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High Energy Physics (Theory) · Cross-listed from math.SG

Quantization of positive Lagrangians

Jake P. Solomon and Bentzion Yavetz

A Lagrangian submanifold in an almost Calabi-Yau manifold is called positive if the real part of the holomorphic volume form restricted to it is positive. It is called $\epsilon$-positive if the ratio of the restrictions of the imaginary and real parts of the holomorphic volume form is bounded by $\frac{1}{\epsilon}.$ An exact isotopy class of positive Lagrangian submanifolds admits a natural Riemannian metric. We prove that the Riemannian metric restricted to the subset of $\epsilon$-positive Lagrangians induces a path metric when the relative Kähler class of the ambient Calabi-Yau manifold lies on a line of rational slope. The proof relies on the construction of a sequence of quantization maps from a circle bundle over the space of positive Lagrangians to the dual of the space of holomorphic sections of powers of a prequantum line bundle. The rationality condition for the relative Kähler class allows us to reduce to the case of Bohr-Sommerfeld Lagrangians. Building on ideas of Tian and Nirenberg-Wells, Hörmander estimates are used to show that functions on a Bohr-Sommerfeld Lagrangian can be approximated by holomorphic sections of a sufficiently high power of the prequantum line bundle. Consequently, the quantization maps eventually separate fibers of the circle bundle.
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Atomic Physics

Fine-structure Raman interferometry with metastable barium for magnetically resilient inertial sensing

Masaki Nagamori, Hiromi Hatano, Toshiyuki Hosoya et al. (+3 more)

Atom-interferometric quantum inertial sensors are promising candidates for inertial navigation systems owing to their high sensitivity and intrinsically low drift. However, their application to next-generation inertial navigation, targeting a drift below 100 m/month, requires exceptionally stringent inertial-sensor bias stability. In conventional Raman atom interferometers based on ground-state hyperfine transitions, suppressing inertial-sensor biases arising from quadratic Zeeman shifts requires highly optimized magnetic shielding. In this work, we propose a Raman atom interferometer based on fine-structure transitions between metastable states of barium, which exhibit a quadratic Zeeman sensitivity approximately three orders of magnitude lower than that of conventional alkali-atom Raman transitions. We show that the proposed scheme increases the allowable spatial gradient of the magnetic-field magnitude by a factor of several tens, thereby relaxing the magnetic-field-control requirements from highly optimized shielding and compensation systems to standard magnetic-field-control techniques. Furthermore, we experimentally demonstrate Mach–Zehnder interference between metastable fine-structure states of barium, validating a key building block of the proposed inertial-sensing scheme.
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All authors Masaki Nagamori, Hiromi Hatano, Toshiyuki Hosoya, Yuki Miyazawa, Tomoya Sato, Mikio Kozuma

High Energy Physics (Phenomenology)

Correlation between gravitational wave frequencies as a signature of new black hole physics

Ngo Phuc Duc Loc

We point out that for black holes (BH) of the same mass, despite of arising from two entirely different physical arguments, the peak frequency of the coarse-grained gravitational wave (GW) spectrum of gravitons $f_\text{peak}^\text{graviton}$ is very close to the peak frequency of the GW spectrum produced from binary BH mergers $f_\text{peak}^\text{merger}$. In particular, we find that $f_\text{peak}^\text{graviton}/f_\text{peak}^\text{merger}\approx 2.3$ independent from BH mass or population. If BHs are still evaporating, the peak frequencies scale as $\propto M_i^{-1}$ with $M_i$ is the initial BH mass. If BHs evaporated in the radiation (matter) dominated era, the peak frequencies scale as $\propto M_i^{1/2}$ ($\propto M_i$) respectively after taking into account redshift effect. Any deviation from the aforementioned magical ratio would indicate new BH physics. The sweetest frequency ballpark to look for this correlation is around $10^{14}\ \rm Hz-10^{20}\ \rm Hz$ where both GW spectra are allowed to have maximum amplitude. As a demonstration of what the new physics could be, we consider a phenomenological self-similar regular BH model of Hayward featuring a single hair parameter. The observed ratio of peak frequencies can be used to directly infer the hair parameter, along with crucial properties of the novel BH solution such as Hawking temperature, horizon size, and innermost stable circular orbit. We also comment on the pros and cons of correlating frequencies among other GW sources such as formation, population fluctuation, and sudden transition of adiabatic perturbation.
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Mathematical Physics

Quantized six-vertex realizations of frustration graphs

Atsuo Kuniba and Souta Oikawa

A recent graph-theoretic criterion for a Hamiltonian to exhibit a free-parafermion spectrum is that its frustration graph be an indifference graph. We show that an arbitrary finite indifference graph can be realized as a frustration graph of the quantized six-vertex model at odd roots of unity, by a suitable choice of the defining wiring diagram and parameters. This provides a concrete realization of the criterion through the quantum Frobenius property of the quantized six-vertex model, recently established from its three-dimensional integrable structure.
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High Energy Physics (Phenomenology)

The dead-cone effect in charm, bottom and top quark jets in angular and momentum space

Redamy Perez-Ramos, Stefan Kluth and Wolfgang Ochs

The dead-cone effect reflects the mass dependence of QCD radiation from heavy quarks. We investigate this phenomenon from charm and bottom to top quarks using two-dimensional angular distributions and single-particle inclusive momentum spectra. The angular distributions illustrate the depletion of radiation around the heavy-quark direction, while the momentum spectra provide a quantitative observable of the effect. For charm and bottom jets, fragmentation functions reconstructed from LEP data at the $Z$ pole exhibit a strong suppression of high-momentum particles, quantitatively described within the Modified Leading Logarithmic Approximation of perturbative QCD. The analysis is extended to $\sqrt{s}=1$ TeV using Monte Carlo simulations. A hypothetical stable-top sample isolates the primary top-quark radiation pattern, whereas the physical decay $t\to bW$ introduces coherent radiation from the $tb$ colour dipole, obscuring the primary dead cone. By exploiting the dependence on the $b$-quark emission angle $\Theta_b$, we reconstruct the primary top-quark parton momentum spectrum through extrapolation to $\Theta_b\to0$. In contrast, the small-angle gluon and parton distributions do not converge to the stable-top dead-cone pattern because of radiation from the decay $b$ quark. These findings establish the inclusive momentum spectrum as a robust quantitative observable of the top-quark dead-cone effect and provide a unified description of mass-dependent QCD radiation from charm to top.
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High Energy Astrophysical Phenomena

Search for High-Energy Neutrinos from Infrared Flares

R. Abbasi, M. Ackermann, J. Adams et al. (+415 more)

IceCube has detected a diffuse flux of high-energy astrophysical neutrinos. While its astrophysical origin is unknown, a significant neutrino emission has been observed from the gamma-ray blazar TXS 0506+056 and the Seyfert galaxy NGC 1068. This suggests accretion by supermassive black holes as one of the candidate mechanisms of the diffuse neutrino flux. Indeed, external studies that made use of IceCube data identified candidate sources, including AT2019dsg, likely a stellar tidal disruption event (TDE), and AT2019fdr, associated with an active galactic nucleus (AGN). An additional study using an optically detected sample of 63 accretion flares revealed another candidate as a potential high-energy neutrino counterpart: AT2019aalc. All of these candidate transients exhibit strong dust echoes, characterized by delayed infrared (IR) emission relative to the initial optical outburst. We look for correlations between the most comprehensive catalog of infrared flares and 10 years of IceCube archival data. We perform a time-dependent stacking analysis testing 393 sources in the Northern Sky against 10 years of through-going tracks. No significant neutrino emission is observed, and we derive upper limits to constrain neutrino emission from this catalog. These limits are subsequently extrapolated to a population-level study. We find that the contribution of IR flares to the IceCube diffuse neutrino flux at 100 TeV is below 2.7% for a spectral index of 2.5.
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All authors R. Abbasi, M. Ackermann, J. Adams, J. A. Aguilar, M. Ahlers, J.M. Alameddine, S. Ali, N. M. Amin, K. Andeen, C. Argüelles, S. Athanasiadou, S. N. Axani, R. Babu, X. Bai, A. Balagopal V., S. W. Barwick, V. Basu, R. Bay, J. J. Beatty, J. Becker Tjus, J. Beise, C. Bellenghi, S. Benkel, S. BenZvi, D. Berley, E. Bernardini, D. Z. Besson, E. Blaufuss, L. Bloom, S. Blot, F. Bontempo, J. Y. Book Motzkin, C. Boscolo Meneguolo, S. Böser, O. Botner, J. Braun, B. Brinson, Z. Brisson-Tsavoussis, L. Brusa, R. T. Burley, D. Butterfield, K. Carloni, J. Carpio, N. Chau, Y. C. Chen, Z. Chen, D. Chirkin, S. Choi, A. Chubarov, B. A. Clark, D. A. Coloma Borja, A. Connolly, J. M. Conrad, D. F. Cowen, C. De Clercq, J. J. DeLaunay, D. Delgado, T. Delmeulle, S. Deng, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, J. C. Díaz-Vélez, S. DiKerby, T. Ding, M. Dittmer, A. Domi, L. Draper, L. Dueser, D. Durnford, K. Dutta, M. A. DuVernois, T. Ehrhardt, L. Eidenschink, A. Eimer, C. Eldridge, P. Eller, E. Ellinger, D. Elsässer, R. Engel, H. Erpenbeck, W. Esmail, S. Eulig, J. Evans, P. A. Evenson, K. L. Fan, K. Fang, K. Farrag, A. Fattorini, A. R. Fazely, A. Fedynitch, N. Feigl, C. Finley, D. Fox, A. Franckowiak, S. Fukami, P. Fürst, J. Gallagher, A. Garcia, M. Garcia, E. Genton, L. Gerhardt, A. Ghadimi, C. Glaser, T. Glüsenkamp, J. G. Gonzalez, S. Goswami, A. Granados, D. Grant, S. J. Gray, S. Griffin, S. Griswold, K. M. Groth, D. Guevel, C. Günther, P. Gutjahr, C. Ha, A. Hallgren, F. Halzen, M. Handt, K. Hanson, J. Hardin, A. A. Harnisch, P. Hatch, A. Haungs, J. Häußler, K. Helbing, J. Hellrung, B. Henke, L. Hennig, F. Henningsen, L. Heuermann, R. Hewett, N. Heyer, S. Hickford, A. Hidvegi, C. Hill, G. C. Hill, R. Hmaid, K. D. Hoffman, A. Hollnagel, D. Hooper, S. Hori, K. Hoshina, M. Hostert, W. Hou, M. Hrywniak, T. Huber, K. Hultqvist, K. Hymon, A. Ishihara, W. Iwakiri, M. Jacquart, S. Jain, O. Janik, M. Jansson, M. Jin, N. Kamp, D. Kang, W. Kang, A. Kappes, L. Kardum, T. Karg, A. Karle, A. Katil, M. Kauer, J. L. Kelley, B. Kern, M. Khanal, A. Khatee Zathul, A. Kheirandish, T. Kim, H. Kimku, F. Kirchner, J. Kiryluk, C. Klein, S. R. Klein, Y. Kobayashi, S. Koch, A. Kochocki, R. Koirala, H. Kolanoski, T. Kontrimas, L. Köpke, C. Kopper, D. J. Koskinen, P. Koundal, M. Kowalski, A. Kravka, N. Krieger, T. Krishnan, K. Kruiswijk, E. Krupczak, E. Kun, N. Kurahashi, C. Lagunas Gualda, L. Lallement Arnaud, M. J. Larson, F. Lauber, J. P. Lazar, K. Leonard DeHolton, A. Leszczyńska, C. Li, J. Liao, C. Lin, Q. R. Liu, Y. T. Liu, M. Liubarska, C. Love, L. Lu, F. Lucarelli, W. Luszczak, Y. Lyu, M. Macdonald, F. Machingal, E. Magnus, Y. Makino, E. Manao, S. Mancina, A. Mand, I. C. Mariş, S. Marka, Z. Marka, I. Martinez-Soler, R. Maruyama, J. Mauro, F. Mayhew, F. McNally, K. Meagher, A. Medina, M. Meier, Y. Merckx, L. Merten, J. M. Mitchell, S. Mondal, T. Montaruli, R. W. Moore, Y. Morii, A. Mosbrugger, D. Mousadi, E. Moyaux, T. Mukherjee, M. Nakos, U. Naumann, R. Neshat, L. Neste, M. Neumann, M. U. Nisa, K. Noda, A. Noell, A. Novikov, A. Obertacke, V. O'Dell, A. Olivas, R. Orsoe, J. Osborn, E. O'Sullivan, B. Owens, V. Palusova, H. Pandya, A. Parenti, C. Parisel, N. Park, V. Parrish, E. N. Paudel, L. Paul, C. Pérez de los Heros, T. Pernice, T. C. Petersen, J. Peterson, S. Pick, M. Plum, A. Pontén, V. Poojyam, B. Pries, R. Procter-Murphy, G. T. Przybylski, L. Pyras, C. Raab, J. Rack-Helleis, N. Rad, M. Ravn, K. Rawlins, Z. Rechav, A. Rehman, R. Reimann, I. Reistroffer, E. Resconi, C. D. Rho, W. Rhode, L. Ricca, B. Riedel, A. Rifaie, E. J. Roberts, S. Rodan, M. Rongen, A. Rosted, C. Rott, T. Ruhe, L. Ruohan, D. Ryckbosch, J. Saffer, D. Salazar-Gallegos, P. Sampathkumar, A. Sandrock, G. Sanger-Johnson, M. Santander, S. Sarkar, M. Scarnera, M. Schaufel, H. Schieler, S. Schindler, L. Schlickmann, B. Schlüter, F. Schlüter, N. Schmeisser, T. Schmidt, F. Schmitt, A. Scholz, F. G. Schröder, S. Schwirn, S. Sclafani, D. Seckel, L. Seen, M. Seikh, S. Seunarine, P. A. Sevle Myhr, R. Shah, S. Shah, A. Sharma, S. Shefali, N. Shimizu, M. Shin, R. Singh, B. Skrzypek, R. Snihur, J. Soedingrekso, D. Soldin, P. Soldin, G. Sommani, D. Song, C. Spannfellner, G. M. Spiczak, C. Spiering, J. Stachurska, M. Stamatikos, T. Stanev, T. Stezelberger, T. Stürwald, T. Stuttard, G. W. Sullivan, I. Taboada, S. Ter-Antonyan, A. Terliuk, A. Thakuri, P. Thelen, M. Thiesmeyer, W. G. Thompson, J. Thwaites, W. Tian, S. Tilav, K. Tollefson, J. A. Torres, S. Toscano, D. Tosi, K. Upshaw, A. Vaidyanathan, N. Valtonen-Mattila, J. Valverde, J. Vandenbroucke, T. Van Eeden, N. van Eijndhoven, L. Van Rootselaar, J. van Santen, J. Vara, F. Varsi, M. Velazquez, M. Venugopal, M. Vereecken, S. Vergara Carrasco, S. Verpoest, A. Vijai, J. Villarreal, C. Walck, A. Wang, E. H. S. Warrick, C. Weaver, P. Weigel, A. Weindl, J. Weldert, A. Y. Wen, C. Wendt, J. Werthebach, M. Weyrauch, N. Whitehorn, C. H. Wiebusch, D. R. Williams, L. Witthaus, J. Woodward, G. Wrede, X. W. Xu, J. P. Yanez, Y. Yao, E. Yildizci, S. Yoshida, F. Yu, S. Yu, T. Yuan, S. Yun-Cárcamo, A. Zander Jurowitzki, A. Zegarelli, S. Zhang, Z. Zhang, P. Zhelnin, P. Zilberman, C. Zilleruelo Cañas, M. Zimmermann

Quantum Physics

Exact analytical spectra of an effective field-modified radial Schrödinger equation by the Nikiforov–Uvarov method

Tunde Joseph Osunmusanmi and Berihu Teklu

We revisit the effective radial Schrödinger equation for a charged spinless particle in collinear static electric and magnetic fields that was formulated in our earlier work within the tridiagonal representation approach (TRA). In that model the angular factor of the electric coupling is replaced by the orientation parameter $C=\cos\theta$, the linear Zeeman term is diagonal in the azimuthal quantum number, and the effective field-modified central potential takes the form $V(r)=\Vt(r)+qECr$. Here we show that the same equation can be solved exactly without the TRA, by the Nikiforov–Uvarov (NU) method, once the potential component $\Vt(r)$ is prescribed. Three examples are worked out in closed form: a Kratzer-type component, which yields a linear-plus-Coulomb-plus-inverse-square central potential; a pseudoharmonic-type component, which yields a linear-plus-harmonic-plus-inverse-square potential; and a Hulthén-type component with a repulsive core (Manning–Rosen form), which yields a screened confining potential with a finite number of $s$-wave bound states. For each case we obtain the energy spectrum, the normalized eigenfunctions in terms of Laguerre or Jacobi polynomials, the location of the potential minimum, and closed-form radial moments. The spectra are independent of the orientation $\theta$ and of the electric field, in agreement with the structure found by the TRA, while the field enters through the shape of $V(r)$, the radial moments, and the expectation value $\langle V\rangle_k$. All analytical results are confirmed by an independent finite-difference diagonalization.
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General Relativity and Quantum Cosmology

All Quiet on the Vector Front: Scalar Growth and Perturbative Control in Horndeski–Weyl-squared Gravity

Antonio De Felice, Guillem Domènech and Jan Tränkle

Higher-order curvature corrections to general relativity arise naturally in many fundamental theories and provide phenomenologically interesting low-energy effective field theories. However, higher-derivative terms can introduce ghost modes, which call the validity of such models into question. Here, we thoroughly investigate the classical linear stability of the most general second-order scalar-tensor theory, namely the Horndeski theory of gravity, augmented by a Weyl-squared term in the action. We consider shift-symmetric de Sitter and power-law FLRW backgrounds and study the evolution of linear perturbations. Vector perturbations are free of gradient and tachyonic instabilities for a positive Weyl-induced mass squared. Tensor perturbations necessarily contain a ghost; their superhorizon branches are bounded, while a frozen-background calculation identifies a separate finite-momentum stability condition. The scalar sector instead contains a growing long-wavelength branch for all expanding backgrounds we consider, which is inherited by at least one of the gauge-invariant Bardeen potentials. We show that this growth enters the Bardeen potentials through an inverse-gradient factor $a^2/k^2$: the dynamical scalar fields remain bounded on the inflationary backgrounds, the direct contribution of the growing shear to the clock-matched tidal field cancels, and the electric part of the Weyl tensor decays. We discuss the implications of our results for perturbative control and for the phenomenological viability of theories including quadratic curvature corrections.
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Materials Science

Access Rate-Dependent Endurance Behavior of Ferroelectric Hafnium Zirconium Oxide Capacitors

Roberto Guido, Julie Laguerre, Pramoda Vishnumurthy et al. (+6 more)

Fluorite-structured ferroelectrics, such as hafnium zirconium oxide ($Hf_{1-x}Zr_{x}O_{2}$), are among the most promising materials for developing the next generation of low-power nonvolatile memories. Emulating realistic operating scenarios for ferroelectric memories requires performing access rate-dependent endurance tests. The access rate-dependent reduction of the switched polarization cannot be described as a mere superposition of fatigue and imprint effects, which are observed in conventional endurance and retention tests, respectively. The interplay between these degradation mechanisms and its correlation with the delay time in between the programming pulses remains unclear. Combining electrical testing through voltage pulses with ab initio and drift-diffusion simulations provides a comprehensive perspective on the microscopic origin of the access rate-dependent reduction of the switched polarization of ferroelectric capacitors based on product-relevant 5 nm thick $Hf_{0.5}Zr_{0.5}O_{2}$ films. The role of oxygen vacancy defects accumulating at the electrode-ferroelectric interface with delay time in reducing the fraction of switchable domains is elucidated considering electron transfer processes which change the defect charge state. Building upon this theoretical understanding, a physics-based model to extrapolate the long-term access rate-dependent endurance performance is developed and experimentally verified for temperatures up to 135{\deg}C and delay times up to 2 ms.
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All authors Roberto Guido, Julie Laguerre, Pramoda Vishnumurthy, Florian Wunderwald, Kristina Holsgrove, Thomas Mikolajick, Sou-Chi Chang, Alfred Kersch, Uwe Schroeder

Quantum Physics

Pinning of a High-Energy Wavepacket by a Single Impurity

Fartash Chalangari, Anant Vijay Varma, Joonas Keski-Rahkonen et al. (+1 more)

We demonstrate that a single repulsive impurity enhances directional confinement of a high-energy wavepacket in a finite two-dimensional lattice of quantum wells. At energies far above the interwell barriers, the impurity suppresses transverse dynamical tunneling while preserving propagation along a principal lattice axis, even as the corresponding classical regular region shrinks. Confinement is strongest at impurity amplitudes comparable to the barrier height and weakens for stronger perturbations. Spectral analysis links this nonmonotonic pinning to the wavepacket's overlap with eigenstates concentrated along the launch direction, consistent with impurity-induced variational scarring. These results show that a single local defect can control quantum propagation over distances far exceeding its own spatial extent.
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All authors Fartash Chalangari, Anant Vijay Varma, Joonas Keski-Rahkonen, Esa Räsänen

General Relativity and Quantum Cosmology

Directional effects of the Unruh effect on steering harvesting

Shu-Min Wu, Rui-Yang Xu and Zhihong Liu

We investigate directional quantum steering harvesting by two uniformly accelerated non-identical Unruh-DeWitt detectors coupled to a massless scalar field in the Minkowski vacuum. We show that the Unruh effect does not simply degrade harvested steering, but can reshape its directionality in a strongly parameter-dependent manner. At low detector energy scales, acceleration predominantly suppresses steering, whereas at higher energy scales, moderate acceleration can enhance steering and even activate an initially absent steering direction. Most strikingly, within a finite acceleration window, the Unruh effect enhances steering in one direction while simultaneously suppressing it in the opposite direction, revealing an intrinsically directional influence of relativistic acceleration. Detector non-identicality provides an additional control mechanism: a moderate energy-gap mismatch can enhance or activate one steering direction while suppressing the reverse one, whereas sufficiently large energy-gap mismatch suppresses the harvested steering. Moreover, the maximal steering asymmetry approximately marks the transition from two-way to one-way steering. Our results establish relativistic acceleration and detector non-identicality as means of controlling the strength and directionality of vacuum-harvested quantum correlations.
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Quantum Physics

Loss-Tolerant Measurement-Device-Independent QKD over Untrusted Repeaters via High-Dimensional Time-Bin Multiplexing

Yu-Chun Yin, Ching-Yi Lai and Alexei Ashikhmin

We propose a loss-tolerant measurement-device-independent quantum key distribution (MDI-QKD) protocol using time-bin-multiplexed single photons entangled with local qubits stored in nitrogen-vacancy (NV) centers. In each round, Alice and Bob each send a single multiplexed photon to an untrusted intermediary, Charlie. Each photon first becomes entangled with Charlie's NV-center qubits; Charlie then performs entanglement swapping between his NV qubits to establish EPR pairs between Alice's and Bob's local qubits. With $d$ time bins per photon, $\log_2 d + 1$ EPR pairs can be generated per transmitted photon, substantially increasing the probability of EPR-pair creation under limited channel bandwidth. To further mitigate the effects of prolonged memory storage, the protocol employs a memory-insensitive (MI) architecture, where multiple banks of qubits and multiplexed photon routing reduce the effective memory lifetime requirements. This approach enhances loss tolerance, enabling higher secret key rates and secure key distribution over longer distances compared to conventional single-photon protocols. Using the Lo-Chau EPR-QKD framework and Shor-Preskill reduction, we prove that the protocol is secure without trusting intermediate nodes, making it suitable for quantum networks with untrusted repeaters.
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Chaotic Dynamics

Online training of Echo State Networks to predict chaotic dynamical systems

Astero Provata, Markos Syroukis and Johanne Hizanidis

Echo State Networks (ESNs) are fundamentally important from the conceptual perspective of AI, because they provide simple and tractable frameworks for understanding temporal information processing, memory, and learning in dynamical systems. They are composed by an interconnected reservoir whose connectivity matrix remains constant over time and only the output weights are updated during the training period. In particular, ESNs employing online training allow the incremental adaptation of the output weights as data is received, making them particularly suitable for applications in which new input data becomes available over time (non-stationary environments). A key objective in the study of such learning structures is to determine which statistical properties of the reservoir enhance computational efficiency and maximize prediction performance. To this end, we investigate the effects of reservoir topology on learning performance, considering weight matrices generated from Erdos-Renyi random networks and Watts & Strogatz small-world networks. As test data we use the Lorenz and Rossler models in the chaotic regime and the FitzHugh-Nagumo model in the limit cycle regime. In the case of random Erdos-Renyi reservoirs, our simulations show that best performances are obtained for sparse reservoirs and especially when the link-density is near and immediately above the critical point of mean-field bond percolation. Watts & Strogatz reservoirs are shown to demonstrate best performance also for small values of link-density, compatible with the mean-field bond percolation when taking into account the specific nonlocal ring structure of the Watts & Strogatz reservoirs. These studies on the influence of the reservoir architecture and hyperparameters on enhancing the accuracy of ESN predictions provide an efficient framework for real-time forecasting in dynamically evolving systems.
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Mathematical Physics · Cross-listed from math.RT

Gaudin from Cherednik

Matthew McMillan

Let $W$ be a complex reflection group and $X$ the De Concini-Procesi wonderful model of its reflection arrangement. Inside Etingof's sheaf of Cherednik algebras on $X$ we define a subsheaf generated by the Dunkl operators that extend the standard ones on the hyperplane complement. We conjecture that at $t=0$ the image of the logarithmic vector fields in a natural module over this subsheaf is the sheaf of Gaudin algebras on $X$ defined by Aguirre, extending a construction of Bonnafé and Rouquier from the hyperplane complement to $X$. We prove the conjecture for $W=S_{3}$.
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Instrumentation and Methods for Astrophysics

R&D activity in INAF on light instrumentation for continuous optical turbulence monitoring

Camilo Weinberger Elena Masciadri, Luca Carbonaro, Marlene de Sepibus et al. (+4 more)

Measurements of optical turbulence are essential in both ground-based astronomy and free-space optical communication systems contexts for multiple reasons including supporting and optimizing Adaptive Optics. Similarly, forecasting these parameters is highly valuable for planning observational campaigns; however, it requires at least two years of continuous data to generate a reliable training dataset. The most commonly used instruments to monitor continuously the optical turbulence include DIMM, MASS, SLODAR, RINGSS sensors. The Arcetri team is leading two operational forecast systems for two different Observatories: ALTA above LBT, and FATE above VLT. Both systems are in continuous evolution and obviously forecast performances depend also on available measurements. Our long-term goal is to develop our own instruments to obtain continuous measurements directly from local observations. In this work, we present an automated system designed for continuous seeing measurements using multiple sensors. This portable station integrates a Cyclope, a RINGSS unit, a scintillometer which operate together to provide comprehensive night-time atmospheric information. We will compare the performance of low-cost sensors, such as the Cyclope and the scintillometer, with that of the RINGSS turbulence profiler, which has been fully installed and programmed by our team in collaboration of LBT team. A dedicated insturment for night and day-time measurements is planned for near future. This system incorporates a fully automatic on-site system that monitors operational status, delivers real-time information on sensor conditions and measurements, and manages synchronization with the data storage unit. The system's real-time acquisition capability enables continuous turbulence analysis, supports R&D activities, facilitates local data generation, and allows on-site testing of forecasting methodologies.
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All authors Camilo Weinberger Elena Masciadri, Luca Carbonaro, Marlene de Sepibus, Fernando Pedichini, Ciro Del Vecchio, Christian Veillet, Sam Ragland

Fluid Dynamics · Cross-listed from math.NA

eMOOD: Entropy-Based Multidimensional Optimal Order Detection for High-Order Shock-Capturing Finite-Volume Schemes

Michał Umiński, Panagiotis Tsoutsanis, Ahmed A Sheikh Al-Shabab et al. (+1 more)

We present eMOOD, an entropy-guided evolution of the Multidimensional Optimal Order Detection (MOOD) framework for high-order finite-volume methods on unstructured meshes. A novel troubled-cell indicator based on numerical entropy production replaces the classical relaxed discrete maximum principle. Using entropy generation as a physically motivated measure of non-smoothness, the detector targets shocks, contact discontinuities and under-resolved flow features with a compact stencil. Compared with conventional MOOD detection, eMOOD reduces flagged cells by up to 75%, improving efficiency and reducing memory-access overhead. The detector is used within both the classical MOOD cascade of progressively reduced-order schemes and a novel MOOD-CWENO hybrid, which retains inexpensive linear reconstruction in smooth regions and activates nonlinear high-order reconstruction only where needed. Implemented in the open-source parallel solver UCNS3D, the methodology is assessed on the Shu-Osher shock-entropy-wave interaction, double Mach reflection, supersonic forward-facing step, shock-helium-bubble interaction and triple material point problems. These benchmarks encompass strong shock interactions, shock-induced instabilities, multi-material interfaces and vortex-dominated flows, testing robustness, shock capturing and accuracy on unstructured meshes. Results show that eMOOD preserves the accuracy and robustness of reference CWENO and MOOD formulations while achieving speed-ups of up to 20% without loss of solution quality. Its compact detection stencil, reduced memory footprint and improved localisation offer a more scalable and efficient framework for massively parallel high-order compressible-flow simulations. UK Ministry of Defence (copyright) Crown owned copyright 2026 AWE.
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All authors Michał Umiński, Panagiotis Tsoutsanis, Ahmed A Sheikh Al-Shabab, Alan S. Dawes

Instrumentation and Detectors

A low-cost compact muon detector for millikelvin operation

Tengiz Ibrayev, Danish Khan, Alex Herscovics et al. (+5 more)

Ionizing radiation produces correlated errors in superconducting qubits, posing some challenges to quantum error correction. In addition, it causes background events in other superconducting cryogenic devices, such as kinetic inductance detectors and superconducting nanowire single-photon detectors. Cosmic muons are a component of this background that can only be partly shielded against at ground level, but can be tagged by an independent detector inside the cryostat, so that the affected data can be vetoed, or the muon tags incorporated into error correction. We present a low-cost, compact muon detector consisting of two plastic scintillator modules, each read out by a silicon photomultiplier (SiPM), operated in coincidence. We characterize the SiPMs from room temperature down to 10 mK, including the breakdown and upper-limit voltages that define the operating bias range. Operated as a muon counter, the detector measures a coincidence rate that, as expected, is independent of temperature within uncertainties and agrees with analytical and Monte Carlo predictions. Below approximately 8 K, each muon event produces two pulses, one narrow and one broad, an effect that, to our knowledge, has not been reported before. Coincidences with an independent muon detector outside the cryostat confirm that muons are still counted reliably in this regime. By studying the appearance of double pulses as a function of temperature and magnetic field up to 4.5 T, we find a behavior consistent with the phase diagram of a type-II superconductor. This links the double pulses to a superconducting material in the SiPM, likely an adhesion layer or diffusion barrier introduced during manufacturing. The mechanism by which the superconducting state produces the second pulse is not yet understood.
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All authors Tengiz Ibrayev, Danish Khan, Alex Herscovics, Komal Kataruka, Matilda Lawton, Sandhya Sharma, Steven Waddy, Laura Manenti

Optics

Near-field contributions to cavity-mediated radiative heat transfer

Antonio Mastropasqua, Martin Eckstein, Daniele Fausti et al. (+1 more)

Embedding materials in optical cavities has emerged as a powerful strategy for controlling their physical properties. In this context, increasing attention has been devoted to the thermal Purcell effect, which describes how the radiative heat transfer between a material and its photonic environ- ment can be modified by the electromagnetic boundary conditions imposed by the cavity. Here, we investigate near-field effects in cavity-mediated radiative heat transfer in planar cavities composed of realistic, dissipative gold mirrors, extending previous work that considered ideal mirrors. We iden- tify the conditions under which near-field effects lead to a substantial enhancement of heat transfer between the material and a photonic thermal bath relative to free space, owing to the strong modi- fication of the photonic local density of states by evanescent modes within the cavity. In particular, we find that radiative heat flow can be enhanced by several orders of magnitude in cavities ranging from nanometer to micrometer scales, depending on the absorber frequency and dipole orientation. These findings suggest that near-field effects may be relevant to polariton chemistry experiments and other systems operating within this cavity length-scale regime. Our results add to the idea that cavities can modify material properties not only by engineering vacuum fluctuations in the strong light-matter coupling regime, but also by controlling radiative dissipation and heat transfer.
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All authors Antonio Mastropasqua, Martin Eckstein, Daniele Fausti, Francesca Fassioli

Strongly Correlated Electrons

Disorder-Induced Griffiths like Phase and Charge Localization in Sr2FeRuO6

Koustav Pal, Shuvendu Ghosh and I. Das

A comprehensive understanding of complex transition-metal oxides is key to designing next-generation spintronic materials with tailored magnetic and transport functionalities. We investigate the interplay among structural disorder, frustrated magnetism, and localized charge transport in the 3d-4d hybrid double perovskite Sr2FeRuO6. The compound adopts a monoclinic structure with significant B-site antisite disorder that drives its unconventional behavior. Magnetic measurements uncover a robust Griffiths phase extending well above the ordering temperature, evidencing stable short-range ferromagnetic clusters within a disordered matrix. Electrical transport remains strongly localized, transitioning from small-polaron hopping at high temperatures to variable-range hopping at intermediate temperatures. These results position Sr2FeRuO6 as a representative 3d-4d hybrid system in which quenched disorder stabilizes spin inhomogeneity, while polaronic and hopping transport are also observed.
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Materials Science

Identification of carbon-related color centers in hBN by high-resolution ab initio photoluminescence modeling

Vytautas Žalandauskas, Marek Maciaszek, Marianne Etzelmüller Bathen et al. (+3 more)

Identification of optically active defects in hexagonal boron nitride (hBN) remains challenging because different defect candidates can produce similar calculated photoluminescence (PL) lineshapes. Here, we demonstrate that force-constant embedding methodology can be extended to calculate high-resolution, vibrationally resolved PL lineshapes in the polar layered material hBN. Benchmarking against the carbon dimer defect, responsible for the 4.1 eV emission, we show that the methodology accurately reproduces the low-energy acoustic phonons and fine spectral features that are inaccessible when using direct supercell calculations. Applying the methodology to neutral carbon trimers ($\mathrm{C_2 C_B}$ and $\mathrm{C_2 C_N}$), we find that the calculated PL lineshape and excitation energy of $\mathrm{C_2 C_N}$ closely match the low-temperature spectrum of the emitter with a zero-phonon line at 1.54 eV. These results establish high-resolution phonon-sideband modeling as a powerful tool for discriminating among candidate defects in polar materials.
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All authors Vytautas Žalandauskas, Marek Maciaszek, Marianne Etzelmüller Bathen, Julius Janušonis, Tadas Paulauskas, Lukas Razinkovas

Mathematical Physics

The WKB Riemann-Hilbert Problem for the Painlevé I System

Mohamad Alameddine, Olivier Marchal, Nikita Nikolaev et al. (+1 more)

In this paper, we solve the direct monodromy problem for the Borel-summed $0$-parameter solution of Painlevé~I. Using the auxiliary time equation, we first construct formal WKB wave matrices whose amplitudes are regular at the double turning point. Rigorous Borel summation then yields exact WKB matrices in each Stokes region. Uniform estimates on moving action strips provide a common exact wave matrix in a full neighbourhood of the double point, proving that all four incident jumps are identities for consistent column normalisations. We formulate the resulting normalised Riemann–Hilbert problem and prove its existence and uniqueness on the Borel domains of the construction. Finally, after Painlevé scaling, the five Borel-summed solutions coincide with the five rotated tritronquée solutions of Painlevé~I.
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All authors Mohamad Alameddine, Olivier Marchal, Nikita Nikolaev, Nicolas Orantin

Astrophysics of Galaxies

Uncovering the origin of complex velocity distributions in edge-on disc galaxies

Sophie Townson, Marie Martig, Robert J. J. Grand et al. (+3 more)

Stellar line-of-sight velocity distributions are a powerful tool for studying galaxy kinematics and formation history, with multiple-peaked LOSVDs often indicating the presence of complex kinematic components. We extract stellar LOSVDs across the disc of a simulated spiral galaxy viewed edge-on, and study how often and why we see multiple-peaked LOSVDs. We find that the multiple-peaked LOSVDs are mainly found close to the midplane because they result from the presence of spiral arms. This is not because the spiral arms have significantly different kinematics to the disc, but because they correspond to over-densities. Variations in the number of arms present along a line-of-sight create variations in the number of peaks in LOSVDs. This can be used to quantify the strength of the spiral arms above the midplane, and how the thickness of spiral arms vary across the disc. We find that the commonly used fourth order Gauss-Hermite moment, $h_4$, is negative in the regions where there are multiple-peaked LOSVDs, and hence traces spiral arms. Finally, we discuss the observability of the multiple-peaked regions and their associated $h_4$ measurements with current integral field spectrographs. We find that the spectral resolution of MUSE might not be high enough to uncover multiple peaks in LOSVDs when they result from spiral arms, but should allow for identification of the regions of negative $h_4$. On the other hand, higher resolution spectrographs like KOALA and WEAVE may be able to recover multiple peaks in LOSVDs, representing a promising avenue for characterising spiral arms in edge-on disc galaxies.
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All authors Sophie Townson, Marie Martig, Robert J. J. Grand, Prashin Jethwa, Jesús Falcón-Barroso, Timothy A. Davis

Optics

Polaritonic self-hybridized critical coupling by Brillouin zone folding induced quasi-bound states in the continuum in bulk WS2 metasurfaces

Kuidong Wang, Xiongwei Guo, Fu Liu et al. (+2 more)

Maximizing the absorption of exciton-polaritons in transition-metal dichalcogenides (TMDCs) under critical coupling conditions is crucial for developing high-efficiency polariton-based photodetectors, solar cells, and perfect absorbers. Here, we propose a polaritonic critical self-hybridized coupling between Brillouin zone folding driven quasi-bound states in the continuum (BZF-QBIC) mode and A excitons in a bulk WS2 metasurface. This polaritonic critical coupling shows robust behavior with respect to the asymmetric parameters of the involved BZF-QBIC mode, in contrast to the asymmetry-sensitive conventional QBIC-based critical coupling. By changing the height of WS2 metasurfaces, we observe a typical anti-crossing behavior with a Rabi splitting of 246.5 meV. Moreover, the maximum absorption value of 0.5 for exciton-polaritons is achieved at the polaritonic critical coupling condition. The large population of excitons provided by bulk WS2 is essential for achieving polaritonic critical coupling and can further enhance polaritonic absorption. This work enables the realization of robust, high-absorption self-hybridized polaritonic critical coupling in TMDCs, and further expedite their applications in high-absorption low-dimensional polaritonic devices.
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All authors Kuidong Wang, Xiongwei Guo, Fu Liu, Jinhai Si, Xun Hou

Quantum Gases

Unconventional quantum spin mixing of two spin-1 atoms beyond the single-mode approximation

Yanhong Liu, Fulin Deng, Haoxue Qiao et al. (+1 more)

The single-mode approximation (SMA) has been widely employed in ultracold spinor gases, where all spin components share the same spatial mode. By adopting generalized Van Vleck (GVV) perturbation theory, we achieve a relative error of $10^{-6}$ in the ground-state energy with a reduced effective Hilbert space dimension of $\sim 10^3$ for two spin-1 bosons confined in a one-dimensional hard-wall trap. With the accurate GVV method, we explore the validity of the SMA across ground-state properties and quench spin dynamics for two $^{7}\text{Li}$, $^{87}\text{Rb}$, or $^{23}\text{Na}$ atoms. Numerical results show that the quadratic Zeeman energy $q$ provides a powerful control knob: by increasing $|q|$, the fidelity between the spin components in the ground state gradually decreases, leading eventually to the breakdown of the SMA (due to the competition between the kinetic energy and the quadratic Zeeman energy). Quench spin dynamics with abruptly increased $q$ further reveals multiple resonances, where the SMA-predicted micromotion and beyond-SMA macromotion appear simultaneously. These results point to a direction to investigate the quantum spin-mixing dynamics beyond the SMA, particularly in recent experiments of strongly interacting spin-1 atomic gases.
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All authors Yanhong Liu, Fulin Deng, Haoxue Qiao, Wenxian Zhang

Physics and Society · Cross-listed from cs.SI

Uncovering higher-order interactions from memory in observed dynamics

Arthur Rondeau, Alain Barrat and Roland Bouffanais

Many complex systems involve group interactions, which can readily be represented by higher-order structures such as hypergraphs. However, when observing a system's dynamical evolution, establishing whether that evolution actually results from higher-order interactions, or whether pairwise interactions suffice to explain the data, remains a challenge. Even in the simple case of a temporal sequence of nodes visited during a diffusion process, such a task is intricate. Indeed, group interactions leave their traces as memory on the observed nodes, while path dependence in a purely pairwise process can mimic that same footprint without any group structure. To resolve this, we propose an inference pipeline based on a hidden Markov model (HMM) that tests, directly from an observed sequence of nodes carrying no group labels, whether higher-order interactions are required to describe the dynamics. The HMM latent states represent higher-order interactions, seen as hyperedges of an unobserved hypergraph, so that their detection becomes a model selection problem between the HMM class and a class of null models without higher-order interactions. We first validate this approach on synthetic node sequences generated from random walks on graphs and hypergraphs, showing that it recovers both the number and the composition of the underlying hyperedges, while correctly rejecting them when the generating process is pairwise. As a second step, we consider a validation based on empirical data, namely empirical trajectories of ball possession in football matches. This application shows that the pipeline goes beyond providing statistical evidence of the presence of higher-order interactions, and yields interpretable underlying structures: the recovered hyperedges map directly onto recognizable tactical team formations.
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Chaotic Dynamics

Partial Multistep Prediction of Chaotic Time Series: What Remains Predictable beyond the Horizon of Predictability?

Vasilii A. Gromov, Maksim Lomakin, Aleksei Kudryashov et al. (+1 more)

Sensitive dependence on initial conditions limits long-horizon prediction of chaotic systems even for deterministic dynamics, yet some dynamical information may remain recoverable after precise state information is lost. Recursive multistep methods are fragile because they reuse each intermediate prediction as input, allowing local errors to propagate through the rollout. We investigate whether partial multistep prediction can recover predictive information beyond the predictability horizon by omitting intermediate positions instead of assigning them unreliable values. The method uses a lightweight pattern-based local predictor. We analyze partial trajectories generated by different omission patterns and quantify the trade-off between accuracy on retained positions and the fraction classified as non-predictable. Experiments on the Lorenz system show that admissible masks contain trajectories that remain accurate far beyond the horizon of predictability, and an agreement-based ensemble recovers part of this information without future observations at the cost of a growing rejected fraction. At short horizons a broad accepted subset retains accuracy at moderate rejection, whereas at long horizons positive geometric skill requires increasingly strong selection. In this regime retained predictions no longer localize the state within a Lorenz scroll but still identify the occupied scroll, so topological structure outlasts geometric accuracy. A noise-based control reproduces this survival only after tuning of its perturbation scale, unlike masking. Across a heterogeneous collection of chaotic systems the ensemble strictly extends the positive-$R^2$ horizon of the recursive baseline for every retained system.
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All authors Vasilii A. Gromov, Maksim Lomakin, Aleksei Kudryashov, Korney K. Tomashchuk

Instrumentation and Detectors

Exploring the proximity effect of thin tungsten-aluminum films for phonon-mediated kinetic inductance detectors

G. Del Castello, M. Mancuso, A. Langenkämper et al. (+18 more)

Lowering the energy threshold of phonon-mediated kinetic inductance detectors is a key step toward next-generation cryogenic calorimeter arrays with large target mass and high sensitivity. In this work, we demonstrate the feasibility of integrating thin tungsten films, so far used for transition-edge sensors, into the fabrication of Kinetic Inductance Detectors (KIDs). Here we present the results from the characterization of a single KID prototype composed of a tungsten-aluminum bilayer of respectively 15 nm and 35 nm thicknesses. The detector was successfully calibrated, and the superconducting film characteristics were measured by operating the device at different temperatures. We show that, by exploiting the proximity effect of superconductors, the device combines the relatively high critical temperature of aluminum with the large kinetic inductance contribution of tungsten. The main feature is a high kinetic inductance, which accounts for 36% of the total inductance, combined with a superconducting critical temperature of around 630 mK.
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All authors G. Del Castello, M. Mancuso, A. Langenkämper, A. Bento, C. Bonomo, M. Cappelli, F. Casadei, E. Cipelli, A. Cruciani, D. Delicato, F. Dominsky, M. Folcarelli, D. Hauff, B. Mauri, C. Moore, L. Pesce, F. Petricca, F. Pröbst, D. Quaranta, M. Vignati, M. Zanirato

Quantum Physics

Strong subadditivity of topological entropy on the torus: Rényi order and non-Abelian structure

Yi Liang

We classify strong subadditivity for the canonical topological Rényi functional at finite positive orders on an unpunctured torus in the topological quantum field theory of any finite unitary modular tensor category. Universal validity means validity for all pure ground states and all regular region pairs with transverse or disjoint boundaries and compatible corner rounding. At von Neumann order one, the inequality holds universally. For each fixed order strictly between zero and one, universal validity is equivalent to pointedness, meaning that every simple anyon type has quantum dimension one. For every nonpointed category and each finite positive order other than one, we construct a violating pure state and an allowed pair. For a fixed pointed category and fixed order above one, universal validity is equivalent to a same-order modular Fourier entropy bound for every pure state. Global homological constraints on actual unions and intersections and established weighted modular uncertainty prove the order-one theorem. For parallel annuli at fixed flux distribution, the order-one functional is affine in their positive count. At other orders, unequal quantum dimensions on the occupied support induce strict curvature that suitable overlapping regions convert into negative deficits. Under the boundary-charge cutting prescription, the von Neumann theorem extends to arbitrary logical density matrices in the same ground space.
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Nuclear Theory

Constraining three-nucleon forces in nuclear lattice effective field theory

Serdar Elhatisari, Ulf-G. Meißner, Zhengxue Ren et al. (+1 more)

We study short-range three-nucleon forces (3NFs) in nuclear lattice effective field theory with a chiral two-nucleon interaction at N${}^3$LO. The one-pion-exchange ($c_D$) and contact ($c_E$) terms of the leading 3NF are decomposed into locally and non-locally smeared components and supplemented by partial-wave-resolved pair contacts coupled to the density of a third nucleon. We determine their coefficients from nuclear binding energies for nuclei in the mass range from $A=3$ to $A=40$ and neutron–alpha finite-volume energies. This allows to work out the minimal three-nucleon force that can be used for future precision studies in NLEFT.
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All authors Serdar Elhatisari, Ulf-G. Meißner, Zhengxue Ren, Shuang Zhang

High Energy Astrophysical Phenomena

Optical constraints on intranight variability in TeV HBLs from a two-year Asiago Schmidt monitoring campaign

Domenico Impiombato, Giacomo Bonnoli, Elisa Prandini et al. (+2 more)

We present a two-year homogeneous optical monitoring campaign of three TeV-emitting high-synchrotron-peaked BL Lac objects, 1ES 1959+650, H 1426+428, and PG 1553+113, carried out with the Asiago Schmidt 67/92 cm telescope. TeV blazars are key targets in high-energy astrophysics, relevant for relativistic jet physics, particle acceleration, multiwavelength variability studies, and, in selected cases, multimessenger programmes. In this context, dense optical monitoring provides a low-energy synchrotron tracer of jet activity over temporal baselines that are difficult to cover continuously with high-energy facilities. The dataset consists of more than 17,000 R- and I-band photometric measurements obtained over 957 source-filter observing sessions between 2024 February 1 and 2026 January 31, for a total monitoring time of about 420 h. We applied a uniform differential-photometry and classical F-test framework based on two independent comparison-star pairs. Robust IDV is detected only in H 1426+428, with 15 out of 43 analysed sessions classified as variable in the R band and 5 out of 40 in the I band. No significant IDV is detected in 1ES 1959+650 or PG 1553+113 within the adopted statistical framework. For H 1426+428, the corresponding duration-weighted duty cycles, computed using only variable sessions with a measured local characteristic timescale, are 28.0% in the R band and 7.0% in the I band. The inferred local extrapolated doubling/halving timescales are of the order of 5-15 min in the observer frame. These results indicate that rapid optical synchrotron variability in TeV HBLs is intermittent and state-dependent. They also show that robotic small- and medium-aperture optical facilities can provide valuable long-term support for high-energy monitoring programmes by supplying dense, uniform, and repeatable optical coverage.
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All authors Domenico Impiombato, Giacomo Bonnoli, Elisa Prandini, Luca Zampieri, Irene Albanese