significance. This preferred direction is primarily determined by the highly inhomogeneous SNLS subsample, whereas the low-$z$ and high-$z$ subsamples act to suppress the anisotropy level along this axis. These subsample-dependent results suggest that the apparent anisotropy arises from local structures or the inhomogeneous distribution of the datasets rather than an intrinsic cosmic anisotropy.

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Optics

Structural and physical properties of gyromorphs and disordered stealthy hyperuniform media

Murray Skolnick, Riccardo Franchi, Luca Dal Negro et al. (+2 more)

Disordered stealthy hyperuniform materials combine liquid-like statistical isotropy with crystal-like homogeneity, suppressed density fluctuations at large length scales, bounded holes, and an isotropic structure factor that vanishes for a finite range of wavevectors. This combination yields unusual physical properties, including optical transparency, effective delocalization, ultrafast spreadability, optimal conductivity, and complete isotropic photonic bandgaps. Gyromorphs, point patterns whose structure factor includes rings of Bragg-like peaks arranged with discrete $G$-fold rotational symmetry, were recently introduced as counterexamples: disordered media that can somehow achieve the same physical properties, in some cases with higher performance, without stealthiness or hyperuniformity. In this paper, we resolve the puzzle of how gyromorphs fit consistently with the stealthy hyperuniform studies. We first show that gyromorphs are actually hyperuniform and, in the large-$G$ limit where they become nearly isotropic, belong to the weakest form of hyperuniformity, known as Class III. Thus, gyromorphs should have comparatively degraded physical properties compared to stealthy hyperuniform media, which belong to the strongest form of hyperuniformity, known as Class I. We verify this expectation using the rigorous spectral Green's matrix method for the calculation of the density of states (DOS) and Purcell factors in large arrays of electric dipoles. We find that gyromorphs display size-dependent pseudogaps richly populated by localized states rather than smooth band gaps like those found for highly stealthy hyperuniform materials or in deterministic structures such as Vogel spiral and triangular lattices. Furthermore, we predict similar disorder-induced degradation relative to stealthy hyperuniformity with regard to transparency, spreadability and diffusion properties.

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All authors Murray Skolnick, Riccardo Franchi, Luca Dal Negro, Paul J. Steinhardt, Salvatore Torquato

Quantum Physics

The Physics Behind Symmetrization

R. E. Kastner

It is often asserted that quantum states for same-type particles must be symmetrized due to “label redundancy,” i.e. the assumption that the permutations of labels in direct-product states do not reflect any real physical distinction and thus their permutations constitute an “exchange degeneracy”. This assumption is directly challenged by the case of scattering of same-type particles such as electrons, which involves two physically distinct scattering channels effectively corresponding to permutation of the labels. I discuss this counterexample with critical attention to an extant portrayal in the literature that omits pertinent physical content. I further note ways in which the assumption that symmetrization must be universally imposed is not supported by actual calculations of particle interactions, nor by seemingly viable particle states based on preparations and outcomes.

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Quantum Physics

Probing Single-Particle Spatial Extent With Helical Neutron Wavefronts

D. Sarenac, O. Lailey, C. W. Clark et al. (+8 more)

Distinguishing transverse coherence length from single-particle wavepacket extent is fundamentally challenging, as both manifest through spatial broadening of observed intensity profiles in conventional experiments. Here we introduce a method based on helical neutron wavefronts that enables this separation. Helical neutron states produce annular intensity profiles whose peak radius depends on the transverse wavepacket extent, while coherence length only contributes to profile broadening. In our experimental geometry we measure a beam divergence of ~1.1 mrad, corresponding to a transverse coherence length of ~180 nm. In contrast, the same measurement places a lower bound of >= 2 um on the spatial extent of the individual neutron wavepackets, more than an order of magnitude larger than the coherence length. These results provide direct experimental evidence that transverse coherence length and single-particle wavepacket extent are distinct physical quantities, resolving a longstanding source of confusion in the neutron literature.

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All authors D. Sarenac, O. Lailey, C. W. Clark, D. G. Cory, H. Ekinci, D. V. Garrad, M. G. Huber, L. Matthews, N. Shentevski, P. R. Vadnere, D. A. Pushin

Strongly Correlated Electrons

Pairing-induced Bloch oscillations in an interacting Kitaev chain

E. S. Ma and Z. Song

We study the peculiar dynamics of the Kitaev chain induced by nearest-neighbor (NN) interaction. We show that a strong NN interaction suppresses single-particle hopping but enhances pairing, resulting in a Wannier-Stark ladder. Based on the spin-fermion correspondence at the symmetry point, the model maps to a transverse field Ising model on a zigzag lattice, providing a clear physical picture and guiding experimental verification. The Wannier-Stark state corresponds to a localized domain wall between ferromagnetic and antiferromagnetic phases. It exhibits Bloch oscillation even in the absence of a longitudinal field, in contrast to previous works. Numerical simulations of time-dependent observables verify these conclusions. Our findings provide an example demonstrating emergent Stark many-body localization.

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Biological Physics

Glass-based physical models for tissue mechanics

Gopika Madhu, Carolyn Delli-Santi, Jenna Efrein et al. (+3 more)

Techniques from glass art and fabrication provide a controllable physical platform for studying tissue mechanics in simple organisms. Here, we use glass-based physical models to investigate tissue deformation in the marine organism Trichoplax adhaerens. Previous studies have shown that the epithelial tissues in T. adhaerens undergo large deformations and form fracture holes under mechanical loading, exhibiting a ductile-to-brittle transition at fast loading rates. To model these behaviors in a tunable and experimentally accessible system, glass is shaped into tissue-like monolayers in a glass studio, heated to its specific process temperature, and subjected to controlled stretching. Rapid cooling arrests the deformed configurations, providing snapshots of tissue-like strain states under load. Under lateral and radial stretching, we quantify changes in the area and eccentricity of individual "cells" in the glass models, and found that eccentricity increases after stretching. We further use tensegrity-based models to quantify deformations in the cellular geometry of the glass tissues, enabling direct comparison between experiments and simulations. The model captures the principal experimental deformation patterns, but underestimates the magnitude of the observed eccentricity changes. Our results demonstrate that glass-based physical models provide an experimentally accessible platform for studying tissue-scale deformation and mechanical behavior, while supporting interdisciplinary approaches that connect methods in the arts and sciences.

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All authors Gopika Madhu, Carolyn Delli-Santi, Jenna Efrein, Prannoy Suraneni, Landolf Rhode-Barbarigos, Vivek N. Prakash

Saturday 20 June

Geophysics

Effects of stochastic and natural seismic noise on the performance of waveform cross-correlation used to recover low-magnitude seismicity prior to the July 29, 2025, Kamchatka earthquake

Ivan Kitov

Waveform cross-correlation (WCC) applied to data from seismic arrays allows for the reduction of the detection threshold by approximately an order of magnitude. When applied to the data of the IMS, the smallest WCC detected events were by at least one magnitude unit lower than those reported by the IDC and revealed that the pattern of low-magnitude activity prior to the July 29, 2025, earthquake was similar to that prior to the May 24, 2013, Sea of Okhotsk earthquake. The consistent increase in the number of events with magnitudes approaching the corner value of the Kamchatka recurrence curve can likely be used as a precursory indicator of a mega-earthquake preparation. The WCC-based events are characterized by detections with a signal-to-noise ratio below the IDC detection threshold and are often not visible to analysts. This makes the statistical significance of the WCC event hypotheses uncertain due to the absence of a random noise reference and the potential side-sensitivity of the IMS arrays. Both problems are addressed. Random noise is used to calculate a WCC bulletin. This exercise shows a negligibly low number of WCC events and confirms the statistical significance of the WCC-based events. The side-sensitivity is modelled using the March 11, 2011, Tohoku earthquake. When master events (MEs) within the Kamchatka region are used in the WCC processing, a large number of false events are generated. When MEs from the Tohoku zone are added, all false events disappear since the Tohoku MEs win the conflict resolution process. When the random noise is scaled to a small fraction of the maximum amplitude within the processed interval, the WCC detection is enhanced with more detections and WCC-based events created. This is an effect similar to noise whitening, which makes the matched filter detector more sensitive and closer to its optimal performance under stochastic noise conditions.

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General Physics

On a geometric interpretation of the 1/4 factor in black hole entropy

Ira Wolfson

The Bekenstein–Hawking entropy $S = k_B A/4\lp^2$ contains a coefficient $1/4$ that has been calculated by many approaches to quantum gravity. We show that this factor arises from the causal geometry of any null boundary in a four-dimensional Lorentzian spacetime. A heuristic accessibility argument is supported by a purely geometric derivation using the canonical symplectic structure on the cotangent bundle and the causal splitting of the space of null rays. No gravitational field equations are invoked.

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