Peer Revenue Publish or profit

Papers

Fresh from arXiv, typeset properly. Highlighted words trade on the market.

Physics

Watch Physics

Thursday 17 September

Materials Science

Divergent Solid-state Conversion Pathways in Evaporated All-perovskite Tandem Solar Cells

Huagui Lai, Amber Wright, Nick Huber et al. (+8 more)

Sequential thermal evaporation (sTE) is emerging as a solvent-free route to high-quality mid-bandgap perovskites, but its extension to mixed-halide wide-bandgap (WBG) and Sn-Pb narrow-bandgap (NBG) absorbers for all-perovskite tandem solar cells (TSCs) remains limited by an incomplete understanding of solid-state conversion. Here, using time-sliced ex situ analysis, we reveal divergent solid-state conversion mechanisms in sequentially evaporated WBG and NBG precursor stacks. In WBG stacks, formamidinium (FA)-containing species penetrate the inorganic template and Br/I redistribution precedes substantial three-dimensional perovskite formation. The photoactive phase then crystallizes from a chemically mixed reservoir, and absolute PbBr$_2$ thickness, rather than nominal PbBr$_2$/PbI$_2$ ratio, determines the final bandgap. In NBG stacks, by contrast, an early Pb-rich perovskite phase forms upon formamidinium iodide deposition, restricting further FA penetration into the buried SnI$_2$ precursor. Subsequent annealing promotes rapid lattice reorganization faster than Sn/Pb interdiffusion, leaving vertical compositional gradients. Guided by these insights, we develop sTE absorbers with bandgaps spanning 1.26-1.96 eV and demonstrate the first evaporated all-perovskite TSC, reaching a power conversion efficiency of 19.2%. Encapsulated tandems retain on average 80% of their initial efficiency after 1,200 h at 65 $^\circ$C (ISOS-D-2). These results establish bandgap-specific control of solid-state conversion as a design principle for sequentially evaporated perovskite tandem photovoltaics.
Read the full abstract

All authors Huagui Lai, Amber Wright, Nick Huber, Niels Uythoven, Federico De Giorgi, Jincheng Luo, Tristan Sachsenweger, Sunil B. Shivarudraiah, Chih-Jen Shih, Wolfgang Tress, Fan Fu

Mesoscale and Nanoscale Physics

Plasmons in twisted bilayer graphene across dispersive and flat bands

Antonio Palamara, Michele Pisarra and Antonello Sindona

The dynamical dielectric response of twisted bilayer graphene is explored in large-angle dispersive-band and small-angle quasi-flat-band regimes using time-dependent density-functional theory within the random-phase approximation. At the reference bilayer-graphene interlayer distance, weak coupling in the largest-angle structures preserves Dirac dispersions and the intrinsic $\pi$ plasmon. Electron doping activates a two-dimensional Dirac plasmon with energies obeying approximate geometric twist-angle scaling, while acoustic-like branches remain embedded in the single-particle continuum. The prohibitively large first-magic-angle supercell is represented by a tractable cell with its interlayer separation reduced to the angle-dependent magic distance, where four quasi-flat bands emerge around the Fermi level. Their partial occupation produces a dispersive low-energy plasmon-like excitation without a clear dielectric zero at resonance. A distinct interband plasmon is instead identified, supported by transitions involving the quasi-flat manifold and neighboring high-density-of-states regions. Band-energy rescaling places its characteristic energy in the mid-infrared range of interband collective excitations measured near the magic angle.
Read the full abstract

Applied Physics

Energy Harvesting for Self-Powered Microsystems: A Critical Review of Materials, Power Management, and System Integration

Lyuye Lin, Feng Zhifu, Ermanno Miele et al. (+12 more)

The relentless proliferation of the Internet of Things (IoT), wearable bioelectronics, and cyber-physical infrastructure has rendered the conventional electrochemical battery the single most prohibitive bottleneck to long-term, maintenance-free autonomous microsystems. Energy harvesting, i.e. the conversion of ambient mechanical, thermal, and radiative energy into usable electrical power, has consequently emerged as a transformative paradigm to realize perpetual, battery-independent operation. This review critically synthesizes the most significant advances in energy harvesting technologies over the recent period, with a focus on triboelectric nanogenerators (TENGs), piezoelectric and pyroelectric transducers, indoor photovoltaics, radio-frequency (RF) rectennas, and their multi-source hybrid integrations. We highlight paradigm-shifting breakthroughs, including liquid-solid TENGs that eliminate mechanical wear, nonlinear piezoelectric oscillators that broaden operational bandwidth by over 300%, machine-learning-accelerated material discovery for high charge-density dielectrics, and multiband and broadband RF harvesting enabled by metamaterial architectures. Crucially, we move beyond conventional materials-centric narratives to critically interrogate the "unseen" system-level bottlenecks: ultra-low-voltage cold-start power management integrated circuits (PMICs), the impedance-matching challenges of hybrid energy sources, and the persistent degradation of micro-supercapacitors and thin-film batteries under realistic field conditions.
Read the full abstract

All authors Lyuye Lin, Feng Zhifu, Ermanno Miele, Giuseppe Cantarella, Elena Degoli, Diego Angeli, Lethy Krishnan Jagadamma, Feng Gao, Michele Magno, Ivano Eligio Castelli, Tommaso Ongarello, Chunbo Liu, Roman Krahne, Denis Garoli, Remo Proietti Zaccaria

Earth and Planetary Astrophysics

Thermal Evolution of Lava Planets Across System Ages: Predictions for Hell of a Survey

Mariana Sastre, Tim Lichtenberg, Lisa Dang et al. (+22 more)

Ultra-short-period (USP) rocky exoplanets can have dayside temperatures high enough to maintain permanent magma oceans, sitting at the intersection of interior geophysics and atmospheric chemistry. Coupled feedbacks between the molten surface and outgassed atmosphere can sustain or enhance a volatile envelope, while stellar interactions can erode it. Understanding which outcome prevails, and its observable imprint, requires a multi-target approach across planets at different stages of thermal evolution. We present predictions for the five targets of JWST Cycle 4 program 8864: TOI-1807 b, TOI-2260 b, TOI-431 b, TOI-6255 b, and TOI-2431 b. Using the PROTEUS coupled interior-atmosphere framework, we construct a simulation grid and classify outcomes into six categories, defined by the final interior melt state and by whether the planet retains a detectable atmosphere thick enough to redistribute heat to the nightside. For targets retaining a non-negligible volatile envelope, our models predict higher partial pressures for most species when the surface is molten, except for S$_{2}$, whose enhancement in the solid regime suggests it may serve as a tracer of interior melt state. Despite some targets showing outcomes across multiple scenarios, most tend toward a bare-rock end-member, with global melt fraction $\leq$ 20% and atmospheric retention sensitive to escape efficiency. Our analysis reveals a minimum escape efficiency threshold below which volatile envelopes survive under energy-limited escape, constraining the conditions required for atmosphere survival on irradiated rocky planets. These predictions will guide interpretation of MIRI-LRS phase curve observations and identify which targets and features best discriminate between competing geophysical states.
Read the full abstract

All authors Mariana Sastre, Tim Lichtenberg, Lisa Dang, Anjali Piette, Haiyang S. Wang, Mercedes López-Morales, Thomas Wilson, Charles-Édouard Boukaré, Mahesh Herath, Nicolas Cowan, Md Abdullah Al Zaman, Madyson G. Barber, Casey Brinkman-Traverse, Nicholas Connors, Ian Crossfield, Lina D'Aoust, Oliver Herbort, Leoni Janssen, Mathilde Kervazo, Owen Lammert, Yamila Miguel, Raymond Pierrehumbert, Allona Vazan, Joost P. Wardenier, Sebastian Zieba

High Energy Physics (Experiment)

Observation of double $s\bar{s}$ production in $e^+e^-$ collision at $\sqrt{s} = 3.08~\textrm{GeV}$

BESIII Collaboration: M. Ablikim, M. N. Achasov, P. Adlarson et al. (+779 more)

We report the observation of significant double-$s\bar{s}$ production in the $e^+e^-$ continuum, based on the measurement of prompt $\phi$ mesons produced in association with hadrons containing an $s$ quark or an $s\bar{s}$ pair. In an analysis of $e^+e^-$ collision data collected by the BESIII experiment at $\sqrt{s}=3.08~\textrm{GeV}$, the ratio $\sigma(e^+e^- \to \phi\ s\bar{s}+\textrm{anything}) / \sigma(e^+e^-\rightarrow\phi+\textrm{anything})$ is determined to be $(40.4\pm1.7_{\rm stat.}\pm1.5_{\rm syst.})\%$ by detecting and measuring $e^+e^-\to\phi + X(s\bar{s})$, where $X(s\bar{s})$ denotes an $\eta$ meson, an $\eta^{\prime}$ meson, or one of the strange-meson pairs $K^+K^-$, $K^+K^{*-}$, $K^-K^{*+}$, $K^0\bar{K}^{0}$, and $K^0\bar{K}^{*0}+\textrm{c.c.}$. The level of double-$s\bar{s}$ production is in line with the double-$c\bar{c}$ production reported by the Belle and \babar\ collaborations, for which theoretical calculations predict lower rates. The experimental measurement of double $s\bar{s}$ production at BESIII can shed light on the understanding of quark hadronization and QCD.
Read the full abstract

All authors BESIII Collaboration: M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. H. An, M. S. Anderson, 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, Chao 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 Boer, D. Dedovich, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De Mori, E. Di Fiore, 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, Shaoxu Du, X. L. Du, Y. Q. Du, Y. Y. Duan, Z. H. Duan, P. Egorov, G. F. Fan, J. J. Fan, K. X. Fan, Y. H. Fan, J. Fang, Jin Fang, S. S. Fang, W. X. Fang, Y. Q. Fang, L. Fava, F. Feldbauer, G. Felici, C. Q. Feng, J. H. Feng, Q. X. Feng, Y. T. Feng, M. Fritsch, C. D. Fu, J. L. Fu, Y. W. Fu, H. Gao, Xu Gao, Y. Gao, Y. N. Gao, Y. Y. Gao, Yunong Gao, Z. Gao, S. Garbolino, I. Garzia, L. Ge, P. T. Ge, Z. W. Ge, C. Geng, A. Gilman, K. Goetzen, J. Gollub, J. B. Gong, J. D. Gong, L. Gong, W. X. Gong, W. Gradl, 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. Hüsken, N. in der Wiesche, 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, S. J. Jiang, X. S. Jiang, Y. Jiang, J. B. Jiao, J. K. Jiao, Z. Jiao, L. C. L. Jin, 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. Kröger, L. Krümmel, Y. Y. Kuang, M. Kuessner, X. Kui, N. Kumar, A. Kupsc, W. Kühn, Q. Lan, W. N. Lan, T. T. Lei, M. Lellmann, T. Lenz, C. Li, C. H. Li, C. K. Li, Chunkai Li, Cong Li, D. M. Li, F. Li, G. Li, H. B. Li, H. J. Li, H. L. Li, H. N. Li, H. P. Li, Hui Li, J. N. Li, J. S. Li, J. W. Li, K. Li, K. L. Li, L. J. Li, L. K. Li, Lei 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, Shanshan 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. H. 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, Zaiyi 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, Feng Liu, G. M. Liu, H. Liu, H. B. Liu, H. M. Liu, Huihui Liu, J. B. Liu, J. J. Liu, K. Liu, K. Y. Liu, Ke Liu, Kun Liu, L. Liu, L. C. Liu, Lu Liu, M. H. Liu, P. L. Liu, Q. Liu, S. B. Liu, T. Liu, W. T. Liu, X. Liu, X. K. Liu, X. L. Liu, X. P. Liu, X. T. Liu, X. Y. Liu, Y. Liu, Y. B. Liu, Yi Liu, Z. A. Liu, Z. D. 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, C. L. Ma, F. C. Ma, H. L. Ma, Heng 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, F. E. Maas, I. MacKay, M. Maggiora, S. Maity, S. Malde, Q. A. Malik, L. M. Mansur, 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, A. F. Mohammad, B. Moses, N. Yu. Muchnoi, 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, I. V. Ovtin, S. Pacetti, Y. Pan, C. Y. Pang, 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. Pöpping, F. Z. Qi, H. R. Qi, L. Y. Qian, 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, Ch. Rosner, M. Q. Ruan, W. R. Ruangyoo, 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, Ch. Y. Shi, H. Shi, J. L. Shi, J. Y. Shi, M. H. Shi, S. Shi, S. Y. Shi, X. Shi, X. D. Shi, H. L. Song, J. J. Song, M. H. Song, T. Z. Song, W. M. Song, Y. X. Song, Zirong Song, S. Sosio, S. Spataro, S. Stansilaus, F. Stieler, M. Stolte, S. S Su, 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, N. T. Tagsinsit, 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, K. Yu. Todyshev, I. Uman, E. van der Smagt, B. Wang, Bin Wang, Bo Wang, C. Wang, Chao Wang, Cong Wang, D. Y. Wang, F. K. Wang, H. J. Wang, H. R. Wang, J. Wang, J. H. Wang, J. J. Wang, J. P. Wang, K. Wang, L. L. Wang, L. W. Wang, M. Wang, Mi Wang, N. Y. Wang, P. Wang, S. Wang, Shun Wang, T. Wang, W. Wang, W. P. Wang, X. F. Wang, X. L. Wang, X. N. Wang, Xin Wang, Y. Wang, Y. D. Wang, Y. F. Wang, Y. H. Wang, Y. J. Wang, Y. L. Wang, Y. N. Wang, Yanning Wang, Yaqian Wang, Yi Wang, Yuan Wang, Z. Wang, Z. L. Wang, Z. Q. Wang, Z. Y. Wang, Zhi Wang, Ziyi Wang, D. Wei, D. H. Wei, D. J. Wei, H. R. Wei, F. Weidner, H. R. Wen, S. P. Wen, U. Wiedner, G. Wilkinson, J. F. Wu, L. H. Wu, L. J. Wu, Lianjie 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, L. Y. Yang, R. J. Yang, X. Y. Yang, Y. Yang, Y. G. Yang, Y. H. Yang, Y. M. Yang, Y. Q. Yang, Y. Z. Yang, Youhua Yang, Z. Y. Yang, W. J. Yao, Z. P. Yao, M. Ye, M. H. Ye, Z. J. Ye, K. Yi, Junhao Yin, Qiqin Yin, 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, Yongchao Yu, C. Z. Yuan, H. Yuan, J. Yuan, Jie Yuan, L. Yuan, M. K. Yuan, S. H. Yuan, Y. Yuan, Z. Y. Yuan, C. X. Yue, Ying Yue, A. A. Zafar, F. R. Zeng, S. H. Zeng, X. Zeng, Y. J. Zeng, Yujie Zeng, Y. C. Zhai, Y. H. Zhan, B. L. Zhang, B. X. Zhang, D. H. Zhang, G. Y. Zhang, Gengyuan Zhang, H. Zhang, H. C. Zhang, H. H. Zhang, H. L. Zhang, H. Q. Zhang, H. R. Zhang, H. Y. Zhang, Han 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, Jianyu Zhang, Jin Zhang, Jiyuan Zhang, L. M. Zhang, Lei Zhang, N. Zhang, P. Zhang, Q. Zhang, Q. Y. Zhang, Q. Z. Zhang, R. Y. Zhang, S. H. Zhang, S. N. Zhang, Shulei Zhang, X. M. Zhang, X. Y. Zhang, Y. T. Zhang, Y. H. Zhang, Y. P. Zhang, Yao Zhang, Yu Zhang, Yu Zhang, Z. Zhang, Z. D. Zhang, Z. H. Zhang, Z. L. Zhang, Z. X. Zhang, Z. Y. Zhang, Z. Z. Zhang, Zh. Zh. Zhang, Zhaoke Zhang, Zhilong Zhang, Ziyang Zhang, Ziyu Zhang, G. Zhao, J.-P. Zhao, J. Y. Zhao, J. Z. Zhao, L. Zhao, Lei 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, Lin 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

Quantum Physics

An exact Jordan signature in cumulative-count first-passage statistics

Lachlan Bridges

For cumulative-count first-passage problems, the Laplace transform of the time $\mathcal T_N$ of the $N$th count is naturally expressed through powers of a one-count kernel. A Jordan defect of that kernel does not, however, automatically survive the complete sum over terminal phases. We give an exact three-state Markov-renewal example in which it does. At $s=1$, the one-count kernel has spectrum $\{1/2,1/8,1/8\}$, with a one-dimensional eigenspace at $1/8$, and for initial phase $1$, \[ \mathbb E_1[e^{-\mathcal T_N}] =\frac56\,2^{-N}+\frac{N+1}{6}\,8^{-N}. \] Thus the ordinary, unconditioned cumulative-count transform contains the explicit Jordan contribution $N/(6\,8^N)$ at every threshold $N\ge1$. For the same fixed stochastic process, the two eigenvalues meeting at $1/8$ unfold as \[ \lambda_\pm(s)=\frac18\pm\frac1{96}\sqrt{s-1} -\frac{131}{2304}(s-1)+O((s-1)^{3/2}), \] and the characteristic discriminant has a simple zero at $s=1$. We place the example beside two structures that suppress such a marginal signature: fixed post-count reset, which gives scalar renewal, and a common total holding rate, for which terminal summation scalarizes the matrix power. The model also admits a monitored-Lindblad realization, but the mechanism is entirely classical. The result provides a small exact benchmark for how generalized spectral modes can remain visible in finite-threshold first-passage statistics.
Read the full abstract

Statistical Mechanics

Landau diamagnetism and the de Haas-van Alphen effect from a single geometric construction

Sung-Hoon Lee

Landau diamagnetism is usually derived from the grand canonical potential, a calculation that yields the correct susceptibility but little physical insight, while the rule that extremal cross sections govern the de Haas-van Alphen (dHvA) oscillations is commonly asserted rather than exhibited. We present an elementary zero-temperature construction in which the occupied states of a free-electron gas are grouped, interval by interval along the field direction, into the Landau levels onto which they condense. Within each interval the field-induced energy cost reduces to a transfer of states between two congruent triangles, and center-of-mass arithmetic yields the Landau susceptibility. The construction fails only in a narrow neighborhood of an extremal cross section of the Fermi surface; there the contribution oscillates with the dHvA period, one oscillation for each Landau level that passes through the extremal cross section. Direct zero-temperature state counting locates the oscillation: the residual is concentrated in the few intervals nearest the extremal cross section, the summed contribution of the distant ones being negligible on the scale of the peak oscillation amplitude.
Read the full abstract

Statistical Mechanics

Higher-Order Interactions in Complex Systems: Mechanisms, Behaviour, Representation and Reducibility

Francisco J. Pérez-Reche

Higher-order interactions couple three or more elements in ways that cannot be decomposed into pairwise contributions. In diverse complex systems they produce striking collective behaviours such as explosive synchronization, discontinuous transitions and altered stability. Neither such behaviour nor a description written in many-body terms establishes a many-body mechanism, since both depend on how the system is represented. This review distinguishes three questions: what mechanism governs the system, what behaviour does it produce, and how is either represented? Representation covers both which variables are included and how relations among them are encoded. We examine direct many-body mechanisms, nonlinear but pairwise mechanisms that mimic them, and indirect routes through shared environments or eliminated variables, together with temporal aggregation, an artefact of observation rather than a mechanism. The same behaviour can arise from different mechanisms, and a given higher-order mechanism has no universal behavioural consequence. We then formulate reducibility, the question of whether a higher-order model can be replaced by a lower-order one, as a comparison between a source model and an admissible class of lower-order models, relative to a target and a tolerance. The target may be a microscopic rule, an observable or a qualitative feature. Information-theoretic and inferential methods are reviewed as complementary tools for detecting higher-order dependence, testing lower-order alternatives and reconstructing interaction structure. However, observational data alone generally cannot establish the mechanism. We close by identifying open problems in linking mechanisms to measurable signatures, coarse-graining, identifiability and causality, and in extending reductions beyond mean field. (Abridged)
Read the full abstract

Optics

Characterization of spatially inhomogeneous chirp in ultrashort multielectron beams via femtosecond hole burning

Yuichi Tachibana and Yuya Morimoto

Direct observation of the temporal-energy structure of pulsed electron beams is crucial for beam-driven light generation and time-resolved microscopic imaging. In this study, we characterized the spatially non-uniform time-energy structure in multi-electron ultrashort pulses exhibiting significant space-charge effects. By combining spectral hole burning originating from the photon-induced near-field electron microscopy (PINEM) effect with angle-resolved energy analysis, we observed time-energy correlations at each beam angle. Applying this method to 37-keV pulses containing up to 17 electrons per pulse, we determined energy spread and chirp rate, which vary by up to 100% and 40%, respectively, across the entire beam. These findings highlight the importance of characterizing multi-electron pulses with spatial or angular resolution and suggest the utility of spatially modulated light for the shaping of high-flux pulsed electron beams.
Read the full abstract

Quantum Physics

Electrostatic Stabilization of Near-Surface Quantum Sensors via Dielectric Interface Engineering

Atharva Paranjape, Kathrin Küster, Olga Shevstova et al. (+6 more)

Control of charge-state stability in near-surface quantum defects is critical for nanoscale sensing, yet remains particularly challenging under ultra-high vacuum (UHV), where surface-induced band bending destabilizes the metrologically relevant charge-state. Here, we present a robust and reproducible approach for stabilizing shallowly implanted (< 10 nm deep) nitrogen-vacancy (NV) centers in near-UHV conditions (P = $3 \times 10^{-9}$ mbar) based on dielectric interface engineering. Through measurements on individually addressable NV centers, we demonstrate that a TiO2 coating on the diamond suppresses surface-induced electrostatic fields, yielding a 79% increase n NV- population and a 45% enhancement in NV-spin resonance contrast at room temperature. Coherent control measurements further reveal suppressed charge-state conversion dynamics. These results establish dielectric screening as a powerful and reproducible strategy to engineer charge transition energetics of NV centers in scanning-probe-compatible geometries under extreme conditions.
Read the full abstract

All authors Atharva Paranjape, Kathrin Küster, Olga Shevstova, Lisa Ebo, Toni Hache, Klaus Kern, Rainer Stöhr, Jörg Wrachtrup, Aparajita Singha

Accelerator Physics

Reconstruction of Beam Transverse Parameters in the Fermilab Side-Coupled Linac Using a Normalized Coordinate Framework

E. V. Chen, J-P. Carneiro, R. V. Sharankova et al. (+1 more)

Quadrupole scans are a commonly used tool for beam second moment reconstruction. Limitations in the strength of the magnets and layout of the beamline elements frequently preclude simple quadrupole-drift-detector scans from collecting sufficient data for reconstruction. Using a normalized coordinate framework, we characterize the prerequisites for a robust simple quadrupole scan and expand these prerequisites to reconstruction from more complex optics. The beam second moments are investigated at two locations in the Fermilab Side-Coupled Linac under simple and complex optics, using this framework to maximize information gained from wire scanner profile measurements.
Read the full abstract

All authors E. V. Chen, J-P. Carneiro, R. V. Sharankova, A. V. Shemyakin

High Energy Physics (Experiment)

A heterogeneous and vectorized sequence for the HL-LHC full tracking reconstruction of the CMS experiment

Emmanouil Vourliotis

This contribution presents the new baseline strategy for the Phase-2 tracking of the CMS experiment for online event reconstruction, and for the main iteration of offline tracking. This tracking sequence takes advantage of the combination of cutting-edge tracking algorithms that are either optimized for parallel execution on GPUs (Patatrack and LST), or vectorized for efficient CPU performance (mkFit). Such a combined approach offers an effective solution to deal with the unprecedented computational challenges caused by the large number of simultaneous collisions per bunch crossing expected at the High-Luminosity Large Hadron Collider (HL-LHC). The proposed combination not only reduces the computational resource requirements but also enhances the physics reach by incorporating displaced tracking and increasingly leveraging machine learning techniques.
Read the full abstract

Quantum Physics

Private communication from Pauli channels with no privacy

Uthirakalyani G, Pritam Halder and David Elkouss

A channel capacity quantifies the communication capability of a noisy physical process. In contrast to communication channels in the classical world, quantum theory makes this capability contextual. We show that two Pauli two-qubit channels, each with zero private classical capacity, can be used to transmit private information when used together. One is a two-qubit Pauli channel whose environment can reconstruct the receiver output up to matrix transposition; the other is an antidegradable channel. We obtain a similar result when the second channel is the 50% qubit erasure channel. A simple binary code built from rank-three mixtures of Bell states activates private communication. The main ingredient in our construction is a transpose-antidegradable channel that is not antidegradable.
Read the full abstract

Optics

Frequency Attraction and Repulsion in Lasers with Complex Mutual Coupling

Amit Pando, Tomer Hacohen, Eran Bernstein et al. (+3 more)

We experimentally investigate laser synchronization under complex mutual coupling, featuring both dissipative and dispersive components. Using a reconfigurable digital degenerate cavity laser with precise control over system parameters, we show that complex coupling can induce both frequency attraction and repulsion, in contrast to common models of coupled oscillators. Furthermore, we show that these frequency shifts can be exploited to significantly enhance global synchronization in multi-laser arrays. Comparison with numerical and theoretical results indicate that amplitude dynamics of complex coupled lasers play an important role in the observed phenomena. Our results establish a versatile platform for exploring non-Hermitian physics and topological states in tailored laser networks.
Read the full abstract

All authors Amit Pando, Tomer Hacohen, Eran Bernstein, Victor Shelukin, Asher Friesem, Nir Davidson

Solar and Stellar Astrophysics

Investigating the inferred spatiotemporal evolution of magnetic fields during an X1-class flare

Dimitri Arramy, Jaime de la Cruz Rodríguez, Adur Pastor Yabar et al. (+1 more)

Several observational studies have reported sudden temporal changes in chromospheric magnetic fields inferred during solar flares using the weak-field approximation (WFA) and nonlocal thermodynamic equilibrium (NLTE) inversions. We investigate whether these variations reflect the rapid evolution of the solar atmosphere or can be influenced by opacity changes caused by flare heating. We perform spatially coupled and regularized NLTE inversions of high-resolution observations and use the inferred atmospheric models to study the formation of the Ca II 854.2 nm line. We also analyze snapshots from a 3D radiative magnetohydrodynamic flare simulation to investigate the evolution of the mapping between column mass and geometrical height. We find that opacity effects alone cannot, in many cases, explain the temporal variations in the reconstructed magnetic fields, suggesting that they reflect real solar evolution. However, in approximately 36% of the regions exhibiting rapid magnetic-field changes, opacity effects are sufficiently strong to bias their detection. Ejected or condensed cold material can also shift the line formation to a different depth, producing an apparent sudden change in the inferred magnetic field. The simulation further shows that, once the flare ribbon forms, a given column mass maps to deeper geometrical layers. These results highlight the need for caution when interpreting the temporal evolution of chromospheric magnetic fields during flares, as neither the WFA nor NLTE inversions based on 1D hydrostatic equilibrium can fully account for these effects.
Read the full abstract

All authors Dimitri Arramy, Jaime de la Cruz Rodríguez, Adur Pastor Yabar, Jorrit Leenaarts

Materials Science

Coherent antiferromagnetic resonance in MnO driven by impulsive terahertz excitation

Yinchuan Lv, Martin J. Cross, Hari Paudyal et al. (+4 more)

Antiferromagnets (AFMs) offer a promising platform for ultrafast information processing owing to their intrinsically fast spin dynamics and vanishing net magnetization. Realizing this potential, however, requires understanding how terahertz fields excite coherent magnons and how the resulting spin motion is transduced into an optical signal. Here we report impulsive terahertz (THz) excitation and time-domain detection of the antiferromagnetic resonance (AFMR) in single-crystal manganese(II) oxide. Time-resolved birefringence measurements reveal long-lived coherent spin oscillations in the AFM phase. The resonance softens and becomes strongly damped upon warming toward the Néel temperature. Despite this similar excitation behavior, the detected birefringence in MnO is markedly weaker than in NiO. We associate this suppressed optical visibility with the weak spin–orbit-mediated magneto-optical coupling of orbital-singlet, high-spin Mn$^{2+}$. These results demonstrate that coherent magnon excitation and its optical detection are governed by distinct microscopic interactions.
Read the full abstract

All authors Yinchuan Lv, Martin J. Cross, Hari Paudyal, Christopher T. Parzyck, A. H. M. Reid, Durga Paudyal, Matthias C. Hoffmann

Nuclear Theory

Bayesian calibration of a regional optical potential and uncertainty-quantified predictions for compound nucleus reactions

Samuel Sullivan, Kyle Beyer, Filomena Nunes et al. (+3 more)

Uncertainty-quantified global optical potential parameterizations are useful for making systematic studies across the nuclear chart and making predictions away from stability. While they generally provide a good description of the reactions on which they were calibrated, predictions can deviate strongly in specific cases and extrapolations incur large uncertainties. We propose a regional optical potential suited for a specific region of the nuclear landscape. We calibrate the potential along isotopic chains to enable both strong data coverage and improved extrapolative power. We modify the Chapel Hill optical potential and the statistical model used previously by Pruitt et al., to perform a Bayesian analysis of elastic scattering of neutrons and protons from zirconium isotopes with improved data coverage. The parameter distributions of our Chapel Hill Regional Potential (CHiRP) are propagated to compound nucleus reaction observables including (n, n'), (n, g) and (n, 2n), which have relevance to various nuclear technology applications. Results are compared to CHUQ, a global calibration of the Chapel Hill potential. The final parameterization of CHiRP differs from CHUQ particularly in the energy and radial dependence of its imaginary components. For elastic scattering, the uncertainties on the observables using CHiRP are smaller than those using CHUQ. CHiRP also provides an improvement over its global counterpart in the agreement with data around 10 MeV, while the regional and global approaches offer similar levels of agreement to elastic data at higher energies. The relative performance of CHiRP and CHUQ when propagating their uncertainty through compound nucleus reaction channels is also reported. The regional potential approach is a viable alternative to global optical model parameterizations for applications that require precise information within a sub-region of the nuclear landscape.
Read the full abstract

All authors Samuel Sullivan, Kyle Beyer, Filomena Nunes, Paul Stevenson, James Benstead, Lee Morgan

Instrumentation and Detectors

Commissioning and Performance of the Time-of-Flight Detector for the T2K Neutrino Oscillation Experiment

C. Alt, L. Amziane, N. Baudis et al. (+23 more)

The T2K ND280 Upgrade aims to reduce systematic uncertainties in measurements of neutrino oscillation parameters and improve sensitivity to the charge-parity (CP)-violating phase, $\delta_{\mathrm{CP}}$. A key component is the Time-of-Flight (ToF) detector, comprising six panels with 118 EJ-200 plastic-scintillator bars surrounding the Super Fine-Grained Detector (SuperFGD) and two High-Angle Time Projection Chambers (HA-TPCs). Each bar is read out at both ends by silicon photomultiplier arrays and digitised using SAMPIC waveform electronics. The ToF provides precise timing and particle-direction information for particle identification and rejection of backgrounds entering the tracker from outside. This article presents the detector design, construction, signal reconstruction, integration, commissioning, and performance. Dedicated single-bar measurements achieve a time resolution of approximately 130 ps and a longitudinal position resolution of 2.6 cm. After installation in ND280, cosmic-ray calibration yields an in situ single-bar time resolution of $169 \pm 1$ ps for Top-Bottom crossing events. Beam data clearly resolve the eight-bunch T2K spill structure, confirming synchronisation with the ND280 trigger and data-acquisition systems. The ToF has been successfully commissioned and operates stably within the upgraded ND280 detector.
Read the full abstract

All authors C. Alt, L. Amziane, N. Baudis, A. Blanchet, S. Bordoni, T. H. Bui, F. Cadoux, P. Collard, M. El Baz, Y. Favre, L. Giannessi, G. Ha, C. Jesús-Valls, V. S. Kasturi, A. Klustová, A. Korzenev, T. A. Le, T. Lux, A. D. Nguyen, D. T. Nguyen, H. Nguyen, S. Samani, F. Sánchez, M. Ta, T. Thaiduc, E. Villa

High Energy Physics (Theory)

Supersymmetric boundary algebras in AdS$_3$ gravity: constraints, Dirac brackets and non-locality

Nabamita Banerjee, Vedant Bhutra, Suvankar Dutta et al. (+1 more)

We study supersymmetric boundary dynamics in AdS$_3$ gravity by treating boundary conditions as constrained reductions of a generic Chern-Simons boundary phase space. We focus on how the constraint structure controls the locality and physical field content of the reduced asymptotic symmetry algebra. For supersymmetric Kac–Moody boundary conditions, the surviving bosonic currents remain local, whereas the fermion–fermion Dirac bracket contains the inverse of a field-dependent first-order differential operator and is therefore intrinsically non-local. Imposing an additional fermionic constraint reveals a further structure: after the bosonic second-class reduction, it becomes first class and generates a fermionic gauge redundancy. Generically the remaining fermionic field can be gauged away, while special backgrounds with periodic zero modes support non-trivial physical fermionic sectors. We further employ the Batalin–Fradkin–Tyutin formalism to eliminate the non-locality of the reduced symmetry algebra by converting the second-class constraints into an equivalent local first-class system on an enlarged phase space.
Read the full abstract

All authors Nabamita Banerjee, Vedant Bhutra, Suvankar Dutta, Soumava Kundu

Astrophysics of Galaxies

Electron irradiation and temperature-programmed desorption of layered ethanolamine-water-methanol ices

Tara L. Stoib, Alejandro Guerrero-Caicedo, Duncan V. Mifsud et al. (+12 more)

Ethanolamine (EtA) is a recently detected interstellar complex organic molecule and a potential precursor to more functionalised N-bearing species. We investigate the electron-driven chemistry of layered EtA–H$_2$O–CH$_3$OH ices deposited at 20~K, combining 2~keV electron irradiation with subsequent temperature-programmed desorption (TPD) while monitoring the solid phase by mid-infrared spectroscopy. These controlled irradiation conditions represent a simplified laboratory analogue of the structural and energetic conditions within interstellar grain mantles. Volatile products released during warming were followed by quadrupole mass spectrometry, and the final residue was analysed by ex situ electrospray ionisation mass spectrometry (ESI-MS). Irradiation produces abundant radiolysis products typical of processed methanol- and water-rich ices, including CO, CO$_2$, H$_2$CO, H$_2$O$_2$, NH$_3$, and OCN$^{-}$. Bands consistent with formic acid and polyoxymethylene-like material are also observed, indicating that carbonyl chemistry and formaldehyde-driven oligomerisation can occur alongside fragmentation in the layered system. Comparison with a choline chloride–H$_2$O reference reveals the emergence of features compatible with methylated EtA derivatives and/or choline-like species, while ESI-MS shows higher-$m/z$ mass families in the residue that are not reproduced in the substrate/background blank. However, spectral congestion and matrix effects preclude an unambiguous assignment of choline. Our results show that energetic processing of EtA-containing ices can generate a diverse inventory of O- and N-bearing products, providing laboratory constraints on radiation chemistry in cold, irradiated grain mantles under idealised conditions.
Read the full abstract

All authors Tara L. Stoib, Alejandro Guerrero-Caicedo, Duncan V. Mifsud, Péter Herczku, Gergő Lakatos, Zuzana Kaňuchová, Zoltán Juhász, Béla Sulik, Nigel J. Mason, Sergio Ioppolo, Paola Caselli, Barbara Michela Giuliano, Karl E. Duderstadt, Felipe Fantuzzi, Heidy M. Quitián-Lara

Instrumentation and Methods for Astrophysics

The SHARPEx space-to-space VLBI experiment

Freek Roelofs, Christiaan Brinkerink, Albert Catalan Artigas et al. (+16 more)

Space is the next frontier for ultra-high resolution imaging of astrophysical sources with very long baseline interferometry (VLBI). The limited size of the Earth and atmospheric absorption and turbulence at high frequencies prevent order-of-magnitude resolution improvements from current black hole imaging with the ground-based Event Horizon Telescope. A two or three-element submm space-based array like SHARP would image the thin black hole photon ring and measure the black hole spin and spacetime. Here, we present the SHARP Experiment (SHARPEx) mission concept. SHARPEx will demonstrate key enabling technologies for space-to-space VLBI, including clock syntonization between two satellites, on-board correlation, and sub-wavelength relative orbit determination. SHARPEx will consist of two CubeSat or SmallSat platforms carrying small (~1 m diameter) antennas, observing at cm wavelengths. While SHARPEx will be a technical demonstrator, a SHARPEx-type follow-up mission with enhanced intersatellite link properties (range and bandwidth) may produce images of bright AGN with unprecedented resolution and fidelity.
Read the full abstract

All authors Freek Roelofs, Christiaan Brinkerink, Albert Catalan Artigas, Heino Falcke, Jaime Fernández, Christian M. Fromm, Felix Glaser, Marc Klein Wolt, Yuri Kovalev, Volodymyr Kudriashov, María Manzano, Rasmus Maråk, Manuel Martin-Neira, Jacobo Pastor Fernández-Posse López, Montserrat Puertolas Turell, Alberto Rodríguez Pérez-Silva, René Rüddenklau, Efthalia Traianou, Roger Vilaseca Miro

Superconductivity

Type-I superconductivity in a quasi-2D topologically nontrivial YbBi$_2$

Karolina Górnicka, Sudip Malick, Joanna Bławat et al. (+13 more)

Intrinsic superconductivity in stoichiometric materials with nontrivial electronic topology remains uncommon, limiting opportunities to investigate how these two phenomena coexist within a single electronic system. Here, we report bulk type-I superconductivity below $T_c$ $\sim$ 0.9~K in YbBi$_2$, a layered rare-earth compound with a nonsymmorphic crystal structure and a quasi-two-dimensional Fermi surface. Thermodynamic and transport measurements establish the superconducting ground state, while quantum oscillations reveal exceptionally light carriers, with a cyclotron mass as low as 0.07 $m_e$, and a nonzero Berry phase of approximately 0.82 $\pi$. The latter closely matches the calculated value of the corresponding Wilson phase 0.99 $\pi$ for the corresponding orbit near a symmetry-protected band degeneracy. ARPES measurements show good agreement with key features of the calculated electronic structure, providing complementary experimental constraints on the normal-state band structure. The combination of intrinsic type-I superconductivity, light quasi-two-dimensional carriers, and signatures of nontrivial electronic topology identifies YbBi$_2$ as a distinct stoichiometric platform for investigating superconductivity in a topologically nontrivial electronic environment.
Read the full abstract

All authors Karolina Górnicka, Sudip Malick, Joanna Bławat, Michał Modrzejewski, Hanna Świątek, Michał J. Winiarski, Federico Mazzola, Ivana Vobornik, Chiara Bigi, Jacob Cook, Brenden R. Ortiz, Andrew F. May, Andrzej P. Kądzielawa, John Singleton, Bartlomiej Wiendlocha, Tomasz Klimczuk

Strongly Correlated Electrons

When Is Kramers-Wannier Duality Invertible?

Akash Sinha, Pramod Padmanabhan and Vladimir Korepin

Kramers-Wannier duality of the quantum Ising chain is naturally realized as a noninvertible transformation on a finite periodic chain. Upon incorporating appropriate symmetry-twisted sectors, however, the duality can be promoted to an invertible unitary transformation. In this Letter, we classify when the Kramers-Wannier duality admits an invertible realization on a finite Hilbert space. We show that this is determined by the representation of the Ising bond algebra and establish a necessary and sufficient condition in terms of its two central elements. This representation-theoretic criterion unifies the conventional noninvertible realization with invertible constructions involving symmetry-twisted sectors and applies equally to other models with the same underlying bond algebra. As an explicit example, we find an order-disorder duality in a non-trivial realization of the Ising bond algebra that admits an invertible Kramers-Wannier duality.
Read the full abstract

Optics

Transient High-Harmonic Generation from Solids: From Spectroscopy and Control to Programmable Emission

Pieter J. van Essen, Torben Ham, Zhonghui Nie et al. (+1 more)

High-harmonic generation (HHG) from solids has emerged as a powerful probe of electronic structure and ultrafast dynamics in condensed matter systems. In this chapter, we review recent advances in solid-state HHG spectroscopy and control, with a focus on semiconductors and correlated materials. We discuss the theoretical foundations of HHG and summarize experimental approaches for extracting information from harmonic emission. HHG has been shown to be sensitive to a wide range of microscopic properties, including band structure, transition dipole moments, Berry phases, crystal symmetry, carrier populations, dephasing processes, and lattice dynamics. This sensitivity enables access to electronic and structural dynamics on femtosecond and attosecond timescales and has established HHG as a versatile spectroscopic tool. At the same time, the strong dependence of HHG on many coupled material and excitation parameters makes the emitted harmonics intrinsically difficult to associate with a single microscopic quantity. Rather than representing a limitation alone, this sensitivity also provides numerous pathways for control. We review how photoexcitation, multicolor driving fields, waveform engineering, and transient modification of material properties can be used to enhance, suppress, and shape harmonic emission. These developments position solid-state HHG not only as a spectroscopic technique, but also as a platform for programmable nonlinear optics with applications ranging from compact extreme-ultraviolet sources to super-resolution microscopy and ultrafast photonic devices.
Read the full abstract

All authors Pieter J. van Essen, Torben Ham, Zhonghui Nie, Peter M. Kraus

Astrophysics of Galaxies

Physical properties of star-forming clumps in nearby galaxies from CLAUDS and HSC-SSP

Jürgen J. Popp, Hugh Dickinson, Stephen Serjeant et al. (+2 more)

Giant Star-forming Clumps (GSFCs) are kpc-scale regions of enhanced star-formation with stellar masses of $10^6$ to $10^{10}\,M_\odot$ that are commonly observed in high-redshift ($z \gtrsim 1$) galaxies but their formation and role in galaxy evolution remain unclear. We applied a Faster R-CNN object detection framework (FRCNN) to identify star-forming clumps in astrophysical imaging data from a mass-complete sample of $\sim$210,000 low-redshift galaxies ($z\lesssim0.32$), located in the HSC-SSP Wide and Deep fields observed by the Hyper Suprime-Cam Subaru Strategic Survey (HSC-SSP) and CFHT Large Area U-band Deep Survey (CLAUDS). We present a population of $\sim$710,000 detected clumps for which we measured the (u)grizy-photometry and derived the physical properties (stellar mass, age, dust extinction and star-formation rate) for each clump by fitting the photometric data to stellar population models. We estimate that the clump Stellar Mass Function (cSMF) for young clumps ($<100\,\mathrm{Myr}$) follows a power law with an exponent of $\alpha=1.98\pm0.02$ down to a completeness limit of $\sim10^{8}\,M_\odot$ which is consistent with an in situ formation through violent disk instabilities (VDI). The clumps show elevated star-formation rates and negative gradients in their ages and stellar masses as a function of galactocentric distance. These gradients are steeper than those measured for the intra-clump regions of the host galaxies and are robust against uncertainties introduced by different modelling assumptions. For nearby galaxies we argue that the observed low-redshift clumps are likely analogues of high-redshift GSFCs and that the inward migration of star-forming clumps directly contributes to the central bulge formation of the host galaxy.
Read the full abstract

All authors Jürgen J. Popp, Hugh Dickinson, Stephen Serjeant, Lucy F. Fortson, Vihang Mehta

Materials Science

Modeling Dynamic Magnetic Response of Spinel Soft Ferrites with the Steepest-Entropy-Ascent Quantum Thermodynamics Formalism

Deepak Dhariwal, William T. Reynolds Jr. and Michael R. von Spakovsky

Selecting soft ferrites for alternating-field applications requires balancing magnetic response, dissipation, nonlinearity, and heating. We use a field-driven steepest-entropy-ascent quantum thermodynamic (SEAQT) model to compare the electron, phonon, and magnon responses of Fe$_3$O$_4$, MnFe$2$O$4$, and (Mn${0.5}$Zn${0.5}$)Fe$_2$O$_4$ within a common first-principles framework. The model treats spatially uniform longitudinal relaxation and neglects domain-wall motion, transverse rotation, resonance, eddy-current effects, and heat removal. We use $\tau_e=0.05$ ps and $\tau_p=3$ ps for all three materials, with effective longitudinal magnon relaxation times of 500, 200, and 85 ps, respectively; these literature-motivated values are model inputs, not fits to measured losses. Within this framework, the Mn–Zn ferrite gives the largest peak longitudinal magnetization change, retains its response best at high frequency, and shows the largest work per cycle and peak-to-peak magnon temperature change, whereas MnFe$_2$O$_4$ gives the largest normalized $\chi''$ peak. Thus, no single ferrite ranks highest across all metrics: the preferred material depends on the property, frequency, field amplitude, and cation configuration of interest. The model therefore provides a spectrum- and kinetics-resolved screening tool for engineering comparison of ferrites rather than a prediction of total core loss.
Read the full abstract

High Energy Physics (Theory)

Explicit construction of the energy-momentum tensor in the large N limit of a four-Fermi theory

Carlo Pagani and Hidenori Sonoda

Using the exact renormalization group (functional RG) formalism, we construct the energy-momentum tensor of a four-Fermi theory in the Euclidean space of dimensions 2 < D < 4 in the large N limit, where N is the number of Dirac fields. The energy-momentum tensor is a functional of the Dirac fields, and its cutoff dependence is controlled by the exact RG equation. In the zero cutoff limit the functional reduces to the one-particle-irreducible effective action with a single insertion of the energy-momentum tensor. At a finite cutoff the energy-momentum tensor satisfies the Ward-Takahashi identity for translation invariance, and its antisymmetric part is determined by rotation invariance. We also show that the critical theory is conformally invariant by deriving the corresponding Ward-Takahashi identity.
Read the full abstract

Quantum Physics

Semiclassical scaling of eigenstate thermalization in single-particle chaotic systems

Yaoqi Ye and Xiao Wang

We study the off-diagonal matrix elements of real-space observables in time-reversal-invariant single-particle chaotic systems. By analyzing the semiclassical expression for the off-diagonal variance derived from Berry's conjecture, we show that the banded structure of the observable matrix emerges naturally. For local observables, we identify a characteristic bandwidth associated with a late-time timescale inversely proportional to the particle velocity. We further show that, for systems with steep-wall confinement, the predicted magnitude follows the entropy scaling of the eigenstate thermalization hypothesis (ETH), multiplied by an additional kinetic-energy-dependent factor that is independent of spatial dimension and is not captured by conventional many-body ETH. We illustrate these results through a case study of quantum billiards and verify the semiclassical scaling numerically in a generalized quarter-Sinai billiard. Our results elucidate the dynamical implications of Berry's conjecture and provide a comparison between single-particle eigenstate thermalization and many-body ETH.
Read the full abstract

High Energy Astrophysical Phenomena

The 2025.6 X-ray Minimum of Eta Carinae

Amit Kashi and Noam Soker

We present observations of the recent 2025.6 X-ray minimum and recovery of $\eta$~Carinae, obtained with NICER/XTI, Swift/XRT, XRISM/Xtend, and Chandra/HRC-I. We construct light curves in the soft (0.5–2 keV) and hard (2–10 keV) bands and derive hardness ratios. The X-ray emission reached its minimum about 10 days earlier than in the previous five cycles. As in previous events, the spectrum softened during the decline, while the X-ray luminosity varied on short timescales. These findings strengthen the conclusion that enhanced line-of-sight absorption, such as that expected during an eclipse, does not have a significant role in producing the spectroscopic event. Instead, they indicate that the X-ray decline is caused by stochastic variations and instabilities in the two stellar winds and their interaction, destruction of the colliding winds region, and accretion of primary wind onto the secondary. The main process behind the deep X-ray minimum near periastron is the accretion of mass lost by the primary star onto the secondary star. Accretion at periastron passages in $\eta$ Carinae implies that accretion occurred at much higher rates during the nineteenth-century Great and Lesser Eruptions, when the primary star lost mass at much higher rates. Such accretion likely launches jets. The broader implication is that accretion events in binary systems, possibly with jet launching, power other luminous blue variable giant eruptions and intermediate-luminosity optical transients.
Read the full abstract

Mesoscale and Nanoscale Physics

Highly uniform first-electron position in qubit arrays fabricated on dedicated QSOI(R) 300mm commercial platform

Johan Pelloux-Prayer, Elise Prin, Giselle A. Elbaz et al. (+11 more)

We report progress toward the development of a quantum silicon-on-insulator (QSOI(R)) technology compatible with 300mm CMOS fabrication and adapted from the 28nm Fully-Depleted SOI (28nm FD-SOI) platform for scalable quantum computing. We compare quantum devices fabricated with standard 28nm FD-SOI and QSOI(R) technologies, and show striking improvements of room temperature electrostatic properties of the individual device. Moreover, the QSOI(R) technology has significantly reduced the device variability and the dispersion of device properties at the wafer level. Transistor metrics are reproduced by TCAD simulations showing that the electrostatics of the devices behave as expected for QSOI(R) technology. Wafer-scale measurements at sub-2K show reproducible quantum dots down to the few-electron regime with 69% yield for successful charge detection of the first electron and a dispersion of the first electron position of $\mathrm{\pm 35 mV}$ over 377 quantum dots. These results establish QSOI(R) as a promising platform for CMOS-compatible quantum device co-integration.
Read the full abstract

All authors Johan Pelloux-Prayer, Elise Prin, Giselle A. Elbaz, Pierre-Louis Julliard, Amaryllis Comiti, Clément Nguyen, Sylvain Martin, Patrick Torresani, Renan Lethiecq, Carlos Augusto Suarez Segovia, Franck Arnaud, Etienne Nowak, Tristan Meunier, Bruna Cardoso Paz