Quantum Physics
Quantum data loading from the learned shared structure of real signals
Pablo Herrero Gómez, Antonio Jimeno Morenilla, David Muñoz-Hernández et al. (+1 more)
Preparing
quantum states from classical data can cost more than the computation they serve; most loaders tailor a
circuit to each input. Here we show that the signals of a real
dataset share structure that can be learned once and reused. Our
quantum-native loader learns a low-dimensional description of a
dataset and prepares every signal with one fixed
circuit set by a few numbers. Across seven views of five public
datasets it meets the targets of the strongest structured loader at equal gate cost with several times fewer numbers per signal. These numbers can be inferred from a random subset: in a preregistered blind replication the subset needed to come within ten per cent of full-signal accuracy stayed constant within a prespecified margin as signals grew sixteenfold, whereas the structured loader needed ever more. It declines what it cannot represent, covering fewer cases than that baseline and no electrocardiogram.
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All authors Pablo Herrero Gómez, Antonio Jimeno Morenilla, David Muñoz-Hernández, Higinio Mora Mora
High Energy Physics (Phenomenology)
Status and Progress of Hamiltonian Effective Field Theory in Light Hadron Spectroscopy
Qi-Liang Xie, Qiu-Rui Wu, Zi-Jun Li et al. (+3 more)
Hadron resonances are intrinsically dynamical states whose observable properties are governed by the interplay between
quark-model configurations and hadronic channels.
Hamiltonian effective field theory provides a practical framework for connecting
hadron dynamics with experimental observables and
lattice QCD results. In this review, we outline the infinite- and finite-volume formulations of
Hamiltonian effective field theory and survey its applications to light-
hadron spectroscopy and resonance structure. By constraining the same
Hamiltonian framework with experimental scattering data and
lattice QCD spectra,
Hamiltonian effective field theory can help distinguish among scenarios that describe the available scattering data comparably well but imply different roles for bare-state and multihadron configurations. We also review recent extensions of the
Hamiltonian framework developed to address more complicated dynamical settings.
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All authors Qi-Liang Xie, Qiu-Rui Wu, Zi-Jun Li, Fang-Chao Han, Yu Zhuge, Zhan-Wei Liu
Quantum Physics
Comparing thresholds of XZZX and rotated surface codes under spatio-temporal correlated noise
Dhruv Koul
While independent and identically distributed noise is typically assumed in
quantum computing research, complex error models such as correlated and spatio-temporal errors remain underexplored. In this paper, the performance of $\mathrm{XZZX}$ and rotated surface codes is evaluated under these complex noise models. Standard graph-based decoders struggle with the hyperedges generated by correlated errors on bias-tailored codes. To address this, we employ the Minimum Weight Parity Factor (MWPF) decoder, which natively processes syndrome hypergraphs without artificial edge decomposition. Our simulations show that under strong Z-biased
circuit-level correlated noise ($\eta=100$), the threshold of the rotated code degrades to $\approx 0.36\%$, while the $\mathrm{XZZX}$ code drops to $\approx 0.70\%$. Furthermore, a distinct non-monotonic threshold dependence is observed for the $\mathrm{XZZX}$ code across different bias ratios. While the $\mathrm{XZZX}$ code effectively absorbs high-density Z-type hyperedges at extreme biases, it exhibits a threshold minimum at moderate biases ($\eta \approx 10$) because transverse X and Y errors actively bridge the diagonal strings, breaking the code's one-dimensional decoupling
symmetry. These findings demonstrate that utilizing hypergraph-aware decoders is critical, as the performance of bias-tailored codes is highly sensitive to the
geometric structure of spatio-temporal correlated noise.
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High Energy Physics (Experiment)
A graph neural network for deep learning-based full event interpretation at FCC-ee
Elena Graverini, Samuel Morand, Rafael Silva Coutinho et al. (+1 more)
This paper presents a deep learning-based full event interpretation prototype developed for the electron-positron Future Circular
Collider (FCC-$ee$) using simulated $e^{+}e^{-}\rightarrow Z\rightarrow b\bar{b}$ events at $\sqrt{s} = 91 \ \mathrm{GeV}$. The study was carried out using the Innovative Detector for Electron positron Accelerators (IDEA) detector concept as case study for future application. The proposed graph neural network framework aims to simultaneously identify and reconstruct the hierarchical decay trees of $b$-
hadrons in each event using information from reconstructed charged particles. Events are represented as graphs, where reconstructed charged particles form the nodes and pairwise observables are encoded as edge features describing the relations between particles. On a test sample, 90% of reconstructed decay chains contain exactly the correct set of particles, irrespective of their inferred decay hierarchy. Across a range of
benchmark $b$-
hadron decays, this clustering efficiency exceeds 93% for decay chains spanning up to three generations of decays.
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All authors Elena Graverini, Samuel Morand, Rafael Silva Coutinho, Felipe Luan Souza de Almeida
Optics
Advances in the Vacuum Magnetic Birefringence measurement using a pulsed Foil Coil
Enzo Rodriguez Alvarez, Jonathan Agil, Julien Billette et al. (+3 more)
In this paper, in the framework of the Biréfringence Magnétique du Vide (BMV) experiment, we present our current apparatus in detail and we discuss its critical points. We also report the results obtained using specially designed pulsed coils called Foil Coils. Our novel measurement of the
vacuum linear
magnetic birefringence constant is $K_{VMB} < 1.7 \cdot 10^{-21}~\text{T}^{-2}$ at a confidence level of 68$\%$, which is an improvement with respect to our previous 2014 measurement.
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All authors Enzo Rodriguez Alvarez, Jonathan Agil, Julien Billette, Jérôme Béard, Rémy Battesti, Carlo Rizzo
High Energy Physics (Phenomenology)
NNLO $N$-jettiness soft function for processes with massless and massive partons
Prem Agarwal, Kirill Melnikov, Ivan Pedron et al. (+1 more)
We compute the NNLO QCD contribution to the $N$-jettiness soft function for processes with two massive and an arbitrary number of massless final-state hard partons. The cancellation of all divergencies is demonstrated analytically. The finite remainder of the soft function is calculated numerically without an infrared regulator. The calculation employs the recently proposed method that uses the so-called inclusive $N$-jettiness variable to simplify the computation of the non-iterative contribution to the soft function.
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All authors Prem Agarwal, Kirill Melnikov, Ivan Pedron, Andrey Pikelner
General Relativity and Quantum Cosmology
Exact Thermodynamics and Two-Horizon Relations of Four Rotating Einstein-Maxwell-Maxwell-Dilaton Embeddings
Hai Huang and Juhua Chen
We establish complete outer-horizon thermodynamics for four exact rotating
embeddings of Kerr–Newman and Kaluza–Klein seeds in four-dimensional, asymptotically flat Einstein–Maxwell–Maxwell–dilaton theory without a scalar potential. Constant-coefficient field maps determine the allowed couplings and charge variations. We obtain single-valued mass functions and verify the first law, Smarr relation, and scalar-shift identity on the stated regular branches and finite-area extremal boundaries, including
magnetic patch contributions where required. For two distinct regular horizons with positive finite areas, the horizon combinations $2T_\pm S_\pm$ and $S_\pm\Omega_\pm/\pi$ satisfy a common quadratic relation with the long-range-force parameter determined by the asymptotic mass, electromagnetic charges, and scalar charge.
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Quantum Physics
Materialised symmetries of 2D translationally invariant codes
Andrew Li, Stephen D. Bartlett, Andrew C. Doherty et al. (+1 more)
There has been significant recent interest in near-term qLDPC codes as high-performance alternatives to surface and color codes. One such class of codes is 2-dimensional translationally invariant (TI) codes, such as bivariate bicycle codes, which share similar properties to topological codes. Fundamental objects in the study of such codes are the materialised
symmetries, which can be used for the construction of matching-based decoders. These decoders generalise the minimum-weight perfect matching decoder for toric codes and provide similar asymptotic performance guarantees that heuristic decoders such as BP and its variants lack. Despite this, the mathematical structure of
symmetries along with their properties under translation and restriction to finite-sized
lattices has not been well-studied. We describe a decomposition of
symmetry spaces of 2D CSS TI codes on infinite
lattices into translation-invariant subspaces which allow us to write an explicit basis of
symmetries in a plane-wave-like form. We then describe how to adapt this infinite
lattice basis so that any corresponding rectangular periodic
lattice basis can be obtained by restriction to basis elements compatible with the periodic boundaries. This allows us to describe how the
symmetry space varies with different rectangular dimensions. We illustrate via examples that it is often straightforward in practice to determine a basis of
symmetries on twisted boundaries as well, without needing to recompute the decomposition. We comment on the applications of this framework to matching-based decoders and provide examples of
symmetries of such codes as the gross code.
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All authors Andrew Li, Stephen D. Bartlett, Andrew C. Doherty, Campbell K. McLauchlan
Quantum Physics
Polynomial neural surrogates for designing photonic quantum experiments
Rohit Chaurasiya and Xuemei Gu
Physics simulators can support the discovery of
quantum experiments by predicting the states generated by experimental configurations. When these simulators are computationally expensive, repeated simulator calls can limit the search for experiments that generate a desired
quantum state. Here, we develop a physics-inspired
polynomial neural surrogate for PyTheus, a graph-based
quantum-optics simulator, to predict
quantum states and use it to design
quantum experiments. Its
polynomial activations are motivated by the relation between graph perfect matchings and the resulting state amplitudes. We train separate surrogate models for four-, six-, and eight-
photon systems and show that they achieve higher prediction accuracy with fewer trainable parameters than standard multilayer perceptrons. We then use the trained surrogates for inverse design of GHZ, W, and linear-cluster states. For the larger systems, the surrogates also enable faster inverse design than direct optimization with PyTheus. These results suggest that incorporating the underlying physics into neural surrogates can provide an efficient approach to
quantum experiment design.
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Instrumentation and Detectors
Investigating Optical Coupling Material Candidates in NaI(Tl) Detectors for the SABRE-North Dark Matter Experiment
Chemseddine Ananna, Gabriella Cataldi, Davide D'Angelo et al. (+21 more)
Direct dark matter detection with NaI(Tl) scintillators requires ultra-low-background materials. Silicone optical pads can couple NaI(Tl)
crystals to photomultiplier tubes (PMTs) if they provide adequate optical transmission and radiopurity. We characterize four candidate materials for the SABRE-North experiment: commercial EJ-560, used as a reference, and three materials produced at the University of Salento (SYLGARD 184, EGel 3002 A/B, and a hybrid formulation) using different catalyst ratios and curing conditions, yielding ten samples in total. Optical transmittance was measured from 310 to 850 nm by UV/Vis/NIR spectrophotometry. Radiopurity was assessed at the STELLA facility at LNGS using high-purity germanium (HPGe) $\gamma$-ray spectrometry and, for EJ-560, high-resolution ICP-MS. At the 410 nm NaI(Tl) emission peak, EJ-560 shows an absorbance coefficient of $0.064\pm0.017$ mm$^{-1}$. The best locally produced samples reach $0.097\pm0.015$ and $0.093\pm0.014$ mm$^{-1}$ for SYLGARD 184 with a 10:2 base-to-catalyst ratio cured at room temperature and at $40^\circ$C, respectively, $0.125\pm0.015$ mm$^{-1}$ for EGel 3002 with a 2B:A ratio cured at $40^\circ$C, and $0.106\pm0.014$ mm$^{-1}$ for the hybrid 10:1 EGel A:CataSYL formulation cured at room temperature. EJ-560 exhibits detectable $^{232}$Th-chain activity at about 1.8 mBq/kg and the highest $^{40}$K activity, $(120\pm20)$ mBq/kg. The locally produced materials show no detectable Th-chain contamination but exhibit $^{226}$Ra activities of about 2.3 mBq/kg and lower $^{40}$K levels. No single material is optimal across all criteria. Additional ICP-MS screening, HPGe measurements of cured pads, and direct NaI(Tl)-PMT light-yield tests are required for a conclusive SABRE-North material selection.
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All authors Chemseddine Ananna, Gabriella Cataldi, Davide D'Angelo, Giulia D'Imperio, Maria Luisa De Giorgi, Giuseppe Di Carlo, Attilio Di Giacinto, Marcella Diemoz, Aldo Ianni, Sana Gul Khattak, Edoardo Martinenghi, Alessandro Miccoli, Marcin Misiaszek, Daniele Montanino, Valerio Pettinacci, Lidio Pietrofaccia, Shahram Rahatlou, Krzysztof Szczepaniec, Claudia Tomei, Valerio Toso, Chiara Vignoli, Samina Zuhra, Francesco Ferella, Stefano Nisi
Biological Physics
Unraveling phenotypic variation in multiscale behavioral dynamics
Gautam Sridhar, Claire Wyart and Antonio Carlos Costa
Behavioral variability reflects differences in internal and external parameters and provides a substrate for natural selection. However, uncovering its structure is challenging because behavior evolves nonlinearly across multiple timescales. Our goal is to reconstruct phenotypic variation from finite behavioral observations without prescribing the scales at which individuals should be compared. To achieve this, we introduce a multiscale dissimilarity that compares dynamics across all statistically resolvable resolutions by constructing reduced transfer operators at progressively finer scales and weighting their differences by finite-sampling uncertainty. This dissimilarity defines a geometry of dynamical phenotypes, which we reconstruct using
diffusion maps. We show that the resulting phenotypic coordinates locally follow the parameter directions to which dynamics are most sensitive. We validate our approach in a
stochastic model and apply it to bacterial and larval zebrafish behavior. In bacteria, we identify run speed as a major component of inter-individual variability, associated with the chemotaxis
protein CheB. In zebrafish, we find that prior prey experience reshapes behavioral dynamics and phenotypic variability, with paramecia experience concentrating fish in a prey-capture-associated region of phenotypic space. Together, these results provide a framework for identifying internal and environmental variables that structure dynamical phenotypes across scales.
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High Energy Physics (Theory) · Cross-listed from math.AG
A proof of GW/DT4 conjecture on local projective plane
Yalong Cao
We prove a closed formula for DT4 invariants of one dimensional stable sheaves on the total space of $\mathcal{O}_{\mathbb{P}^2}(-1,-2)$ for all degree curve classes. During the proof, orientations of
moduli spaces are chosen in a canonical way. Combining with Gopakumar-Vafa type invariants proposed and computed by Klemm-Pandharipande, we verify a
conjecture proposed by the author, Maulik and Toda.
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Nuclear Theory
Interplay between final-state nucleon distortion, nuclear transparency and intranuclear cascade models in neutrino event generators
R. González-Jiménez, A. Nikolakopoulos, J. McKean et al. (+7 more)
We present an overview of the relativistic distorted-wave impulse approximation (RDWIA) for
lepton-
nucleus scattering, with emphasis on its use as an elementary-vertex model in event generators. In the intermediate-energy regime,
neutrino-
nucleus event generators typically follow a two-step scheme: an elementary
neutrino-
hadron interaction is first generated, and the outgoing
hadrons are then propagated through the
nuclear medium using an intranuclear cascade (INC) model. Using exclusive and inclusive $(e,e'p)$ and $(e,e')$ data for several
nuclei, we assess how
nuclear effects should be distributed between these two stages. In particular, we identify which effects should be included in the elementary-vertex description and which can be treated more effectively by the INC, while addressing the consistency required between both components. We also discuss
nuclear transparency in quasielastic scattering. We show that it is directly connected to $(e,e'p)$ data below the two-nucleon knockout threshold; and depends on the full
nuclear density distribution and the initial position of the nucleon, therefore, it varies substantially with the shell from which the nucleon is removed. We demonstrate that this shell dependence can be incorporated straightforwardly into the INC component of event generators.
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All authors R. González-Jiménez, A. Nikolakopoulos, J. McKean, K. Niewczas, T. Franco-Munoz, J. García-Marcos, M. Hooft, N. Jachowicz, G. D. Megias, J. M. Udías
Strongly Correlated Electrons
Nonthermal nonlinear many-body excitonic dynamics in high-purity silicon
Patrick Pilch, Siyu Duan, Yang Liu et al. (+3 more)
We report time-resolved optical pump-terahertz third-harmonic generation spectroscopy of picosecond nonthermal many-body charge dynamics in high-purity silicon at room temperature. Although in thermal
equilibrium excitons in silicon are unstable due to a lower binding energy than the thermal energy at room temperature, following pulsed non-resonant optical pumping we can identify the formation of transient excitonic states on the picosecond time scale in our high-resolution nonlinear spectroscopic measurements. In contrast to unbound electron-hole pairs, the nonthermal many-body excitonic dynamics feature a characteristic time-dependent
evolution, a distinct dependence on charge density, and a nonperturbative nonlinear terahertz response.
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All authors Patrick Pilch, Siyu Duan, Yang Liu, Manfred Bayer, Marc Assmann, Zhe Wang
High Energy Physics (Phenomenology)
A non-invertible Fibonacci selection rule for two-Higgs-doublet models
Yu Hamada
We study two-
Higgs-doublet models, extensions of the Standard Model (SM) containing two
Higgs doublets rather than one. Tree-level
Higgs-mediated interactions that change
quark or
lepton flavor are conventionally suppressed by a discrete $\mathbb{Z}_2$
symmetry. Motivated by string compactifications, we instead impose a non-invertible Fibonacci selection rule at a matching scale $\Lambda$ for that purpose. This rule also forbids the independent mass parameter that normally allows the additional
Higgs particles to become arbitrarily heavy, while renormalization-group
evolution regenerates it below $\Lambda$. An allowed $\mathbb{Z}_2$-breaking quartic interaction simultaneously avoids stable cosmological domain walls. In the exact
alignment limit, requiring perturbative unitarity and boundedness from below up to the matching scale bounds the masses of the three non-SM
Higgs states; for $\Lambda=10^{19}\,\mathrm{GeV}$, they lie below about $150\,\mathrm{GeV}$. The scanned parameter space predicts a suppressed
Higgs diphoton signal strength within the projected reach of the HL-LHC. This illustrates how a stringy non-invertible selection rule can leave testable signatures in
Higgs physics.
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High Energy Physics (Phenomenology)
Hidden-heavy Pentaquarks in the Born-Oppenheimer Approximation for QCD
Fareed Alasiri, Eric Braaten and Roberto Bruschini
Hidden-heavy pentaquarks can be identified as bound states in diabatic Born-Oppenheimer potentials that are repulsive color-Coulomb potentials at short distance, cross below a heavy-
hadron-pair threshold, and then approach that threshold at long distance. We identify the pentaquarks $P_{c\bar{c}}(4312)^+$, $P_{c\bar{c}}(4337)^+$, $P_{c\bar{c}}(4440)^+$, and $P_{c\bar{c}}(4457)^+$ as the ground-state quartet for $c \bar c$ in the two coupled potentials associated with a
spin-$3/2$ adjoint
baryon. We predict that their $J^P$
quantum numbers are $\frac{1}{2}^-$, $\frac{3}{2}^-$, $\frac{3}{2}^-$, and $\frac{5}{2}^-$, respectively. Our prediction for $P_{c\bar{c}}(4457)^+$ differs from almost all previous predictions. Our prediction that there are only four hidden-charm pentaquarks differs qualitatively from that of simple molecular models that there should be seven. We identify the strange hidden-charm pentaquarks $P_{c\bar{c}s}(4338)^0$ and $P_{c\bar{c}s}(4459)^0$ as two members of the ground-state triplet for $c \bar c$ in the potential associated with a
spin-$1/2$ strange adjoint
baryon. We also present model-independent predictions for pentaquark decays into charmonium plus a light
baryon and into a charm
baryon and a charm
meson.
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Quantum Physics
Metastability in Quantum Dynamics for Optimization
Yuchen Lu, Zherui Chen and Tongyang Li
Metastability separates apparent equilibration from true convergence: a dynamical system can remain near an intermediate state long before reaching its stationary state. In
quantum dynamics used for optimization, such a plateau can delay progress toward a target concentrated near the global minimizers of a nonconvex potential. In this paper, we initiate the study of the general mechanisms by which coherent
evolution and dissipation shape metastability, using
quantum Langevin dynamics (QLD) as a concrete example [CLW+25], where the objective function is encoded in the potential and coherent transfer between wells interacts with tunable dissipation. To quantify this interaction, we solve a two-state model precisely and derive a spectral-separation criterion in terms of tunneling frequency, dissipation strength, and damping imbalance. Extending the analysis to multi-state models, we show that sufficiently weak tunneling between wells can separate slow population transfer from fast relaxation within each well. In addition, we establish conditions under which changing the structure of dissipation shortens the time needed to approach a prescribed target state. Numerical experiments on double-well and multi-well potentials demonstrate these improvements while keeping the target and accuracy fixed and accounting for the time spent on control.
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Quantum Physics
Free fermion models with an operator entanglement growing as $O(\sqrt{t})$
Federico Tonetto and Jérôme Dubail
We study the time
evolution of the Operator Space
Entanglement Entropy (OSEE) of one-dimensional number-conserving free
fermions subject to a random space- and time-dependent
evolution. It is known that, in free-
fermion systems without randomness, the OSEE of local operators grows at most logarithmically in time. Here we show that, in the presence of randomness, the OSEE of local
spin operators involving a Jordan-Wigner string grows as $\mathcal O(\sqrt t)$, for all values of the Rényi index. We establish this in two models: a Brownian
Hamiltonian and a brick-wall matchgate
circuit. We also consider the OSEE of the
evolution operator, and we show that it also grows as $\mathcal O(\sqrt{t})$, in contrast with the linear growth generically expected without randomness. We analytically compute the average
entropies of the two operators by mapping the
quantum models to the symmetric simple exclusion process, relying on an assumption of self-averaging which we support numerically. We also consider two other types of randomness: random
evolution in time that keeps spatial translation invariance, and quenched disorder. In the former case, we find that the OSEE also grows as $\sqrt{t}$. In the latter case, we find that the
entropy grows as $\mathcal O( \log \log t)$ for
Hamiltonian evolution both for local operators with a Jordan-Wigner string and for the
evolution operator, whereas it remains bounded at all times in the brick-wall matchgate
circuit.
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Quantum Physics
Joint GKP Encoding for GHZ States Transmission over Bosonic Quantum MIMO Channels
Seid Koudia, Selssabil Kadid, Symeon Chatzinotas et al. (+1 more)
We study transmission of a Greenberger-Horne-Zeilinger (GHZ) state over nonunitary
quantum multiple-input multiple-output (QuMIMO) channels using finite-energy Gottesman-Kitaev-Preskill (GKP) encoding. A coupled-mode model describes coherent mixing, mode-dependent attenuation, and Gaussian noise. The transceiver combines programmable passive meshes,
quantum-limited MMSE gain, local GKP recovery, and joint classical syndrome decoding. We optimize complex-Givens
lattices using instantaneous channel-state information (CSI), current singular values with channel statistics, or statistics alone. Simulations show that joint
lattice shaping outperforms product GKP processing. Under coherent-basis drift, full instantaneous CSI improves GHZ-state preservation, whereas singular-value conditioned and fully statistical designs perform similarly because neither resolves the current singular frames. These findings identify singular-frame geometry as a critical resource beyond attenuation knowledge where joint GKP processing adapts the logical
lattice and receiver to anisotropic bosonic noise rather than merely inverting multimode mixing.
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All authors Seid Koudia, Selssabil Kadid, Symeon Chatzinotas, Mérouane Debbah
Nuclear Experiment
Threshold resonances in relativistic $^{16}$O and $^{22}$Ne dissociation
D.A. Artemenkov, N.K. Kornegrutsa, V.V. Rusakova et al. (+2 more)
The
nuclear emulsion method is applied to study binary dissociation leading to the formation of $\alpha$-particles from $^{16}$O
nuclei at 3.65 GeV per nucleon and $^{22}$Ne
nuclei at 3.22 GeV per nucleon. The invariant mass distribution for the $^{16}$O$\to$$^{12}$C(0$^+_1$)+$\alpha$ channel indicates decays of the $^{16}$O(0$^+_6$) excitation, whose probability exceeds the estimate for the $^{12}$C(0$^+_2$)+$\alpha$ channel by a factor of 20. The invariant mass distribution for $^{22}$Ne$\to$$^{18}$O+$\alpha$ exhibits a peak corresponding to $^{22}$Ne excitations around 11.6 MeV.
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All authors D.A. Artemenkov, N.K. Kornegrutsa, V.V. Rusakova, A.A. Zaitsev, P.I. Zarubin
Atomic Physics
Sub-Doppler cooling in a compact conical hollow mirror integrated with anti-Helmholtz coils
Shintaro Nagase, Naoya Ozawa, Teruhito Nakashita et al. (+7 more)
We demonstrate sub-Doppler cooling of rubidium ($^{87}$Rb) atoms using a compact, single-beam configuration based on a conical hollow mirror integrated with anti-Helmholtz coils. The conical geometry converts a single incident beam into an effective six-beam magneto-optical trap (MOT) configuration while focusing the light towards the cone axis, thereby reducing the required
laser power. The number of atoms in the conical MOT is maximized at an incident intensity of 6.5 $\mathrm{mW/cm^2}$ in our conical MOT, several times lower than in conventional six-beam MOTs. Under optimal conditions, we trap $\sim 1 \times 10^7$ $^{87}$Rb atoms. We obtain sub-Doppler temperature of $T_r=13.4\pm 1.2\ \mathrm{\mu K}$ and $T_z=106\pm 11\ \mathrm{\mu K}$ by polarization gradient cooling (PGC), revealing a strong anisotropy that we attribute to the polarization pattern created by the conical mirror. In addition, a modified release-and-recapture measurement in the MOT yields a radial temperature $T_r = 1.20\pm 0.02$ mK, approximately five times higher than that expected for comparable light-shift parameters in a six-beam MOT, in agreement with previous simulations. Our results establish conical hollow mirrors as a practical and power-efficient platform for compact cold-atom sources and integrated
quantum sensors.
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All authors Shintaro Nagase, Naoya Ozawa, Teruhito Nakashita, Masaki Nakazawa, Kota Abe, Yu Nezu, Ryosuke Tsutsui, Hideki Ueno, Hiromitsu Haba, Yasuhiro Sakemi
High Energy Physics (Experiment)
Search for Diffuse Supernova Neutrino Background of All Flavors with PandaX-4T
Yingxin Zhang and PandaX Collaboration
We present the first search for the diffuse
supernova neutrino background utilizing coherent elastic
neutrino-
nucleus scattering with the PandaX-4T
liquid xenon detector at the China Jinping Underground Laboratory. Based on a total exposure of $1.54~\mathrm{tonne \cdot year}$ from the commissioning and first science runs, we observe no significant event excess over the expected background. We therefore set an upper limit of $(2.27 - 2.43) \times 10^3~\mathrm{cm^{-2}s^{-1}}$ per
flavor at 90% confidence level on the $\nu_x$ flux (each of $\nu_\mu, \bar{\nu}_\mu, \nu_\tau, \bar{\nu}_\tau$) of the diffuse
supernova neutrino background for incident
neutrino energies above 19.3~MeV. The result is comparable to the current world best limit.
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Materials Science
Geometrical Confinement of Magnetic Domains and Domain Walls on Two-Dimensional Cylindrical-Shaped Ferromagnetic Surfaces
Gabriel Martínez-Carracedo, Aurelio Hierro-Rodríguez, Amador García-Fuente et al. (+1 more)
The rolling of two-dimensional (2D) van der Waals (vdW)
magnetic monolayers into cylindrical architectures provides an ideal platform for confining
magnetic domain walls (DWs) without edge-pinning effects. Here, we present a combined analytical and numerical investigation of DW confinement and interaction in
ferromagnetic (FM) nanotubes. Using an analytical Heisenberg model on a 2D rectangular
lattice, we show that transversal
curvature introduces an azimuthal exchange energy penalty that intrinsically compresses the DW width. This model demonstrates excellent quantitative agreement with atomistic Landau-Lifshitz-Gilbert (LLG)
spin dynamics simulations. By extending our study to realistic CrSBr (CSB) nanotubes, we model a bound state of two interacting DWs arising from a balance between long-range dipolar attraction and short-range exchange repulsion. Micromagnetic simulations reveal a non-monotonic
evolution of the inter-wall distance with the tube perimeter. These findings highlight vdW
magnetic nanotubes as robust platforms for stable domain confinement in quasi-one-dimensional spintronic architectures.
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All authors Gabriel Martínez-Carracedo, Aurelio Hierro-Rodríguez, Amador García-Fuente, Jaime Ferrer
Mathematical Physics · Cross-listed from math.DG
Manton's Vortex Equations and Anti-Self-Dual Connections
Takashi Ono
We study four of Manton's five
vortex equations on a Riemann surface $X$ in relation to anti-self-dual connections. From a solution of each
vortex equation, we construct an equivariant holomorphic bundle over $X$$\times$$\mathbb{P}^1$, $X$$\times$$\Delta$, or $X$$\times$$\mathbb{C}$, together with an invariant Hermitian or pseudo-Hermitian metric whose associated connection is anti-self-dual. The equivariant structures are given by the actions of $SU(2)$, $SU(1,1)$, and $SE(2)$, respectively. Conversely, we show that an equivariant holomorphic bundle equipped with an invariant (pseudo-)Hermitian metric gives rise to a solution of the corresponding
vortex equation when the associated connection is anti-self-dual.
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Cosmology and Nongalactic Astrophysics
Limited Impact of CMB B-mode Polarization on Constraints on Cosmic Topology
Ryota Himeno, Atsushi J. Nishizawa and Kiyotomo Ichiki
The global spatial structure of the universe is a fundamental question in cosmology. Although the standard model usually assumes a trivial
topology, a multiply connected universe can break statistical isotropy and generate off-diagonal covariance between the spherical-harmonic coefficients of
cosmic microwave background fluctuations. In this work, we investigate whether CMB B-mode polarization improves constraints on the cubic three-
torus, or $E_1$
topology. We construct the full harmonic-space covariance
matrices of the temperature, E-mode, and
primordial B-mode anisotropies, including correlations between different $(\ell,m)$ modes, and evaluate Gaussian likelihoods using random realizations generated from a statistically isotropic $\Lambda$CDM model with trivial
topology. To isolate the intrinsic topological information carried by each CMB observable, we consider the ideal
cosmic-variance-limited case, neglecting instrumental noise and gravitational
lensing. We find that adding
primordial B-mode polarization yields only a marginal improvement in the ability to distinguish the $E_1$
topology from the trivial
topology, even under these ideal conditions. The different constraining powers of the temperature, E-mode, and B-mode anisotropies can be understood through the combined effects of their transfer-function responses and the
topology-induced off-diagonal correlations in harmonic space. }
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High Energy Physics (Phenomenology)
Phenomenological study of diquark effects in $\bar{B}_{(s)}^0 \to D_{(s)}^{(*)+} L^-$ decays
Fang-Min Cai, Xin-Qiang Li, Tong-Kai Liu et al. (+2 more)
Motivated by the deviations between experimental data and SM predictions for the branching fractions of $\bar{B}_{(s)}^{0} \to D_{(s)}^{(*)+}L^-$ decays with $L=\pi,K^{(*)},\rho$, we investigate whether the type-IV scalar diquark can offer a plausible explanation for them. By matching the renormalized amplitudes in the full theory onto those in the low-energy effective theory formulated in the diquark operator basis, we extract the corresponding Wilson coefficients up to NLO in $\alpha_s$ at the NP scale $\mu_\phi=M_{\phi}$. We then rewrite the obtained operators in the SM basis and apply the renormalization-group running to evolve the Wilson coefficients down to the hadronic scale $\mu_b=m_b$. For the hadronic
matrix elements of the relevant NP operators, we employ the QCD factorization approach to evaluate the non-factorizable one-loop vertex corrections, and confront our theoretical predictions to the latest data to constrain the diquark parameter space. In the single-coupling case, we find that the purely left-handed coupling $\Delta_{d(s)}^{LL}$ can reconcile the discrepancies at $1\sigma$, while the mixed right-left coupling $\Delta_{d(s)}^{RL}$ remains compatible with data only at about $2\sigma$. Extending to the two-coupling case, we find viable parameter regions as long as $\Delta_{d(s)}^{LL}\neq 0$. Incorporating the LHCb measurement of the ratio $R_{\pi/\mu\nu_{\mu}}$ further reduces the allowed range of $\Delta_{d}^{LL}$, but does not yield meaningful extra restriction on $\Delta_{d}^{RL}$. Hence, while either $\Delta_{d(s)}^{LL}$ or $\Delta_{d(s)}^{RL}$ can separately provide an acceptable NP interpretation, our phenomenological results favor a scenario dominated by purely left-handed diquark-
quark couplings. Finally, we present updated predictions for the branching fractions and the ratios $R_{(s)L}^{(*)}$, which can be probed by forthcoming LHCb and Belle II measurements.
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All authors Fang-Min Cai, Xin-Qiang Li, Tong-Kai Liu, Yan Shi, Ya-Dong Yang
High Energy Physics (Theory)
IR flow of stochastic power spectra for interacting spectator scalars in the inflationary de Sitter spacetime
Vishal Nath and Sourav Bhattacharya
In this work we investigate the behaviour of early inflationary
cosmic correlation functions under the flow of the infrared scale for interacting spectator scalar field theories. We start with the derivation of the one-loop effective potentials for $\phi^4$, $\phi^4$-Yukawa and broken phase $O(N)$ model in the inflationary de Sitter spacetime, first using the local Schwinger-DeWitt expansion propagator, and next using the exact de Sitter propagator. The Schwinger-DeWitt expansion being valid in a sub-Hubble length scale, furnishes suitable framework to determine the leading
curvature corrections to high energy phenomena having sub-Hubble Compton wavelengths. These effective potentials show spontaneous
symmetry breaking pattern, and are next used as ultraviolet boundary conditions in the Wetterich equation generating the desired IR flow. The flow is shown to drive the theory towards
symmetry restoration. Using these IR-improved effective potentials, we next compute the
stochastic power spectra and spectral indices for the temporally coincident two point correlation function of the spectator scalar. We show that the results corresponding to the aforementioned two kind of propagators are roughly in qualitative agreement with each other, but may differ quantitatively significantly. Both of them show increase in the spectral index in the deep IR for $\phi^4$ and $\phi^4$-Yukawa. The effect of fermionic interaction has been emphasised. Also for the case of the $O(N)$ scalar, we demonstrate that the effective potential's shape becomes more and more insensitive to the flow as $N$ gets large. Implication of this on the correlation function has been discussed.
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Solar and Stellar Astrophysics
Coherent radio bursts, polarity reversal, and quiescent emission from the M4V dwarf WW PsA
Jackson Mitchell-Bolton, Laura Driessen, Tara Murphy et al. (+6 more)
Coherent
radio emission from magnetically active M
dwarfs is largely observed in two varieties:
stochastic solar-like bursts and beamed, rotationally modulated emission including auroral pulses. Detailed monitoring of these
stars is critical for probing the
plasmas and
magnetic fields driving the emission. We conducted a search for polarised
radio emission from
stars within 85 pc, covering $2.2\times10^4$ h of
stellar dynamic spectra from the ASKAP Deep Investigation of Neutral Gas Origins (DINGO) survey. We report the discovery of coherent
radio bursts from the M4V
dwarf WW PsA. In addition to quiescent emission, we detect three long-duration ($\gtrsim$30 min) bursts, each ~100% circularly polarised, in 283.3 h of data. We also report a fourth burst in an epoch not covered by our search, detected using the VASTER pipeline. One of the bursts features a polarity reversal midway through, based on which we favour the electron cyclotron maser (ECM) mechanism over
plasma emission. We tentatively propose the bursts are due to rotationally modulated ECM pulses of variable intensity. We infer the required physical properties of WW PsA, including a high obliquity $\beta = 74^{+6}_{-22}$ deg under an oblique rotator model.
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All authors Jackson Mitchell-Bolton, Laura Driessen, Tara Murphy, Joshua Pritchard, Barnali Das, Richard Dodson, Martin Meyer, Jonghwan Rhee, Yuanming Wang
Quantum Physics
Fast mixing of the SYK model at high temperatures
Yiyi Cai, Yongtao Zhan and Alexander Zlokapa
The Sachdev-Ye-Kitaev (SYK) model is a strongly interacting fermionic system. Its dynamics are difficult to analyze with Lieb-Robinson bounds and cluster expansions due to its all-to-all disordered interactions. We prove that, with high probability over the disorder, the SYK model admits a
quantum Gibbs sampler with a system-size-independent spectral gap at sufficiently high constant temperatures. This yields
polynomial-time preparation of SYK Gibbs states on a
quantum computer. While prior non-rigorous computations that suggested SYK thermalization were limited to studying local correlators, we emphasize that our result holds up to arbitrary inverse
polynomial trace distance. Our proof introduces the pseudo-Lindbladian approach to
fermions and uses an especially simple SYK analysis based on a comparison to classical dynamics.
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Earth and Planetary Astrophysics
SPIRou near-infrared spectropolarimetry of the ultra-hot Jupiter KELT-9b: tentative detection of the planet magnetic field
Alexis Lavail, Florian Debras, David Rogé Royo et al. (+23 more)
Exoplanetary
magnetic fields govern atmospheric escape and circulation but have eluded detection in close-in
planets. In the ultra-hot Jupiter KELT-9b, atmospheric dynamo is predicted to generate atmospheric fields of 400–4000 G. We search for the circular polarization in atomic lines that a
magnetic field would imprint, through the Zeeman effect, on the transmission spectrum of KELT-9b. We observed three transits with SPIRou at the CFHT, on 07 September 2025 and 03 and 06 July 2026, and applied least squares deconvolution to 1398 atomic lines to map the transit-averaged Stokes $V$ and null spectra against orbital semi-amplitude $K_{\rm p}$ and systemic velocity $v_{\rm sys}$. The 2025 transit shows a Stokes $V$ signature of $V/I_c = 9.3 \times 10^{-5}$ at $K_{\rm p} = 219 \pm 11$ km s$^{-1}$, $v = -34.0 \pm 1.2$ km s$^{-1}$, close to the expected planetary velocity. Its false-alarm probability is $1.9 \times 10^{-4}$, formally a marginal detection. Both 2026 transits are of comparable sensitivity but neither exhibits a signal at that location, setting $3\sigma$ limits of $4.9$ and $6.0 \times 10^{-5}$; the 2025 amplitude would have been recovered at $4.9\sigma$ and $4.0\sigma$. The 2025 signature is robust to the tests we applied to it, but qualifies as a marginal detection at best. Spurious signals of comparable strengths occur elsewhere in our Stokes $V$ and null maps, and we cannot exclude that our marginal detection is excess noise. It is not reproduced ten months later.
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All authors Alexis Lavail, Florian Debras, David Rogé Royo, Arturo López Ariste, Nicholas W. Borsato, Jean-François Donati, Pascal Petit, Julian D. Alvarado Gómez, Laurène Jouve, Claire Moutou, Andres Carmona, Baptiste Klein, Julia V. Seidel, Luc Arnold, Etienne Artigau, Clément Baruteau, Estelle Chabrol, Ryan Cloutier, Neil J. Cook, Nicolas B. Cowan, Xavier Delfosse, Neda Heidari, Eder Martioli, Adrien Masson, Joost P. Wardenier, Vincent Yariv