Optics
Perturbative Deformation Mechanism of Metasurface
Tuo Li, Xin Liu, Lin Zhu et al. (+1 more)
Metasurfaces enable precise manipulation of light-matter interactions, and meta-atom coupling and scaling dominates their resonant properties and functional responses. Conventionally, although theories such as CMT and CDT can explain many metasurface phenomena, a unified mechanism that reveals how the deformation of metasurface affect its performance remains lacking. Here, by combining transformation optics and spatial perturbation, we proposed a universal deformation mechanism of metasurface, which establishes a general physical picture. Based on this mechanism, we interpret the resonance frequency drift caused by coupling of the meta-atoms, clarify the tuning law of resonant frequency via
geometric scaling of unit structures, and further demonstrate the anisotropic shift of grating resonant peak. Theoretical predictions show consistency with full-wave simulation results in all three scenarios. Given the broad applicability of the transformation optics and perturbation theory, the universal mechanism with intuitive physical picture should be widely existed in diverse fields including photonics
crystals, Bragg fibers, two-dimensional materials and crystalline optical properties.
Read the full abstract ▾
All authors Tuo Li, Xin Liu, Lin Zhu, Lei Liang
Atomic Physics
Photoelectron spectroscopy with a resonant dichromatic field: Role of geometric phase
Evan Munaro-Langloÿs, Axel Stenquist and Jan Marcus Dahlström
We investigate
geometric-phase control in resonantly driven two-level atoms exposed to near-degenerate dichromatic
laser pulses. In contrast to conventional two-color schemes based on widely separated frequencies, the closely spaced frequency components generate a slowly varying beating envelope that repeatedly reverses the pseudo-
spin rotation on the Bloch sphere. This enables coherent control of the
geometric phase accumulated during Rabi dynamics and strongly modifies the resulting photoelectron spectra. Using an exactly solvable model for flat-top pulse envelopes, we derive the essential-state dynamics analytically and analyze photoionization induced both by an auxiliary field and by the dichromatic driving field itself. We show that the formation of Autler–Townes doublets can be interpreted in terms of destructive interference associated with
geometric phases acquired during completed pseudo-
spin rotations. Beyond the canonical Autler–Townes regime, beat-induced reversal dynamics lead to qualitatively different spectral structures, including re-emergent central peaks and higher-order sidebands. These effects originate from the nonuniform temporal
evolution induced by the beating envelope, which modifies the balance between positive and negative excitation amplitudes. Our results establish beating-field control as a route toward engineering
geometric-phase interference in ultrafast light–matter interactions and suggest broader applications in coherent control of atoms, molecules, and x-ray-driven systems.
Read the full abstract ▾
Chemical Physics · Cross-listed from quant-ph
Resource-efficient energy-based operator selection in fermionic ADAPT-VQE via exact Hamiltonian transformation
Emanuele Rossi, Erik Rosendahl Kjellgren, Artur F. Izmaylov et al. (+3 more)
Energy-based variants of ADAPT-VQE select operators by minimizing a one-parameter cost function for each candidate generator. In fermionic implementations, the cost of reconstructing this function often becomes a bottleneck. We reduce this cost using exact fermionic
Hamiltonian transformations to obtain a generator-dependent partition of the
Hamiltonian that reconstruct the same one-parameter energy function from fragment measurements. This method reproduces the fermionic Rotoselect scoring function exactly with approximately half the Pauli-string measurements. We use this formulation to
benchmark the gradient-based and energy-based selection approaches in combination with two ansatz-optimization strategies—$\textit{last}$, where only the appended operator is optimized, and $\textit{full}$, where the full ansatz is re-optimized—and with both fixed-orbital and orbital-optimized formulations. The
benchmark comprises $\text{LiH}$, $\text{BeH}_2$, and $\text{H}_2\text{O}$ at both
equilibrium and stretched geometries. In the most weakly correlated system, pairing energy-based selection with $\textit{last}$ optimization enables the resource-efficient construction of an accurate ansatz, which avoids any VQE optimization. As correlation increases, full ansatz re-optimization and orbital optimization become the main factors governing convergence and overall resource cost. This study shows how exact
Hamiltonian transformations provide an effective route to reducing the measurement overhead of fermionic energy-based ADAPT-VQE. Moreover, the
benchmark clarifies the relative role of operator selection approach, parameter reoptimization strategy, and orbital optimization in the performance of ADAPT-VQE.
Read the full abstract ▾
All authors Emanuele Rossi, Erik Rosendahl Kjellgren, Artur F. Izmaylov, Stephan P.A. Sauer, Karl Michael Ziems, Sonia Coriani
Atomic Physics
Ionization energies for Rydberg $^4 \mathrm{He}$ ($1snp\,^{1,3}P$) states using the correlated B-spline basis function method
Jing Chi, Hao Fang, Yong-Hui Zhang et al. (+2 more)
We extend the correlated B-spline basis function (C-BSBF) method to high-precision calculations of the ionization energies of helium Rydberg $n^{1,3}P$ states ($n=24$–$35$). Using a unified basis set, we evaluate nonrelativistic energies, relativistic corrections of order $m\alpha^4$ (including finite-mass
recoil), QED contributions of order $m\alpha^5$, and partial $m\alpha^6$ terms (singlet-triplet mixing, one- and two-loop radiative corrections). The remaining higher-order contributions are estimated via $1/n^3$ scaling. The resulting ionization energies achieve kHz-level accuracy and are in excellent agreement with independent Hylleraas calculations, thereby providing cross-validation between two distinct theoretical approaches. From these data, the
quantum-defect parameters are determined and used to extrapolate the ionization energies up to $n=102$. Combining our Rydberg ionization energies with high-precision experimental $2S \rightarrow nP$ transition frequencies yields the ionization energies for the metastable $2^{1}S$ and $2^{3}S$ states as \num{960332040.533(10)}$_\mathrm{stat}(20)_ \mathrm{sys}$ MHz and \num{1152842742.7274(53)}$_\mathrm{stat}(25)_ \mathrm{sys}$ MHz, respectively. The C-BSBF result for the $2 \, ^1 S$ state is consistent with the experimental ionization energy obtained from Rydberg-series extrapolation, while for the $2 \, ^3 S$ state the difference is 0.019(10) MHz.
Read the full abstract ▾
All authors Jing Chi, Hao Fang, Yong-Hui Zhang, Li-Yan Tang, Ting-Yun Shi
Biological Physics · Cross-listed from cond-mat.soft
Tunable supramolecular polymerization from protein charge heterogeneity and architecture
Nynke Marije Hettema, Meng Shen, Frank van Opstal et al. (+2 more)
Multidomain
proteins with flexible unstructured sequence regions are abundant in cellular signaling. This
protein architecture enables self-assembly into supramolecular structures, but how structured interaction domains and overall
protein architecture jointly regulate the assembly size, structure and kinetics remains unclear. Here we use the budding yeast
protein Bem1 as a model multidomain system to show that supramolecular polymerization can be tuned by charge heterogeneity and
protein architecture. We experimentally demonstrate that Bem1's isolated PB1 domain forms extended filaments, whereas full-length Bem1 forms substantially shorter assemblies, indicating that the PB1 domain drives assembly while the remaining
protein architecture tunes filament length. To understand these observations, we develop minimal coarse-grained models approximating the PB1 as a polar 5-bead domain and the full-length Bem1 as a 6-bead model with an additional bead representing the remainder of Bem1. The weight distribution of supramolecular filaments assembled by the 5-bead model quantitatively follows reversible Flory-like polymerization theory, which is tunable within a narrow charge polarity regime. In contrast, the 6-bead model shifts chain-length distributions towards shorter
polymers despite retaining the same driving domain. We show that this deviation arises from steric and
geometric constraints imposed by the appended unstructured regions, where the rotational flexibility between the charge-polar structured domain and the unstructured region emerges as key physical parameter governing self-limited self-assembly. Together, our results establish charge polarity,
protein architecture, and conformational flexibility as programmable control knobs for supramolecular polymerization and suggest a general framework for understanding how multidomain
proteins assemble into tunable biomolecular structures.
Read the full abstract ▾
All authors Nynke Marije Hettema, Meng Shen, Frank van Opstal, Emmett Lim, Liedewij Laan
Atomic Physics · Cross-listed from quant-ph
Comment on "Possibility of superradiant neutrino emission by atomic condensate" by M. Blasone, L. Gastaldo and F. Romeo, Phys. Rev. D 113, 053010 (2026)
Wolfgang Ketterle, Hanzhen Lin and Yu-Kun Lu
We show that the recent proposal for superradiant emission of
neutrinos cannot evade our proof that superradiant
neutrino emission is fundamentally impossible. Pairing two
fermions in a molecule does not remove the cancellation of interference terms in
neutrino emission due to fermionic anticommutators.
Read the full abstract ▾
Optics
Higher-order exceptional points in a multimode continuum optoacoustic system
Anton Montag, Julius T. Gohsrich, Quentin Levoy et al. (+2 more)
Exceptional points appear in non-Hermitian systems as degeneracies, where not only
eigenvalues but also eigenvectors coalesce. They are of great theoretical and experimental interest due to their exotic topological properties and enhanced sensitivity to perturbations. Experimental realizations of higher-order exceptional points, where more than two eigenvectors coalesce, rely on highly fine-tuned setups. Recently, stimulated Brillouin scattering has been employed to generate second-order exceptional points in a fabrication-free setup by leveraging off-resonant scattering. In this work we generalize this approach, and we develop an off-resonant, multimode theory for stimulated Brillouin scattering as an avenue towards realizing
symmetry-induced exceptional points of any order. We present the experimental implementation of our program in an accompanying paper. Our multimode theory could also be employed in applications in optoacoustic sensing, synthetic neuromorphic computing, microwave photonic filters, and optoacoustic
quantum signal processing.
Read the full abstract ▾
All authors Anton Montag, Julius T. Gohsrich, Quentin Levoy, Birgit Stiller, Flore K. Kunst
Chemical Physics · Cross-listed from cond-mat.mtrl-sci
Electron-Ion Path Integral Monte Carlo with Hard Core
Riccardo Fantoni
We performed numerical (restricted) path integral Monte Carlo experiments on metallic Hydrogen from first principles. We study a
quantum two component
plasma where one component is made of pointwise particles of negative
unitary charge and the other is made of charged hard spheres of positive
unitary charge. We study both the additive mixture and a nonadditive mixture where we only keep a hard core between unlike species. We specialize to the case of the electron-
proton plasma with a 1:1 ratios between the molar fraction of the two species. We measured thermodynamic and structural properties of the
plasma. From an analysis of the structure we see a transition from a metallic Hydrogen phase, to a molecular Hydrogen phase as the temperature is lowered. As expected at high density the correlations are diminished.
Read the full abstract ▾
Applied Physics
Low Distortion Fusion Bonding using Pneumatically Warped Wafers
Utkarsh Jain, Koen D'have, Philipp Schmidt et al. (+8 more)
Backside power-delivery-network (BSPDN) schemes require wafer-to-wafer bonding steps that do not leave high order shape changes or localized stresses in the bonded stack to ensure that these don't get transferred to the thinned wafer for further lithographic exposure. However, bonding mechanics involve strong adhesive forces which can inherently create localized distortions that lithography tools must eventually compensate. Some contributors to grid distortion of the target wafer are, method of bond initiation, bond front velocity variations, and lack of
symmetry between the wafers. In this work, we evaluate a low-distortion bonding approach in the SUSS XBA tool, where some of these contributors are tackled at the source, namely by initiating the bond without a localized external force, and keeping the wafers compliant & symmetric during bonding. Wafers are bonded with a slight pre-stress due to controlled gas pressure applied over the whole backside of the wafers throughout bonding. Wafer-shape measurements of the bonded stacks are used to perform gradient-based in-plane-displacements (IPD) modelling to estimate bonding-induced grid distortion. Dense scanner metrology is used on patterned-bonded wafers to confirm the location and severity of distortion predictions from patterned wafer geometry (PWG) measurements. On the PWG distortion maps and scanner grid readouts, we perform
alignment and CPE modelling with different field layouts. Sub-10 nm levels of residual grid distortion are achievable with relatively low-order correction models, and less than or equal to 3 nm by using advanced CPE models. These results demonstrate that pneumatically warped bonding yields low-distortion bonded stacks, and that simple process tuning can decouple the dominant distortion source from edge-related variability.
Read the full abstract ▾
All authors Utkarsh Jain, Koen D'have, Philipp Schmidt, Damien Leech, Serena Iacovo, Philippe Muller, Dennis Bumuller, Thomas Schmidt, Koen Kennes, Steven Brems, Eric Beyne
Plasma Physics
High-beta runaway transitions in a fluid model of electromagnetic ion-temperature-gradient turbulence
Y. Zhang, M. Barnes, A. A. Schekochihin et al. (+2 more)
Gyrokinetic simulations of tokamak
turbulence indicate that fluctuation levels increase abruptly and dramatically when the
plasma beta exceeds a certain critical value. This increase in fluctuation levels coincides with a transition from a state dominated by zonal flow to one in which turbulent eddies form radially-elongated `streamers'. Here we derive from gyrokinetics a minimal fluid model for electromagnetic ion-temperature-gradient (ITG)
turbulence that captures the key features of this transition. Due to the relative simplicity of the model, we are able to conduct a detailed numerical study of the interplay between the
turbulence and the zonal flow across a broad range of values of the
plasma beta and the ITG. We find that the transition occurs when the Reynolds stress, which tends to strengthen zonal flows, is overwhelmed by the Maxwell and diamagnetic stresses, which tend to weaken them. Power-law scalings of the stress ratios with
plasma beta and ITG are obtained, indicating a possible means by which the location of the transition could be predicted with minimal computational cost.
Read the full abstract ▾
All authors Y. Zhang, M. Barnes, A. A. Schekochihin, P. G. Ivanov, T. Adkins
Optics
Confocal Subsurface Backscattering Microscopy for Optical Identification of Nanoscale Threading Dislocations in SiC Substrates
Russel Cruz Sevilla, Hsiu-Ming Hsu, Irwan Saleh Kurniawan et al. (+8 more)
High density threading dislocations in SiC wafers facilitate reverse leakage and degradation, yet commercial defect inspection systems based on surface profiling and PL dark-contrast miss nanoscale TDs because they lack resolvable surface signatures and band-edge PL is uniformly quenched by background dopants or compensating defects. Here, we develop confocal subsurface backscattering microscopy to nondestructively detect TDs, based on the synergy of confocal filtering induced dark field configuration and strain induced photoelastic mechanism. By simultaneously suppressing specular reflection while enhancing optical scattering from TD induced refractive index perturbation, CSBM enables high contrast, high resolution TD imaging. Moreover, TD types can be distinguished by their distinct photoelastic scattering patterns. Our work establishes a simple but effective optical approach for direct TD identification that is more tolerant of surface imperfections, providing a practical route toward industrial in line inspection.
Read the full abstract ▾
All authors Russel Cruz Sevilla, Hsiu-Ming Hsu, Irwan Saleh Kurniawan, Ruth Jeane Soebroto, Hsiu-Ying Huang, Jia-Ren Wu, Chia-Shain Chuang, Chao-Ming Fu, Sheng-Hsiung Chang, Wen-Chung Li, Chi-Tsu Yuan
Fluid Dynamics · Cross-listed from cond-mat.soft
Contact-network organization and motion statistics in shear-thickening suspensions
Michel Orsi, Rahul Pandare, Brolin Adu-Poku et al. (+2 more)
We use lubricated-flow discrete-element-method (LF–DEM) simulations to examine how contact-network organization shapes particle motion in dense shear-thickening suspensions. The primary system studied is a two-dimensional bidisperse monolayer where rigid clusters are identified by the $(3,3)$ pebble game; three-dimensional simulations are shown to have qualitatively similar rotational velocity statistics. Across the stress–solid-fraction state diagram, frictional contact number, $k\ge 3$ percolation, and rigid-cluster fluctuations all strengthen in the same region where translational velocity correlations grow, \Revision{consistent with coherent translation within rigid clusters and a state-dependent contrast in relative motion between particles inside and outside them}. Rotational motion provides a complementary view: non-affine angular-velocity distributions broaden, \Revision{near-contact non-affine rotational fluctuations become increasingly anti-correlated, and particles inside and outside rigid clusters carry distinct statistics}. Connectivity,
rigidity, and velocity correlations are related but distinct signatures of the constrained collective motion that accompanies shear thickening and the approach to shear jamming.
Read the full abstract ▾
All authors Michel Orsi, Rahul Pandare, Brolin Adu-Poku, Bulbul Chakraborty, Jeffrey F. Morris
Atmospheric and Oceanic Physics
The relationship between atmospheric stratification and internal wave processes
A. V. Kochin
The atmosphere is a resonant system and its oscillation spectrum is determined by the spatial distribution of parameters. For example, the frequency of internal
gravity waves depends on the vertical temperature gradient. Therefore, the study of the spectra of internal wave processes can be used to estimate the spatial distribution of atmospheric parameters. The work is aimed at detecting wave fluctuations in the atmosphere and calculating atmospheric parameters based on the measured spectra. The rate of ascent of the radiosondes was used as a reference information, which was compared with the spectra of pressure fluctuations at the surface. The stratification parameters were calculated based on the frequency of internal
gravity waves and showed good agreement with the upper-air sounding data.
Read the full abstract ▾
Optics
Magnetic field free nonreciprocity in tapered atomic cladded nano waveguide
Ilan Sher, Benyamin Shnirman, Arieh Grosman et al. (+6 more)
Optical nonreciprocity is a fundamental requirement for modern optical communications and
quantum information processing, where it is essential to protect sensitive sources from destabilizing feedback and preserving
quantum coherence. Conventional nonreciprocal devices are based on the Faraday effect; however, their dependence on bulky permanent magnets poses a significant barrier to chip-scale integration and scalability. Moreover, the application of a
magnetic field is undesired in many
quantum atomic systems. In this work, we demonstrate magnet-free optical nonreciprocity on a fully integrated platform utilizing a Nanophotonic Alkali Silicon Waveguide (NASWAG) interfaced with hot rubidium vapor. By employing velocity-selective optical pumping (VSOP), we break time reversal
symmetry by taking advantage of the Doppler effect-generated by the thermally moving atoms, a phenomenon traditionally viewed as a limitation in atomic spectroscopy. We show that the use of suspended tapered waveguides significantly mitigates transit-time broadening, thereby enabling the observation of a robust nonreciprocal response. We further characterize the dependence of the isolation contrast on pump power, finding that the experimental measurements and numerical simulations correspond and provide mutual support for the underlying physical model. With proper optimization, the demonstrated effect may be used in the future for applications such as
magnetic free optical isolators.
Read the full abstract ▾
All authors Ilan Sher, Benyamin Shnirman, Arieh Grosman, Roy Zektzer, Markus Greul, Mathias Kaschel, Tilman Pfau, Robert Löw, Uriel Levy
Computational Physics
Reconstructing Unobservable Temperature Fields via Simulation-Aided Intelligent Sensing
Monika Stipsitz, Hèlios Sanchis-Alepuz, Jacob Reynvaan et al. (+1 more)
Real-time monitoring of the temperature distribution within components and sub-structures is a challenging topic in many systems due to restrictions on feasible sensor locations. While machine learning (ML) proves a versatile tool in many applications, its adoption for high-resolution thermal monitoring is hindered by the availability of high-quality
datasets for training. In this work, we propose a novel approach for generating
datasets for industrial applications based on randomized physics-based simulations. We demonstrate the approach in a proof-of-concept hardware setup: A neural network (NN) trained only on such a synthetic
dataset, is used to reconstruct the internal temperature field from sparse sensors embedded in the hardware. The NN-based reconstructions do not only outperform Kriging in robustness but also enable real-time inference, making the method suitable for online monitoring of otherwise unobservable thermal states.
Read the full abstract ▾
All authors Monika Stipsitz, Hèlios Sanchis-Alepuz, Jacob Reynvaan, Silvester Sabathiel
Plasma Physics · Cross-listed from cond-mat.soft
Vibrational model of entropy in dense two-dimensional fluids
Sergey Khrapak
A vibrational paradigm of atomic dynamic in dense fluids is known to provide useful insight on the transport and thermodynamic properties of fluids in three dimensions. In this paper, a vibrational model is generalized to describe the excess
entropy of two-dimensional (2D) fluids. A simple practical implementation of this model is demonstrated to deliver accurate results for various systems, such as one-component
plasmas with Coulomb and logarithmic interactions, a 2D fluid of dipole particles, and a 2D Yukawa fluid. The applicability limits, relevance to three-dimensional fluids, relations to other 2D phenomena, and potential practical applications are briefly discussed.
Read the full abstract ▾
Classical Physics · Cross-listed from math-ph
Discussion on the Physics Problem of a Boat Crossing a River
Kyle Kou Yuchang, Simon Meng Zimin and Paul Zhang Yixing
This study addresses the boat river-crossing problem under non-uniform flow velocities by constructing three models: constant flow (Model 1), linear distribution (Model 2), and even-power function distribution (Model 3, adjustable via parameter n ). By using the vector addition, combined with the solutions of calculus and differential equations, the analytical expression of the ship's spatial trajectory under a fixed heading angle relative to the water flow is derived. For the shortest-time control problem, the Lagrange multiplier method is introduced to construct a constrained optimization model, and the analytical solution of the optimal heading angle that satisfies the boundary condition of reaching the direct opposite bank is solved. The research results provide theoretical support for the path planning of inland ship intelligent
navigation systems, and the proposed multi-model analysis framework can effectively simulate the complex flow velocity distribution scenarios of real rivers.
Read the full abstract ▾
Computational Physics
Factorizing binary tensors into quantics tensor trains
Paul Haubenwallner and Matthias Heller
The conversion of functions to quantics tensor trains is a well-established procedure and can either be done analytically or numerically. Numerical conversion schemes are based on singular value decompositions, where access to the full tensor is necessary, or on cross interpolations, which only depend on sampling a function. When dealing with large binary tensors, the first approach becomes prohibitively expensive while the second approach might fail to converge due to the non-smoothness of the data. In this work, we provide insight into how binary tensors, where the positions of the non-zero entries are defined by some Boolean function, can be converted into quantics tensor trains with a hybrid analytical-numerical approach utilizing the rank product. The proposed construction scheme nicely reproduces results from the literature and can be used for discrete convolutions, the construction of discrete wavelet transforms or slicing and assignment operations of multi-dimensional quantics tensor trains.
Read the full abstract ▾
Chemical Physics
DeltaDiff: Training-Free, Physics-Guided Machine Learning for Predicting Mutant Protein Structures
Yajie Cai, Yanbin Wang and Ming Chen
Determining mutant
protein structures is critical for understanding the mechanistic roles of mutations in biochemical processes. However, experimental characterization and conventional theoretical modeling are often expensive and time-consuming. Recent advances in machine learning provide new opportunities to efficiently predict
protein structures from primary sequences. Nevertheless, applying these models to
proteins with single-site or few-site mutations remains challenging because mutant sequences are often highly similar to their wild-type counterparts. Here, we introduce DeltaDiff, a physics-guided inference framework for mutant-structure generation that incorporates mutation-aware physical guidance into a baseline
diffusion model. We evaluate DeltaDiff on three representative systems: Chignolin T8P, Novispirin G-10, and BBL D162N. All three examples involve nonlocal structural changes, making accurate mutant-structure prediction challenging. DeltaDiff captures key mutation-induced conformational changes without requiring retraining or fine-tuning of the baseline model. These results establish a foundation for efficient mutant-structure prediction at a fraction of the cost of conventional methods, facilitating rational mutant design.
Read the full abstract ▾
Computational Physics
ATLAS-NN: Adaptive Transfer Learnable Symplectic-aware Neural Network for Long-Time Hamiltonian Dynamics
Changhong Mou, Dinghua Xu, Xiyue Zuo et al. (+2 more)
Modeling
Hamiltonian systems over long temporal intervals remains a significant challenge due to intrinsic multiscale structures and rapid nonlinear transitions. While
Hamiltonian Neural Networks (HNNs) incorporate
geometric invariants to improve stability, they typically rely on a fixed, externally prescribed temporal structure. This lack of adaptability often leads to accumulated phase errors and degraded accuracy in systems with heterogeneous temporal scales. To address these limitations, we put forward the Adaptive Transfer Learnable
Symplectic-aware Neural Network (ATLAS-NN). Our framework augments the HNN architecture with a learnable temporal scaling mechanism that parametrize a nonlinear mapping of time, automatically adapting to the system's intrinsic complexity. We propose a two-stage transfer learning strategy: the model is first trained on a short-time source interval to identify the
Hamiltonian structure and optimal temporal reparameterization; the learned scaling function is then frozen and transferred to an extended target interval for fine-tuning. Numerical experiments on nonlinear oscillators and the chaotic Hénon–Heiles system demonstrate that ATLAS-NN provides a more efficient alternative to standard HNNs and traditional
symplectic integrators, yielding nearly an order of magnitude reduction in long-time prediction error.
Read the full abstract ▾
All authors Changhong Mou, Dinghua Xu, Xiyue Zuo, Keji Liu, Yeyu Zhang
Data Analysis and Statistics
A practical methodology for $\Lambda$ global polarization extraction in fixed-target experiments
Tan Lu, Chengdong Han, Chenlu Hu et al. (+7 more)
Non-central heavy-ion collisions generate large orbital angular momentum in the created medium, which leads to polarization of final-state particles via
spin-orbit coupling, known as global
spin polarization. The observation of significant global polarization of $\Lambda$ hyperon in heavy-ion collisions indicates that the
quark-
gluon plasma is the most vortical fluid known in nature. Exploring $\Lambda$ global polarization at lower energies is important for understanding
spin dynamics across different regions of the
quantum chromodynamics (QCD) phase diagram. Low-energy
nuclear experiments are typically conducted with asymmetric detector acceptance, as in fixed-target collisions at RHIC-
STAR, and at facilities such as FAIR, NICA, HIAF and HIRFL-CSR. The asymmetric rapidity coverage in these experiments enhances the coupling between directed flow and detector inefficiencies, creating significant bias in $\Lambda$ global polarization measurements. In this paper, we propose a methodology to eliminate such bias arising from asymmetric detector acceptance. The method is validated using realistic detector simulations based on the
STAR fixed-target configuration.
Read the full abstract ▾
All authors Tan Lu, Chengdong Han, Chenlu Hu, Xionghong He, Diyu Shen, Subhash Singha, Shusu Shi, Xing Wu, Guannan Xie, Yapeng Zhang
Atomic Physics
Ramsey Atom Interferometry with Transverse Optical Modes
Ryan Husband, Ryan J. Thomas, Yosri Ben-Aïcha et al. (+10 more)
We experimentally demonstrate atom interferometry using the transverse phase profile of an optical mode. As proof-of-principle, we use the helical phase windings of Hypergeometric Gaussian beams for Ramsey interferometry with ensembles of ballistically-expanding cold Rb87 atoms, and we show that the interferometer can measure rotations induced by a motor with a sensitivity that scales linearly with orbital angular momentum and interferometer time. We characterize the thermal decoherence of the interferometer, deriving and experimentally confirming a closed-form expression for the spatially-varying interferometer visibility arising near the singularity of the helical phase winding, motivating the use of condensed atoms in ring-shaped traps.
Read the full abstract ▾
All authors Ryan Husband, Ryan J. Thomas, Yosri Ben-Aïcha, Rhys H. Eagle, Jessica Eastman, John E. Debs, Patrick J. Everitt, Michael Larsen, Eric Imhof, Charles A. Sackett, John D. Close, Simon A. Haine, Samuel Legge
Fluid Dynamics
Shear-driven dynamics of surfactant-laden droplets on rough substrates
Ninad Vinayak Mhatre and Satish Kumar
The depinning of
liquid droplets due to flow of a surrounding immiscible fluid plays a crucial role in applications such as enhanced oil recovery, surface cleaning, and crossflow emulsification. Although surfactants are often present in these systems, the role of Marangoni stresses on droplet depinning by an external flow remains unclear. To address this, we develop a lubrication-theory-based model for a thin Newtonian droplet laden with insoluble surfactant on a substrate with Gaussian-shaped defects which are used to account for the effects of surface roughness. The droplet is surrounded by a surfactant-free immiscible Newtonian fluid in a long, narrow rectangular channel, with flow driven by an applied pressure gradient. Using a precursor-film/disjoining-pressure approach for contact-line motion, we derive nonlinear
evolution equations for the droplet thickness and interfacial surfactant concentration, which are solved numerically. The pressure gradient transports surfactant from the receding to the advancing contact line, generating a Marangoni flow opposing the pressure-driven flow. This reduces the net shear force on the droplet, leading to depinning at a higher critical pressure gradient. These findings reveal a previously unexamined regime in which interfacial Marangoni stresses, rather than uniform interfacial-tension reduction, govern the critical flow rate. The results provide a mechanistic basis for using surfactant-concentration gradients as a tunable handle to control droplet motion on rough substrates.
Read the full abstract ▾
Medical Physics · Cross-listed from eess.IV
L-TGVN: Leveraging Longitudinal Priors for Personalized Rapid MRI
Arda Atal{\i}k, Sumit Chopra and Daniel K. Sodickson
MRI provides excellent soft-tissue contrast without ionizing radiation, but long acquisition times increase patient discomfort while also raising exam costs and limiting scanner throughput. A common approach to reduce scan time is to acquire fewer measurements, which yields an ill-posed linear inverse problem; recovering diagnostic-quality images therefore requires incorporating prior knowledge beyond the measured data. In follow-up exams, the most recent prior scan of a patient can provide a highly informative subject-specific context, but practical use is complicated by temporal changes (including pathology progression), misalignment between scans, and protocol drift across acquisitions. In this work, we introduce L-TGVN, a Longitudinal Trust-Guided Variational Network that leverages prior scans as side information to reconstruct the current scan from heavily undersampled measurements. Crucially, L-TGVN constrains the influence of prior scans to be consistent with the acquired measurements. Unlike many existing longitudinal reconstruction methods, it does not require explicit pre-registration between prior and current scans. It further accommodates differences in acquisition protocols across visits (e.g., changes in sequence parameters). We evaluate L-TGVN against matched-capacity baselines, including prior-guided methods and methods that do not use longitudinal priors, and observe consistent improvements in standard quantitative metrics together with better preservation of fine structures at challenging accelerations. Source code is available at github.com/sodicksonlab/L-TGVN.
Read the full abstract ▾
Optics
Near-Perfect Chirality and Giant Spin-Orbit Conversion in a Single Plasmonic Cavity
Lin Ma, Zhong-Jian Yang, Xiao-Jing Du et al. (+4 more)
To overcome the difficulty of single nanostructures in approaching the theoretical limit of chiroptical performance, we design a single plasmonic twisted dimer cavity whose
magnetic gap plasmon mode enables
magnetic polarization near-field engineering for high chirality. The structure exhibits strong extinction under circularly polarized excitation with one handedness, while its response to the orthogonally circularly polarized light is almost perfectly suppressed, yielding a
chiral g-factor as high as 1.94. Meanwhile, the structure demonstrates strong
chiral-selective
spin-orbit angular momentum conversion: the conversion efficiency is ~95% under circularly polarized excitation with one handedness and only ~1% under the other. By tuning
geometric parameters, the g-factor can be continuously adjusted from 0 to 1.94. Without relying on periodic coupling or collective effects, this work achieves near-perfect chirality and highly efficient angular momentum manipulation solely through intrinsic near-field matching, providing a new design strategy and theoretical basis for highly selective, ultra-compact integrated
chiral photonic devices.
Read the full abstract ▾
All authors Lin Ma, Zhong-Jian Yang, Xiao-Jing Du, Yue You, Kun Zhang, Jun He, Jianfang Wang
Atomic Physics
Photon shot-noise-limited Rydberg-EIT electrometry
Gyeongmin Ju, Ye Jin Yu, Heewoo Kim et al. (+4 more)
Rydberg-atom electrometry is a core technique in the development of highly sensitive
quantum electric-field sensors. Its sensitivity based on atom-
photon interaction is typically limited by
photon shot-noise (PSN) and spectral broadenings. Here, we experimentally demonstrate a near PSN-limited Rydberg electrometry from a 85Rb atomic vapor
cell. By engineering atomic coherence through control of residual
magnetic fields and
laser frequency noise, we achieve the Rydberg electromagnetically induced transparency (EIT) with the narrow linewidth of 1.6 MHz, yielding an enhanced spectral slope for high-sensitivity Rydberg-EIT electrometry. Under optimized superheterodyne detection conditions, we obtain an electric-field sensitivity of 12.5(8) nV cm^-1 Hz^-1/2 at 37 GHz, in close agreement with the calculated PSN limit. These results provide direct experimental evidence of the high-sensitive
quantum electrometry and establish a practical route toward
quantum-noise-limited Rydberg electrometry.
Read the full abstract ▾
All authors Gyeongmin Ju, Ye Jin Yu, Heewoo Kim, Hansol Jeong, Jinhyuk Bae, Changhoon Baek, Han Seb Moon
Chemical Physics
Floquet Nonadiabatic Dynamics for Light-Matter Interactions: Recent Advances and Emerging Opportunities
Jiayue Han, Yu Wang, Vahid Mosallanejad et al. (+2 more)
Light-matter interactions provide versatile routes for probing and controlling chemical reactivity, charge transport, and material properties. Time-periodic external fields can reshape electronic states and open new dynamical pathways beyond the field-free Born-Oppenheimer (BO) picture. Floquet nonadiabatic dynamics has consequently emerged as an important framework for describing coupled electron-
nuclear dynamics under periodic driving. In this Perspective, we first discuss recent developments in Floquet nonadiabatic dynamics methods for closed and open
quantum systems. We then highlight how this framework provides mechanistic insights into electron transfer at molecule-metal interfaces,
quantum transport in molecular junctions, carrier dynamics in crystalline solids, and multicolor Floquet engineering. Finally, we outline key conceptual and computational challenges that must be addressed to transform Floquet nonadiabatic dynamics from model-based demonstrations into predictive, first-principles simulations of realistic light-driven processes.
Read the full abstract ▾
All authors Jiayue Han, Yu Wang, Vahid Mosallanejad, Wei Liu, Wenjie Dou
Optics
Coincidence-pumping upconversion detector based on passively synchronized fiber laser system
Weiyan Kang, Bowen Li, Yan Liang et al. (+4 more)
We experimentally demonstrated a high-performance frequency upconversion detector for telecom-band
photons based on a passively synchronized fiber
laser system. The involved coincidence pumping technique enabled to spectrally convert the pulsed infrared
photons into the visible regime with a conversion efficiency of 72%. The overall detection efficiency of the upconversion detector reached to 30% with a low noise equivalent power of $3\times10^{-17}\ \text{W/Hz}^{1/2}$. In contrast to previous demonstrations, the whole upconversion detection system was constructed in an all-polarization-maintaining fiber structure, thus favoring substantial improvement of compactness and robustness. Moreover, the long-term stability was manifested by at least ten-hour operation with a relative fluctuation of count rates as small as 0.26%. The achieved features here would be desirable in many practical applications requiring efficient and robust coherent manipulation of pulsed optical fields by nonlinear frequency conversion.
Read the full abstract ▾
All authors Weiyan Kang, Bowen Li, Yan Liang, Qiang Hao, Ming Yan, Kun Huang, Heping Zeng
Plasma Physics
Radiation-induced electron spin polarization in ultrarelativistic kinetic turbulence
Peng Liu, Karen Z. Hatsagortsyan, Christoph H. Keitel et al. (+1 more)
Electron
spin polarization in radiative
plasmas with ultrarelativistic kinetic
turbulence under highly magnetized conditions is investigated using particle-in-
cell simulations. We observe that a significant
spin polarization can be sustained when the
leptons undergo energetic
photon emission accompanied by
spin flips during the nonequilibrium turbulent
evolution. By analyzing the time
evolution of spatially dependent
spin polarization, we identify an electromagnetic (EM) regime of kinetic
turbulence, distinct from the well-known density-dominated regime characterized by
vortex currents and
magnetic islands. While in the latter regime the
spin polarization exists only transiently, in the EM regime significant anisotropic net polarization emerges and persists in non-dissipative scenarios. The correlation between
spin signals and
turbulence features is leveraged to introduce the characteristic parameter delimiting the EM regime via the ratio of electric and
magnetic energy densities and to gain insight into complex
plasma turbulence. This study demonstrates the versatility of a
spin-resolved study of the
plasma turbulence in extreme environments, such as black holes and magnetar magnetospheres.
Read the full abstract ▾
All authors Peng Liu, Karen Z. Hatsagortsyan, Christoph H. Keitel, Zheng Gong
Optics
Highly efficient difference-frequency generation for mid-infrared pulses by passively synchronous seeding
Kun Huang, Yinqi Wang, Jianan Fang et al. (+5 more)
We have proposed and experimentally demonstrated a novel scheme for efficient mid-infrared difference-frequency generation based on passively synchronized fiber
lasers. The adoption of coincident seeding pulses in the nonlinear conversion process could substantially lower the pumping threshold for mid-infrared parametric emission. Consequently, a picosecond mid-infrared source at 3.1 $\mu$m was prepared with watt-level average power, and a maximum power conversion efficiency of 77% was realized from pump to down-converted light. Additionally, the long-term stability of generated power was manifested with a relative fluctuation as low as 0.17% over one hour. Thanks to the all-optical passive synchronization and all-polarization-maintaining fiber architecture, the implemented
laser system was also featured with simplicity, compactness and robustness, which would favor subsequent applications beyond laboratory operation.
Read the full abstract ▾
All authors Kun Huang, Yinqi Wang, Jianan Fang, Huaixi Chen, Minghang Xu, Qiang Hao, Ming Yan, Heping Zeng