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Physics

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Friday 24 July

Strongly Correlated Electrons

Exact Neural-Network Representations of the Motzkin States

Runde Zha, Yuntian Gu, Chaohui Fan et al. (+3 more)

Motzkin spin chains are paradigmatic frustration-free one-dimensional quantum systems whose ground states feature exactly solvable combinatorial structures and exotic, area-law-violating entanglement scaling. Specifically, colorless Motzkin states exhibit critical logarithmic entanglement divergence \(\log N\) with system size \(N\), while their colorful counterparts host supercritical sublinear \(\sqrt{N}\) entanglement growth. Such unconventional entanglement behaviors place these states well beyond the expressive capability of standard matrix product states, which are fundamentally constrained by the entanglement area law. Here, we systematically construct exact, training-free neural-network representations for both colorless and colorful Motzkin states across four mainstream architectures, including recurrent, feedforward, convolutional, and transformer networks. Our core design leverages a causal prefix-sum module, implementable via recurrent updates, feedforward mappings, or masked attention layers, combined with position-selective rectified linear gates that enforce the Motzkin height constraints. For the colorful states, we further introduce a dedicated causal stack module that explicitly encodes the last-in-first-out color-matching rule. Our results demonstrate that neural architectures can accurately capture highly non-trivial entanglement features inaccessible to conventional tensor networks, providing prototypic examples for benchmarking and a constructive design framework for future neural-network quantum state developments targeting strongly entangled quantum systems.
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All authors Runde Zha, Yuntian Gu, Chaohui Fan, Jia-lin Chen, Hai-Jun Liao, Tao Xiang

Quantum Physics

Critical Sensing with Autonomous Devices: The Self-Oscillation Threshold of a Frequency-Locked NV-Centre Magnetometer

Joan Toledo Aguilera, Gonzalo Reina Rivero, Marcel Morillas-Rozas et al. (+1 more)

Feedback locking of a probe frequency to a spin resonance is the standard operating mode of precision quantum sensors. Here we deliberately operate such a lock outside its stable regime: a continuous-wave nitrogen-vacancy (NV) ensemble magnetometer, frequency-modulation (FM) locked to one flank of its optically detected magnetic resonance (ODMR), is driven through the flip (period-doubling) bifurcation of its discrete feedback map by raising the software loop gain $G$. Beyond a critical gain $\Gc$ the lock becomes a self-sustained oscillator whose limit cycle is generated by the loop itself. We derive the threshold condition $\Gc = 2\,\Dcal/\Dtrue$, which identifies the measurable content of the threshold: the ratio of the transduction slope of the ODMR lock-in signal at calibration time $D_{cal}$ to its value at present $D_{true}$. We present an identifiability analysis showing which physical parameters this single scalar can and cannot distinguish, characterize the estimators of $\Gc$ under realistic noise, and report measurements on our current setup: an experimental bifurcation diagram with onset at $\Gc \approx 2$ as predicted for a self-calibrated loop, sub-threshold critical fluctuations following the predicted $\sqrt{G/(2-G)}$ divergence.
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All authors Joan Toledo Aguilera, Gonzalo Reina Rivero, Marcel Morillas-Rozas, Javier Cerrillo

High Energy Physics (Theory)

Integral Scaling for EFT Strings from the Bottom-Up

Muldrow Etheredge, Alvaro Herráez, Dieter Lüst et al. (+1 more)

Near the core of an EFT string in a 4d $\mathcal{N}=1$ theory, the scalars are dynamically driven to infinite field distance and a tower of states becomes light, with mass scaling with the string tension in Planck units as $m^2\sim \mathcal{T}^{\,w}$. According to the Integral Scaling Conjecture, $w$ takes only values 1, 2 and 3. In this paper, we examine how this conjecture can follow from the brane-taxonomy rules associated with the Emergent String Conjecture. In this context, we classify the relevant types of duality frames into 74 classes, identify which lattice sites can be relevant EFT candidates, and exhaustively test integral scaling for all of these candidates. We find that it holds with $w\leq 3$ for all the leading towers and also for the subleading towers below the species scale (up to half-integral subtleties that also appear in top-down examples). We further find evidence that the oscillator modes of EFT string candidates generate the lattices of particles and strings. Moreover, $w=1$ implies a perturbative string limit, but the converse is not true. We compare our classification with concrete type IIA, F-theory and M-theory compactifications.
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All authors Muldrow Etheredge, Alvaro Herráez, Dieter Lüst, Luca Melotti

Astrophysics of Galaxies

Is S301 the Captured Companion of the Hypervelocity Star S5-HVS1?

Andrea Caputo and Giovanni Maria Tomaselli

Stellar binary disruptions through the Hills mechanism produce two fossils: a hypervelocity star (HVS), and a star tightly bound to the supermassive black hole. Among known galactic HVSs, only S5-HVS1 has unambiguous galactic-centre origin. Its measured mass and velocity determine a relation between the mass and semi-major axis of its captured companion. GRAVITY has now discovered S301, whose orbit and photometrically inferred mass satisfy this relation, making it the only compelling candidate for the captured companion of S5-HVS1. We build a forward model for the Hills origin and compare it to the null hypothesis. This confirms that S301's orbit aligns much more closely with that of S5-HVS1's companion than a typical S-star. However, the catalog-level Bayes factor remains of order unity and dependent on the probabilities of survival and detection. S301 is thus a compelling candidate, but establishing its association with S5-HVS1 will require improved mass measurements, chemical comparisons and GRAVITY-calibrated selection functions.
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Quantum Physics

Quantum Spectral Model: Data Reuploading with Input-Conditioned Frequency Support

Peiyong Wang, Udaya Parampalli and Casey R. Myers

A central design principle in modern machine learning and artificial intelligence is to align a model's inductive bias with the structure of its input data. For matrix-valued inputs, relevant matrix-level relationships can be characterised through spectral values and spectral subspaces; however, common coordinate-wise rotation-gate data-encoding unitaries used in most quantum machine learning models do not explicitly construct such a matrix-level representation. We introduce Quantum Spectral Models (QSMs), in which we construct the generator of the data-encoding unitary directly from each input matrix. We study three QSM variants based on symmetric, global block, and non-overlapping patch-local block Hamiltonians. Their outputs admit truncated Fourier representations in which input-dependent spectral gaps supply candidate phase carriers, while spectral subspaces help determine their coefficients. We evaluate the QSMs and comparison quantum models on two matrix representations of Pendigits and two controlled synthetic tasks defined by spectral statistics. At the largest evaluated circuit depth, QSM variants lead the tested quantum models in mean test accuracy across all four benchmarks. The patch-local QSM leads on Pendigits, whereas the global block-Hamiltonian QSM leads on the controlled spectral tasks. Ablations show a task-dependent reversal: subspace-preserving controls perform better on Pendigits, whereas spectral-value-only controls lead among the tested ablations on the synthetic tasks. Together, these results shed new light on quantum machine-learning model design by showing how input-conditioned spectral representations can provide an analysable inductive bias, while offering a broader perspective on structure-aware model design in machine learning and artificial intelligence.
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Materials Science

Inference Limits of Routine Cement Characterization for CEM I Performance: Evidence From a Multi-Producer Dataset

Marchellino Ghorayeb, Christiane Rößler, Horst-Michael Ludwig et al. (+2 more)

This study evaluates the prediction of 28-day compressive strength from routine cement characterization across independent producers. Industrial records from 23 European producers cover nearly three decades of testing in a single laboratory, encompassing 476 samples. The archive includes CEM I, CEM II, CEM III, and other blended cements, with the main analysis focused on CEM I. Chemistry and fineness descriptors were evaluated using linear and nonlinear models. Strength class and water demand were also examined as performance labels from standardized testing. Mean absolute errors in 28-day strength prediction were approximately 3 MPa, with linear models performing comparably to nonlinear models. Producer holdout tests assessed transfer to cements from producers excluded from training and yielded absolute errors of the same order. Equivalent alkali showed a consistent negative association with 28-day strength, with K$_2$O carrying most of this signal. Together, these results highlight the value of industrial data collected under common laboratory conditions for interpretable 28-day strength prediction, with potential to inform cement design targeting lower production costs and CO$_2$ emissions.
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All authors Marchellino Ghorayeb, Christiane Rößler, Horst-Michael Ludwig, Leon Herrmann, Stefan Kollmannsberger

High Energy Physics (Experiment)

Measurement of Born Cross Section for $e^+e^-\to K_S^0\bar{\Xi}^+\Sigma^-+\rm{c.c.}$ at $\sqrt{s} = 3.51-4.95$ GeV

BESIII Collaboration: M. Ablikim, M. N. Achasov, P. Adlarson et al. (+758 more)

Using $e^+e^-$ collision data collected with the BESIII detector at the BEPCII collider corresponding to a total integrated luminosity of 44~fb$^{-1}$, we present the first measurement of the Born cross sections for the process $e^+e^-\to K_S^0\bar{\Xi}^+\Sigma^-$ at 56 center-of-mass energies from 3.510 to 4.951~GeV. By fitting the dressed cross sections of $e^+e^-\to K_S^0\bar{\Xi}^+\Sigma^-$ with the assumption of a power-law function plus a charmonium(-like) resonance, i.e. $\psi(3770)$, $\psi(4040)$, $\psi(4160)$, $Y(4230)$, $Y(4360)$, $\psi(4415)$, $Y$(4500), $Y(4660)$, and $Y$(4710), no significant signal of any charmonium(-like) state decaying into the $K_S^0\bar{\Xi}^+\Sigma^-$ is observed. Upper limits on the product of the electronic width and branching fraction at the 90% confidence level are given for each resonance. Combining this result with the previous measurement of the isospin-symmetric process $e^+e^-\to K^{-} \bar{\Xi}^{+} \Sigma^{0} $, the ratio of the Born cross sections, $R=\sigma^{B}(e^+e^-\to K_S^0\bar{\Xi}^+\Sigma^-)/$$\sigma^{B}(e^+e^-\to K^-\bar{\Xi}^+\Sigma^0)$, is found to be consistent with unity.
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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, 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, C. Q. Deng, Z. Y. Deng, A. Denig, I. Denisenko, M. Destefanis, F. De Mori, E. Di Fiore, X. X. Ding, Y. Ding, Y. X. Ding, Yi. Ding, J. Dong, L. Y. Dong, M. Y. Dong, X. 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, 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, L. 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, E. M. Gersabeck, A. Gilman, K. Goetzen, J. Gollub, J. B. Gong, J. D. Gong, L. Gong, W. X. Gong, W. Gradl, S. Gramigna, M. Greco, M. D. Gu, M. H. Gu, C. Y. Guan, A. Q. Guo, H. Guo, J. N. Guo, L. B. Guo, M. J. Guo, R. P. Guo, X. Guo, Y. P. Guo, Z. Guo, A. Guskov, J. Gutierrez, J. Y. Han, T. T. Han, X. Han, F. Hanisch, K. D. Hao, X. Q. Hao, F. A. Harris, C. Z. He, K. K. He, K. L. He, F. H. Heinsius, C. H. Heinz, Y. K. Heng, C. Herold, P. C. Hong, G. Y. Hou, X. T. Hou, Y. R. Hou, Z. L. Hou, H. M. Hu, J. F. Hu, Q. P. Hu, S. L. Hu, T. Hu, Y. Hu, Y. X. Hu, Z. M. Hu, G. S. Huang, K. X. Huang, L. Q. Huang, P. Huang, X. T. Huang, Y. P. Huang, Y. S. Huang, T. Hussain, N. 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, H. B. 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, 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. G. Li, Y. P. Li, Z. H. Li, Z. J. Li, Z. L. Li, Z. X. Li, Z. Y. Li, C. Liang, H. Liang, Y. F. Liang, Y. T. Liang, 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. M. Liu, W. T. Liu, X. Liu, X. K. Liu, X. L. Liu, X. P. Liu, X. Y. Liu, Y. Liu, Y. B. Liu, Yi Liu, Z. A. Liu, Z. D. Liu, Z. L. Liu, Z. Q. Liu, Z. X. Liu, Z. Y. Liu, X. C. Lou, H. J. Lu, J. G. Lu, X. L. Lu, Y. Lu, Y. H. Lu, Y. P. Lu, Z. H. Lu, C. L. Luo, J. R. Luo, J. S. Luo, M. X. Luo, T. Luo, X. L. Luo, Z. Y. Lv, X. R. Lyu, Y. F. Lyu, Y. H. Lyu, F. C. Ma, H. L. Ma, 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, Y. M. Ma, F. E. Maas, I. MacKay, M. Maggiora, S. Maity, S. Malde, Q. A. Malik, H. X. Mao, Y. J. Mao, Z. P. Mao, S. Marcello, A. Marshall, F. M. Melendi, Y. H. Meng, Z. X. Meng, G. Mezzadri, H. Miao, T. J. Min, R. E. Mitchell, X. H. Mo, B. Moses, N. Yu. 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, S. Pacetti, Y. Pan, A. Pathak, Y. P. Pei, M. Pelizaeus, G. L. Peng, H. P. Peng, X. J. Peng, Y. Y. Peng, K. Peters, K. Petridis, J. L. Ping, R. G. Ping, S. Plura, V. Prasad, L. Pöpping, F. Z. Qi, H. R. Qi, M. Qi, S. Qian, W. B. Qian, C. F. Qiao, J. H. Qiao, J. J. Qin, J. L. Qin, L. Q. Qin, L. Y. Qin, P. B. Qin, X. P. Qin, X. S. Qin, Z. H. Qin, J. F. Qiu, Z. H. Qu, J. Rademacker, K. Ravindran, C. F. Redmer, A. Rivetti, M. Rolo, G. Rong, S. S. Rong, F. Rosini, Ch. Rosner, M. Q. Ruan, N. Salone, A. Sarantsev, Y. Schelhaas, M. Schernau, K. Schoenning, M. Scodeggio, W. Shan, X. Y. Shan, Z. J. Shang, J. F. Shangguan, L. G. Shao, M. Shao, C. P. Shen, H. F. Shen, W. H. Shen, X. Y. Shen, B. A. Shi, Ch. Y. Shi, H. Shi, J. L. Shi, J. Y. Shi, M. H. Shi, S. Y. Shi, X. Shi, H. L. Song, J. J. Song, M. H. Song, T. Z. Song, W. M. Song, Y. X. Song, 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, C. J. Tang, G. Y. Tang, J. Tang, J. J. Tang, L. F. Tang, Y. A. Tang, Z. H. Tang, L. Y. Tao, M. Tat, J. X. Teng, J. Y. Tian, W. H. Tian, Y. Tian, Z. F. Tian, I. Uman, E. van der Smagt, B. Wang, Bin Wang, Bo Wang, C. Wang, Chao Wang, Cong Wang, D. Y. Wang, H. J. Wang, H. R. Wang, J. Wang, J. J. Wang, J. P. Wang, K. Wang, L. L. Wang, L. W. Wang, M. Wang, Mi Wang, N. Y. 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, M. Wolke, 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, C. J. Xu, G. F. Xu, H. Y. Xu, Q. J. Xu, Q. N. Xu, T. D. Xu, X. P. Xu, Y. Xu, Y. C. Xu, Z. S. Xu, F. Yan, L. Yan, W. B. Yan, W. C. Yan, W. H. Yan, W. P. Yan, X. Q. Yan, Y. Y. Yan, H. J. Yang, H. L. Yang, H. X. Yang, J. H. Yang, R. J. Yang, X. Y. Yang, Y. Yang, Y. 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, Junhao 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, 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. 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. Zhang, Y. T. Zhang, Y. H. Zhang, Y. P. Zhang, Yu Zhang, Z. Zhang, Z. D. Zhang, Z. H. Zhang, Z. L. Zhang, Z. X. Zhang, Z. Y. Zhang, Zh. Zh. 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, 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

Correlated Coherent Errors in Stabilizer Codes: A General Cumulant Framework and Interference-Based Error Suppression

Rohan N Rajmohan, Antoine Brillant, Peter Groszkowski et al. (+3 more)

Coherent errors in stabilizer codes are often correlated across qubits and QEC cycles. Having a general analytical treatment of such noise would thus be extremely valuable. We derive here the exact logical channel induced by repeated QEC cycles under correlated coherent $Z$ noise, and develop a broadly general cumulant-expansion framework that yields a tractable expression for the noise-averaged logical infidelity. Crucially, this expression is non-perturbative in the noise, and applies to arbitrary stabilizer codes and correlation structures. It reveals a feature with no analogue in standard stochastic Pauli error models: the induced channel depends on which stabilizer eigenspace is chosen as the codespace. Exploiting this, we introduce protected stabilizer eigenspace (PROSE) encoding, an error-suppression strategy that selects the optimal codespace. We show that this eigenspace can be efficiently identified in many relevant situations. Further, when combined with logical Pauli twirling, PROSE matches or outperforms standard error suppression techniques (dynamical decoupling, Pauli twirling of physical qubits). We also show that noise correlations, usually assumed to be harmful to QEC, can instead be a resource: with the right encoding, even positive correlations reduce the logical infidelity below the uncorrelated baseline. Our results offer a new, broadly applicable lens on correlated coherent noise in stabilizer codes.
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All authors Rohan N Rajmohan, Antoine Brillant, Peter Groszkowski, Alireza Seif, Jens Koch, Aashish Clerk

High Energy Physics (Phenomenology)

Finite Formation Time Antenna Radiation: Color Spectators Break Single-Emitter BDMPS-Z

Fabio Domínguez, Pablo Guerrero-Rodríguez and Carlos A. Salgado

We compute the direct contribution to the squared matrix element for the in-medium soft gluon emission off a color-singlet quark-antiquark pair. To do this, we incorporate medium interactions that take place during the finite formation time of the antenna, thereby accounting for a largely neglected source of modifications with respect to the vacuum baseline. As a consequence, non-trivial correlations with the spectator (i.e.\ non-emitting) leg of the antenna emerge, greatly increasing the complexity of the result even at leading-$N_c$ order. The observed modifications entail a significant departure from the limit of instantaneous antenna formation, where the calculation effectively reduces to the well-known BDMPS-Z spectrum.
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High Energy Physics (Theory)

One-loop effective potential in Kalb-Ramond scalar electrodynamics

Pratik Chattopadhyay and M. J. Neves

In this work, we study the effective potential at one loop for the Kalb-Ramond scalar electrodynamics. The model is based on a complex scalar field coupled to the electromagnetic field as usual, and also to the Kalb-Ramond field through the dual vector associated with the strength tensor of the $2$-form gauge field. There is an additional topological coupling of the electromagnetic field and the Kalb-Ramond field. The quantum corrections generated by the Kalb-Ramond sector are computed using dimensional regularization, and the ultraviolet divergences are removed by introducing the appropriate counterterms, leading to a finite renormalized effective potential. We find that the effective potential at one-loop generates terms of the form $\phi^6$, which is not present in the original bare Lagrangian. As a result, we introduced new counter terms to eliminate such divergences. The theory thus considered is not closed under renormalization.
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Instrumentation and Methods for Astrophysics

Pollux: decisions affecting the optical architecture of a high-resolution spectrograph and polarimeter for the Habitable Worlds Observatory

Eduard Muslimov, Luca Fossati, Coralie Neiner et al. (+5 more)

POLLUX is a candidate European instrumental contribution to the Habitable Worlds Observatory. It is a high-resolution spectrograph with polarimetric capabilities, covering from the far ultraviolet (FUV; 100nm) to the near infrared (NIR; 1.75mum). Such a broad spectral coverage is achieved by splitting the instrument into five channels, each comprising an echelle spectrograph: FUV, medium-UV (MUV), near-UV (NUV), optical (OPT), and NIR. A set of custom-made dichroics enables simultaneity across the MUV, NUV, OPT, and NIR channels.We present the latest developments in the optical design of the three UV channels. Specifically, we estimate the impact of telescope residual jitter on resolving power and sampling and discuss possible options to enable pure spectroscopy in the FUV channel without implementing a fully retractable polarimeter and to compensate the defocus when inserting MUV and NUV polarimeters. Finally, we estimate the impact of detector size limitation and potential advantages of shrinking or extending the wavelength coverage in the NUV channel.
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All authors Eduard Muslimov, Luca Fossati, Coralie Neiner, Jean-Claude Bouret, David Le Mignant, Kjetil Dohlen, Jean-Michel Reess, Adrien Girardot

Solar and Stellar Astrophysics

Payne4GAIN: NLTE Corrections for Red Giants in Milky Way Mapper using H-Band Neural Network Emulators

Pierre Thibodeaux, Alexander P. Ji, Nicholas Storm et al. (+12 more)

The majority of spectroscopic surveys assume local thermodynamic equilibrium (LTE) during the modeling of stellar spectra. This assumption begins to break down for luminous stars, like the red giants targeted by SDSS-V's Milky Way Mapper Survey in its Galactic Genesis program. In this work, we present non-LTE (NLTE) abundances for 360,000 red giant stars in Milky Way Mapper DR19, from infrared APOGEE spectra. We generate NLTE spectra using precomputed departure coefficient grids for Na, Mg, Si, Al, Ca, Ti, Mn, and Ni. To fit APOGEE spectra at scale, we train neural network emulators (NNEs) to synthesize LTE and NLTE H-band spectra. After verifying that the NNEs are accurate, we fit the APOGEE spectra with ASPCAP results that fall within the same parameter range as the training data. We find strong NLTE effects on the order of 0.1\,dex for Al, Mn, and Ti, and smaller effects for Si and Ni. We provide a catalog of the results of our LTE and NLTE fits, as well as NLTE-corrected ASPCAP abundances using a polynomial fit correction.
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All authors Pierre Thibodeaux, Alexander P. Ji, Nicholas Storm, Maria Bergemann, Rana Ezzeddine, Yuan-sen Ting, Andrew R. Casey, Emily Griffith, José Fernández-Trincado, Guilherme Limberg, Szabolcs Mészáros, Amaya Sinha, Danny Horta, Andrew K. Saydjari, Joel Brownstein

Quantum Physics

Automated Flag-based Fault-Tolerant State Preparation using Integer Linear Programming

Ben Criger, Aaron Hankin, Justin J. Burau et al. (+1 more)

Post-selected stabilizer state preparation is a necessary subroutine in fault-tolerant quantum computation, both for initialization of logical qubits, and for logical-ancilla-based error correction gadgets (e.g. Steane and Knill). Therefore, reducing the number of gates needed to prepare a stabilizer state fault-tolerantly can simultaneously reduce time-to-solution and increase reliability. For small, low-distance codes such as the [[7, 1, 3]] Steane code, circuits with low gate counts can be found by inspection. This becomes impractical for larger codes, necessitating automation. There are two state-of-the-art methods for automated fault-tolerant state preparation, SAT-based stabilizer measurement and flag-at-origin. In this work, we optimize state preparation circuits using the circuit gauge operator formalism to express the construction of flag circuits as an integer linear program. This allows the construction of circuits with equal or lower gate count than the state of the art, while detecting up to three errors. We use this technique to derive a Steane error correction gadget for the [[24, 10, 4]] two-block group algebra code, and test it on Quantinuum's System Model H2 quantum computer with 10,000 shots, resulting in a logical block error rate ~0.00014 (~0.000014 per logical qubit), with ~1.6% of the shots post-selected due to weight-two errors.
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All authors Ben Criger, Aaron Hankin, Justin J. Burau, Abigail R. Perry

High Energy Physics (Theory)

Dilatonic states, phase transitions, and criticality in holography

Daniel Elander and Maurizio Piai

The dilaton is the hypothetical scalar particle associated with spontaneous breaking of approximate scale invariance. It has been predicted to arise dynamically, as a bound state, in special extensions of the standard model of particle physics based on composite dynamics. In confining gauge theories, generic arguments suggest that the scale of explicit symmetry breaking coincides with the confinement scale, that governs also its spontaneous breaking, by setting the size of all the condensates, as well as the masses of bound states and their excitations. Whether a light dilaton can nevertheless exist in such a context is an open question in quantum field theory, answering which has potentially transformative implications from a conceptual viewpoint, besides having striking phenomenological ramifications. It has been suggested that the mass of the dilaton might be suppressed, in respect to the confinement scale, in the special case in which the underlying strongly coupled dynamics undergoes a zero-temperature (weak) phase transition. Identifying the special conditions under which this happens is the subject of ongoing investigations. A dedicated programme of exploration, carried out within the context of gauge-gravity dualities (holography), has been set up to test the viability of this mechanism. We review the relevant technology within holography, and the status of such a programme, by comparing results obtained in a survey of explicit examples. We do so both within the bottom-up, simplified version of gauge-gravity dualities, but also within the more refined, and complete, top-down approach to holography, in which the gravity theory is known to have a more fundamental origin. We highlight the first examples of confining theories in which a parametrically light holographic dilaton forms as a bound state in a region of parameter space in proximity to a critical point of the field theory.
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Quantum Physics

Quantum many-body scars with tunable entanglement and Hamiltonian inverse design from ZX-calculus

Marcin Szyniszewski

Diagrammatic languages such as ZX-calculus provide compact and intuitive descriptions of quantum processes and have become established tools for circuit simplification, verification, and compilation. However, their potential as a framework for constructing many-body states and the Hamiltonians that host them remains largely unexplored. Here, we introduce families of fractal many-body states obtained from ZX-diagrams based on the Sierpiński triangle and Sierpiński carpet. By construction, the underlying graph connectivity imposes atypical subvolume-law minimum-cut upper bounds on entanglement: at most logarithmic scaling for the triangle family and sublinear power-law for the carpet family. By adjusting the free parameters of the ZX-diagram construction, we can tune the actual entanglement scaling: we demonstrate both area-law and logarithmic scaling for the triangle, and both log law and power-law for the carpet. Additionally, their local observables retain fractal-like spatial structure, identifying these states as natural candidates for atypical eigenstates in otherwise thermalizing systems. For the triangle family, we combine parent-Hamiltonian methods, insights from ZX-calculus, and local ZX identities that certify exact annihilation of the target state, producing frustration-free Hamiltonians whose terms admit simple representations in the same diagrammatic language as the states themselves. We then construct a local deformation that produces chaotic level statistics while embedding the fractal ZX state in the bulk of the energy spectrum as an exact quantum many-body scar. Our results demonstrate, through this explicit construction, that ZX-calculus can serve as a framework for Hamiltonian inverse design, in which quantum many-body scars, their local annihilators, and the chaotic Hamiltonians embedding them can be constructed and related through a set of graphical identities.
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Mathematical Physics · Cross-listed from math.AP

The semiclassical limit from Hartree to Vlasov at positive density: strong uniform-in-time convergence and scattering

Marnie Smith

Strong semiclassical convergence from the Hartree equation to the Vlasov equation is established in three dimensions near Penrose-stable homogeneous steady states at positive density. For sufficiently regular integrable interaction kernels, an $O(\hbar^2)$ convergence rate in weighted Sobolev spaces is proved on finite time intervals. Combining this estimate with earlier uniform-in-$\hbar$ phase-mixing and scattering bounds for the Hartree equation yields global existence and scattering for the corresponding Vlasov solution through the semiclassical limit. If the quantum and classical initial perturbations are aligned, the semiclassical convergence is uniform for all times, and the Wigner transforms of the quantum scattering profiles converge to the classical scattering profile at the explicit rate $O((\ln\hbar^{-1})^{-1/3})$.
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Strongly Correlated Electrons

Exactness of Symmetry-Broken Self-Interaction Correction in the Strongly-Correlated or Classical Limit: Harmonium as a Demonstration

Cody Woods, Yunzhi Li, Wenqing Yao et al. (+2 more)

Strong electron correlation is an important challenge to both wavefunction and density functional theory. It has been argued that the Perdew-Zunger 1981 self-interaction correction to any density functional approximation, after symmetry breaking, can correctly describe the ground-state energy in the strongly-correlated limit in which each electron is described by a highly-localized and non-overlapped one-electron spin orbital. It has also been argued that the classical limit, in which Planck's constant tends to zero, is the strongly-correlated limit of quantum mechanics, where standard density functionals fail badly, as demonstrated by the exactly-solvable problem of harmonium (two Coulomb-interacting electrons bound by a spherically-symmetric harmonic-oscillator external potential). Here we combine these two ideas and demonstrate that, for harmonium, symmetry-broken self-interaction correction is exact in the limit where Planck's constant tends to zero, and usefully accurate for all values between 0 and the physical value (1 in atomic units). We also show that the Planck-constant-dependent symmetric ground-state density can be restored by spherical averaging of the broken-symmetry density.
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All authors Cody Woods, Yunzhi Li, Wenqing Yao, Chen Li, John Perdew

Strongly Correlated Electrons

Quasiparticle interference as a tool to study quantum materials

Luke C. Rhodes, Yuhki Kohsaka, Tetsuo Hanaguri et al. (+2 more)

To understand the properties of quantum materials a detailed knowledge of the material's low energy electronic structure is key. Details of the electronic structure drive the ground state through electronic instabilities, electronic correlation effects, new electronic orders or just the absence of electronic states near the Fermi energy - making a realistic and detailed understanding crucial to be able to control and design properties of quantum materials. The past 25 years have seen a significant improvement in experimental techniques to observe the true electronic structure, in particular in techniques such as Angle resolved photoemission spectroscopy (ARPES) where energy resolutions of 2meV are routinely achievable now, which however is limited to zero magnetic field and only provides information about the occupied states. Scanning tunneling microscopy (STM) achieves a significantly better energy resolution <100${\mu}$eV and can operate at temperatures well below 50mK and in magnetic fields. While per se a real-space technique, by imaging quasiparticle interference (QPI) STM can also provide information about the electronic structure. This technique has been used over the past decades to study a wide range of quantum materials to understand correlated electron behaviour. Recent theoretical progress now enables routine modelling of QPI, a key requirement to interpret the complex data. Here, we review the principles of QPI, its origin, experimental detection, and the physical insight gained from the study of QPI and possible future directions for this technique.
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All authors Luke C. Rhodes, Yuhki Kohsaka, Tetsuo Hanaguri, Carolina de Almeida Marques, Peter Wahl

High Energy Physics (Phenomenology)

Nambu-Goldstone emissions from the cosmological evolution of global monopoles

Yukihiro Kanda and Naoya Kitajima

We show the emission of the Nambu-Goldstone (NG) bosons from the cosmological evolution of global monopoles. The NG bosons are non-thermally produced from the dynamics of global monopoles such as the pair annihilation of monopole and anti-monopole. Our numerical lattice simulations demonstrate that the spectrum of NG bosons emitted from the scaling evolution of global monopoles has a peak around the horizon scale, as in the case with the global string and the semilocal string. We also estimate the abundance of the pseudo-Nambu-Goldstone (pNG) dark matter when one (or both) of the NG modes has a soft mass.
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Instrumentation and Detectors

Performance of a first multi-cell WOM-based liquid scintillator detector as prototype for the SHiP Surrounding Background Tagger

M. Böhles, A. Brignoli, P. Deucher et al. (+20 more)

The Search for Hidden Particles (SHiP) Experiment was approved by CERN in 2024. Feebly-interacting particles that are produced in a proton Beam Dump Facility (BDF) will decay in the 50m-long Decay Volume of the experiment, which needs to be enveloped by a hermetic veto detector: The Surrounding Background Tagger (SBT). Its technology relies on liquid scintillator, composed of linear alkylbenzene and 2,5-diphenyloxazole, as active detector material and Wavelength-shifting Optical Module (WOM) tubes collecting the primary scintillation photons. The liquid scintillator volume is segmented in large cells of typically 120cm x 80cm x 20cm that are equipped with two WOMs each. Here, we report on the performance of a full-scale 2x2-cell prototype detector which was exposed to 5GeV muons at the CERN PS T9 test beam facility to study the detector response and its time and spatial resolution for minimum ionising particles crossing multiple detector cells.
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All authors M. Böhles, A. Brignoli, P. Deucher, C. Eckardt, H. Fischer, A. Hollnagel, A. Krolla, H. Lacker, P. Luther, F. Lyons, J. Molins i Bertram, T. Molzberger, A. S. Müller, S. Ochoa Guaman, F. Rehbein, T. J. Rock, M. Schaaf, C. Scharf, M. Schumann, J. M. Webb, J. Wenk, I. Wöstheinrich, M. Wurm

Materials Science

Reversible photo-switching optical functionality in two-dimensional mixed-halide hybrid perovskites

Enamul Haque, Wenxin Mao and Javier Cerrillo

Ion migration in halide perovskites is often associated with defects, irreversible processes, and structural instability, making them largely impractical for photo-switching applications. Here, we demonstrate a physical mechanism for reversible, defect-free light-induced halide-ion swapping in two-dimensional mixed-halide perovskites. We find that the halide-ion swapping process arises from strong light-lattice coupling rather than defects. By combining nudged elastic band and photo-force calculations, we show that photo-induced forces perform non-equilibrium work that drives halide ions along the halide-exchange path without reaching the fully swapped configuration. Thus, the cumulative light-induced work can only partially overcome the ground-state activation energy barrier in the presence of light. Analysis of lattice dynamics identifies a few soft phonon modes, two of which are IR-active with oscillator strength $\approx -0.14$ e/(amu)$^{1/2}$, which may be considered the microscopic origin of light-induced halide-ion swapping. This microscopic origin is further supported by band-edge-selective electron-phonon coupling, which amplifies interactions among excited carriers under illumination and with halide-ion motion without inducing a uniform dynamical instability. Using GW (G-Green's function and W-screened Coulomb interaction) calculations, we accurately reproduce the experimentally observed optical absorption spectra in the absence of light, enabling us to describe the light-induced excited state reliably. We demonstrate a clear redshift in the optical spectra in the presence of light, which is due to light-induced bandgap renormalization. Overall, these findings not only establish an intrinsic, defect-free mechanism for photoswitchable optical functionality in 2D mixed-halide perovskites but also demonstrate an intrinsic self-resetting feature in the absence of light.
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Chaotic Dynamics · Cross-listed from cs.CE

On the alleged chaos in periodically forced traveling-wave reductions of fractional WBBM models: a quantitative re-examination

Kaixuan Niu

A large literature applies a standard pipeline to fractional nonlinear evolution equations – traveling-wave reduction to a planar Hamiltonian system, addition of periodic forcing, and visual inspection of phase portraits – to claim bifurcations, quasi-periodicity, and chaos, often without any quantitative diagnostic. This is particularly problematic because the reduced systems are undamped, near-integrable oscillators for which KAM theory confines chaos, if present at all, to thin stochastic layers, so the burden of proof for a chaos claim is high. We analyze these pitfalls and quantitatively re-examine a representative example, Ullah, Ali and Roshid's study of the second fractional Wazwaz-Benjamin-Bona-Mahony (WBBM) model [PLoS ONE 19(7): e0307565 (2024)], using analytical arguments and four independent diagnostics (Benettin largest Lyapunov exponents in two configurations, a separation-growth test over 3x10^6 time units, stroboscopic Poincare sections, spectral analysis). We find that (i) its linear stability analysis concludes "unstable propagation" from a dispersion relation that is real for every real wave number: all modes are neutrally stable, and the reported singularity is a pole, not a temporal instability; (ii) its unforced "quasi-periodic" system is necessarily periodic, being a planar autonomous Hamiltonian system; (iii) all four chaos assertions fail every diagnostic – exponents bounded by 5x10^{-7}, linear-in-time separation growth, smooth closed invariant Poincare curves – while the quasi-periodic assertion is confirmed; (iv) its equilibrium classification and phase portraits are correct. We also document a false positive of the Gottwald-Melbourne 0-1 test on a regular orbit and show that stroboscopic parameter sweeps of conservative systems yield "chaotic-looking" diagrams for purely regular tori, closing with a checklist of standards for chaos claims.
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Accelerator Physics

Generalized Theory of Blowout-Regime Plasma Wakefields via a Lagrangian Formulation

Y. Kang, P. Manwani, S. S. Baturin et al. (+3 more)

The blowout regime of plasma wakefield acceleration is a strongly nonlinear plasma response in which an intense relativistic beam or laser pulse expels plasma electrons forming a nearly uniform ion column. Existing self-consistent theories describe this structure primarily in the axisymmetric limit, reducing the bubble dynamics to a single radial degree of freedom. This restriction is inadequate for flat beams with highly asymmetric transverse emittances, as required in future linear colliders to control luminosity and beamstrahlung. Using a reduced Lagrangian formulation, we generalize the existing theory beyond axisymmetry and derive a coupled system of equations governing the wake potential driven by an asymmetric beam. This theory self-consistently predicts the focusing fields and their variation along the co-moving coordinate, as well as the accelerating field and its transverse nonuniformity. The resulting theoretical predictions are benchmarked against particle-in-cell simulations, demonstrating the theory's ability to describe and interpret wakefields driven by nonaxisymmetric sources.
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All authors Y. Kang, P. Manwani, S. S. Baturin, G. Andonian, B. Naranjo, J. B. Rosenzweig

Mathematical Physics

Essential self-adjointness of semi-bounded operators

M. Griesemer and V. Kußmaul

A semi-bounded operator that is bounded below by one is essentially self-adjoint if the kernel of the adjoint is trivial. This is the case if the kernel of the adjoint belongs to the form domain of the Friedrichs extension. We describe a local version of this criterion, where locality is defined in terms of bounded operators approaching the identity. The result is an abstract operator theoretic framework that generalizes the method by Wienholtz and Simader developed in the context of semi-bounded elliptic partial differential operators. As applications, we obtain competitive results on essential self-adjointness of many-particle Schrödinger operators, pseudo-relativistic Hamiltonians, and the standard model of non-relativistic quantum electrodynamics.
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Soft Condensed Matter

Effects of long-chain branching, short-chain branching, and polydispersity on pressure sensitive rheology of polymer melts

Lilian Lin, Matthew Joe and Heon E. Park

The rheological behavior of polymer melts under high pressure is a critical factor in many industrial processes like injection molding and extrusion, yet it is often inadequately characterized. At operating pressures that can exceed 100 MPa, viscosity can increase by orders of magnitude, making atmospheric-pressure data insufficient for accurate process simulation. This pressure induced viscosity increase is highly dependent on molecular architectures of the materials. This study aims to deconstruct the influence of specific structural features such as short-chain branching (SCB), long-chain branching (LCB), and polydispersity on the pressure sensitivity of the viscosity of polyethylene. Utilizing a high-pressure sliding plate rheometer (HPSPR) to ensure accurate measurements under uniform shear and pressure, we characterized four distinct polyethylene melts. All samples, regardless of their structure, exhibited piezorheologically simple behavior, allowing the application of time-pressure superposition over the entire shear rate range. A key finding is that the long-chain branched sample, known from the literature to be thermorheologically complex, was found to be piezorheologically simple. This dichotomy is explained by the different physical mechanisms of temperature and pressure. The pressure sensitivity of the viscosity, quantified by the pressure-viscosity coefficient, was found to be strongly dependent on molecular branching. Both SCB and LCB significantly increase the pressure sensitivity while polydispersity had a negligible effect. These results demonstrate that molecular branches are the dominant structural parameter controlling the rheological response of polyethylene to pressure, providing crucial insights for the development of more accurate predictive models for high-pressure polymer processing.
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Quantum Physics

Learning to Prepare Molecular Ground States with Transformer Models

Alex Koziell-Pipe, Jasmine Brewer, Jem Guhit et al. (+14 more)

Quantum state preparation is a key component of many quantum algorithms. Performing this step efficiently is essential for realizing practical quantum advantage in quantum chemistry applications. Iterative algorithms like ADAPT-VQE can produce shallow ground-state preparation circuits, but become computationally prohibitive for the larger molecules relevant to materials science and pharmaceutical development. Here, we introduce ADAPT-GQE, a generative AI framework that learns to synthesize ground-state preparation circuits for electronic structure calculations. We first use ADAPT-VQE to generate high-quality reference circuits, which are then used as targets for training models for circuit generation. Once trained, the model can efficiently propose and score circuits, enabling reinforcement learning (RL) to drive circuit generation accuracy beyond the accuracy of the ADAPT-VQE training data. This pipeline achieves order-of-magnitude reductions in circuit generation time relative to ADAPT-VQE while maintaining comparable or improved state-preparation accuracy. We demonstrate ADAPT-GQE on imipramine, a well-established tricyclic antidepressant that serves as a representative, challenging target for computational modelling in drug stability protocols. We execute generated circuits on Quantinuum Helios-1, representing a milestone for AI-generated quantum chemistry circuits on state-of-the-art quantum hardware. These results establish a pathway toward automated quantum circuit synthesis for utility-scale quantum computational chemistry.
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All authors Alex Koziell-Pipe, Jasmine Brewer, Jem Guhit, Marwa H. Farag, Kripa Panchagnula, Gabriel Laude, Fabian Finger, Carlo Gaggioli, Ludmila Szulakowska, Oliver J. Backhouse, Christos Papalitsas, Jason G. Mustakis, Thomas Soini, David Munoz Ramo, Stephen Clark, Elica Kyoseva, Enrico Rinaldi

Quantum Physics

Multiplexed storage and interaction of Rydberg spinwaves via the gradient echo memory protocol

Bartosz Niewelt, Stanisław Kurzyna, Bartosz Kasza et al. (+2 more)

Collective Rydberg excitations offer strong and controllable interactions for quantum information processing, sensing, and nonlinear quantum optics, but their integration with temporally or spectrally multiplexed schemes, such as the Gradient Echo Memory (GEM) protocol, is hindered by rapid motional dephasing caused by the large spinwave wavevector. We demonstrate a new type of multi-photon addressing and interfacing scheme (with levels following the shape of the letter Ń) that allows us to generate collective Rydberg excitations with near-zero momentum transfer, extending the Rydberg spinwave lifetime almost tenfold. The scheme relies on two additional off-resonant driving fields arranged at a magic angle, forming a closed wavevector loop while remaining compatible with GEM-induced inhomogeneous broadening. This enables storage and manipulation of long-lived Rydberg spinwaves in a multimode quantum memory. Using microwave coupling between neighboring Rydberg states, we can control the attenuation between stored excitation modes by interaction-induced decay and demonstrate interaction-controlled diffraction of a retrieved optical signal. Our results reestablish compatibility between Rydberg excitations and GEM, providing a route toward multimode quantum memories with controllable long-range interactions and applications in quantum networking, sensing, and quantum information processing.
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All authors Bartosz Niewelt, Stanisław Kurzyna, Bartosz Kasza, Wojciech Wasilewski, Michał Parniak

Mathematical Physics · Cross-listed from math.DS

Resonance in coupled nonlinear oscillators with decaying perturbations

Oskar A. Sultanov

The influence of nonautonomous perturbations on a system of two coupled nonlinear non-identical oscillators is studied. Both the coupling intensity and the perturbation strength are assumed to decay in time according to a power law. We focus on resonance effects associated with the commensurability of the natural frequencies of the oscillators at some energy levels. In particular, we describe the conditions on perturbations and coupling parameters under which phase-locked solutions appear with the oscillator energies remaining asymptotically close to resonant levels. By combining the averaging method with the construction of Lyapunov functions, we derive a nonautonomous model system governing the perturbed dynamics and analyse the stability of resonant solutions in the phase-locking regime. The theoretical results are illustrated for a system of non-identical Duffing oscillators with decaying coupling.
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Soft Condensed Matter

Pulsatile poromechanics in layered soft media controls fluid flow and solute transport: from fundamentals to brain clearance

Matilde Fiori and Sylvie Lorthois

Soft porous media often feature a heterogeneous structure. Notably, biological tissues - such as cartilage and the brain tissue - consist of two or more layers, with varying mechanical and fluid-flow properties. Despite the ubiquity of periodic loading in these systems, the physical implications of layering on nonlinear poromechanics and solute transport remain poorly understood. Uncovering these coupled mechanisms could clarify the fundamental physics behind pressing topics, such as brain metabolic clearance. Here, we address this gap using a bilayer model of a generic soft porous medium. To isolate the specific role of layering, we select combinations of material properties (porosity, permeability, and p-wave modulus) that maintain an identical poroelastic timescale, $T_{\mathrm{PE}}$, across four layered configurations and a reference homogeneous case. We demonstrate that while $T_\mathrm{PE}$ is the key parameter governing the response in a homogeneous medium, the same $T_\mathrm{PE}$ leads to non-trivial localization/propagation patterns for strain, fluid flow and solute transport in a bilayer medium. These non-intuitive results suggest that layered architectures may provide functional benefits for cellular homeostasis over homogeneous ones. Finally, we show that pathological alterations to the brain's layered structure significantly disrupt fluid-flow and metabolic waste clearance, offering a possible mechanical explanation for impaired transport in disease.
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Cosmology and Nongalactic Astrophysics

Probing dark energy evolution with Quaia quasars through the integrated Sachs-Wolfe effect

M. Ghodsi Yengejeh, J. R. Bermejo-Climent, A. Kovács et al. (+2 more)

The Integrated Sachs–Wolfe (ISW) effect probes the late-time evolution of gravitational potentials and provides a complementary test of the nature of dark energy. We investigate whether the redshift evolution of the ISW effect can provide new constraints on the time evolution of dark energy. We consider theoretical predictions for the standard $\Lambda$CDM cosmology and alternative $w_0w_a$CDM models favoured by recent DESI BAO and DES Y6 constraints. We perform a tomographic cross-correlation analysis of the Quaia quasar catalogue and Planck CMB temperature maps to measure the ISW signal over a broad redshift range, spanning about $(10h^{-1}~\mathrm{Gpc})^3$ comoving volume. We assess the robustness of the inferred ISW amplitude against variations in sky coverage, multipole range, and tomographic binning. We detect the ISW effect at a significance of $2.8 \, \sigma$, corresponding to an amplitude of $A_{\rm ISW}\simeq1.69\pm0.61$ relative to the Planck $\Lambda$CDM prediction. The inferred signal remains stable against various analysis choices, including various CMB maps (SMICA, NILC, SEVEM), different choices of $\ell_{\rm max}$ and the number of multipole bins, and an alternative quasar bias model. The measured ISW amplitude is moderately stronger than predicted by the fiducial $\Lambda$CDM cosmology, and the alternative $w_0w_a$CDM models do not account for this discrepancy. Future tomographic ISW measurements with improved quasar catalogues from Gaia and forthcoming wide-area galaxy surveys such as Euclid and DESI will help clarify the origin of this difference.
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All authors M. Ghodsi Yengejeh, J. R. Bermejo-Climent, A. Kovács, I. Szapudi, I. Csabai