Geophysics · Cross-listed from cond-mat.other
Entropic Approach to Critical Materials Assessment
Alan J. Hurd
Most methodologies for materials criticality assessment score supply risk and societal importance.
Market-based criteria offer quantitative measures for assessment. Here we develop a statistical approach based on a geologic
entropy function in which flexible constraints, such as economic, national security related, or regulatory, can be applied. As an example, the formulation describes the relation between elemental price and crustal abundance for selected elements, both important to supply risk. The method may be applicable to parameters resulting from collective decisions exhibiting a highly peaked probability distribution.
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Computational Physics · Cross-listed from math-ph
A coupled Kolmogorov-Arnold Network and Level-Set framework for evolving interfaces
Tarus Pande, V M S K Minnikanti and Shyamprasad Karagadde
Kolmogorov-Arnold Networks (KANs) require significantly smaller architectures compared to multilayer perceptron (MLP)-based approaches, while retaining expressive power through spline-based activations. Moving boundary problems are ubiquitous in physical systems, whose numerical solutions are quite complex. We propose a shallow KAN framework combined with a Level-set formulation that directly approximates the temperature distribution $T(\mathbf{x},t)$ and the moving interface $\Gamma(t)$, enforcing the governing PDEs, phase
equilibrium, and Stefan condition through physics-informed residuals. Numerical experiments in one and two dimensions show that the framework achieves accurate reconstructions of both temperature fields and interface dynamics, highlighting the potential of KANs as a compact and efficient alternative for moving boundary PDEs. First, we validate the model with semi-infinite analytical solutions. Subsequently, the model is extended to 2D using a level-set based formulation for interface propagation, which is solved within the KAN framework. This work demonstrates that KANs are capable of solving complex moving boundary problems without the need for measurement data.
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Optics
Programmable on-chip synthesis and reconstruction of partially coherent two-mode optical fields
Amin Hashemi, Abbas Shiri, Bahaa E. A. Saleh et al. (+2 more)
Partially coherent light is typically studied in the context of freely propagating continuous fields. Recent developments have indicated the existence of a `coherence advantage' in multimode optical communications, where partially coherent light outperforms coherent light. However, exploiting partial coherence in such applications requires manipulating multimode field coherence in programmable on-chip platforms. We present here the first example of on-chip synthesis and characterization of two-mode optical fields in an integrated on-chip hexagonal mesh of Mach-Zehnder interferometers. Starting with incoherent two-mode light, we adjust the degree of coherence on the chip with non-
unitary transformations, construct $2\times2$
unitary transformations to synthesize prescribed coherence
matrices, and reconstruct the coherence
matrices via measurements of the spatial Stokes parameters. These results indicate the possibility of deploying programmable photonics for producing large-dimensional structured partially coherent light for applications in communications, cryptography, sensing, and spectroscopy.
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All authors Amin Hashemi, Abbas Shiri, Bahaa E. A. Saleh, Andrea Blanco-Redondo, Ayman F. Abouraddy
Optics
Free-space Optical Diffraction and the Fisher Information
Jonathan M. Nichols and Frank Bucholtz
Using the transport-of-intensity approach for free-space optical propagation in the paraxial regime, we show that diffraction is fundamentally related to the Fisher information associated with models of the transverse intensity distribution. By interpreting intensity as a probability density, we show that a) free-space diffraction will always act to flatten the intensity distribution as the beam propagates, and consequently b) diffraction will monotonically minimize the Fisher Information with respect to any parameterization of the intensity distribution model that depends on propagation distance.
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Instrumentation and Detectors
DC response of an interferometer topology with an L-shaped cavity: a tabletop study
Junlang Li, Jiehong Huang, Xinyao Guo et al. (+11 more)
A new interferometer
topology for kilohertz gravitational-wave detection was recently proposed in [Zhang et al. Phys. Rev. X 13, 021019 (2023)]. The design is based on an L-shaped optical cavity pumped through a Sagnac-like
vortex. We report a tabletop experiment that characterizes the interferometer's optical response near DC. When the
laser frequency is locked to the resonance of the L-shaped cavity, we observe that the cavity input coupler becomes effectively transparent, yielding a simple Michelson-like response. Moreover, the Sagnac
vortex separates into upper and lower paths, which behave as two independent pumping paths driving the cavity. These observations are in agreement with theoretical predictions. Our results provide an intuitive physical picture of this interferometer
topology and offer insight into its lock acquisition strategy.
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All authors Junlang Li, Jiehong Huang, Xinyao Guo, Haixing Miao, Yuchao Chen, Xiaoman Huang, Yuan Pan, Chenjie Zhou, Raffaele Flaminio, Jameson Graef Rollins, Bram Slagmolen, Fan Zhang, Teng Zhang, Mengyao Wang
Classical Physics
Remarks on Galilean electromagnetism
Anton Galajinsky
It is shown that equations describing the Galilean electromagnetism in the presence of sources hold invariant under the l-conformal Galilei group for an arbitrary (half)integer parameter l. The group contains transformations which link an inertial frame of reference to those moving with constant accelerations of order up to 2l-1, thus pointing at potential dynamical instability.
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History and Philosophy of Physics
Viewpoint: On the Emergence of van der Waals Magnets: A Personal Reflection
Je-Geun Park
The observation of magnetism in atomically thin van der Waals (vdW) antiferromagnets (FePS$_3$, NiPS$_3$, and MnPS$_3$) in 2016 marked an important moment in the development of two-dimensional (2D) physics. In this personal reflection, I describe how a simple question, posed in the early 2010s, motivated experimental efforts that culminated in the demonstration of
antiferromagnetic order in monolayer FePS$_3$. Alongside subsequent reports of vdW ferromagnets in 2017, these developments helped establish intrinsic magnetism as a viable degree of freedom in atomically thin materials. I close with personal lessons drawn from this period and a perspective on the opportunities that now shape the field's second decade and beyond.
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Atomic Physics
Static dc electric field orientation effects on two-photon Rydberg EIT
Rob Behary, William Torg, Mykhailo Vorobiov et al. (+7 more)
We examine the influence of a static dc electric field on Electromagnetically Induced Transparency (EIT) resonances that involve highly excited Rydberg states. Our focus is on how these resonances are altered when the relative orientation between the
laser polarization and the external electric field vectors are varied. We experimentally demonstrate characteristic variations in the amplitude of the Stark-split EIT resonances, which can be explained by the selection rules in various geometries. We also present a simplified semi-analytical model that closely resembles the experimental observations. We use these findings to obtain information about the spatially inhomogeneous electric field, produced by a biased wire, using EIT fluorescence measurements that agrees with the expected angular dependencies. These results suggest that simultaneous analysis of frequency shifts and amplitudes of Rydberg EIT resonances may enable vector electrometry of electrostatic fields, necessary for many
quantum sensing applications.
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All authors Rob Behary, William Torg, Mykhailo Vorobiov, Nicolas DeStefano, Adam Vernon, Charles T. Fancher, Neel Malvania, Eugeniy E. Mikhailov, Seth Aubin, Irina Novikova
Instrumentation and Detectors
Radiation tolerance tests on key components of the ePIC-dRICH readout card
S. Geminiani, B.R. Achari, N. Agrawal et al. (+60 more)
The dual-radiator RICH (dRICH) detector of the ePIC experiment will employ over 300000 SiPM pixels as photosensors, organized into more than 1000
Photon Detection Units. Each PDU is a compact module, approximately 5x5x12 cm^3 in size, including four custom ASICs connected to 256 SiPMs and an FPGA-based readout card (RDO) responsible for data acquisition and control. Considering the moderately harsh radiation environment expected in the dRICH detector, this study reports on
proton irradiation tests performed on key components of the RDO card to assess their tolerance to cumulative Total Ionizing Dose (TID) and Single Event Effects (SEE). All tested components demonstrated radiation tolerance beyond the TID levels expected for the dRICH environment, with the exception of the ATtiny817 microcontroller, which showed destructive failure. Furthermore, as expected, the observed Single Event Upset (SEU) rates call for appropriate mitigation strategies in the final system design.
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All authors S. Geminiani, B.R. Achari, N. Agrawal, M. Alexeev, C. Alice, R. Ammendola, P. Antonioli, C. Baldanza, L. Barion, A. Biagioni, A. Calivà, M. Capua, F. Capuani, A. Ciardiello, E. Cisbani, M. Chiosso, M. Contalbrigo, F. Cossio, M. Da Rocha Rolo, A. De Caro, D. De Gruttola, G. Dellacasa, D. Falchieri, S. Fazio, O. Frezza, N. Funicello, M. Garbini, N. Jacazio, F. Lo Cicero, A. Lonardo, R. Malaguti, F. Mammoliti, M. Martinelli, M. Mignone, C. Mingioni, M. Nenni, F. Noto, L. Occhiuto, A. Paladino, D. Panzieri, P. Perticaroli, S. Plavully, L. Polizzi, L. Pontisso, R. Preghenella, R. Ricci, L. Rignanese, C. Ripoli, C. Rossi, E. Rovati, N. Rubini, M. Ruspa, A. Saputi, F. Simula, F. Spizzo, U. Tamponi, E. Tassi, G. Torromeo, C. Tuvè, G.M. Urciuoli, S. Vallarino, P. Vicini, R. Wheadon
Physics and Society
A probabilistic match classification model for low-scoring sports
László Csató and András Gyimesi
All existing match classification models in the tournament design literature suffer from two major limitations: a contestant is considered indifferent only if uncertain future results do never affect its prize, and competitive matches are not distinguished with respect to the incentives of the contestants. We propose a probabilistic framework to address both issues. For each match, our approach relies on simulating all other matches played simultaneously or later to compute the qualifying probabilities for the three main outcomes (win, draw, loss), thereby classifying each match into six categories. The suggested model is applied to the last round of the previous group stage and the new incomplete round-robin league, introduced in the 2024/25 season of UEFA club competitions. The incomplete round-robin tournament is found to contain fewer unimportant matches with two indifferent teams, and substantially more matches where both teams should play offensively. However, the robustly higher proportion of potentially collusive matches can threaten with serious scandals.
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Biological Physics
Constitutive parameter inference using physics-based data-driven modeling in full volume datasets of intact and torn rotator cuff tendons
Carla Nathaly Villacís Núñez, Siddhartha Srivastava, Ulrich Scheven et al. (+3 more)
In this work, we characterized the material properties of an animal model of the rotator cuff tendon using full volume
datasets of both its intact and injured states by capturing internal strain behavior throughout the tendon. Our experimental setup, involving tension along the fiber direction, activated volumetric, tensile, and shear mechanisms due to the tendon's complex geometry. We implemented an approach to model inference that we refer to as variational system identification (VSI) to solve the weak form of the stress
equilibrium equation using these full volume displacements. Three constitutive models were used for parameter inference: a neo-Hookean model, a modified Holzapfel-Gasser-Ogden (HGO) model with higher-order terms in the first and second invariants, and a reduced
polynomial model consisting of terms based on the first, second, and fiber-related invariants. Inferred parameters were further refined using an adjoint-based partial differential equation (PDE)-constrained optimization framework. Our results show that the modified HGO model captures the tendon's deformation mechanisms with reasonable accuracy, while the neo-Hookean model fails to reproduce key internal features, particularly the shear behavior in the injured tendon. Surprisingly, the simplified
polynomial model performed comparably to the modified HGO formulation using only three terms. These findings suggest that while current constitutive models do not fully replicate the complex internal mechanics of the tendon, they are capable of capturing key trends in both intact and damaged tissue, using a homogeneous modeling approach. Continued model development is needed to bridge this gap and enable clinical-grade, predictive simulations of tendon injury and repair.
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All authors Carla Nathaly Villacís Núñez, Siddhartha Srivastava, Ulrich Scheven, Asheesh Bedi, Krishna Garikipati, Ellen M. Arruda
General Physics
Constraint-Induced Effective Mass in Massless Field Propagation
Charles Wood
Constrained propagation of massless fields is ubiquitous in physical systems, arising from boundaries, material structure, or other restrictions on admissible modes. This paper shows that such constraints generically induce mass-like terms in the effective dispersion relation, without modifying the underlying field equations or introducing new degrees of freedom. Working at an abstract level, constraints are represented as linear operators acting on the field's mode space. Restriction of the admissible mode
manifold produces a spectral gap whose magnitude is set by the smallest non-zero
eigenvalue of an associated positive semidefinite operator. This gap may be identified with an effective mass parameter, yielding a Proca-like dispersion relation in the long-wavelength limit. The resulting Mass Induction Principle identifies rank reduction of the accessible mode space as the structural mechanism responsible for effective mass generation in constrained massless fields. Familiar systems such as
plasmas,
superconductors, and periodic media realise this structure as special cases, without introducing new dynamics. The analysis is deliberately dispersion-level and non-phenomenological: it does not assert a field-theoretic mass term, does not address
vacuum propagation, and does not make claims about bounds on intrinsic particle masses.
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Atomic Physics
Constraining axion-like dark matter with a radio-frequency atomic magnetometer
A. Rigoulet, S. Nanos, I. K. Kominis et al. (+1 more)
We report on a broadband search for
axion-like-particle (ALP) interactions using a
radio-frequency-operated $^{87}\mathrm{Rb}$ atomic magnetometer. The instrument provides wide spectral coverage and sensitivity to an oscillating pseudomagnetic field that may be generated by the gradient coupling of the ALP field to the constituent
fermions of atoms. We search for an ALP-gradient signature in the mass range $2.40\times10^{-10}\,\mathrm{eV}/c^{2}$–$2.11\times10^{-9}\,\mathrm{eV}/c^{2}$. No statistically significant signatures of an oscillating
magnetic field are observed, and we derive upper limits on the corresponding ALP-
proton, -
neutron and -electron couplings, $g_{\alpha pp}$, $g_{\alpha nn}$ and $g_{\alpha ee}$, respectively. The result on $g_{\alpha pp}$ improves over previous laboratory searches, while the limits on $g_{\alpha nn}$ and $g_{\alpha ee}$ complement earlier laboratory searches and astrophysical bounds. The work extends searches for ALP-
fermion interactions into a mass region largely unexplored in a dark-matter context, demonstrating the potential of our method for broadband
axion-like particle searches targeting the
Galactic dark-matter
halo.
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All authors A. Rigoulet, S. Nanos, I. K. Kominis, D. Antypas
Optics · Cross-listed from cond-mat.mtrl-sci
Light-induced Magnetization by Quantum Geometry
Hiroki Yoshida and Takehito Yokoyama
We propose a mechanism for the inverse Faraday and the inverse Cotton–Mouton effects arising from
quantum geometry, characterized by the
quantum metric quadrupole and the weighted
quantum metric. Within a semiclassical framework based on the Boltzmann transport theory, we establish a general formalism describing light-induced magnetization in electronic systems as a second-order response to the electric field of light. Using continuum and tight-binding models, we discuss the
symmetry constraints on these effects and estimate the magnitudes of the resulting magnetizations. Our results highlight a direct manifestation of
quantum-
geometric quantities in nonlinear magneto-optical responses and suggest a viable pathway for experimental detection.
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Instrumentation and Detectors
Characterization of Silicon-Membrane TES Microcalorimeters for Large-Format X-ray Spectrometers with Integrated Microwave SQUID Readout
Avirup Roy, Robinjeet Singh, Joel C. Weber et al. (+17 more)
We present the electro-thermal characterization of transition-edge sensor (TES) detectors suspended on Si membranes fabricated using a silicon-on-
insulator (SOI) wafer. The use of an all-silicon fabrication platform, in contrast to the more commonly used silicon nitride membranes, is compatible with monolithic fabrication of integrated TES and SQUID
circuits. The all-silicon architecture additionally allows efficient use of focal plane area; the readout circuitry may be positioned out of the focal plane by bending a thinned portion of the chip. Compatibility with integrated fabrication and efficient use of focal plane area provide a path to an efficient soft X-ray spectrometer. This work is motivated by our goal to develop a 10,000-pixel TES spectrometer to overcome critical measurement limitations in catalysis research. The characterization of fragile, carbon-based intermediates via techniques like Resonant Inelastic X-ray Scattering (RIXS) is often precluded by the slow, high-flux nature of existing technologies. The new instrument will allow for fast RIXS measurements to be made without causing sample damage. We verify the detector models and measure the energy resolution using a pulsed optical
laser, demonstrating the viability of this approach for the final instrument to be deployed at the National Synchrotron Light Source II (NSLS-II).
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All authors Avirup Roy, Robinjeet Singh, Joel C. Weber, W. B. Doriese, Johnathon Gard, Mark W. Keller, John A. B. Mates, Kelsey M. Morgan, Nathan J. Ortiz, Daniel S. Swetz, Daniel R. Schmidt, Joel N. Ullom, Evan P. Jahrman, Thomas C. Allison, Sasawat Jamnuch, John Vinson, Charles J. Titus, Cherno Jaye, Daniel A. Fischer, Galen C. O'Neil
Optics
Parity-Induced Exceptional Points with Localized Loss
J.R. Silva
We explore the existence and stability of exceptional points (EPs) in finite waveguide arrays subject to single-site dissipation using an exact Laplace-transform framework. We show that the EP landscape is governed by a parameter-free Wronskian condition and a geometry-dependent parity effect, yielding strictly distinct spectral behaviors for even versus odd numbers of waveguides. Specifically, odd chains with edge loss suppress coalescence via a protected central mode, whereas even chains with central loss feature a universal threshold that gives rise to imaginary zero modes. These findings clarify the fundamental rules of non-Hermitian
symmetry breaking in finite systems, offering a deterministic framework to predict, engineer, or avoid spectral singularities in integrated photonic
lattices.
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Fluid Dynamics · Cross-listed from math.NA
A Structured Review of Reduced Order Modeling for Domain Decomposition Problems: State of the Art and Perspectives
Shenhui Ruan, Andreas G. Class and Gianluigi Rozza
Reduced Order Models (ROMs) have been regarded as an efficient alternative to conventional high-fidelity Computational Fluid Dynamics (CFD) for accelerating the design and optimization processes in engineering applications. Many industrial geometries feature repeating subdomains or contain sub-regions governed by distinct physical phenomena, making them well-suited to Domain Decomposition (DD) techniques. The integration of ROM and DD is promising to further reduce computational costs by constructing local ROMs and assembling them into global solutions. Due to the complexity and necessity of coupling ROMs, many approaches have been proposed in recent years. This review provides a concise overview of existing methodologies combining ROM and DD. We categorize existing methods into intrusive (projection-based) and non-intrusive (data-driven) frameworks. Various strategies for generating local reduced bases and coupling them across subdomains are illustrated. Particular emphasis is placed on intrusive techniques, including equations, numerical
algorithms, and practical implementations. The non-intrusive framework is also discussed, highlighting its general procedures, basic formulations, and underlying principles. Finally, we summarise the state of the literature, identify open challenges, and present perspectives on future implementation from an engineering viewpoint.
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Fluid Dynamics
Theodore D. Drivas
In these notes, we emphasize
Theorems rather than Theories concerning turbulent fluid motion. Such
theorems can be viewed as constraints on the theoretical predictions and expectations of some of the greatest scientific minds of the 20th century: Lars Onsager, Andrey Kolmogorov, Lev Landau, Lewis Fry Richardson among others.
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Plasma Physics
Comparison of plasma response models for RMP effects on the divertor and scrape-off layer in KSTAR
H. Frerichs, J. Van Blarcum, T. Cote et al. (+3 more)
Resonant
magnetic perturbations (RMPs) are beneficial for control of edge localized modes (ELMs) in tokamaks. Nevertheless, a side effect is the appearance of a helical striations in the particle and heat loads onto divertor targets. The extent and field line connection of these striations is significantly altered by the
plasma response to external perturbations. For an ELM suppressed H-mode
plasma at KSTAR,
magnetic footprints are computed by
FLARE based on
plasma response from GPEC, MARS-F, M3D-C1 and JOREK with substantial differences in the resulting footprints (from 2 cm to 14 cm). This is reflected in EMC3-EIRENE simulations of the resulting heat loads: it is found that either the peak value or the extent of the striations appear to be overestimated compared to IRTV measurements. Reasonable agreement can only be achieved for the smallest footprint for lower input power and lower cross-field transport, or for higher upstream density and radiative power losses.
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All authors H. Frerichs, J. Van Blarcum, T. Cote, S.K. Kim, Y.Q. Liu, S.M. Yang
Optics
A High Intensity Attosecond Light Source in Compact Geometry at ELI ALPS User Facility
Arjun Nayak, Mathieu Dumergue, Sourin Mukhopadhyay et al. (+12 more)
High-order harmonic generation (HHG) has become a standard technique for producing attosecond XUV pulses in the laboratory, yet the high flux necessary for nonlinear XUV photoionization remains accessible to only a few research groups. Here, we introduce the SYLOS Compact high-harmonic beamline at ELI ALPS, specifically designed to provide the flux required for non-linear optics in the XUV. We present a detailed characterization of the beam line demonstrating its capability to generate and utilize both intense attosecond pulse trains and isolated attosecond pulses. We further showcase the two-XUV-
photon double ionization of neon (Ne) and argon (Ar), achieved in a user campaign. The results underscore the beamline's capability to support cutting-edge attosecond experiments and investigations of ultrafast electron dynamics on the attosecond scale.
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All authors Arjun Nayak, Mathieu Dumergue, Sourin Mukhopadhyay, Debobrata Rajak, Naveed Ahmed, János Csontos, Szabolcs Tóth, Prabhash Prasannan Geetha, Ioannis Orfano, Emmanouil Skantzakis, Paraskevas Tzallas, Dimitris Charalambidis, Katalin Varjú, Subhendu Kahaly, Zsolt Diveki
Plasma Physics
Plasma wakes driven by Compton scattering: Non-linear regime and particle acceleration
Thomas Grismayer, Fabrizio Del Gaudio and Luís O. Silva
We investigate
plasma wake generation via Compton scattering from
photon bursts, a non-ponderomotive process relevant when the
photon wavelength is smaller than the interparticle distance but larger than the Compton wavelength. In this regime, electrons can reach relativistic velocities. We extend linear theory to the nonlinear regime, showing that
plasma waves can reach the wave-breaking limit. Perfectly collimated drivers produce wakes propagating at the speed of light, allowing electron phase-locking (limited by driver depletion). Non-collimated drivers induce subluminal phase velocities, limiting acceleration via dephasing. Two-dimensional simulations reveal unique transverse fields compared to
laser wakefields, with a DC
magnetic field leading to consistent focusing. The work considers observational prospects in laboratory and astrophysical scenarios such as around highly luminous compact objects (e.g.,
pulsars, gamma-ray bursts) interacting with tenuous interstellar or intergalactic
plasmas, where conditions favor Comptondominated wakefield acceleration.
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Atomic Physics
High-Resolution Spectroscopy of $^{173}$Yb$^{+}$ Ions
J. Jiang, A. V. Viatkina, Saaswath JK et al. (+7 more)
Compared to other stable isotopes of $\rm{Yb}^+$, $^{173}\rm{Yb}^+$ has a richer hyperfine structure, which leads to more favorable clock transitions, spectroscopic techniques for probing new physics, and more sophisticated
quantum computing architectures. However, to date, its electronic spectrum remains poorly characterized. Here, we report on efficient
laser cooling, state preparation, and detection of a single trapped $^{173}\rm{Yb}^+$ ion. The previously unobserved $^2\!S_{1/2} \rightarrow {}^2\!D_{3/2}$ electric quadrupole transition at 436 nm is coherently excited, and the isotope shift between $^{171}\rm{Yb}^+$ and $^{173}\rm{Yb}^+$ on this transition is determined with an uncertainty of 1.4 Hz. Using microwave spectroscopy, we resolve the hyperfine structure (HFS) of the ${}^2\!D_{3/2}$ state with a relative uncertainty below $10^{-8}$. From the HFS measurement data, we infer for ${}^{173}$Yb a
nuclear magnetic octupole moment $\Omega = -0.062(8)\,({\rm b} \times \mu_N)$ with uncertainty reduced by more than 2 orders of magnitude compared to previous studies. The data also allow us to determine hyperfine anomalies for the ${}^2\!S_{1/2}$ and ${}^2\!D_{3/2}$ states.
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All authors J. Jiang, A. V. Viatkina, Saaswath JK, M. Steinel, M. Filzinger, E. Peik, S. G. Porsev, M. S. Safronova, A. Surzyhkov, N. Huntemann
Accelerator Physics
Square matrix-based six-dimensional convergence map for nonlinear beam dynamics analysis
Jinyu Wan and Yue Hao
The square
matrix-based convergence map (CM) method has proven effective in characterizing nonlinear dynamics in several 4-D dynamical systems. However, when time-dependent perturbations, such as crabbing kicks in
colliders, are present, a comprehensive 6-D analysis becomes essential to accurately capture the coupling between transverse and longitudinal motions. In this work, we extend the CM method to the full 6-D phase space by employing an eigen-decomposition-based formulation of the square
matrix combined with iterative procedures. The proposed 6-D CM approach is first validated using a simplified crabbing map. We demonstrate that the 6-D CM preserves computational efficiency by using only one-turn map, while successfully resolving high-order resonance structures that remain unresolved by conventional frequency map analysis (FMA). This method is subsequently applied to the dynamic aperture (DA) study of the future Electron-Ion
Collider (EIC). The results obtained from the CM analysis exhibit close agreement with those derived from FMA, demonstrating its potential as a powerful tool for nonlinear beam dynamics analysis and DA evaluation, as well as for broader applications in other nonlinear dynamical systems.
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Applied Physics · Cross-listed from cond-mat.mes-hall
Dynamical Stabilization of Inverted Magnetization and Antimagnons by Spin Injection in an Extended Magnetic System
Emir Karadza, Hanchen Wang, Niklas Kercher et al. (+4 more)
Dynamical perturbations can modify the energy landscape of a physical system, such that unstable
equilibrium configurations become stable when subject to an external drive. The
magnetic analog of such dynamical stabilization corresponds to saturation of the magnetization against an external field. Here we report dynamical stabilization of the magnetization in thin film bismuth-substituted yttrium iron garnet by
spin current injection from an adjacent Pt layer. Magneto-optical Kerr effect measurements demonstrate magnetization reversal against
magnetic fields up to 3000 times larger than the film's coercivity once the
spin injection surpasses a critical threshold associated with negative damping. Micromagnetic simulations reveal that this process is mediated by the excitation of a large population of incoherent
magnons with non-zero wave vector, leading to a transient shortening and subsequent stabilization of the inverted magnetization. The elementary excitations of the high-energy inverted magnetization state are shown to be antimagnons, quasi-particles carrying opposite energy and
spin relative to
magnons. Our results further reveal how the system's size and minimization of nonlinear
magnon scattering processes play a key role in dynamical stabilization, opening new avenues for
magnetic state control beyond conventional magnetization switching. Dissipation-driven phase transitions in large-area
magnetic systems provide a solid-state platform to study magnonic analogs of relativistic phenomena, such as Klein tunneling and black holes, as well as
spin-wave amplification and lasing.
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All authors Emir Karadza, Hanchen Wang, Niklas Kercher, Paul Noel, William Legrand, Richard Schlitz, Pietro Gambardella
Applied Physics · Cross-listed from cond-mat.mtrl-sci
Is it possible to determine unambiguously the Berry phase solely from quantum oscillations?
Bogdan M. Fominykh, Valentin Yu. Irkhin and Vyacheslav V. Marchenkov
The Berry phase, a fundamental
geometric phase in
quantum systems, has become a crucial tool for probing the topological properties of materials.
Quantum oscillations, such as Shubnikov-de Haas (SdH) oscillations, are widely used to extract this phase, but its unambiguous determination remains challenging. This work highlights the inherent ambiguities in interpreting the oscillation phase solely from SdH data, primarily due to the influence of the
spin factor $R_S$, which depends on the Landé $g$-factor and effective mass. While the Lifshitz-Kosevich (LK) theory provides a framework for analyzing oscillations, the unknown g-factor introduces significant uncertainty. For instance, a zero oscillation phase could arise either from a nontrivial Berry phase or a negative $R_S$. We demonstrate that neglecting $R_S$ in modern studies, especially for topological materials with strong
spin-orbit coupling, can lead to doubtful conclusions. Through theoretical analysis and numerical examples, we show how the interplay between the Berry phase and Zeeman effect complicates phase determination. Additionally, we also discuss another underappreciated mechanism - the
magnetic field dependence of the
Fermi level. Our discussion underscores the need for complementary experimental techniques to resolve these ambiguities and calls for further research to refine the interpretation of
quantum oscillations in topological systems.
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Fluid Dynamics
Effects of correlated collisions and intermittency on the growth of lucky droplets
Tobias Bätge, Johannes Zierenberg and Michael Wilczek
To trigger precipitation, water droplets in warm clouds need to attain a sufficient size. Theoretical estimates based on condensation and gravitational collisions alone fail to explain the observed timescales for the onset of precipitation for a range of droplet sizes. This suggests the involvement of collisional growth mediated by
turbulence to resolve the so-called “size-gap problem”. For the onset of rain, it is sufficient that statistical outliers, coined “lucky droplets”, cross the size gap. In this study, we explore the influence of
turbulence on droplet growth, focusing on correlated collisions and intermittency. Using direct numerical simulations of droplets in turbulent flow, we constrain a non-Markovian
stochastic framework that allows us to assess
memory effects on the droplet-size distribution arising from correlations between consecutive collisions. Using our framework, we find that correlated collisions accelerate the initial growth of lucky droplets but have sub-leading effect at later stages. Consequently, we neglect correlations from collisions and model an ensemble of cloud parcels representing fluctuations in the volume-averaged dissipation rate. Here, the distribution of droplet sizes in each parcel is described by a linear master equation with a time-dependent collision rate according to the volume-averaged dissipation rate. Our analyses of this toy model show that intermittency can significantly reduce the time required by lucky droplets to cross the size gap.
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Optics
Multimode Single-Ring Photonic Molecule
Jinsheng Lu, Ileana-Cristina Benea-Chelmus, Vincent Ginis et al. (+3 more)
Photonic molecules can mimic interactions of atomic energy levels, offering new ways to manipulate cavity eigenstates. Current methods using evanescent coupling of multiple cavities face challenges in scalability, flexibility, and coupling control, especially for complex systems. Here we introduce a new method that uses a single multimode optical ring resonator to create photonic molecules. Our design uses multiple waveguide transverse modes in one resonator, providing flexibility to engineer complex interactions without typical coupling constraints. We demonstrate arbitrary inter-mode coupling through transmissive mode converters, allowing precise tuning of resonance splitting and intrinsic losses. This approach enables selective bright-dark mode pair generation and the exploration of novel photonic phenomena such as exceptional points. This multimode photonic molecule overcomes traditional limitations and offers new possibilities for integrated photonic
circuits, optical processing, and studies in non-Hermitian and nonlinear photonics.
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All authors Jinsheng Lu, Ileana-Cristina Benea-Chelmus, Vincent Ginis, Marcus Ossiander, Danilo Shchepanovich, Federico Capasso
Fluid Dynamics
Analysis and simulations of droplet generation regimes in a coaxial microfluidic device
Alessio Innocenti, Andrea Poggi, Simone Camarri et al. (+1 more)
The generation of microdroplets via
segmentation in microfluidic devices is of interest in many applications, from biochemical to pharmaceutical. This technique permits indeed much higher control on the droplet size, uniformity and generation rate than in standard batch generation processes. In this work we have evaluated the suitability of the open-source software Basilisk to accurately predict microdroplet generation by
segmentation. We have validated the numerical tool with analytical solutions for the dynamics of droplets in confined flows, namely with Bretherton theory, and by comparison with literature experimental results. We have then performed several campaigns of numerical simulations for a coaxial device, analyzing the different regimes of droplet generation, and evaluating how the physical and flow parameters affect the production mechanisms and {the diameters of the generated droplets}. Finally we have proposed new scaling laws for the prediction of droplet diameters in the dripping and jetting regimes, refining existing ones by taking into account additional physical effects, like the viscosity ratio.
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All authors Alessio Innocenti, Andrea Poggi, Simone Camarri, Maria Vittoria Salvetti
Applied Physics
A complete fs-laser-ablation route to miniaturized single-crystal PMN-PT piezoelectric actuators
Menotti Markovic, Lucia Oberndorfer, Tobias M. Krieger et al. (+15 more)
This article presents a novel fabrication route for miniaturized piezoelectric actuators that relies exclusively on processes based on femtosecond (fs)
laser ablation. Previous work has already demonstrated that fs-
lasers are uniquely suited for the fabrication of piezoelectric actuators based on PMN-PT, which are required for multiaxial strain-tuning of
quantum dots (QDs) to enable, e.g. the generation of highly entangled
photon pairs. Building on these foundations, the present work advances actuator performance and capabilities by introducing a local thinning strategy. This approach allows the realization of smaller devices, which in turn enables lower operating voltages, while simultaneously offering the possibility of integrating multiple
quantum light sources on a single chip. The article provides a detailed description of the full fabrication chain, entirely based on fs-
laser processing steps, from substrate thinning to metal layer structuring and final device definition. A particular focus is placed on the final cutting process, where the implementation of a third-harmonic ultraviolet (UV) fs-
laser wavelength significantly improves edge quality and shape definition compared to the second harmonic (SH) wavelength used in previous work. The device fabricated through the combination of local thinning and UV-based cutting promises not only to enhance the efficiency of strain transfer but also to ensure the mechanical stability required for practical applications. These results establish fs-
laser-based fabrication as a versatile and scalable method for next-generation piezoelectric actuators, paving the way for advanced strain-engineering approaches in
semiconductor quantum optics and integrated
quantum photonics.
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All authors Menotti Markovic, Lucia Oberndorfer, Tobias M. Krieger, Ievgen Brytavskyi, Barbara Lehner, Julia Freund, Vishnu Prakash Karunakaran, Matthias Domke, Dorian Gangloff, Christian Schimpf, Peter Michler, Simone Luca Portalupi, Michael Jetter, Rinaldo Trotta, Javier Martín-Sánchez, Armando Rastelli, Fadi Dohnal, Sandra Stroj
Physics Education
Personalized Multimodal Feedback Using Multiple External Representations: Strategy Profiles and Learning in High School Physics
Natalia Revenga-Lozano, Karina E. Avila, Steffen Steinert et al. (+4 more)
Multiple external representations (MERs) and personalized feedback support physics learning, yet evidence on how personalized feedback can effectively integrate MERs remains limited. This question is particularly timely given the emergence of
multimodal large
language models. We conducted a 16-24 week observational study in high school physics (N=661) using a computer-based platform that provided verification and optional elaborated feedback in verbal, graphical and mathematical forms. Linear mixed-effects models and strategy-cluster analyses (ANCOVA-adjusted comparisons) tested associations between feedback use and post-test performance and moderation by representational competence. Elaborated multirepresentational feedback showed a small but consistent positive association with post-test scores independent of prior knowledge and confidence. Learners adopted distinct representation-selection strategies; among students with lower representational competence, using a diverse set of representations related to higher learning, whereas this advantage diminished as competence increased. These findings motivate adaptive feedback designs and inform intelligent tutoring systems capable of tailoring feedback elaboration and representational format to learner profiles, advancing personalized instruction in physics education.
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All authors Natalia Revenga-Lozano, Karina E. Avila, Steffen Steinert, Matthias Schweinberger, Clara E. Gómez-Pérez, Jochen Kuhn, Stefan Küchemann