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Physics

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Sunday 27 September

Fluid Dynamics

A wave-particle decomposition framework for multiscale kinetic transport: continuous-spectrum equations and coupled wave-particle iteration

Chang Liu and Kun Xu

The wave-particle decomposition is presented as a framework for multiscale kinetic transport, comprising a theory and an algorithm. Along the characteristics of the kinetic equation, the equilibrium integral of the solution over a local kinetic horizon defines a wave, which depends only on the conservative variables, and its exact complement defines a particle. Both obey kinetic equations whose moments are extended Navier-Stokes equations, and the conservation laws together with the particle equation form a closed system that is equivalent to the kinetic equation for every horizon. Parametrized by the ratio of the horizon to the relaxation time, these systems form a continuous spectrum from kinetic theory to Navier-Stokes hydrodynamics that adapts to the flow from cell to cell. The algorithm is a coupled wave-particle iteration for steady flows. It alternates a macroscopic iteration for the conservative variables, with the particle frozen, and a kinetic iteration for the particle, with the wave fixed. Its fixed point is the discrete kinetic solution, it is asymptotic preserving, and its near-continuum convergence factor is bounded by the share of the transport carried by the particle, a share that decays exponentially with the horizon-to-relaxation ratio. The collision model enters only through a conservative remainder, and the equations and the iteration are written out for the Bhatnagar-Gross-Krook, Shakhov and ellipsoidal statistical models, the Boltzmann and Landau equations, neutron transport and radiative transfer. The decomposition is related to the unified gas-kinetic wave-particle method, the micro-macro decomposition, penalization and synthetic acceleration. Computations of hypersonic flows past a cylinder and around the three-dimensional X38 vehicle illustrate how the division of the distribution adapts to the flow and how strongly the iteration is accelerated.
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Statistical Mechanics

Boolean Cumulants and Exact Reduced Descriptions of Renewal-Driven Systems

Marco Bianucci and Riccardo Mannella

Reduced descriptions of unresolved fluctuations are commonly based on Gaussian processes, although many realistic forcings have finite correlation times and a renewal structure. For memoryless step (Kubo–Anderson) noise, we show that the reduced dynamics admit two exact and complementary descriptions: a kernel representation governed by the Boolean cumulants of the jump distribution, and a frozen-noise representation adapted to stationary probability densities. For exponentially distributed waiting times, the totally time-ordered $G$-cumulants coincide with the Boolean cumulants of the jump law, and the memory kernel is resummed exactly as the Boolean generator $\eta$ evaluated on a resolvent operator. Second-order closure is exact if and only if the jump law is symmetric Bernoulli; otherwise, the leading closure error is controlled by $(b_4/b_2)\lambda^2$. The Boolean hierarchy, however, acts on the kernel, not on the stationary measure. Stationary densities are approximated by replacing the jump law with its $N$-point Gauss quadrature: each surrogate preserves all multi-time correlations up to order $2N-1$ for any waiting-time law, its kernel is a Padé resummation of the Boolean one, and it is itself an exactly solvable renewal problem. For the linear system with linear multiplicative interaction (LIMI/CAM), the frozen-noise representation reduces the dynamics to a random affine recursion and yields exact support boundaries, singularity exponents and Kesten tail indices, confirmed numerically. Rates, moments and closure errors are governed by the Boolean hierarchy, whereas stationary densities are determined by the geometry of the jump distribution. For memoryless renewal noise, the combinatorial structure controlling finite-correlation reductions is Boolean.
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Chemical Physics

Accelerating Quantum Simulations of Materials Through Parameter and Ansatz Transfer Strategies

Saurabh Shivpuje, Vinit Singh, Manas Sajjan et al. (+1 more)

Quantum computing offers a promising route for electronic-structure calculations, but practical condensed-matter applications often require solving large families of related Hamiltonians arising from $\mathbf{k}$-point sampling, compositional variation, defects, and changes in system size. Here, we develop strategies for transferring variational information between related Hamiltonians to accelerate quantum simulations. For Hamiltonians of the same embedded size, optimized variational parameters are transferred between related calculations. For different sizes, we introduce Augmented Ansatz Reuse for Target Initialization (AARTI), which transfers compatible Pauli-generator structure and optimized source parameters, then augments the ansatz with target-specific generators. Our workflow combines density functional theory, Wannier downfolding, embedded tight-binding Hamiltonians, variational quantum algorithms, and neural-network quantum states, with quantum-circuit simulations implemented using NVIDIA's CUDA-Q platform. Using Li$_x$CoO$_2$ as a representative battery cathode material, we study Hamiltonian families spanning multiple delithiation levels, dense $\mathbf{k}$-point meshes, and increasing sizes. Parameter and ansatz transfer substantially reduce the optimization steps required to solve these related Hamiltonians while maintaining the common target accuracy, with lower terminal errors in several cases. The calculated electronic-structure evolution with delithiation exhibits pronounced non-rigid-band behavior consistent with experiment. These results establish a framework for exploiting similarity among related Hamiltonians to improve the efficiency and scalability of quantum workflows for realistic condensed-matter systems.
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All authors Saurabh Shivpuje, Vinit Singh, Manas Sajjan, Sabre Kais

General Relativity and Quantum Cosmology

Exact solutions of Maxwell vacuum equations in null homogeneous Petrov spaces with non-solvable motions groups

V. V. Obukhov

A complete classification of exact solutions of Maxwell vacuum equations for invariant electromagnetic fields in null homogeneous Petrov spaces with unsolvable groups of motions $G_3$, acting simply transitively on null hypersurfaces of null homogeneous Petrov spaces, is conducted. The classification of exact solutions of Maxwell vacuum equations is based on using the representation of components of the contravariant metric tensor and components of the invariant electromagnetic field in terms of vector fields of a canonical frame. The classification results are presented in a form convenient for further use.
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High Energy Physics (Experiment)

Improved search for $\psi(3770) \to \gamma \eta_{c}(1S, 2S)$ radiative transitions

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

Based on an integrated luminosity of $20.3~\mathrm{fb}^{-1}$ of $e^{+}e^{-}$ annihilation data collected at a center-of-mass energy of $3.773~\rm{GeV}$ with the BESIII detector operating at the BEPCII collider, an improved search for the radiative transitions $\psi(3770) \to \gamma \eta_{c}(1S, 2S)$ is performed using the hadronic decays $\eta_{c}(1S, 2S) \to K^{0}_{S} K^{\pm} \pi^{\mp}$. No significant signal is observed. The corresponding 90$\%$ confidence level upper limits on the product branching fractions are set to be $5.0 \times 10^{-6}$ for the $\eta_{c}(1S)$ transition and $3.7 \times 10^{-6}$ for the $\eta_{c}(2S)$ transition. The 90$\%$ confidence level upper limits on the partial decay widths are also reported to be $\Gamma(\psi(3770) \to \gamma \eta_{c}(1S)) < 5.5$ keV and $\Gamma(\psi(3770) \to \gamma \eta_{c}(2S)) < 29.4~\rm{keV}$. With about seven times larger integrated luminosity than used previously, these results lower the upper limits by approximately a factor of three and two for the $\eta_{c}(1S)$ and $\eta_{c}(2S)$ transitions, respectively.
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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, J. Y. Hao, 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, N. D. Hoffman, 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, 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. H. Li, Y. B. Li, Y. C. Li, Y. G. Li, Y. P. Li, Yi 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, 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, X. Q. Yan, Y. Y. Yan, H. J. Yang, H. L. Yang, H. X. Yang, J. H. Yang, L. Y. Yang, N. 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. R. 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. 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. R. Zhang, Z. X. Zhang, Z. Y. 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

General Relativity and Quantum Cosmology

Stochastic gravitational-wave background from self-interacting superradiant clouds

Yin-Da Guo, Richard Brito and Chen Yuan

Gravitational-wave (GW) observations offer a powerful probe of new fundamental fields. One well-motivated source is black hole (BH)–boson cloud systems, in which an ultralight scalar field forms a cloud around a rotating BH via superradiance and emits long-lived nearly monochromatic GWs. In this work, we compute the stochastic GW background (SGWB) from such systems, extending previous work by including scalar self-interactions, and discuss its detectability with next-generation ground-based GW detectors. We find that self-interactions can suppress the SGWB and thereby relax existing LIGO-Virgo-KAGRA constraints inferred from null searches. Namely, the LIGO detectors at design sensitivity are insensitive to a SGWB produced by scalar fields with a decay constant $f_\mathrm{s} \lesssim 3\times 10^{17}$ GeV, independently of the scalar field mass. Looking ahead, we show that a moderately self-interacting cloud can still produce a detectable SGWB with next-generation detectors. Under conservative assumptions, for a decay constant $f_\mathrm{s} = 10^{17}$ GeV, the Einstein Telescope (ET) will be sensitive to scalar masses in the range $\sim[10^{-13.0},10^{-11.8}]$ eV, while Cosmic Explorer (CE) will be sensitive to scalar masses in the range $\sim[10^{-13.2},10^{-11.7}]$ eV. We also find that the minimum decay constants that still yield a detectable SGWB for ET and CE are $f_\mathrm{s}\sim 6\times10^{16}\,$GeV and $\sim 3\times10^{16}\,$GeV, respectively.
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High Energy Physics (Theory) · Cross-listed from math.CO

A Hopf Algebraic Theory of the Quantum Magnusian

Li Guo, Joon-Hwi Kim, Jung-Wook Kim et al. (+3 more)

We develop a Hopf-algebraic theory of graph coefficients arising in the quantum Magnus expansion. At the classical level, the expansion is governed by directed trees, whereas its quantum counterpart involves loop graphs, multiple edges, and several types of edge data. We introduce a contraction Hopf algebra of mixed quivers containing these diagrams and closed under contraction. On this algebra we define a character $e$ from normalized linear-extension data, directed-tadpole factors, and a prescription for undirected edges, and let $\omega$ be its convolution inverse. Our main result is a universal closed formula for the connected function $\omega_c$ on every finite mixed quiver, expressed as a finite sum over ordered set partitions of the vertices. We also construct a weighted vertex-splitting Hopf structure on the unlocalized mixed-quiver algebra, with convolution $\star_V$ and canonical edge-weight character $\zeta_V$, such that $\omega_c=\log_{\star_V}\zeta_V$. Compatibility of the two coproducts and an explicit identity between their characters explain this equality. We further prove that the two-vertex contraction identity, tadpole factorization, vanishing on disconnected graphs, and boundary data uniquely determine $\omega_c$. For acyclic quivers, the formula reduces to a permutation formula with coefficients depending only on descent numbers. We derive this formula independently from the quantum Magnus expansion using operator products and Wick contractions, showing that the physical graph coefficients are governed by the convolution structure of the contraction Hopf algebra. Further consequences include a refined quantum Murua formula and orientation-sum identities related to Tutte and chromatic polynomials.
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All authors Li Guo, Joon-Hwi Kim, Jung-Wook Kim, Sungsoo Kim, Sangmin Lee, Jian-Rong Li

Mathematical Physics

Effective atom-dimer bands of three-body lattice systems at strong coupling: exact critical mass ratios and a statistics-quasimomentum duality

Mikhail V. Dolgopolov

We study three particles on the square lattice with contact interactions of infinite strength, for all total quasimomenta, for three statistics: three identical bosons, two identical fermions plus a third particle, and two identical bosons plus a third particle. Previous work treated only the trimer and zero quasimomentum. Here the atom-dimer sector is analyzed on the whole Brillouin zone. A Feshbach-Schur reduction onto the infinitely degenerate eigenvalue 1 of the pair-contact operator gives explicit effective Hamiltonians with proved first-order error. The threshold problem reduces to a 4x4 Hermitian matrix criterion built from the two-point resistances of the square lattice, and hence to a quartic polynomial. This yields the complete atom-dimer zone and the critical mass ratio on the Brillouin zone, with bound between 1 and pi/(pi-2), and closed forms at all symmetry points. We prove: the zones in closed form; the critical mass ratio with exact value pi/(pi-2) at zero quasimomentum, reproducing a numerical value; at most two atom-dimer states for every quasimomentum and mass ratio; the onset laws, an essential singularity on the zone boundary and a linear-over-logarithm onset in the pure p-wave; two exact dualities showing that a change of statistics is equivalent to a shift of quasimomentum by pi; and the global range of the second fermionic threshold. The onset laws admit a renormalization-group reading: the inverse lattice Green function is a marginal s-wave coupling, binding energies arise by dimensional transmutation with lattice scale 16, and the zone boundary is of marginal (BCS/Kondo) type rather than of Berezinskii-Kosterlitz-Thouless type. All constants are verified independently by lattice quadrature, computer algebra, exact diagonalisation, and infinite-lattice solvers.
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Quantum Physics

Interactions Protect Periodically Driven Time Crystals Against Dephasing but Destabilise Multipolar-Driven Order

Karthikeya Machiraju and Kaustav Bhowmick

We show that stronger interactions protect periodically driven time-crystal order against dephasing but destabilise order under random multipolar drives, and that coordination matters beyond the total interaction strength. We studied a disordered kicked Ising model of $N=12$ and $16$ spins with imperfect $\pi$ pulses and per-site dephasing by exact diagonalisation, comparing a periodic drive, random multipolar drives of order $n=0,1,2$ and the Thue-Morse sequence, and separated coupling strength from coordination by comparing a grid with a ring at equal total interaction strength $zJ$. For the periodic drive the coherence time scales approximately as $1/\gamma$, and stronger coupling reduces the transverse tilt on which dephasing acts. For multipolar drives of order $n\ge1$, doubling the coupling on a ring shortens the coherence time to $0.54$ ($n=1$), $0.37$ ($n=2$) and $0.44$ (Thue-Morse) at $N=16$, while random signs ($n=0$) are unaffected. A disorder scan supports a toggling-frame picture in which interactions spoil the block cancellation of the pulse error. At equal $zJ$ the grid outlives the ring by $2.15$ ($N=12$) and $2.78$ ($N=16$) for the periodic drive despite an identical transverse tilt, a coordination effect beyond this picture. All ratios hold under three definitions of the coherence time.
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Strongly Correlated Electrons

Generalized {\eta}-pairing eigenstates in three-component Hubbard models under a transverse field

F. X. Liu and Z. Song

We investigate three-component Hubbard models on a bipartite lattice in the presence of a trans?verse field. Unlike the two-component Hubbard model, where the {\eta}-pairing symmetry survives the transverse field, the three-component model possesses neither {\eta}-pairing symmetry nor conservation of the particle number of each component. We introduce a generalized {\eta}-pairing operator, formed as a hybridization of three types of two-component pairing operators, and employ the restricted spectrum-generating algebra to construct a family of exact eigenstates. These eigenstates exhibit off-diagonal long-range order. Furthermore, we construct an exact tensor-product state whose co?herent periodic dynamics provide an exact realization of quantum many-body scar dynamics while simultaneously exhibiting long-range magnetic order. We also propose three protocols for preparing this state via quench dynamics, and verify their effectiveness through numerical simulations.
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Quantum Physics

Terminal-Register Certification for Finite-Measurement Learning of Multiscale Quantum States

Bhvain Makwana, Kashyap Patel, Manjunath Joshi et al. (+1 more)

Structured quantum-state learning not only depends on an expressive ansatz but also on an operational certificate that stays meaningful with finite measurements and imperfect implementation. We study pure one dimensional states learning by an inverse binary multiscale entanglement renormalization ansatz (MERA). In the learning procedure, the qubits removed during coarse graining are controlled coherently and measured together at the terminal register. We confirm that an ideal sequential and terminal measurement schedule delivers the same complete bit string distribution under matched causal operations, while normalized postselection can amplify perturbations inversely with prefix acceptance. A noise aware theorem introduces an individual calibrated total variation implementation budget to the finite shot certificate. The protocol is estimated on an open boundary transverse field Ising ground state. A frozen 8-qubit schedule using $560$ million simulated training measurements per run achieves fidelity above $0.99$ in all $60$ held-out runs, with a mean fidelity of $0.996886$. 1080 circuit-noise cells and 6480 confidence-coverage rows are covered by fixed-circuit robustness validation without a locked soundness violation. We then address architectural fairness at $n=16$ using three new studies. In a 120-run exact-gradient multistart diagnostic, MERA has higher fidelity in 58/60 paired restarts and lower long-range error in 60/60, although no run met the prespecified stationarity criterion. Finally, a causal cone-complete, parameter matched local circuit achieves $2.62\times$ greater aggregate gate exposure yet loses all 30 paired comparisons in fidelity, long-range error, energy, and entropy.
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All authors Bhvain Makwana, Kashyap Patel, Manjunath Joshi, Jaideep Mulherkar

Physics and Society

When groups attract: coevolutionary dynamics of cooperation and individual- and group-based imitating rules

Dini Wang, Peng Yi, Gang Yan et al. (+1 more)

Success-driven imitation is a fundamental aspect of social learning, yet group interactions beyond pairwise require more subtle imitating rules since success can be observed at either the group or individual level. How such heuristic imitating rules based on these distinct levels of social information compete and coevolve with collective behavior, particularly cooperation, remains poorly understood. Here, we address this issue by studying the coevolutionary dynamics of cooperation in public goods games and individual- and group-based imitating rules on hypergraphs. We distinguish three rules according to whether payoff-biased imitation operates at the individual level, the group level, or both. Our results identify a mutual reinforcement between cooperation and group-biased imitation: preferentially learning from successful groups promotes cooperation, while cooperators in turn favor group-biased imitation. We confirm this synergy between cooperation and group-biased imitation across diverse synthetic and empirical higher-order network populations. We further show that the subtle scale and organization of group interactions critically shape this coevolution, with intermediate group sizes providing the greatest advantage for cooperation. Our results reveal how learning whom to imitate can jointly evolve to shape collective cooperation.
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All authors Dini Wang, Peng Yi, Gang Yan, Feng Fu

Quantum Physics

Engineering Defect-Phonon Interactions Through Heterophase-Interfaces in Silicon Carbide Membranes

Kirlie Iulius Figuera Michal, Jin Hee Lee, Keiju Sato et al. (+2 more)

Point defects in wide-bandgap semiconductors offer spin and photonic qubits in a solid-state platform, making them important building blocks for quantum information processing, communication, and sensing. While these systems have the strong advantage of room-temperature operation, intrinsic electron-phonon interaction induces broad phonon-sideband emission and weak zero-phonon-line transitions, limiting efficient spin-photon interfaces and scalable photon-mediated interaction. Here, we introduce a controlled heterophase interface based on the remote epitaxy technique as a crystal heterogeneity-engineering strategy. While stacking faults are treated as imperfections to be eliminated, our results instead show that crystal-phase interfaces can provide an additional degree of freedom to engineer defect-phonon interaction beyond the intrinsic properties of a single crystal. In comparison with single-phase 4H-silicon carbide (SiC) membranes, Vsi in 3C/4H heterointerface SiC exhibits a drastic enhancement of zero-phonon optical transitions, with a substantially narrower zero-phonon linewidth of 4.71 meV even at room temperature. These results establish heterophase-interface engineering as an effective route for tailoring defect-phonon interactions and realizing bright room-temperature quantum emitters with enhanced zero-phonon optical transitions.
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All authors Kirlie Iulius Figuera Michal, Jin Hee Lee, Keiju Sato, Takuji Maekawa, Je-Hyung Kim

Adaptation and Self-Organizing Systems · Cross-listed from math.DS

An Analytical Framework for a Multi-Particle Oja Flow

Sixu Li

We develop an analytical framework for studying a family of interacting particle systems that we refer to as the multi-particle Oja flow. The common interaction structure underlying this family arises in a variety of applications, including higher-order synchronization models, opinion dynamics, and self-attention dynamics derived from Transformer architectures, motivating a unified mathematical framework for their analysis. We first establish well-posedness for both the finite-particle and the mean-field systems. We also prove convergence of the finite-particle dynamics to the mean-field equation as the number of particles tends to infinity. We then investigate low-dimensional structures underlying the dynamics. In particular, we show that the mean-field solution admits a representation through a time-dependent normalized linear transformation acting on the initial distribution, with the transformation governed by a matrix ODE. Building on this representation, we identify a broad class of parametric families that are invariant under the mean-field dynamics. When the initial distribution belongs to one of these families, the evolution remains within the same family for all time and can therefore be characterized through the dynamics of the corresponding family parameters. As a concrete example, we develop this reduction within the angular central Gaussian family and illustrate how the resulting parameter dynamics provide reduced descriptions of the mean-field evolution for several representative systems.
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Atmospheric and Oceanic Physics · Cross-listed from stat.AP

Early warning of road icing from antecedent meteorological conditions without consistent critical slowing down

Chaeyeon Yi and Yun Am Seo

Critical slowing down (CSD), the slowing of recovery from perturbations as a system approaches a critical transition, is widely used for early warning, but whether such signals appear in environmental transitions subject to rapidly changing external forcing has rarely been tested with observations. Here we show, using 2,427 icing-onset events in 1-min observations from 121 South Korean road weather stations, that such signals do not consistently precede road icing. Icing began from different prior surface states, but conditions at onset varied continuously with weak separation among pathways. Cold dose, deposition dose and freeze-thaw accumulation at onset exceeded those at non-icing control times, with cold-dose discrimination highest at decay timescales of 30 min or less. However, the increases in variance and lag-1 autocorrelation expected under CSD did not distinguish icing from control times; the same procedure recovered these increases in synthetic series with a declining recovery rate, and the null result was replicated for 3,091 events at 127 independent stations. Predictive information was nevertheless present: adding recent changes and cumulative antecedent conditions to current conditions improved discrimination, and surrounding meteorological fields increased the area under the ROC curve by 0.030-0.032 for forecast windows of 1 to 12 h and reduced false alarms by 62-67% at 3 and 6 h. These results suggest that road icing is more consistent with recent meteorological forcing moving the road surface into icing-favourable conditions than with a progressive decline in internal stability, and they indicate where early warning should look when a transition is externally forced.
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High Energy Physics (Phenomenology)

Mono-Z signal for dark matter searches at future lepton colliders and cosmological interpretation

Anupam Ghosh, Partha Kumar Paul, Abhik Sarkar et al. (+3 more)

We investigate mono-$Z$ signature at the future electron-positron collider within the dark matter effective field theory (DMEFT) framework, considering operators up to dimension six for scalar, fermionic, and vector dark matter (DM) candidates. The operators are classified according to their underlying production mechanisms. We identify the phenomenologically viable parameter space by imposing the observed DM relic abundance together with direct and indirect detection constraints, Higgs invisible decay limits, and LHC mono-$Z$ bounds obtained through a recasting analysis. We study the discovery prospects of the surviving DM operators at the future $e^-e^+$ collider including initial and final state radiation, detector simulation, and the reconstruction of both leptonic and hadronic $Z$-boson decay modes. We exploit missing energy, missing transverse momentum, recoil mass, $Z$-boson pseudorapidity, together with beam polarization, which play a significant role to distinguish the signal from the Standard Model background. We find that fermionic dipole, scalar leptophilic, vector Higgs-portal, and gauge-portal DM operators offer robust mono-$Z$ discovery potential, probing multi-TeV effective scales.
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All authors Anupam Ghosh, Partha Kumar Paul, Abhik Sarkar, Rituparna Ghosh, Rachit Sharma, Subhaditya Bhattacharya

General Relativity and Quantum Cosmology

Polar-metric/axial-gauge perturbations of the Maldacena-Milekhin-Popov wormhole

Abhishake Sadhukhan

We study linear perturbations of the Maldacena-Milekhin-Popov (MMP) traversable wormhole. On a magnetically charged background, polar metric perturbations couple to axial perturbations of the gauge field. We treat this sector and reduce it to two coupled master equations of Zerilli-Moncrief type. The wormhole has two regions. In the mouths the geometry is a nearly extremal magnetic Reissner-Nordstrom black hole with no quantum source. In the throat the Casimir energy of the lowest Landau level of charged fermions holds the wormhole open. We show that the throat equations are consistent only if the fermions respond to the perturbation, computed exactly from the two-dimensional conformal anomaly with the full stress tensor including the trace part that MMP discard. This response must be accompanied by an induced Hall current of the fermions. With both effects included, the linearised Bianchi identities hold at first order in the fermionic backreaction $\alpha$. Deriving the Hall current from the fermion effective action instead requires an Euler term with coefficient $c/48\pi$, which becomes a coupling between magnetic flux and curvature similar to a Wen-Zee term. At $\alpha=0$ the throat is exact AdS$_2\times S^2$ and the modes decouple into two Poschl-Teller problems with masses $l(l-1)$ and $(l+1)(l+2)$, with levels spaced by $1/\ell$ in frequency. We give the $O(\alpha)$ corrections in closed form. They mix the two modes and depend on frequency, and match the mouths in the overlap region. The symmetric part of the potential is positive throughout the wormhole, excluding purely exponential growth. The corrections lower the normal frequencies and split the levels shared by the two modes, with real shifts at first order in $\alpha$. This sector has no growing mode for $l\ge2$ at this order.
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Quantum Physics

The Fully Depolarizing Noise Conjecture for Entangled Physical States: A Twenty-Year Perspective

Gil Kalai

In this paper I revisit my 2006 conjecture on correlated errors in entangled physical qubits, originally proposed as a potential obstruction to quantum fault tolerance. The conjecture asserts that, in any physical implementation of a quantum computer, the effective noise channel acting on entangled physical qubits contains a joint fully depolarizing component, with a rate comparable to that of two-qubit gate errors. This hypothesized structural constraint goes beyond standard noise models and, if valid, would pose a significant challenge to scalable quantum fault tolerance. The conjecture remains open, but recent advances in experimental quantum computing bring it within reach of empirical testing on current devices. I also discuss two related directions in my critical study of quantum computation: the role of noise sensitivity and computational complexity in noisy intermediate-scale quantum systems, and the statistical analysis of experimental claims of quantum advantage. Finally, since this paper is written for a volume honoring Yuri Gurevich, I include some reflections on the ways in which my scientific and personal trajectory became intertwined with Yuri's.
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Plasma Physics

A Rapid Integrated Tokamak Modelling Approach for Coupled Profile and Equilibrium Evolution

Ruohan Zhang, Huasheng Xie, Feng Wang et al. (+1 more)

During plasma heating and current ramps the thermal and magnetic states of a tokamak evolve on different timescales. We present a rapid integrated tokamak modelling approach, which couples a variational fixed-boundary Grad–Shafranov equilibrium to sparse particle and energy flux matching and to weak-form current diffusion. An ITER-like pure-deuterium scenario is examined: a current ramp from 10 to 15~MA over 20~s, a 20~s flat-top and a 20~s ramp-down to 14~MA, under 80~MW of electron-cyclotron heating applied at the start. The toroidal current density at the pedestal top more than doubles during the ramp-up and then decreases during the flat-top as current redistributes inward. Thermal stored energy rises from 185.52 to 252.70~MJ and approaches its final value within the first few seconds. An independent calculation with the Fusion Synthesis Engine (FUSE) gives a stored-energy difference of 0.02% at 60~s, whereas the largest profile differences occur in the core current density. Halving the coupling interval changes stored energy by at most 0.006% at the selected radial resolution. The 60~s pulse, advanced through 600 coupling intervals of 0.1~s, takes 8.62~s on an Apple M4 Pro, which is at least two orders of magnitude faster than conventional integrated tokamak modelling solvers.
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All authors Ruohan Zhang, Huasheng Xie, Feng Wang, Zheng-Xiong Wang

Mathematical Physics

Minimal output entropy for the channels that add or remove a box of a Young diagram, and a Pauli principle for every permutation symmetry

Robin Reuvers

Two irreducible representations of $U(d)$ whose Young diagrams differ by a single box are connected by four covariant quantum channels: the box can be removed or added, and one keeps either the new diagram or the box ($\mathbb{C}^d$ or its dual). We prove that for each of these channels the output of a coherent state majorizes every other output, so that coherent states minimize the output entropy, and we compute the optimal output explicitly in terms of hook lengths. For the two channels that keep the box we also determine all minimizers; these need not be coherent, even when they are pure. As an application we consider $N$ particles with a given permutation symmetry and find sharp bounds on the spectrum of the reduced density matrix of a single particle, as well as the exact set of spectra that mixed states can reach (for fermions these are the Pauli principle and Coleman's theorem).
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Atomic Physics

Non-dipole effects in a multielectron atom

Alexey N. Hopersky, Alexey M. Nadolinsky and Rustam V. Koneev

This Letter establishes the analytical structure of the dipole radiation transition operator, taking into account non-dipole effects for a multielectron atom. The results summarize those of Komninos Y. et al., Phys. Rev. A 86, 023420 (2012), obtained in an approximation of a "split" electron of a continuous spectrum. The result for the complete operator of a multipole radiation transition [see formula (10)] can be specified within the framework of the methods of the theory of irreducible tensor operators and for higher multipoles.
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Plasma Physics

Continuous Laser-Driven {\alpha} Source

Noam Popper, Griffin D. Glenn, Girik Jain et al. (+7 more)

Laser-driven proton-boron fusion offers a path for generation of $\alpha$ particles on a compact scale. Conventional solid-target experiments, however, are fundamentally limited by target degradation and low shot-repetition capacity. Here, we demonstrate a continuous laser-driven $\alpha$ particle source utilizing target-normal sheath acceleration from a continuously replenishable ultrathin water-leaf jet target. The proton beam interacts with a downstream boron nitride converter, driving the $^{11}\text{B}(p,\alpha)^{8}\text{Be}$ reaction which yields three $\alpha$ particles. The measurement was repeated across $18{,}000$ consecutive shots at a rate of $10\,\text{Hz}$. The outgoing $\alpha$-particle yield and spectral fluence were measured and benchmarked against comprehensive particle-transport simulations. The numerical and experimental results reveal a pronounced flattening in the energy-differential $\alpha$-particle spectrum escaping from the converter, driven by depth-dependent reaction yield and stopping power effects. The sustained stable $\alpha$-particle production at high cumulative yields paves the way for applications in targeted particle therapy and laser-driven plasma-fusion research.
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All authors Noam Popper, Griffin D. Glenn, Girik Jain, Raz Halifa Levi, Tomer Catabi, Michal Elkind, Aviv Levinson, Assaf Levanon, Siegfried H. Glenzer, Ishay Pomerantz

Materials Science

Toward catalyst-mediated growth of diamond and cubic boron nitride wires

Rodney S. Ruoff

A reproducible method for sustained catalyst-mediated growth of diamond and cubic boron nitride (cBN) wires has yet to be established. Catalyst-assisted growth has produced carbon and boron nitride nanotubes and a wide range of elemental, compound and alloy nanowires. Diamond and cBN wires could combine high specific stiffness and strength with heat conduction and electrical insulation. I propose vapor-liquid-solid (VLS) and vapor-solid-solid (VSS) routes in which temperature, feed, catalyst or starting contact changes between formation of the first diamond or cBN segment and its continued growth. The approaches include switching from carbide or boron-rich starter wires, depositing catalyst on selected facets of existing crystals, and using local solid feedstock to supply the catalyst during initial growth. Historical diamond-whisker reports motivate renewed tests of diamond-metal contacts. The proposed experiments ask whether these contacts can favor tetrahedral bonding while maintaining a supply of atoms to the growing wire. Both single-crystal and polycrystalline products, from nanometer to micrometer and larger diameters, are of interest.
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Quantum Physics

How many photons can a molecule scatter before its coherence is lost?

M. R. Tarbutt

Molecular qubits held in conservative optical traps may lose coherence when they scatter photons from the trapping lasers. The rate for this process has two parts, one equal to the mean Raman scattering rate of the two qubit states, and the other proportional to the square of the difference in their Rayleigh scattering amplitudes. This paper calculates the decoherence rate, expressing results in terms of the vector and tensor parts of the molecular polarizability, $\alpha_1$ and $\alpha_2$. While the decoherence rate is generally much larger for molecules than for atoms, it is suppressed at wavelengths where $\alpha_1$ and $\alpha_2$ are both small. The wavelengths where this occurs are identified for CaF molecules.
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Mesoscale and Nanoscale Physics

Bare-Die Antiferromagnetic Computing

Yu Liu, Zhuoting Han, Zexin Feng et al. (+15 more)

Semiconductor electronic devices are increasingly constrained by fundamental quantum tunneling effects and charge-based mechanisms, which severely limit further miniaturization, write-speed scaling, and environmental robustness of silicon-based technologies. These limitations are particularly prohibitive for deep-space exploration, where extreme temperatures, ultra-strong magnetic fields, and intense radiation rapidly incapacitate conventional electronics without massive shielding. Here, we present an intrinsically resilient, strain-mediated antiferromagnetic MnIr/PMN-PT edge processor that operates reliably as a bare die under temperatures up to 500 K, magnetic fields of 55 T, and radiation doses of 1.5 Mrad. By exploiting an input-modulated in situ self-refreshing encoding mechanism, the device performs nonlinear feature extraction and classification directly from raw analog signals, enabling an analog computing architecture that requires no time-frequency transformation. This architecture achieves 99.8% accuracy in speech recognition without digital preprocessing and 100% accuracy in astronaut visual object recognition. Furthermore, an all-hardware integrated drone vision system demonstrates real-time in situ command execution and autonomous navigation, delivering a terahertz-level response frequency and an ultra-low energy consumption of approximately 0.2 fJ per operation. This work expands the functional scope of antiferromagnetic devices beyond memory and logic, establishing them as a promising materials platform for energy-efficient physical computing and autonomous intelligence in extreme environments.
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All authors Yu Liu, Zhuoting Han, Zexin Feng, Peixin Qin, Zhiyuan Duan, Yuhao Ye, Zengwei Zhu, Chengyan Zhong, Li Liu, Guojian Zhao, Wenbin Shen, Jingyu Li, Sixu Jiang, Xiaoyang Tan, Xiaoning Wang, Ziang Meng, Chengbao Jiang, Zhiqi Liu

Strongly Correlated Electrons

Kitaev-Heisenberg model on the square-hexagon-dodecagon lattice

Saeed Barari, Yasir Iqbal, Ganapathy Baskaran et al. (+3 more)

We study the spin-$1/2$ Kitaev-Heisenberg model on the square-hexagon-dodecagon lattice with a symmetry-preserving tri-coloring of the Kitaev exchanges. We focus on two cases: (i) the pure Kitaev model with anisotropic exchanges and (ii) the Kitaev-Heisenberg model with isotropic Kitaev exchange. In the absence of Heisenberg interactions, we use the standard mapping of the Kitaev model onto a quadratic Majorana-fermion problem in a $\mathbb{Z}_2$ gauge field. We find a gapped energy spectrum throughout the positive-coupling phase diagram, except at a single point where the twofold-degenerate energy bands form a Dirac cone. This unique gapped region corresponds to a toric code phase. However, depending on the couplings, vortex excitations on square, hexagonal, and dodecagonal plaquettes realize three distinct relative assignments to the $e$ and $m$ anyons. We determine these relative assignments from the physical fermion parity of the vortex sectors and locate their boundaries by tracking zero crossings of vortex-bound Majorana levels. For the isotropic Kitaev-Heisenberg model, we combine graph-based projected entangled-pair-state calculations, exact diagonalizations, and linear spin-wave theory to study the entire phase diagram. Apart from the toric code topological phases that are robust around the Kitaev limits, we obtain four collinear magnetically ordered phases that can be characterized by their local and relative orderings of hexagonal plaquettes. We also identify a special point at which the ground state is a product state.
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All authors Saeed Barari, Yasir Iqbal, Ganapathy Baskaran, Saeed S. Jahromi, Chunxiao Liu, Julien Vidal

Quantum Physics

Local Many Worlds in Spacetime: Deutsch-Hayden Descriptors and Local Wavefunctions

Mordecai Waegell

Bell's theorem establishes that a local and spatially separable physical theory with no superdeterminism or retrocausality must be a theory of many local worlds. The local many worlds formalism of quantum mechanics is a transparent separable physical theory in spacetime with a Lorentz covariant causal structure. Unlike the Everett many worlds interpretation, there is no nonseparable universal wavefunction in configuration space, but like Everett, there is only local unitary evolution which conserves probability (fluid) current, and no wavefunction collapse. Each event in spacetime has its own local wavefunction which is built up using only the local wavefunctions and local unitary evolution operators within its past light cone, and which is entirely disconnected from spacelike separated local wavefunctions. We call this the local Schrödinger picture. Local many worlds can also be described in the Heisenberg picture by ascribing Deutsch-Hayden (DH) descriptors to each individual system, each of which evolves under local unitary operations. Both the local wavefunctions and DH descriptors contain records of past interactions, and while the local wavefunctions provide a clear and intuitive physical narrative, the descriptors contain all of the same information in a much more compact form. Unfortunately, the compact form is also somewhat cryptic, which has made the local Heisenberg picture relatively inaccessible. The purpose of this article is to show that the local wavefunctions for any $N$-qubit system can always be constructed directly from the DH descriptors, allowing us to combine the benefits of both pictures.
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General Relativity and Quantum Cosmology

Dimensional (In)dependence of Lorentzian Quantum Cosmology

Masazumi Honda, Hiroki Matsui, Kota Numajiri et al. (+2 more)

We study transition amplitudes of the quantum universe in $D$-dimensional spacetime within the de Sitter minisuperspace approximation in Einstein gravity. Using the Lorentzian path integral combined with Picard-Lefschetz theory, we identify the saddle points that contribute to the integral and derive a well-defined transition amplitude under Dirichlet boundary conditions. We further show numerically that a resurgence analysis based on Borel-Padé resummation is effective in resolving the residual Stokes ambiguities that arise in certain cases. Analyzing three-, four-, and five-dimensional cases, as well as the large-$D$ limit, we find that the tunneling proposal is commonly realized for the creation of the universe from nothing. This result implies a universal feature of quantum cosmology based on Einstein gravity across dimensions.
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All authors Masazumi Honda, Hiroki Matsui, Kota Numajiri, Kazumasa Okabayashi, Takahiro Terada

High Energy Physics (Phenomenology)

Thermal masses in the Standard Model at three loops

Mikael Chala

We compute the Higgs thermal mass and the electroweak and colour Debye mass parameters to full $\mathcal{O}(g^6)$ in dimensional reduction, where $g$ represents a gauge coupling or the top Yukawa. We employ new methods to evaluate previously unknown mixed-signature sum-integrals.

Mathematical Physics · Cross-listed from math.AG

Landau–Ginzburg mirror symmetry for ADE singularities

Alexey Basalaev

We prove Landau-Ginzburg mirror symmetry conjecture for ADE singularities with the nontrivial symmetry groups. In particular, we consider $(f,G)$ with $f \in \mathbb{C}[z_1,z_2,z_3]$ defining ADE singularity and $G$ — nontrivial group of diagonal symmetries of $f$. We show that orbifold Saito theory of $(f,G)$ is isomorphic to the Fan-Jarvis-Ruan-Witten theory of its Berglund-Hübsch-Henningson dual pair $(\widetilde f, \widetilde G)$.
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