Optics
Self-partitioned Interfacial Time Crystals
Joseph Huang and Yi Yang
Nonequilibrium many-body systems can spontaneously break
symmetry in time, as in time
crystals, or in space, through self-organized domains and interfaces. Whether these two forms of
symmetry breaking can intertwine so that an emergent interface alone hosts time-crystalline order remains unknown. In this work, by introducing the Rabi-Hatano-Nelson model, we unveil the existence and mechanism of a self-partitioned interfacial time
crystal (SPITC), where a homogeneous system generates its own internal and tunable interface, at which the time-translation
symmetry is also spontaneously broken. Such a SPITC phase is intrinsically induced by nonreciprocity and open boundary conditions, without external pumping or long-range interaction. The periodic and open boundary phase diagrams of the system are both mapped out;
vacuum and Dicke-like superradiance with static or active orders are identified, with analytical phase boundaries in the weak coupling limit. The frequency of the SPITC is found to scale quadratically with the
spin-
photon coupling strength, as we derive analytically for the slow dynamics of the
spins. The position of the SPITC boundary scales with a critical exponent of $-1$ as a function of the degree of nonreciprocity, in stark contrast to $-1/2$ for an otherwise stationary boundary. Our construction of SPITC establishes a route to spatiotemporal order in non-Hermitian many-body systems.
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Mathematical Physics
Explicit Bound States and Threshold Resonances for Two Identical Fermions on a One-Dimensional Lattice
Sobir S.Ulashov and Shakhobiddin I. Khamidov
We study a two-particle
lattice Schrödinger operator describing two identical
fermions on the one-dimensional
lattice $\mathbb Z$ with nearest-neighbor interaction of strength $\lambda\in\mathbb R$. Using the direct-integral decomposition with respect to the total quasi-momentum $k\in\mathbb T:=(-\pi,\pi]$, we reduce the problem to fiber operators $H_\lambda(k)$ acting in the odd relative-coordinate space. For $k\in(-\pi,\pi)$, the essential spectrum is \[ \sigma_{\mathrm{ess}}(H_\lambda(k)) = [4-4\cos(k/2),\,4+4\cos(k/2)]. \] We give a complete description of the spectral transition at both edges. The operator has a unique simple
eigenvalue outside the essential spectrum if and only if \[ |\lambda|>2\cos(k/2), \] in which case \[ E(k,\lambda) = 4+\lambda+\frac{4\cos^2(k/2)}{\lambda}. \] For $|\lambda|<2\cos(k/2)$ there is no discrete
eigenvalue. At the critical coupling $|\lambda|=2\cos(k/2)$, the
eigenvalue merges with the corresponding spectral edge and becomes a threshold resonance, with a bounded non-square-integrable odd solution. We also derive the threshold and strong-coupling asymptotics of the
eigenvalue and eigenfunction. In the strong-coupling regime the eigenfunction localizes at the interaction sites, whereas at critical coupling it converges pointwise to the corresponding resonant solution. The exceptional fiber $k=\pi$, where the hopping vanishes and the essential spectrum collapses to $\{4\}$, is treated separately.
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Fluid Dynamics
A high-order polynomial-corrected shifted boundary method for simulating fully nonlinear water waves
Jens Visbech, Allan P. Engsig-Karup, Harry B. Bingham et al. (+1 more)
We present a novel unfitted computational framework for simulating fully nonlinear potential flow-based water waves. Focusing on wave propagation, we describe the core methodology, which involves a high-order
polynomial-corrected shifted-boundary approximation on unfitted spectral elements. This approach allows for the simulation of a curved, highly time-dependent (moving and deforming) free surface affected by bathymetric changes. All that on a simple Cartesian background mesh without re-meshing or further approximations of non-affine
geometric features. In addition, we highlight the importance of proper gradient recovery using a
polynomial-preserving technique to accurately capture the vertical free-surface velocity. Ultimately, the goal is to develop a high-order convergent numerical scheme capable of simulating highly nonlinear waves over long periods. This is achieved through an arbitrary-order finite-difference approximation of the free surface combined with added hyperviscosity for numerical stability. We present verification and validation test cases for wave propagation in both periodic and finite domains. Emphasis is placed on convergence studies, the justification for using high-order approximations, the importance of optimal gradient recovery, long-time simulation of highly nonlinear waves, and nonlinear wave interactions with both affine and curved bathymetry changes, as well as with vertical walls, for highly nonlinear stream function waves and high-amplitude
solitons. The novel computational model offers a comprehensive, all-in-one framework for simulating ocean waves and their interactions with offshore structures. It provides significant
geometric flexibility, enabling boundaries such as the free surface to move and deform over time without the need to re-mesh a boundary-fitted mesh.
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All authors Jens Visbech, Allan P. Engsig-Karup, Harry B. Bingham, Mario Ricchiuto
Strongly Correlated Electrons
Field-tuned quasiparticles and electronic structure in heavy-fermion YbNi4P2
Will Broad, Owen Moulding, Takaki Muramatsu et al. (+7 more)
We study the
Fermi surface
topology and quasiparticle properties in the heavy
fermion compound YbNi4P2 at high
magnetic fields using
quantum oscillation measurements. We observe a large decrease of the quasiparticle mass with increasing field and demonstrate good qualitative agreement with the single-ion Kondo model. At the putative Lifshitz transition at 17 T, we observe a sudden change of
quantum oscillation frequencies suggesting an abrupt change of the electronic structure and/or quasiparticle characteristics. Our results demonstrate the ability to tune the electronic structure and provide input for theoretical models of YbNi4P2 and correlated electron systems in high
magnetic fields.
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All authors Will Broad, Owen Moulding, Takaki Muramatsu, Manuel Brando, Alix McCollam, Femke Bangman, Gertrud Zwicknagl, Kristin Kliemt, Cornelius Krellner, Sven Friedemann
Soft Condensed Matter
Geometry-Controlled Dynamic Tensiometry Resolves Intrinsic Surfactant Adsorption Kinetics
Camille Brigodiot, Boxin Deng, Christine Dalmazzone et al. (+2 more)
At short times, interfacial tension depends on experimental geometry because surfactant transport to the interface depends on the mass-transfer conditions.A predictive description therefore requires more than a dynamic tension curve or a fitted adsorption constant: interfacial thermodynamics,
diffusion, and adsorption kinetics must be identified separately. Here, we combine
equilibrium and
diffusion measurements with a microfluidic EDGE tensiometer that provides a nearly stationary interface and controlled micrometer-scale transport.
Equilibrium properties and
diffusion are determined independently, leaving adsorption kinetics as the key unknown. Dynamic tension is then calculated using a nonequilibrium thermodynamic description, without assuming instantaneous
equilibrium between the adsorbed layer and the subsurface solution. For the nonionic surfactant C$_{10}$E$_{8}$,
equilibrium thermodynamics and transport are independently constrained, and a single intrinsic adsorption rate constant describes several concentrations. We extend the framework to SDS by including electrostatic interactions and subsurface-concentration dynamics, capturing transient depletion and replenishment. Once thermodynamic, transport, and kinetic parameters are identified, the model predicts dynamic interfacial tension beyond the geometry and conditions used to determine them. The microfluidic EDGE tensiometer thus provides both a reliable short-time tensiometry method and a quantitative framework for identifying the physical mechanisms governing surfactant mass transfer at interfaces.
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All authors Camille Brigodiot, Boxin Deng, Christine Dalmazzone, Karin Schroën, Annie Colin
Astrophysics of Galaxies
Dissecting ultra-diffuse galaxies in the field
A. Vanzanella, K. Malek, Junais et al. (+16 more)
Context. Ultra-diffuse
galaxies (UDGs) in the field are faint, diffuse systems that remain poorly represented in the literature due to the need for spectroscopic confirmation and the difficulty of obtaining high S/N emission line measurements. Aims. We present a spectroscopic study of 17 blue UDG candidates in the field using optical emission lines to confirm their diffuse nature and properties. Methods. We derived spectroscopic
redshifts($z_{\rm spec}$) for our field UDG candidates. We then computed their effective radii ($r_{\rm eff}$) and central surface brightnesses ($\mu_{0,g}$). We measured the H$\alpha$ and H$\beta$ emission line fluxes in the 17 spectra and derived
star-formation rates (SFR) from the line-luminosity relation. We performed forced photometry on our sample to obtain photometric fluxes and applied an aperture correction on the H$\alpha$ integrated fluxes, propagating the correction to the derived SFRs. We then computed
stellar masses ($M_*$) using colour relations and estimated
dust attenuation and corrected the SFRs accordingly. Two sources were further examined as potential
giant low surface-brightness
galaxies(GLSBGs). Results. We identify nine confirmed UDGs, eight other low surface-brightness
galaxies (LSBGs), including one GLSBG. The $z_{\rm spec}$ of our field UDGs span a range of $0.015-0.037$, their $r_{\rm eff}$ spans $1.69-4.99$ kpc and $\mu_{0,g}$ between $24.05-24.98~{\rm mag~arcsec}^{-2}$.
Galaxies exhibit low to moderate
dust content, with an average V-band attenuation of 0.29 mag. The spectroscopically confirmed UDGs presented in this work, after the aperture correction performed, lie along the
star-forming main sequence. Conclusions. Our results indicate that blue field UDGs are characterised by heterogeneous
dust attenuation and occupy the same region of the
star formation-
stellar mass plane as
dwarf LSBGs.
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All authors A. Vanzanella, K. Malek, Junais, E. Bernaud, A. Gargiulo, H. Thuruthipilly, K. Lisiecki, A. Pollo, M. Scodeggio, P. M. Weilbacher, S. Boissier, P. Franzetti, G. Lorenzon, A. Nanni, C. Adami, R. Gavazzi, O. Ilbert, S. Pal, N. Principi Cavaterra
Materials Science
Charge transfer and competing symmetry breaking drive orbital reconstruction and emergent ferromagnetism in insulating oxide superlattices
Nandana Bhattacharya, Ranjan Kumar Patel, Siddharth Kumar et al. (+13 more)
Electron correlation, hopping, and ligand-to-metal charge transfer collectively lead to diverse electronic and
magnetic phenomena in 3$d$ transition-metal
oxides, where directional d orbitals make hopping highly sensitive to
symmetry-dependent orbital overlap.
Heterostructure engineering with atomically flat interfaces adds
symmetry-breaking charge transfer as a further route to emergent behavior, yet whether interfacial mismatch between constituent
oxides of a superlattice shapes ground states independent of epitaxial strain remains unresolved. Here we examine superlattices combining NdNiO$_3$ with Mott-insulating NdMnO$_3$. Varying layer thickness and combining transport with X-ray spectroscopy, we show that electron transfer from NdMnO$_3$ to NdNiO$_3$ drives a room-temperature insulating state with a distinct electronic structure, accompanied by a reversal in orbital
symmetry beyond simple strain considerations, underscoring the interface's central role. These reconstructions stabilize an emergent
ferromagnetic insulating state arising from interfacial Ni$^{2+}$-O-Mn$^{4+}$ superexchange. Our results establish a pathway to interface-engineered
ferromagnetic insulating phases via competing interactions, with potential for
spin-insulatronic applications.
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All authors Nandana Bhattacharya, Ranjan Kumar Patel, Siddharth Kumar, Sourav Chowdhury, Manav Beniwal, Suresh Chandra Joshi, Prithwijit Mandal, Jayjit Kumar Dey, Weibin Li, Manuel Valvidares, Zhan Zhang, Hua Zhou, Andrei Gloskovskii, Christoph Schlueter, Christoph Klewe, Srimanta Middey
High Energy Physics (Phenomenology)
Expansion attractor in classical Yang-Mills theory
Clemens Werthmann
Applications of the concept of a hydrodynamic attractor have been mostly constrained to the context of hydrodynamization in heavy ion collisions. Deepening the understanding of the general phenomenon requires generalizing it to other contexts in order to see which facettes are truly universal and not a peculiarity of equilibrating conformal Bjorken flow. As part of this endeavor, this work aims to study the behaviour in a system that does not hydrodynamize, but nevertheless loses
memory through expansion. We find that the system goes through three stages. At early times, expansion drives the ratio $P_L/\epsilon$ to converge to $-1$ as $\tau^{-2}$. This
memory loss is partially restored at intermediate times, when interaction dominated degrees of freedom through expansion dominated
evolution grow quadraticallly in time. At late times, interactions shuffle of information in state space without significant
memory loss or restoration.
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Materials Science
Band-like Carriers in a Soft, Anharmonic Lattice: Lead-Halide Perovskites
Young Mi Lee, Inhee Maeng, Jinwoo Park et al. (+2 more)
Lead-halide perovskites APbX3 present a striking dichotomy: they exhibit band-like electronic transport despite their exceptionally soft and anharmonic
lattices. Optically and electrically, they resemble conventional direct-gap
semiconductors, exhibiting light carrier masses and steep absorption onsets, whereas their
lattices display
liquid-like dynamics, including overdamped octahedral motions, quasielastic Raman central peaks, and exceptionally low thermal conductivities. Solution-processed films nevertheless sustain micrometre-scale carrier
diffusion at defect densities that would severely suppress transport in conventional
semiconductors. Here, we argue that these apparently disparate properties emerge from a common microscopic framework: a soft, strongly anharmonic, and polar [PbX3]- framework, strongly influenced by the Pb 6s2 lone pair, which simultaneously shapes the antibonding orbital character of the band edges, the magnitude and multiple timescales of the dielectric response, and the slow relaxational dynamics that dress every charge carrier. We therefore invert the conventional order and develop the
lattice before the electronic structure, because the nominally cubic phase is better viewed as a thermally fluctuating ensemble of locally
symmetry-broken configurations rather than a single geometry. Within this framework, we discuss
excitons, Frohlich large polarons in the intermediate-coupling regime, carrier transport, defect tolerance, dimensional reduction in two-dimensional and nanocrystalline derivatives, and
symmetry-breaking phenomena. We critically assess three contested issues - defect tolerance, ferroelectricity, and the interpretation of the T-3/2 mobility law - and identify seven open questions together with the key measurements needed to resolve them
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All authors Young Mi Lee, Inhee Maeng, Jinwoo Park, Seung-Jae Oh, Min-Cherl Jung
Computational Physics
A Synthetic Iterative Scheme for Non-Gray Phonon Boltzmann Transport Equation with Dual Relaxation Times
Dingtao Shen, Jia Liu and Wei Su
Solving the non-gray Callaway
phonon Boltzmann transport equation allows a dual-relaxation-time approximation of separate normal and resistive scatterings and resolving the mode-dependent spectrum. The conventional iterative scheme (CIS) for deterministic solutions avoids a monolithic phase-space inversion, but its collision-source iteration can become prohibitively slow at a large characteristic length of a material. Existing synthetic acceleration schemes address either non-gray single-relaxation models or gray dual-relaxation models, leaving mode-resolved dual-relaxation transport without a dedicated acceleration framework. We develop a general synthetic iterative scheme (GSIS) for the stationary, linearized, non-gray Callaway equation, where synthetic approximations for the normal-process pseudo-temperature and
phonon drift velocity are provided by exact energy and quasi-momentum balance laws closed with first-order Chapman-Enskog constitutive relations and non-
equilibrium terms evaluated from the kinetic solution. The resistive-process pseudo-temperature is retrieved from the two quantities. Each iteration couples an upwind nodal discontinuous Galerkin kinetic sweep and a hybridizable discontinuous Galerkin solution of the synthetic equations to achieve high-order spatial discretization. A branch- and frequency-resolved
Fourier analysis identifies the deterioration of CIS and shows that the GSIS contraction factor remains bounded away from unity for the considered
graphene material. Asymptotic analysis indicates that GSIS reduces to a consistent discretization of a Guyer-Krumhansl-like equation and
Fourier's law of heat conduction in the hydrodynamic and diffusive limits, respectively.
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Materials Science
uMOF: A Universal Database, Benchmark, and Machine Learning Interatomic Potentials for Metal-Organic Frameworks
Théo Jaffrelot Inizan, Prathami Divakar Kamath, Alin Marin Elena et al. (+1 more)
Foundation machine learning interatomic potentials (MLIPs) deliver near-ab-initio accuracy at a fraction of the computational cost, yet their promise for Metal-organic Frameworks (MOFs) remains largely unrealized as large unit
cells make first-principles training data expensive to generate, fine-tuned models are scarce, and experimentally grounded
benchmarks are scarcer still. We introduce uMOF, a three-part contribution addressing this gap. First, we release the largest and most accurate density functional theory
dataset for MOFs to date, computed at the r$^2$SCAN-D4 level of theory across 85524 configurations spanning 19950 unique frameworks and 79 elements, covering empty and gas-loaded structures, geometry optimizations, equations of state, and finite-temperature molecular dynamics. Second, we release a literature-mined
benchmark of 3986 verified property values (3146 experimental) extracted from 626 papers by a seven-stage, checkpointed multi-pass large
language model pipeline, linked to more than 650 crystallographic information files. Third, we release two universal MLIPs for MOFs, uMOF-MH and uMOF-POLAR, fine-tuned from two architecturally distinct MACE foundation models on the uMOF
dataset. On near-
equilibrium, “Tier-1” properties (bulk modulus,
phonon-derived heat capacity) the uMOF models perform comparably to existing foundation and fine-tuned baselines. On harder, dynamics-sensitive properties like gas adsorption enthalpies via Widom insertion and adsorption isotherms, the uMOF models outperform every baseline we test, including MOF-specialized gas-capture models trained on
datasets up to three orders of magnitude larger, cutting error by more than 80% to within experimental uncertainty. We trace this advantage to the physical diversity of the training data and to level of theory where a small (1.7%) fraction of MD simulations is decisive for MLIP stability.
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All authors Théo Jaffrelot Inizan, Prathami Divakar Kamath, Alin Marin Elena, Kristin A. Persson
Instrumentation and Methods for Astrophysics
Broadband heterodyne interferometry with a chirped femtosecond laser in the H-band
Félix Gudin and Nicolas Forget
Infrared heterodyne interferometry offers a scalable alternative to direct interferometry for long-baseline
telescope arrays. However, at near-infrared wavelengths, its sensitivity is limited by the electronic detection bandwidth and shot noise from the optical reference. Parallel detection via spectral multiplexing has long been identified as a potential means to increase the signal-to-noise ratio of heterodyne interferometers. We propose a new heterodyne detection architecture based on highly dispersed broadband pulses from a mode-locked
laser, fast photoreceivers, and numerical correlation. This enables straightforward spectral multiplexing with commercial components to increase the SNR, while extending instantaneous wavelength coverage to simultaneous J- and H-band operation. The scheme also supports high-resolution spectroscopic imaging ($R \simeq 10^{3}-10^{4}$). We derive the SNR of a two-arm heterodyne interferometer based on balanced photodetection and apply the model to the proposed scheme, using measurements from a single-spectral-channel, all-fiber interferometer operating at 1.56 micrometer over an 8 nanometer bandwidth. We experimentally demonstrate an SNR exceeding 2 for a spectral flux density of 188 pW/nm, with an integration time of 0.4 ms. Scaling the integration time and number of spectral channels suggests that fringe visibility of the brightest H-band
stars could be achieved with 1 m$^2$
telescopes within the typical atmospheric coherence time. These results represent a significant step toward broadband, scalable heterodyne interferometers, demonstrating the potential of ultrafast
laser and telecommunications technologies for astronomical interferometry in the J+H bands. By combining broadband spectral multiplexing with numerical correlation, the architecture also opens a route to direct spectro-imaging without an additional spectrometer.
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High Energy Physics (Experiment)
Characterizing Single-Signal Events from Atmospheric-Neutrino Neutral-Current Interactions in Large Liquid Scintillator Detectors
Zhenning Qu, Jie Cheng, Wan-lei Guo et al. (+3 more)
Neutral-current interactions of atmospheric
neutrinos in large
liquid scintillator detectors offer a new opportunity to study single-signal events (hereafter singles), characterized by a
prompt energy deposition on the MeV-to-GeV scale and no identified delayed signal. In this work, we systematically investigate the model dependence of atmospheric-
neutrino singles due to the primary
neutrino-
nucleus interaction, residual-
nucleus de-excitation, and secondary interactions in the scintillator. Our results show that the dominant model dependence originates from the primary
neutrino-
nucleus interaction, especially for neutral-current processes on carbon, whereas de-excitation is essential for the singles selection yet leads to relatively small spectral variations among realistic models. Secondary-interaction effects are also subdominant overall. We further present the predicted event rates and
prompt-energy spectra for neutral-current singles, along with the charged-current contribution. Separately, we estimate the low-energy contribution from elastic scattering of sub-\SI{100}{\MeV} atmospheric
neutrinos on free
protons. These results highlight the physics potential of current and future large
liquid scintillator detectors, such as the Jiangmen Underground
Neutrino Observatory, to study atmospheric-
neutrino singles, probe
neutrino-
nucleus interaction models, and improve background estimates for rare-event searches.
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All authors Zhenning Qu, Jie Cheng, Wan-lei Guo, Gaosong Li, Yu-Feng Li, Liang-jian Wen
Nuclear Theory
The iconic $^{238}$U: ab initio nuclear structure theory towards the limit of the periodic table
A. Scalesi, T. Duguet and V. Somà
The ab initio description of heavy and superheavy
nuclei constitutes one of the holy grails of
nuclear theory, bearing on the synthesis of the heaviest elements and the limits of
nuclear stability. Over the last fifteen years, many-body expansion methods, whose numerical cost scales polynomially with system size, have extended first-principles calculations to medium-mass
nuclei and a few spherical closed-shell heavy systems. The largest portion of the
nuclear chart is however composed of heavy deformed doubly open-shell
nuclei and has remained completely out of reach. This is due to two major obstacles: (i) the huge computational cost of beyond mean-field calculations in very large single-particle bases, and (ii) a dubious collapse of the mean-field energy at large prolate deformation. While a highly efficient numerical implementation of the novel deformed self-consistent Green's function formalism removes the first difficulty, the second is cured by the inclusion of many-body correlations beyond the deformed mean field. Presenting the first ab initio calculation of the iconic $^{238}$U
nucleus, this work brings the upper-end of the
nuclear chart within reach of theoretical predictions based on first principles.
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High Energy Physics (Experiment)
Next generation tracking and vertexing detectors
Armin Ilg
Precise and efficient track and vertex reconstruction is essential to exploit the physics potential of
collider experiments. The requirements of future tracking systems are determined by the
collider type and its collision environment, required measurement precision, and beam structure. This contribution reviews the requirements and challenges of vertexing and tracking detectors at future $e^+e^-$, $e^-$-
hadron, $\mu^+\mu^-$, and
hadron colliders. Several common trends emerge across the different
collider types. Tracking systems require increasingly precise spatial measurements, low-material designs, and, in some cases, integrated particle identification capabilities. Monolithic active pixel sensors are currently the leading option for vertex detectors at $e^+e^-$ and $e^-$-
hadron colliders. Tracker concepts range from gaseous detectors, which provide many measurements per track and can achieve very low material budgets, to silicon and scintillating-fibre trackers, which provide fewer but more precise measurements and can tolerate higher hit rates. At 10 TeV parton centre-of-mass
colliders, precision timing throughout the tracking system is needed for beam-background rejection or pile-up mitigation. For future
hadron colliders specifically, radiation tolerance beyond that demonstrated by existing sensor technologies is required. Ultimately, meeting the vertexing and tracking requirements of future
colliders will require substantial R&D and the integrated optimisation of sensors, front-end electronics, readout, cooling, powering, and mechanics.
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High Energy Physics (Experiment) · Cross-listed from cs.LG
Comparing Classical and Quantum Machine Learning for Regression in High Energy Physics Collision Data
Tariq Mahmood, Zain ul Abidin, Itzel Luviano Soto et al. (+1 more)
The classification and regression of particle collision events constitute a persistent computational challenge in experimental high energy physics, where large volumes of simulated data must be processed with both speed and precision. This work carries out a systematic comparison of four classical machine learning architectures, support vector machines (SVM), artificial neural networks (ANN), convolutional neural networks (CNN), and long short-term
memory (LSTM) networks against their
quantum counterparts:
quantum SVM (QSVM),
quantum neural networks (QNN),
quantum CNN (QCNN), and
quantum LSTM (QLSTM). All models are trained on simulated
proton-
proton collision events with electron-positron and
muon-antimuon final states from the CERN Open Data portal, using transverse-momentum components as input features and transverse-momentum magnitude as the regression target. Classical architectures, and in particular the CNN and LSTM, achieve marginally better quantitative performance under current hardware and
dataset constraints.
Quantum models, however, reach competitive accuracy with substantially fewer trainable parameters: the QCNN reproduces the performance of the deep classical CNN using only four
qubits and a
circuit of depth three, pointing to a genuine parameter-efficiency advantage on near-term
quantum devices. A baseline analysis confirms that the regression problem is non-trivial for shallow
polynomial fits, supporting the relevance of the architectural comparison. These results characterize the trade-offs between classical and
quantum approaches under realistic, resource-constrained conditions and provide a
benchmark for future studies on actual
quantum hardware.
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All authors Tariq Mahmood, Zain ul Abidin, Itzel Luviano Soto, Alfredo Raya
Fluid Dynamics
How Surface Viscoelasticity Eliminates Satellite Drops
Xiaocong Yang, Qingfei Fu, Lijun Yang et al. (+1 more)
Satellite drops form widely during the breakup of
liquid threads and constitute deleterious byproducts across a broad range of industrial technologies, yet their complete suppression has remained a longstanding challenge. Here, we experimentally report that surface viscoelasticity introduced by a small amount of bovine serum albumin can fully eliminate satellite drops, via modulating the localized spatiotemporal
topology near pinch-off singularity. During the late thinning stage, surface shear viscosity counterbalances the capillary and stably anchors the thinning neck at the midpoint between the two primary beads, fundamentally precluding satellite droplet formation. We further propose a scaling law to describe the unique self-similar thinning behaviors dictated by surface viscosity. These results shed light on the thinning dynamics of
liquid threads with surface rheology and offer a promising strategy to eliminate satellite drops in practical applications.
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All authors Xiaocong Yang, Qingfei Fu, Lijun Yang, Bingqiang Ji
Solar and Stellar Astrophysics
Extremely Low Mass Ratio Contact Binaries. III. Photometric and Spectroscopic Investigations of Eleven Systems
Youmo Lai, Kai Li, Raul Michel Murillo et al. (+6 more)
We present photometric and spectroscopic investigations of 11 totally eclipsing contact binaries with mass ratios below 0.15, classifying them as extremely low mass ratio contact binaries. The ground-based multiband light curves were modeled with PHysics Of Eclipsing BinariEs to derive the photometric parameters of these systems. The TESS light curves of J011323 and J002747 show pronounced asymmetries and continuous variations. Markov Chain Monte Carlo modeling suggests that these variations are related to longitudinal migration of spots on the primary components. Spectral subtraction of the LAMOST spectra reveals excess chromospheric emission in six systems, while no detectable excess emission is found in the other five. The O$-$C analysis indicates secular period increases in six systems and secular decreases in five systems. We estimated their orbital angular momenta and performed a dynamical analysis. {Within our adopted semi-analytical framework without energy transfer, the formation of these observed systems requires additional angular momentum loss beyond saturated
magnetic braking and gravitational radiation, but this requirement could be modified by different assumptions on mass transfer or radius
evolution.
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All authors Youmo Lai, Kai Li, Raul Michel Murillo, Difu Guo, Liheng Wang, Xiang Gao, Han-ning Zhang, Xing Gao, Guo-You Sun
Disordered Systems and Neural Networks
Landau theory of quenched criticality in linear in-context learning
Daesik Kim, Sumin Choi, Hyojae Jeon et al. (+1 more)
In-context learning (ICL) allows a pretrained model to infer a new task from examples supplied in its
prompt without updating its parameters. In linear models of ICL, the prediction error develops a double-descent singularity when the number of pretraining samples becomes comparable to the number of learnable parameters. We formulate this interpolation singularity as a critical phenomenon of a quenched disordered system. By comparing annealed and quenched descriptions of the same linear ICL model, we identify the connected sample-to-sample fluctuations of the learned parameters as the microscopic origin of the singular error. A Landau potential is constructed by integrating the cavity self-consistency equation for the renormalized ridge parameter $\xi$. The role of (magnetization) order parameter is played by $\xi$, while the bare ridge parameter $\lambda$ becomes its conjugate
magnetic field. The normalized sample complexity $\tau$ acts as a temperature and the double-descent singularity occurs at the critical temperature $\tau_c =1$. The Landau susceptibility is precisely the quantity that diverges in the fluctuation contribution to the prediction error. The order parameter is closely related to the fraction of zero
eigenvalues of the empirical relaxation
matrix in the ridgeless limit, which define flat directions in the learning dynamics. The Landau theory is generically cubic in the order parameter with critical exponents $(\beta_{\rm cr},\delta_{\rm cr},\gamma_{\rm cr})=(1,2,1)$. In the large-context regime, there appears a pseudogap-like regime characterized by suppressed order parameter. Predictions of the Landau theory are independently confirmed from numerical solutions of the original learning problem with good quantitative agreement. Our results pave the way for solid statistical-physics understanding of the interpolation criticality in linear in-context learning.
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All authors Daesik Kim, Sumin Choi, Hyojae Jeon, Jung Hoon Han
High Energy Physics (Phenomenology)
Quantum computation of partonic Drell-Yan scattering cross sections and interference effects
Erik Bashore, Stefano Moretti and Timea Vitos
We probe the possibilities of efficiently constructing simple Feynman diagrams into
quantum devices. More precisely, we study Drell-Yan
lepton pair creation at the partonic level of the form q qbar -> gamma/Z -> l- l+. We develop
quantum gates that build up the relevant diagrams using simple Feynman rules, such as vertex and propagator gates V and P. We show how the
quantum circuit may compute simultaneous amplitudes in the phase space and how to reach the full integrated cross section from the outputs. In addition to this, we also show how the
circuit is able to simultaneously isolate the interference effects of the contributing diagrams by a simple basis rotation. The
circuit design is made to be general, and thus this work constitutes a step towards the implementation of arbitrary scattering process computations and efficient interference analyses.
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Soft Condensed Matter
Weakly non-linear creep of amorphous polymers near their glass transition, comparisons between models and experiment
Martin Roman-Faure, Zhaocheng Zhang, Catalin Picu et al. (+2 more)
The non-linear mechanics of amorphous
polymers near the glass transition reveals a stress-induced acceleration of stress relaxation of nanometric sub-units. Recent theoretical work predicts that the local acceleration within these nano-domains should scale as the exponential of the squared local stress, a behavior now supported by experiments. However, this local dynamics has some complex consequences on the macroscopic mechanical response, as dynamical heterogeneities generate complex stress and strain fields in
polymers close to the glass transition. In this study we consider the non-linear creep of an amorphous
polymer near its glass transition and evaluate the relation between local and global acceleration and the emerging load-carrying structure, by comparing experimental data with predictions of three models of increasing complexity: a two-states (2S) model, a self-consistent (SC) model and a finite-element (FEM) model. The experimentally observed trend of accelerated creep under increasing applied stress is reproduced by the SC and FEM models, while the 2S model overestimates stress localization. The macroscopic, homogenized acceleration is predicted to be close to the microscopic one, albeit with an apparent yield stress that depends on compliance. The FEM model evidences the development of a load carrying sub-structure that occupies a small fraction of the total material volume driven by the interaction of sub-domains. This work shows that complexity and heterogeneity emerge due to non-linear interactions and that their adequate representation is essential for predicting the macroscopic mechanical response of amorphous
polymers near their glass transition.
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All authors Martin Roman-Faure, Zhaocheng Zhang, Catalin Picu, Antoine Chateauminois, Francois Lequeux
Strongly Correlated Electrons
Spin-Selective Spectral Flattening and Wave-Packet Dynamics in a Flux-Engineered Lieb Lattice
Nana Chang, Xiaoji Zhou, Yanglin Zhou et al. (+1 more)
We investigate reversible internal-state-selective wave-packet transport induced by
spin-dependent Peierls phases in a two-dimensional nearest-neighbor Lieb
lattice. The two conserved
spin components experience effective fluxes $\alpha_{\sigma}=\alpha_{0}+s_{\sigma}\alpha_{s}$, where $s_{\uparrow,\downarrow}=\pm1$. At the working point $\alpha_{0}=\alpha_{s}=1/4$, the
spin-up and
spin-down components experience $\alpha_{\uparrow}=1/2$ and $\alpha_{\downarrow}=0$, respectively. A band-resolved calculation in the $q=2$
magnetic unit
cell shows that the
spin-up spectrum contains two zero-energy flat subbands associated with the sublattice-imbalance flat-band sector, whereas the remaining four subbands retain finite bandwidths. The half-flux sector therefore fails the all-bands-flat condition and does not realize exact Aharonov–Bohm caging for a generic localized initial state. Nevertheless, real-time simulations reveal a pronounced suppression of
spin-up propagation relative to the dispersive
spin-down component, manifested by a smaller mean-square displacement and an enhanced finite-region retention probability over the pre-reflection time window. Reversing the state-dependent flux interchanges the slow and fast
spin channels, while the dynamical contrast remains robust against moderate flux detuning. These results establish
spin-dependent synthetic flux as a reversible means of controlling internal-state-resolved matter-wave transport without
spin-flip processes or interactions, and provide complementary spectral and real-space criteria for distinguishing exact caging from finite-time dynamical slowing in atomic and photonic flat-band simulators.
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All authors Nana Chang, Xiaoji Zhou, Yanglin Zhou, Song Ci
Solar and Stellar Astrophysics
CoBiToM project. III. Physical characterisation of the potential merger candidates AL Lep, ASAS J082243+1927.0, and ZZ PsA
Sofia Palafouta, Kosmas D. Gazeas, Pasi Hakala et al. (+3 more)
Contact binaries (CBs) are key systems for investigating the late evolutionary stages that may lead to
stellar coalescence. Systems with an extremely low mass ratio and high fill-out factor are of particular interest as potential merger candidates and possible progenitors of luminous red novae. A combined photometric and spectroscopic study of the CB systems AL Lep, ASAS J082243+1927.0, and ZZ PsA is presented. The aim is to derive self-consistent orbital and physical parameters, assess their evolutionary state, and examine whether they have reached the terminal and unstable phase of their
evolution. High-resolution VLT/UVES spectra were analysed to derive radial velocity values, spectroscopic mass ratio, and
metallicity. The results were combined with multi-band light-curve modelling within a Monte Carlo framework to determine the system geometries and absolute parameters. Orbital period variations were investigated through O-C analysis, while the evolutionary status of the systems was assessed using the Darwin instability criterion, critical mass ratio estimates, fill-out factor, and orbital period variation. Mass ratio values of q = 0.1332, 0.1041, and 0.0789 were derived for AL Lep, ASAS J082243+1927.0, and ZZ PsA, respectively. The corresponding primary mass values are M1 = 1.656 +/- 0.081 Msun, 1.275 +/- 0.078 Msun, and 1.795 +/- 0.111 Msun. The locations of their components show significant deviations from single-
star ZAMS and TAMS reference curves, indicating strong binary interaction and energy redistribution through the common envelope. The
spin-to-orbital angular momentum ratio for AL Lep and ASAS J082243+1927.0 remains below the standard Darwin instability threshold, while ZZ PsA lies close to the instability regime and may be consistent with an unstable configuration within the derived uncertainties.
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All authors Sofia Palafouta, Kosmas D. Gazeas, Pasi Hakala, Stanislaw Zola, Athanasios Kafkas, Maria Garro
High Energy Astrophysical Phenomena
Spherical Accretion onto Konoplya Zhidenko Black Holes: Sonic Point Analysis and Fluid Dynamics
M H Waheed and M Z A Moughal
We investigate the spherical
accretion onto a static Konoplya Zhidenko black hole and examine how the deformation of the spacetime affects the dynamics of the accreting matter. By applying the conservation laws of particle number and energy-momentum, we formulate the
accretion problem and derive the corresponding
Hamiltonian describing the fluid motion. The critical points and sonic transitions are then analyzed for ultra stiff, ultra relativistic, radiation, and sub relativistic fluids. We study the dependence of the critical point structure and flow trajectories on the KZ deformation and compare the results with those obtained for asymptotically safe, Schwarzschild MOG, and Reissner Nordström black holes. The comparison shows that the location and behavior of the critical points vary significantly with the underlying BH geometry and the equation of state of the fluid. In particular, the KZ deformation produces noticeable changes in the radial structure of the
accretion flow, with different effects observed for the considered fluid models. These results provide a comparative picture of spherical
accretion in different black hole spacetimes and help clarify how modifications of the background geometry influence matter dynamics in the strong field region.
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Nuclear Experiment
Doppler-shift attenuation method (DSAM) lifetimes in $^{54}$Cr - a re-evaluation
Andrew E. Stuchbery
Background: Contemporary stopping powers for fp-shell
nuclei slowing in tantalum can differ by a factor of two from the 1963 Lindhard, Scharff and Schiøtt (LSS) theory [Mat. Fys. Medd. Dan. Vid. Selsk. 33 no. 14, (1963)] used in Doppler-shift attenuation method (DSAM) lifetime measurements dating back to the 1970s. In recent work [Phys. Rev. C 113, 044306 (2026)], it was found that anomalously high collectivity in the $4^+_1 \rightarrow 2^+_1$ transition of 58Fe given in the literature [Nucl. Data Sheets 111, 897 (2010)] could be traced back as due to the use of these historical stopping powers in the Doppler-shift lifetime measurements. Satisfactory agreement with shell-model calculations was obtained from a re-analysis of the measurement of Bolotin et al. [Nucl. Phys. A 311, 75 (1978)] once the stopping powers were replaced by up-to-date values. Purpose: The DSAM measurement on 54Cr by the same group [Nucl. Phys. A 337, 1 (1980)], which used the same experimental methods and procedures, is re-examined. Method: The computer code used in the original DSAM analysis has been rebuilt and upgraded with the capacity to use contemporary stopping powers. E2 transition strengths derived from the revised lifetimes are compared with shell-model calculations. Results: The lifetimes increase by 16% to 27%, with the larger increase generally corresponding to shorter lifetimes where electronic stopping dominates. Conclusions: Revised lifetimes, based on current stopping powers, imply E2 transition rates between states up to the 6$^+_1$ state in 54Cr that compare well with shell-model calculations. The lifetime data together with branching ratios and the shell-model calculations strongly suggest revision of the
spins assigned to the levels at 3.786 (currently (4)$^+$) and 4.043 MeV (currently 5$^+$). These levels are suggested to be the 5$^+_1$ and 6$^+_2$ states, respectively.
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Statistical Mechanics
Emergent aggregation from collective foraging
Gorka Muñoz-Gil, Andrea López-Incera, Vide Ramsten et al. (+3 more)
Collective behaviour in living systems is usually modelled as the outcome of a direct social drive:
agents are rewarded, or hard-wired, to align with or approach their neighbours. Here we show that aggregation can instead emerge from an indirect objective. We let reinforcement learning foragers, initially performing a random walk, optimize their dynamics from a purely individual reward for finding replenishable targets, while perceiving only their conspecifics and never the targets themselves. As the visual range grows, the
agents undergo a sharp crossover from an environment-tuned individual search to a scale-agnostic collective one, and this crossover coincides with the onset of spatial aggregation. Thus a collective phase arises as a by-product of optimal foraging, without any direct reward for grouping. A minimal analytical first-passage model reproduces the transition as a crossover between the two search strategies. Our results identify indirect, resource-driven reward as a generic route to emergent collective phenomena.
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All authors Gorka Muñoz-Gil, Andrea López-Incera, Vide Ramsten, Giovanni Volpe, Thomas Müller, Hans J. Briegel
Nuclear Theory
Nuclear surface energy in a semiclassical Extended Thomas-Fermi approach with finite-range interactions
D. Davesne, Y. Lallouet, A. Pastore et al. (+2 more)
Using the Gogny finite-range interaction, we investigate a series of semiclassical approximations to the Fock term entering the calculation of the
nuclear surface energy. By comparing these approximations with the exact results obtained from the full Hartree-Fock solution in semi-infinite
nuclear matter, we derive a simple pocket formula that can be incorporated into fitting protocols to estimate the surface energy coefficient with excellent accuracy.
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All authors D. Davesne, Y. Lallouet, A. Pastore, J. Navarro, X. Viñas
Soft Condensed Matter
Mechanics and statistics of a solvable model of an autophoretic colloidal chain
Arvin Gopal Subramaniam and Rajesh Singh
Equilibrium statistical mechanics owes much of its analytical tractability to
symmetry: detailed balance, gradient flows, and the resulting vanishing of steady-state
entropy production follow directly from the structure of the underlying dynamics, not from any smallness of the driving. Exact solutions of this kind are rare away from
equilibrium. Here we identify a class of far-from-
equilibrium active colloidal chains – coupled via roto-translational, autophoretic (monopolar) interactions – that admit an exact quasi
equilibrium description: at fixed chain geometry, the orientational equations of motion for every monomer are derivable from a scalar potential, detailed balance holds exactly in the orientational sector, while the positional sector breaks the
equilibrium structure. The associated steady-state
entropy production rate (EPR) vanishes identically for this sector, even though the full system is manifestly driven and dissipative. We solve this reduced dynamics exactly for dimers and semi-analytically for general $N$-mers, obtain the orientational fluctuations and the full-system EPR in closed form, and show that all dissipation is carried by the translational (center-of-mass) sector. We further examine the effect of dipolar chemical emission – expected from asymmetric micelle deposition at the monomer scale – and find that the
equilibrium structure holds exactly for dimers, whereas for longer chains no such description is possible. A purely dipolar coupling instead producesa genuinely non-
equilibrium state with no static attractor, sustaining non-monotonic drift with no fixed limit, and an EPR that itself never reaches steady state. Monopolar coupling remains necessary and sufficient for the polarized state; dipolar coupling alone breaks the quasi-
equilibrium structure without replacing it with a new static one.
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Solar and Stellar Astrophysics
A decade of radial-velocity monitoring of rho Leo: moment analysis and periodic variability
V.A. Checha, A. Aret, I. Kolka et al. (+6 more)
We investigate the origin of long-term spectroscopic and photometric variability in the blue supergiant rho Leo, with particular emphasis on distinguishing between intrinsic pulsations and variability induced by a possible companion. Our analysis is based on an 11.5-year spectroscopic time series obtained at Tartu Observatory, complemented by high-cadence, high-resolution spectroscopy from the Hertzsprung SONG
telescope and space-based photometry from TESS. We studied line-profile variability using normalised moments of the HeI 6678, HeI 5875, and SiIII 4552 lines. Periodic signals were identified using the generalised Lomb-Scargle periodogram with iterative pre-whitening, and their temporal stability was examined with the weighted wavelet Z-transform. We detect a persistent periodic signal at P = 16.46 d in the first and third moments, present throughout the full observing interval, with a radial-velocity amplitude of 3.9 km/s. This signal is also present in the SONG data and is visible in multiple spectral lines, indicating a global origin. Photometric observations reveal a dominant variability timescale near 33 d, approximately twice the spectroscopic period. The stable 16.46-day period, present throughout the entire observing interval, most likely results from non-radial pulsations of the supergiant. A binary origin of the signal is not excluded, but distinguishing between these scenarios is complicated by the supergiant's complex variability pattern.
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All authors V.A. Checha, A. Aret, I. Kolka, T. Liimets, V. Mitrokhina, A. Kasikov, T. Eenmäe, S. P. D. Borthakur, H. Ramler
General Relativity and Quantum Cosmology
Devoured by a Hairy Gargantua: Probing Massive Scalar Charges with Non-minimal Curvature Coupling with Extreme-Mass-Ratio Inspirals
Leif Lui, Adrian Ka-Wai Chung and Alejandro Torres-Orjuela
Ultralight scalar fields nonminimally coupled to
curvature can endow rotating black holes with stationary hair and alter nearby orbits. Using recently constructed hairy black-hole spacetimes, we model the transition to plunge of an extreme-mass-ratio inspiral. For scalar masses $\mu M=0.01$ and $0.1$ and dimensionless
curvature coupling $\zeta=10^{-3},10^{-4}$, we find $\mathcal{O}(10)$ rad of gravitational-wave dephasing relative to general relativity over $\mathcal{O}(10^3)$ orbits. A multimode Fisher forecast at $\mu M=0.2$, where neighbouring hair solutions permit a numerical $\mu$-derivative, suggests that $\zeta$ and $\mu$ could be measured to precisions of $\simeq0.2\%$ and $0.6$–$1.1\%$, respectively, for a source with signal-to-noise ratio of about 80 in LISA.
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