Exactly Solvable and Integrable Systems
Long-time asymptotics for the focusing coupled Kundu-Eckhaus equation
Tianwei Qiu and Zhen Wang
The focusing coupled Kundu-Eckhaus (CKE) equation extends the coupled nonlinear Schrödinger (CNLS) equation by adding quintic and derivative nonlinearities. We study the Cauchy problem for the focusing CKE equation with Schwartz initial data under the assumption of no discrete spectrum and no spectral singularities on the real axis. Based on the gauge equivalence between the focusing CKE and CNLS equations, we analyze the associated $3\times3$
matrix Riemann-
Hilbert problem by the Deift-Zhou nonlinear steepest descent method. By establishing joint error estimates for the CNLS solution and the gauge phase, we obtain a uniform long-time asymptotic formula for the dispersive radiation of the CKE equation with an $O(t^{-1}\log t)$ remainder in bounded velocity cones.
Read the full abstract ▾
Astrophysics of Galaxies
Identifying the principal mechanism of star formation feedback
Chong Li, Rouyu Li, Keping Qiu et al. (+27 more)
Feedback from massive
stars regulates the formation of next-generation
stars and
planets and thus shapes the
evolution of
galaxies, yet observational evidence capable of determining which mechanism dominates the feedback process has long been lacking. Here,we present a large-scale HI survey toward Orion A$.$ With an unprecedented sensitivity and superior resolution, FAST (Five-hundred-meter Aperture Spherical
radio Telescope) reveals a well-defined heart-shaped expanding HI bubble, enshrouding the well-known "Veil" bubble of ionized gas. The photoionization-driven and wind-driven gas expands at 10.9 and 13.8 kilometers per second, respectively, with a kinetic energy ratio of 1:2 assuming a spherical
symmetry and a uniform HI-to-H2 ratio. This first direct comparison within a single bubble shows that radiation does not dominate the feedback process as predicted by classical theories; instead, stellar winds contribute a comparable share of the injected kinetic energy.
Read the full abstract ▾
All authors Chong Li, Rouyu Li, Keping Qiu, Marko Krco, Di Li, Hongchi Wang, Xin Lyu, Yan Duan, Min Fang, Xuepeng Chen, Lile Wang, Haoran Feng, Shuinai Zhang, Miaomiao Zhang, Shaobo Zhang, Yue Cao, Yao Wang, Yan Gong, Fujun Du, Zhiwei Chen, Yang Su, Yuehui Ma, Yuchen Xing, Yinghui Zheng, Tianwei Zhang, Shu Niu, Chenrui Li, Jiawei Liu, Zhijun Zhang, Yulian Guo
Soft Condensed Matter
Activity-Induced Structural and Dynamical Heterogeneity in Colloidal Gels
Santu Nath, Sudipta Mandal and Smarajit Karmakar
Active gels are intrinsically non-
equilibrium materials whose structural and dynamical heterogeneity emerges from the interplay of attractive interactions, thermal fluctuations, and self-propulsion. We investigate a model active gel, simulated using large-scale Brownian dynamics simulations, to explore the effects of temperature $T$, active force strength $f_0$, persistence timescale $\tau_p$, and active particle concentration $\rho_a$. We characterize the structure of the evolving gel network through morphological analysis, while dynamical changes are quantified by the relaxation timescale and dynamical heterogeneity (DH). We show that an optimal choice of activity parameters yields a percolating gel network with faster gelation and larger voids and clusters, enhancing mechanical stability. Conversely, the structural relaxation timescale and DH decrease with increasing activity, indicating enhanced particle rearrangements and reduced spatial correlations of mobile and immobile regions. An effective temperature ($T_\text{eff}$) framework for colloidal gels maps structural quantities and relaxation timescales in an active gel onto those of a passive gel. More interestingly, the growth of DH with increasing swim force can also be described by the same effective-temperature framework, in stark contrast to observations in active glasses. Our findings show that, in colloidal gels, temperature and active force compete, giving rise to similar structural ordering and, consequently, similar DH at the same $T_\text{eff}$. These findings highlight the crucial role of structural ordering in governing DH in active colloidal gels, as compared to active glasses.
Read the full abstract ▾
Solar and Stellar Astrophysics
Aditya-L1 and SDO Observations of a Confined X-Class Flare with an EUV Late Phase: Thermal and Nonthermal Emission, Magnetic Topology, and Flux Rope Confinement
Vishwa Vijay Singh, Bhuwan Joshi and N.P.S. Mithun
We study a long-duration, confined X2.0-class solar
flare exhibiting three distinct episodes of HXR emission, along with an accompanying EUV late phase. A key highlight of this work is the novel observations from the high-resolution solar X-ray spectrometers SoLEXS and HEL1OS onboard Aditya-L1, providing insights into the
evolution of thermal and non-thermal emissions. Simultaneous EUV observations from AIA/SDO in hot channels, combined with multi-band X-ray light curves, reveal a two-stage confined eruption of a large MFR, separated by $\sim$10~minutes. The first stage corresponds to an M4.6
flare, while the overall event reaches X2.0 on the GOES scale. During the first phase,
magnetic reconnection beneath the large EUV hot channel causes
plasma heating to $\sim$19~MK, with a non-thermal spectral index of $\sim$4.3. In the second phase, characterized by external reconnection and confinement of the MFR hot channel, the temperature increases to $\sim$22~MK, accompanied by further hardening of the spectral index to $\sim$3.9. Despite pronounced non-thermal signatures and enhanced particle acceleration, the MFR fails to erupt through the overlying coronal loops because of the strong strapping force exerted by the large overlying coronal loops. Importantly, the stalled eruption, together with reconnection in the higher overlying loops, results in enhanced heating within a closed
magnetic configuration, with temperatures peaking at up to $\sim$15~MK during the late phase. The paper also provides the first observations of detectable non-thermal X-ray emission during the early EUV late phase, albeit briefly, providing direct evidence for reconnection-induced heating, likely occurring in the higher overlying coronal loops.
Read the full abstract ▾
Materials Science
Real-space obstruction control of the shift current in two-dimensional Quantum Spin Hall insulators
Michele Bagaglini, Mattia Iannetti, Jonas Erhardt et al. (+4 more)
The search for materials exhibiting a large bulk photovoltaic effect has recently expanded to low-band-gap systems capable of operating in the infrared regime, with potential applications in optoelectronics. Among the microscopic mechanisms contributing to this phenomenon, the shift current is one of the dominant sources of photocurrent generation. Owing to its
geometric origin, the shift current is not only determined by the optical transition probability but also by the real-space displacement associated with the optical excitation, making non-centrosymmetric materials with obstructed electronic wave functions particularly promising candidates. In this work, using a tight-binding model of a
quantum spin Hall
insulator on a triangular
lattice, we investigate the nonlinear photocurrent across trivial,
quantum spin Hall, and higher-order topological insulating phases. We show that obstructed topological phases exhibit a substantially enhanced shift-current response, despite the similar electronic band structure. We identify the origin of this enhancement in optical transitions between states belonging to distinct Wannier-center sectors, which allow for a large real-space displacement upon photoexcitation and, depending on the topological phase, control the sign of the shift current. Our results extend the search for controllable bulk photovoltaic effects to materials characterized by real-space electronic obstruction and identify indenene, a monolayer of In on SiC(0001), as a promising candidate for realizing this phenomenon.
Read the full abstract ▾
All authors Michele Bagaglini, Mattia Iannetti, Jonas Erhardt, Jörg Schäfer, Ralph Claessen, Giorgio Sangiovanni, Gianni Profeta
Cosmology and Nongalactic Astrophysics
CosmoAgent: AI Agent for Theoretical Cosmology
Stephon Alexander, Loukas Gouskos, Savvas M. Koushiappas et al. (+2 more)
We present CosmoAgent, an agentic AI framework using large
language models (LLMs) to search for dark-energy and modified-
gravity models. We define a covariant grammar that allows LLM
agents to explore the space of modified-
gravity Lagrangians. An in-house computational pipeline derives the equations of motion, solves the background dynamics, and evaluates the likelihood using late-time expansion data, including the DES 5-year type Ia
supernova sample and the DESI Data Release 2 BAO measurements. Theories are ranked by the Akaike Information Criterion (AIC) to balance simplicity and likelihood. We benchmarked 8 frontier LLMs from ChatGPT, Claude, Gemini, Kimi, DeepSeek, and Qwen, and all LLMs are able to find theories with a lower nominal AIC than flat $\Lambda$CDM, with a best improvement of $\Delta$AIC = -3.328. Seven recover quadratic quintessence. Exploratory searches also return induced-
gravity and scalar-Gauss-Bonnet structures. The modest AIC improvements do not establish an observational preference for these models over flat $\Lambda$CDM. The code is publicly available at wsunamoutlook-prog/AI-Modified-
Gravity.
Read the full abstract ▾
All authors Stephon Alexander, Loukas Gouskos, Savvas M. Koushiappas, Cooper Niu, Wenrong Sun
Materials Science
Interlayer Registry Controls Polar Topology in Twisted Bilayer h-BN
Di Fan, Changming Ke and Shi Liu
Twisting van der Waals bilayers creates a moir'e stacking field with periodically varying local interlayer registry, enabling spatially patterned polarization. However, a systematic understanding of how this registry-controlled polar
topology evolves with twist angle, temperature, and mechanical strain is still lacking. Here, using first-principles-trained deep-potential molecular dynamics simulations, we show that spatially varying interlayer registry governs the polarization texture and can be directly tuned by twist and relative layer deformation. As the twist angle decreases, the moir'e polarization texture evolves from compact, nearly circular
vortex-like patterns to extended triangular AB/BA domains. This crossover arises from enhanced
lattice relaxation at small twist angles, which expands low-energy, oppositely polarized AB/BA regions and confines in-plane polarization mainly to domain boundaries. Despite this reconstruction, the local in-plane winding remains tied to interlayer registry and persists up to 1000 K, indicating robust
topology against thermal fluctuations. We further show that the mechanical response is dictated by whether deformation changes the relative registry: homogeneous deformation of both layers produces only weak distortions, whereas layer-selective deformation strongly reconstructs the moiré polarization texture. A mismatch-
matrix registry-mapping model is developed to capture this response, explaining deformation-induced changes in
vortex radii at larger twist angles and triangular-domain geometry at smaller twist angles. These results identify interlayer registry as the central control parameter for forming and tuning moir'e polar
topology in twisted bilayer h-BN.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Blackbody evolution and circumstellar medium properties of broad-lined H-rich superluminous supernovae
Tuomas Kangas, Takashi Nagao, Uliana Pylypenko et al. (+2 more)
Broad-lined H-rich superluminous
supernovae (SLSNe II) tend to show signs of interaction, including a UV excess compared to a blackbody function. However, a quantitative analysis of the CSM configuration and the UV excess has so far not been performed for most of the literature sample. Additionally, SN 2023gpw showed signs of asymmetry in its peculiar blackbody and spectral
evolution, raising the question of whether similar properties can be found in other SLSNe II. We aim to characterize the circumstellar environment of SLSNe II by searching for signs of asymmetry, quantifying the UV excess, and investigating any IR echoes produced by dust. Diversity among SLSNe II is also explored. We fit blackbody functions to the SEDs of SLSNe II to quantify the UV excess luminosity and its
evolution. We use this to investigate mass-loss rates required to produce the excess through interaction. We also investigate the line profiles in SLSN II at late times and compare line velocities to the blackbody radius
evolution. We examine public WISE IR images and place constraints on IR echoes. We find mass loss rates of $\sim10^{-4}$ to $\sim0.03\, \mathrm{M_\odot}$~yr$^{-1}$ when assuming all interaction luminosity emerges in the UV, i.e., conservative lower limits for the total mass loss rate. Radii calculated from line velocities in late-time spectra are mostly too large for a spherical interaction photosphere, only compatible with the blackbody radius
evolution if the CSM is non-spherical with a low filling factor. This is in some cases supported by a mismatch between spectroscopic and blackbody expansion velocities. Considerable diversity is seen in the sample, probably as a result of different viewing angles and CSM masses. WISE images seem too shallow to observe IR echoes in SLSNe II beyond $z\sim0.1$, but in the nearest event, SN 2020jhm, a likely IR echo is detected, suggesting pre-existing dust.
Read the full abstract ▾
All authors Tuomas Kangas, Takashi Nagao, Uliana Pylypenko, Steve Schulze, Lin Yan
Quantum Gases
Bogoliubov excitations of a Bose-Einstein condensate in the presence of the non-Hermitian skin effect
Carlo Panu, Ulf Peschel, Oleg A. Egorov et al. (+2 more)
The non-Hermitian skin effect is one of the most remarkable topological features of non-conservative physics. It causes a macroscopic accumulation of states at the boundaries of a confined system, opening new ways for controlling and directing waves in non-Hermitian settings. This effect has recently been observed in experiments with Bose-Einstein condensates of
exciton polaritons and ultracold bosonic
quantum gases. The underlying physics is captured by a mean-field
Hamiltonian with a trapping potential and an imaginary gauge field. While prior work has examined the effect of the imaginary gauge field term on the condensate itself, its effect on the collective excitations on top of the condensate remained unexplored. Here, we develop a new theory for the Bogoliubov excitations in a non-Hermitian framework and systematically study their spectrum across different interaction regimes. By analysing the position expectation values, we find that while the repulsive interactions oppose the localisation of the condensate due to the skin effect, the excitations remain strongly affected by the imaginary gauge field. As a consequence, in the presence of harmonic confinement, we predict a strong shift in the dipole oscillation frequency, which can be observed in experiments. This is in contrast to Hermitian systems, where this frequency is fixed by the trap dimensions. Furthermore, we develop a consistent second-quantised field theory of the collective excitations in this non-Hermitian system. Strikingly, we find that a second-quantised treatment removes the shift of the dipole oscillation frequency entirely. This intriguing discrepancy between the two theoretical approaches to the treatment of elementary excitations in a non-Hermitian system can be resolved in experiments.
Read the full abstract ▾
All authors Carlo Panu, Ulf Peschel, Oleg A. Egorov, Elena A. Ostrovskaya, Eliezer Estrecho
Materials Science
Theoretical Investigation of Oxygen-Vacancy Diffusion in SrTiO$_3$ using Neural Network Potentials
Kazutaka Nishiguchi, Ryota Yamamoto and Seiichiro Ten-no
Oxygen-vacancy formation and
diffusion play important roles in determining the electronic and atomic transport properties of SrTiO$_3$ (STO). Accurate analysis of such point defects requires sufficiently large-scale and long-time molecular dynamics (MD) simulations; however, direct investigations of oxygen-vacancy dynamics using ab initio MD (AIMD) based on density functional theory (DFT) are limited to relatively small systems and short time scales because of their high computational cost. In this study, we develop a neural network potential (NNP) for pristine and oxygen-deficient STO using a reference
dataset generated from AIMD simulations. The trained NNP model accurately reproduces the DFT reference energies, atomic forces, and virials for both pristine STO and STO containing an oxygen vacancy. The NNP also reproduces the supercell-size dependence of the total energies and oxygen-vacancy formation energies, including the formation energy extrapolated to the dilute limit. Large-scale and long-time MD simulations using the NNP (NNP-MD) are then performed to investigate oxygen-vacancy
diffusion. The resulting oxygen-vacancy
diffusion coefficients show substantially better agreement with experimental data than those obtained from conventional classical MD simulations. An Arrhenius analysis yields an oxygen-vacancy migration enthalpy of 0.64 eV, in close agreement with the experimental value of 0.67 eV. These results demonstrate that NNPs trained on first-principles data provide an accurate and computationally efficient framework for investigating defect formation and long-time vacancy transport in perovskite oxides.
Read the full abstract ▾
Instrumentation and Detectors
Readout chain of SPD DAQ system
L. Afanasyev, A. Berngardt, A. Boikov et al. (+8 more)
The
Spin Physics Detector (SPD) experiment at the NICA
collider of the Joint Institute for Nuclear Research (JINR) aims to study the
spin structure of the nucleon and
spin-related phenomena. The experimental conditions, including the high interaction rate and the large number of readout channels, require a triggerless data acquisition system with high throughput and a scalable architecture. This work presents a hardware implementation of the readout chain that extends the previously proposed SPD DAQ architecture. The chain is based on two levels of concentrators. The L1 concentrator provides the interface between the front-end electronics and the next system level and distributes synchronous signals. The L2 concentrator aggregates data streams from several L1 concentrators before transmitting them to the computing system. A key feature of the L2 implementation is the offloading of data reception, buffering, and aggregation from the host CPU to the FPGA, motivated by the large number of small packets generated by the readout electronics. The developed hardware platforms and their operating logic are presented, together with experimental results for the main interfaces and data-path components. The obtained results demonstrate the feasibility of the proposed hardware architecture and its application in a scalable SPD data acquisition system.
Read the full abstract ▾
All authors L. Afanasyev, A. Berngardt, A. Boikov, V. Borshch, D. Erofeev, V. Frolov, K. Gritsay, V. Olshevsky, A. Kulikov, S. Tereshchenko, V. Tereshchenko
Other Condensed Matter
Optically driven ultrafast lattice contraction in a topological crystalline insulator
M. H. Berntsen, W. Chen, D. Phuyal et al. (+9 more)
The ability to dynamically control topological order remains a central challenge in the exploration of
quantum materials. Here, we investigate the
lattice and electronic response of the topological crystalline
insulator (TCI) Pb$_{1-x}$Sn$_x$Se to ultrafast optical excitation using time- and angle-resolved photoemission spectroscopy (tr-ARPES) in combination with X-ray diffraction (XRD) and first-principles calculations. Static XRD measurements establish the
lattice constant as the key control parameter for the topological transition, with a critical value $a_\mathrm{c}=6.073$ Åseparating the normal-
insulator and topological phases. Despite generating electronic temperatures far above the topological-to-normal transition temperature $T_\mathrm{c}$, optical excitation in the TCI phase does not induce a phase transition. Instead, it drives an ultrafast
lattice contraction of $\Delta a \approx -0.45$ pm within less than 1 ps that counteracts thermal expansion and prevents the system from reaching $a_\mathrm{c}$. The optical excitation therefore pushes the system deeper into the topological phase, providing a direct explanation for the absence of an optically driven transition. Total-energy calculations reveal that this behavior originates from the band inversion in the topological regime, which reverses the character of the photoinduced charge transfer and transiently strengthens atomic bonding. These findings identify band inversion as a mechanism that fundamentally alters the nonequilibrium
lattice response, with general implications for ultrafast optical control of topological materials.
Read the full abstract ▾
All authors M. H. Berntsen, W. Chen, D. Phuyal, J. Wu, A. Grubišić-Čabo, M. Dendzik, Q. Guo, A. Orthaber, C. Li, R. M. Geilhufe, J. Weissenrieder, O. Tjernberg
Quantum Physics
Towards the Geometry of Quantum Optical Measurements: Kraus Trajectories in the Instrumental Weyl-Heisenberg Group Manifold
Tzula B. Propp and Chris S. Jackson
Since ancient Greek times, geometry has been a method by which humans can make inferences, by the use of similar triangles, about the world far beyond their immediate senses. Similarity plays an equally important role in
quantum measurement, except that instead of triangles, the similarity is between the infinitesimal generators of rotation, canonical transformation, or some other virtual
symmetry. For many
quantum optical measurements of a single mode, these generators produce Kraus operators that are contained within a twelve-dimensional Lie group: the Instrumental Weyl-Heisenberg group
manifold ($\mathrm{IWH}^{\textbf{12}}$). In particular, $\mathrm{IWH}^{\textbf{12}}$ is general enough to include all diffusively generated 'dyne measurements. In this paper, $\mathrm{IWH}^{\textbf{12}}$ will be used to develop two more general classes of 'dyne measurement: one that interpolates between diffusive homodyne and diffusive heterodyne (“slomodyne”) and one that adds to 'dyne measurements adaptive squeezing and displacement. Our analysis uses an approach known as the Instrument
Manifold Program (IMP). In particular, a Harish-Chandra-like decomposition of $\mathrm{IWH}^{\textbf{12}}$ is used to calculate the vielbein transformation from a right-invariant basis to the corresponding coordinate basis, allowing us to universally and autonomously navigate $\mathrm{IWH}^{\textbf{12}}$ and locate the Kraus-operator of whatever selective process is being considered as it evolves in time according to the measurement record.
Read the full abstract ▾
Astrophysics of Galaxies
Nearly pristine gas in a galaxy 1 billion years after the Big Bang
Sarah E. I. Bosman, Frederick B. Davies, Louise Welsh et al. (+22 more)
Excitation of carbon and oxygen ions is the primary mechanism by which collapsing gas clouds dissipate heat to form new
stars. At early
cosmic times, in
galaxies with chemically pristine gas, many
stars are expected to have masses far larger than the mass of our sun due to the deficit in these elements. We searched for ultra-metal-poor
galaxies using their spectroscopic absorption signatures in front of bright background
quasars, employing the new GHOST high-resolution spectrograph. Here we report the discovery of the first
galaxy containing a reservoir of neutral hydrogen gas with
metallicity below the ultra-metal-poor threshold: with a measured carbon-to-hydrogen ratio 11,000 times lower than the Sun, it is the most pristine ever found by a factor of four. UMP-DLA-1 is the only known
galaxy with measured carbon and oxygen abundances too low to enable efficient formation of
stars with solar mass or below. The low
metallicity alone therefore guarantees a top-heavy stellar population, providing a direct view of the chemical composition imprinted by massive low-
metallicity stars that perished long before the present day: an elevated oxygen-to-carbon ratio. The abundance pattern of UMP-DLA-1 is likely a close representation of the atomic yields of first- or early second-generation
stars.
Read the full abstract ▾
All authors Sarah E. I. Bosman, Frederick B. Davies, Louise Welsh, Emanuele P. Farina, Prakash Gaikwad, Benedetta Spina, Barun Maity, Ryan Cooke, Klaudia Protušová, Valentina D'Odorico, Eduardo Bañados, James S. Bolton, Rebecca L. Davies, Xiaohui Fan, Martin G. Haehnelt, Joseph F. Hennawi, Tahlia J. Hill, Seyeon Hwang, Vid Iršič, Laura Keating, Girish Kulkarni, Samuel Lai, Emma V. Ryan-Weber, Lasse Seyberlich, Molly Wolfson
High Energy Physics (Phenomenology)
Concurrence Dynamics in Self-Gravitating Mixed Neutrinos
Raoul Serao, Gianpaolo Torre and Antonio Capolupo
We study the
entanglement generated by Newtonian self-
gravity in a two-particle system of mixed
neutrinos and quantify it by means of the concurrence. Starting from the gravitational coupling between the mass operators, we show that the two-particle
Hamiltonian splits into local single-particle terms and an effective Ising interaction in the mass basis, the latter being solely responsible for the generation of correlations. For initially separable flavor states the concurrence is obtained in closed analytic form: it oscillates between zero and a maximum fixed by the mixing angle alone, while the gravitational coupling sets the recurrence time. We further establish a one-to-one correspondence between the concurrence and the reduced-state purity previously derived for this model, thus providing an independent
quantum-information description of the same gravitationally induced correlations. Finally, we show that the concurrence does not depend on the Majorana phase, so that Dirac and Majorana parametrizations yield identical
entanglement dynamics. These results isolate the genuinely entangling sector of the gravitational
evolution and provide a compact analytic characterization of
gravity-induced
quantum correlations in mixed
neutrino systems.
Read the full abstract ▾
Superconductivity
Superconductivity from altermagnetic fluctuations: the crucial role of sublattice polarization
Mats Barkman, Andreas Kreisel and Brian M. Andersen
Unconventional superconductivity in correlated systems often appears in the vicinity of a magnetically ordered state. This situation is also relevant for altermagnets, characterized by a nonrelativistic
spin-split electronic structure in the presence of Néel order. Many proposed altermagnetic candidates, however, never cross the
magnetic instability. We study superconductivity arising from altermagnetic fluctuations in such systems and show that the sublattice polarization (SLP) of the normal-state bands plays a pivotal role in determining the superconducting state. SLP, an inherent property of altermagnetic band structures that persists even without
magnetic order, prevents Cooper pairs from forming between different sublattices. This suppresses pairing mediated by the nearest-neighbor antiferromagnetic exchange, which favors
spin-singlet superconductivity, and leaves longer-range same-sublattice bonds dominant. When the next-nearest-neighbor exchange is ferromagnetic, as expected for frustration-free Néel order, this results in
spin-triplet superconductivity. This mechanism is fundamentally different from that in altermagnets with long-range Néel order, where the
spin-split Fermi surfaces favor equal-
spin pairing. Finally, when longer-range interactions in the disordered phase instead favor singlet pairing, SLP leads to singlet states with characteristic properties distinct from nearest-neighbor pairing states.
Read the full abstract ▾
Mathematical Physics · Cross-listed from math.OA
Quantum integrals II: Dominated and almost uniform convergence
David P. Blecher
One main aim of our paper is to formulate noncommutative versions of the Lebesgue dominated convergence
theorem in the setting of
quantum integration theory on von Neumann
algebras. Our starting point is a reformulation of classical dominated convergence in terms of weak* convergence. Using our recent sequential-continuity
theorem, we obtain dominated convergence formulations for sequentially normal states and, under domination by a fixed bounded integrable majorant, for sequentially normal weights. Integrable, possibly unbounded, majorants are treated first in the tracial setting, then for arbitrary von Neumann
algebras using Haagerup's L1 space, and finally using normal semifinite weights and their GNS representations. For any faithful normal semifinite weight $\phi$, weak* convergence of norm-bounded sequences is characterized by `integrating against' bounded positive integrable majorants. We also study noncommutative almost uniform and local almost uniform convergence. In particular, for norm-bounded sequences, local $\phi$-bilaterally almost uniform convergence implies weak* convergence and L1 convergence to 0 of $h^{1/2}(x_n-x)h^{1/2}$ for every positive Haagerup L1 density h, without assuming sigma-finiteness. We also prove a dominated convergence
theorem in the predual: fixed positive order domination and Petz's almost uniform convergence imply convergence in the predual norm. We establish implications and equivalences among these convergence notions, connecting dominated convergence with tracial and nontracial integration.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Sensitivity of calibration-free DESI DR2 BAO–supernova constraints to a distance-duality tilt
Stéphane Fay, Mikel Artola and Leandros Perivolaropoulos
Recent measurements from DESI baryon acoustic oscillations (BAO) have reported a moderate preference for dynamical dark energy, challenging the standard $\Lambda$CDM paradigm. Nonetheless, such a trend could reflect a tension between the shape and the offset of the Hubble diagrams predicted by current BAO and Type Ia
supernovae (SN) data, which may underpin a possible breakdown of the
cosmic distance duality relation (CDDR) linking luminosity distances $D_{\rm L}$ and angular-diameter distances $D_{\rm A}$. We explore this possibility by parametrizing deviations from this relation as $\eta(z) \equiv D_{\rm L} / [{(1+z)}^2 D_{\rm A}] = \alpha{(1+z)}^\varepsilon$, and investigate how the preference for a Chevallier-Polarski-Linder (CPL) dynamical dark energy is modified once $\varepsilon \!\neq\! 0$ is allowed. Using DESI DR2 and uncalibrated SN data (Pantheon$+$, DES-Dovekie, Union3, and Union3.1), we find that allowing $\varepsilon$ to vary freely in both $\Lambda$CDM and CPL reduces the CPL preference with respect to $\Lambda$CDM by a larger amount than the addition of spatial
curvature $\Omega_k$; only Union3.1 exhibits comparable reductions. We also find that the preference reduction is robust to alternative $\eta(z)$ parametrizations, and that the $\eta(z)$ constraints remain stable under the removal of BAO tracers or low-
redshift cutoffs for Pantheon$+$, whereas the DES-Dovekie preference largely disappears once $z < 0.1$ SN are removed. In a separate calibrated analysis, illustrative Planck sound-horizon and SH0ES absolute-magnitude priors give $\alpha \simeq 0.942 \pm 0.014$, quantifying the normalization mismatch under those assumptions. We also map the CDDR violation onto
photon-loss and varying-$G$ scenarios, concluding that the cosmological constraints are much weaker than existing constraints on these physical mechanisms.
Read the full abstract ▾
Chaotic Dynamics
Geometric Transition of Latent Dynamics in Intermittent Chaos: SVD-based Effective Dimension for Detection and Proactive Control
Takashi Hikihara and Tetsushi Saburi
This paper investigates the
geometric detection of latent dynamic transitions (where the latent space is defined as a finite-dimensional state space reconstructed via a delay-
embedding Hankel
matrix) in mutually coupled phase-locked loops (PLLs) exhibiting on-off intermittent chaos. We propose a data-driven approach to identify the transition of the effective dimension in latent dynamics as a precursor to physical bursting events. By applying Singular Value Decomposition (SVD) to a Hankel
matrix constructed from high-resolution oversampled data, we extract the effective dimension that reflects the dynamical shift of intrinsic variables - from a synchronized two-dimensional
manifold to a higher-dimensional chaotic state - prior to the actual burst. This
geometric indicator enables a proactive, event-driven intervention using Pyragas-type delayed feedback control, which is activated only when the detected dimension exceeds a critical threshold. Simulation results demonstrate that this
geometric precursor effectively compensates for control latencies and substantially reduces accumulated control energy compared to conventional continuous feedback. The findings establish a methodological strategy for stabilizing infinite-dimensional delayed systems by exploiting early warning signals embedded in dimensional transitions of latent dynamics.
Read the full abstract ▾
Strongly Correlated Electrons
Scalable Quantum Monte Carlo for Shannon-Rényi Entropy: An Experiment-visitable Probe of Quantum Phases and Criticality
Dong-Xu Liu, Zhe Wang, Zenan Liu Yi-Ming Ding et al. (+1 more)
The Shannon-Rényi (SR)
entropy characterizes the probability distribution of many-body wave functions in a chosen basis and is directly accessible from single-shot measurement snapshots in cold-atom experiments, yet its theoretical evaluation in interacting systems carries exponential cost. Here we construct a field-theoretic spacetime
manifold for the SR
entropy in which $q$ replicas are glued at the imaginary-time boundaries, recasting it as a ratio of generalized partition functions amenable to large-scale
quantum Monte Carlo simulation. On this basis we develop a reweight-annealing framework with two complementary strategies: a virtual-parameter scheme interpolating between unglued and fully glued limits via binomial-weighted partial gluing, and a real-parameter scheme using a physical coupling constant as the annealing variable within
stochastic series expansion. Both reduce the computational cost from exponential to
polynomial. Most importantly, we establish for the first time a finite-size scaling theory for the SR
entropy near a
quantum critical point, $S_q=a(g)L^2+S_q^0\left((g-g_c)L^{1/\nu}\right)$; data collapse of its first derivative yields the correlation-length exponent $\nu$ for both the O(3) and Ising universality classes, realized in the
spin-$\frac{1}{2}$ columnar dimerized Heisenberg model and the bilayer Heisenberg-Ising model. The same simulations extract the Goldstone-mode count $N_G=2$ and the $Z_2$ ground-state degeneracy $\ln 2$ from subleading terms. These results elevate the SR
entropy to a standalone, order-parameter-free diagnostic of
quantum criticality with the same scaling status as the
entanglement entropy, and close the loop between theory and
quantum simulation by enabling quantitative benchmarking of experimental snapshots from state-of-the-art
quantum simulators.
Read the full abstract ▾
All authors Dong-Xu Liu, Zhe Wang, Zenan Liu Yi-Ming Ding, Zheng Yan
Quantum Physics
Bell's go theorem: regaining local causality with a new notion of realism
Lorenzo Catani, Nesta van der Schaaf and Rui Soares Barbosa
Bell's
theorem is popularly stated as the inconsistency of
quantum theory with local realism. Realism is here formalized by the ontological models framework, where elements of reality are points of a measurable space and probabilities obey the Kolmogorov axioms. In the Bell scenario, locally causal ontological models posit a common cause supporting a global valuation, a joint assignment of outcomes to all measurements at once, across incompatible contexts. Within this notion of realism, Bell's
theorem makes any realist explanation of the
quantum predictions conspiratorial: any mechanism, whether superluminal, superdeterministic, or retrocausal, must be finely tuned so as never to manifest operationally. We redefine realism through a new ontological framework that generalizes the standard one. The elements of reality, which we call records, are no longer points but relational parts of a point-free generalization of a topological space (sublocales of a locale). A record shared by two incompatible contexts establishes the sameness of a measurement across them, without such pairwise identities composing into a global valuation, and the common cause is then a web of such records. Within this framework, Bell's no-go
theorem becomes a go
theorem: local causality, restated for records, is no longer at odds with the
quantum statistics. This is possible because modularity, the inclusion-exclusion law of classical probability, fails across incompatible contexts, so that the probability theory generalizes Kolmogorov's. We exhibit explicit models reproducing several
quantum strategies, including the optimal CHSH violation. More broadly, locally causal models of this kind attain every Bell-CHSH value up to the algebraic maximum. A realist explanation of the
quantum predictions need not be conspiratorial; every causal influence posited by these models is reflected in the operational predictions.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Emergence of Nonlocal Hydrodynamics in Many-Body Radiative Heat Transport
Mauricio Gomez Viloria, Florian Herz, Riccardo Messina et al. (+1 more)
We develop a nonlocal hydrodynamic theory of radiative heat transport in many-body systems by coarse graining their microscopic electrodynamic interactions. Long-range radiative exchange naturally generates a spatially nonlocal constitutive relation in which the heat current at a given position depends on temperature gradients over an extended region, while energy conservation retains its local conservative form.
Fourier transport emerges as a controlled long-wavelength limit when the interaction kernel has a finite second spatial moment. When this moment fails to converge, spatial nonlocality survives coarse graining and gives rise to non-
Fourier transport. The resulting framework establishes a systematic bridge between discrete many-body fluctuational electrodynamics and a continuous description of radiative heat transport.
Read the full abstract ▾
All authors Mauricio Gomez Viloria, Florian Herz, Riccardo Messina, Philippe Ben-Abdallah
Superconductivity
Molecule-intercalated van der Waals Josephson junctions uncover complex multiband superconductivity
Daniel Margineda, David Caldevilla-Asenjo, Covadonga Álvarez-García et al. (+6 more)
Intercalation of molecular species provides a route to tailor the electronic structure in van der Waals
superconductors, yet intercalated compounds have rarely been integrated into phase-sensitive
quantum devices. Here, we realize hybrid molecular Josephson junctions based on TaS2/NbSe2
heterostructures. Selective intercalation of the TaS2 electrode induces monolayer-like Ising superconductivity, while the junctions exhibit asymmetric Fraunhofer interference, field-induced and spontaneous Josephson diode effects. The zero-field diode disappears upon reversing the electrode stacking and re-emerges after intercalating the lower NbSe2 electrode. These findings indicate that the hybrid superconducting electrode hosts unconventional superconductivity underlying the nonreciprocal transport, while molecular intercalation acts as a tuning knob for its internal phase structure. This behavior is consistent with a time-reversal-
symmetry-breaking multiband superconducting state characterized by a nontrivial relative phase between superconducting condensates. Our results establish hybrid molecular Josephson junctions as a
quantum-device platform for phase-sensitive investigation and integration of molecularly engineered
superconductors, opening opportunities to uncover and engineer unconventional superconducting phases.
Read the full abstract ▾
All authors Daniel Margineda, David Caldevilla-Asenjo, Covadonga Álvarez-García, Daniel Tezze, Raul Arenal, Maxim Ilyn, Celia Rogero, Luis E. Hueso, Marco Gobbi
Quantum Physics
Quantum state texture of maximal-resource Fourier states under Hawking radiation
Shengyan Ma, Yiding Wang, Xiaofen Huang et al. (+1 more)
Quantum state texture (QST) is a recently proposed
quantum resource that characterizes the nonuniformity of a density
matrix in a given computational basis. In the resource theory of QST, the
Fourier states f_k are maximally resourceful states, attaining the maximum QST measure. We study the QST behavior of three maximally resourceful states in a two-mode Dirac field under Hawking radiation from a Schwarzschild black hole, using a fidelity-based measure. We consider three cases: only mode B undergoes radiation, only mode A undergoes radiation, and both modes undergo radiation simultaneously. Our results show that for single-mode radiation, if the mode unaffected by radiation is orthogonal to the single-mode textureless state, the QST of the overall output state remains maximal and is independent of the Hawking temperature; we call this phenomenon orthogonality protection. When both modes undergo radiation simultaneously, orthogonality protection vanishes, and the QST of all three
Fourier states decreases with increasing Hawking temperature. Notably, the QST measure of f_3 under two-mode radiation is higher than that under only mode B radiation, indicating that QST can be redistributed among modes: QST gained by one mode under radiation can partially compensate for QST lost by the other. We further provide a general resource-theoretic explanation of orthogonality protection, showing that this phenomenon is independent of the specific form of the QST measure. These results reveal how QST degrades under Hawking radiation and provide a new perspective on the redistribution of
quantum resources in black hole backgrounds.
Read the full abstract ▾
All authors Shengyan Ma, Yiding Wang, Xiaofen Huang, Tinggui Zhang
Materials Science · Cross-listed from cs.AI
PXRD-Bench: How Close Are We to Determining Crystal Structures from Powder Diffraction?
Dongyeop Woo, Nofit Segal, Nayoung Kim et al. (+3 more)
Determining
crystal structures from powder X-ray diffraction (PXRD) would enable routine characterization of newly synthesized materials, including those absent from reference databases. Generative models offer a promising approach, but existing evaluations remain fragmented and largely assume single-phase samples with known composition. To fill this gap, we introduce PXRD-Bench, a unified
benchmark that extends evaluation to unknown per-element atom counts and recovery of both structures in two-phase mixtures. It provides approximately 4.1 million training structures with simulated PXRD, tests generalization to unseen compositions and structural prototypes, and evaluates recovery from experimental PXRD after excluding structurally matching training entries. To provide a strong reference baseline, we also introduce Bragglite, a PXRD-to-structure model developed through a systematic study of PXRD modeling choices. It achieves a 44.2% Top-1 match rate on experimental RRUFF patterns with known composition, 24.6% above the strongest prior baseline. Further analysis yields several key findings: some models fail to benefit from experimental PXRD, while generalization to unseen structural prototypes and recovery from two-phase mixtures remain challenging. Together, our
benchmark, systematic studies, and Bragglite clarify the capabilities and limitations of current PXRD-to-structure models.
Read the full abstract ▾
All authors Dongyeop Woo, Nofit Segal, Nayoung Kim, Minkyu Kim, Rafael Gomez-Bombarelli, Sungsoo Ahn
Optics
Asynchronous Terahertz-field sampling with soliton microcombs
Alexandra Sakharova, Alexander E. Ulanov, Konstantin Wenzel et al. (+6 more)
Terahertz time-domain spectroscopy records the electric field of terahertz transients and underpins applications from materials science to non-destructive testing. Asynchronous optical sampling enables systems without moving parts, but its acquisition rate remains fundamentally limited by the repetition-rate of the driving femtosecond
lasers. Here, we demonstrate asynchronous terahertz-field sampling with two chip-based
soliton microcombs. Their ultrahigh 25 GHz pulse repetition-rate drastically reduces dead-time during acquisition, and stabilization via sideband injection-locking enables coherent averaging without active feedback loops. At 10 kHz acquisition rate, we achieve a dynamic range of 74 dB in a single 100 $\mu$s scan, and 100 dB after 50 ms of coherent averaging with a 1.6 THz bandwidth. Acquisition rates of up to 100 kHz are demonstrated, limited only by detection electronics. Together with a proof-of-concept silicon wafer thickness measurement, these results establish
soliton microcombs as compact sources for rapid terahertz-field sampling.
Read the full abstract ▾
All authors Alexandra Sakharova, Alexander E. Ulanov, Konstantin Wenzel, Milan Deumer, Alexander Dohms, Bastian Ruhnke, Lars Liebermeister, Robert B. Kohlhaas, Tobias Herr
Nuclear Theory
Representation dependence of the neutron-proton kinetic energy in adiabatic deuteron stripping
Jin Lei
Deuteron stripping reactions such as (d,p) are a main tool for studying the single-particle structure of
nuclei, and they are usually analyzed with the adiabatic distorted-wave approximation (ADWA). With nonlocal nucleon optical potentials, ADWA cross sections change by tens of percent, up to a factor of two, depending on which realistic
neutron-
proton interaction describes the deuteron. Continuum-discretized calculations change much less, and exact Faddeev calculations reduce the spread by about a factor of ten. Should this sensitivity be read as a probe of
neutron-
proton physics at short distances? One identified route for it in ADWA is a single number, the
neutron-
proton kinetic energy averaged over the region where the two nucleons interact. I change the AV18 interaction only at short distances, keeping
neutron-
proton scattering, the deuteron binding energy, and the long-range tail of the deuteron unchanged. This number then rises from 218 to 314 MeV, more than half of its spread among five realistic interactions, while the coefficient that sets the low-momentum shape of the form factor moves by only one percent of its realistic range. The number therefore reflects how the interaction is written, not anything measured. It enters ADWA through two features that the other calculations treat differently: ADWA weights the deuteron where the two nucleons are close, and it assigns the deuteron energy to the pair however fast the two nucleons move. For this short-range change, an average that keeps the full Gaussian shape of the nonlocal potential, instead of expanding it to lowest order, rises by only 6 MeV against 96 MeV.
Read the full abstract ▾
Other Condensed Matter
Deterministic positioning accuracy of B centers in hBN by electron irradiation
A. Núñez Marcos, C. Arnold, J. Barjon et al. (+3 more)
Hexagonal boron nitride (hBN) is a promising material platform for
quantum technologies, enabling both the realization of nanophotonic devices and the hosting of point defects that act as high-quality single-
photon emitters (SPEs). Among these defects, B centers, which reproducibly emit at 436 nm, can be generated individually at predefined positions using electron beam irradiation, a crucial capability for top-down
quantum photonics. Yet, the spatial accuracy of emitter creation strongly conditions the potential applications. Here, we generate arrays of individual B centers in a scanning electron microscope (SEM) with in-situ cathodoluminescence (CL) monitoring. We characterize the sources of random deviations from the target positions to identify the limitations to their deterministic positioning. In particular, we measure the distance between the electron beam and the emitter at the moment the emitter is created based on CL mapping. This approach provides a direct estimation of the spatial extent of the beam-emitter interaction. We find this contribution to be the main constraint to the emitter fabrication accuracy, yielding a standard deviation of 27 nm. Additional contributions, primarily from the finite density of UV-emitting carbon dimer precursors, increase the overall positional standard deviation to 40 nm. Our results highlight the possible improvements to the B center creation technique to reach sub-10 nm accuracy.
Read the full abstract ▾
All authors A. Núñez Marcos, C. Arnold, J. Barjon, S. Buil, J.-P. Hermier, A. Delteil
Materials Science
Modelling the dynamics of the martensitic transformation in Ni$_2$MnGa with machine-learning force-fields
Markus E. Gruner, Yulia Klunnikova, Mike J. Bruckhoff et al. (+2 more)
The martensitic transformations in stoichiometric Ni$_2$MnGa and related Heusler
alloys are governed by a delicate interplay between electronic structure, magnetism, and
lattice dynamics. While density functional theory (DFT) has successfully mapped the energy landscape of modulated martensites, it remains computationally prohibitive for capturing finite-temperature dynamics across relevant length and time scales. Here, we bridge this gap by constructing DFT-trained machine-learning force-fields (ML-FF) interpolated from ab initio molecular dynamics. We demonstrate that ML-FF trained on DFT data can reproduce key features of Ni$_2$MnGa, including the soft TA$_2$
phonon and a preference for nanotwinned martensites. Using classical molecular dynamics simulations, we explore the impact of adaptive nanotwinning on the austenite-martensite transition, which facilitates the dynamics of both, forward and backward transformation. We demonstrate, that the negative twin boundary energy along the entire transformations path predicted by DFT for $T=0$, supports the formation of ordered modulated martensites at finite temperatures. Our results pave the way for large-scale simulations of
magnetic shape
memory alloys with near-DFT accuracy.
Read the full abstract ▾
All authors Markus E. Gruner, Yulia Klunnikova, Mike J. Bruckhoff, Konstatin P. Skokov, Olga N. Miroshkina
Superconductivity
Photon echo from Maki-Thompson interference in a fluctuating s-wave superconductor
Hui Zhou and Yuan Wan
We study theoretically the nonlinear optical response of a fluctuating s-wave
superconductor driven by two successive terahertz pulses. We show that the response exhibits a
photon echo signal that arises from the
quantum interference between the time-reversed electron and hole trajectories in the Maki-Thompson process. By contrast, the transport of the fluctuating Cooper pairs responsible for the Aslamazov-Larkin conductivity does not generate an echo. The
photon echo signal can be readily measured using terahertz two-dimensional coherent spectroscopy, highlighting its potential to distinguish different fluctuation conductivity mechanisms.
Read the full abstract ▾