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At least 451 records · Page 25

Characterizing the initial state and dynamical evolution in XeXe and PbPb collisions using multiparticle cumulants

For the first time, correlations among mixed-order moments of two or three flow harmonics —( v n k , v m l ) and ( v n k , v m l , v p q ), with k, l, and q denoting the respective orders—are measured in xenon–xenon (XeXe) collisions and compared with lead–lead (PbPb) results, providing a novel probe of collective behavior in heavy ion collisions. These measurements compare a nearly spherical, doubly-magic 208 Pb nucleus to a triaxially deformed 129 Xe nucleus, emphasizing the sensitivity to initial-state geometry fluctuations arising from nuclear deformation. The dependence of these results (v n , n = 2 , 3 , 4 ) on the shape and size of the nuclear overlap region is studied. Comparisons between v 2 , v 3 , and v 4 demonstrate the importance of v 3 and v 4 in exploring the nonlinear hydrodynamic response of the quark-gluon plasma (QGP) to the initial spatial anisotropy. The results constrain initial-state model parameters that influence the evolution of the QGP. The CMS detector was used to collect XeXe and PbPb data at nucleon-nucleon center-of-mass energies of S N N = 5.44 and 5.36 TeV, respectively. Correlations are extracted using multiparticle mixed-harmonic cumulants (up to eight-particle cumulants) with charged particles in the pseudorapidity range |η| < 2.4 and transverse momentum range 0.5 < p T < 3 GeV/c.

CMS↗

Differential analysis of incompressibility in neutron-rich nuclei

Both the incompressibility K A of a finite nucleus of mass A and that (K ∞ ) of infinite nuclear matter are fundamentally important for many critical issues in nuclear physics and astrophysics. While some consensus has been reached about K ∞ , accurate theoretical predictions and experimental extractions of K τ characterizing the isospin dependence of K A have been very difficult. We propose a differential approach to extract K τ and K ∞ independently from the K A data of any two nuclei in a given isotope chain. Applying this method to the K A data from isoscalar giant monopole resonances (ISGMR) in even-even Pb, Sn, Cd, and Ca isotopes taken by Garg et al. at the Research Center for Nuclear Physics (RCNP), Osaka University, Japan, we find that the 106 Cd– 116 Cd and 112 Sn– 124 Sn pairs having the largest differences in isospin asymmetries in their respective isotope chains measured so far provide consistently the most accurate up-to-date K τ value of K τ = –616 ± 59 MeV and K τ =–623 ± 86 MeV, respectively, largely independent of the remaining uncertainties of the surface and Coulomb terms in expanding K A , while the K ∞ values extracted from different isotopes chains are all well within the current uncertainty range of the community consensus for K ∞ . Moreover, the size and origin of the “soft Sn puzzle” is studied with respect to the “stiff Pb phenomenon.” Furthermore, it is found that the latter is favored due to a much larger (by ≈ 380 MeV) K τ for Pb isotopes than for Sn isotopes, while K ∞ from analyzing the K A data of Sn isotopes is only about 5 MeV less than that from analyzing the Pb data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Advanced Processing of Rare Earth Elements and Critical Minerals from Acid Mine Drainage Feedstocks

Ongoing work by the project team identified a process for extracting rare earths and critical mineral (REE/CM) concentrates from acid mine drainage from coal mines, a major stream pollutant. The process removes harmful metals and separates REE/CM into economically attractive concentrates. This project explored the processing of those concentrates into individually separated, high purity metals, suitable for domestic manufacturers. The team brought unique experience in working with AMD-based feedstocks since the inception of USDOE’s coal-based REE/CM program in 2016. The project team has pioneered the recovery of rare earth/critical minerals (REE/CM) from acid mine drainage (AMD). This environmentally beneficial strategy will incentivize AMD treatment while recovering materials critical to the Nation’s defense and advanced manufacturing industries. In addition, the project will investigate the co-production of five high purity CMs from AMD, namely Co, Mn, Li, Cr, Ge. This team’s upstream and midstream recovery and processing technology has been demonstrated at the continuous, small scale pilot scale. In conjunction with the West Virginia Department of Environmental Protection, the team is constructing a full-scale, integrated, 500 gpm AMD treatment plant coupled with an REE/CM facility that will produce 21 tons REE/CM per year. Commissioning is scheduled for September 2021. This will provide feedstock for the team’s proprietary downstream processes that met the project objective: production of individually separated, high purity (ISHP) REE/CM oxides and their further processing to elemental metals (REM). To facilitate entry into the U.S. market, we have teamed up with companies that would use our products to strengthen their domestic supply chains and grow REE/CM based manufacturing in the U.S. They include Rockwell Automation, Rivian, Endress+Hauser, Inc., Northrop Grumman and Hela Novel Metals.

01 COAL, LIGNITE, AND PEAT↗

GAAF: Searching Activation Functions for Binary Neural Networks Through Genetic Algorithm

Binary neural networks (BNNs) show promising utilization in cost and power-restricted domains such as edge devices and mobile systems. This is due to its significantly less computation and storage demand, but at the cost of degraded performance. To close the accuracy gap, in this paper we propose to add a complementary activation function (AF) ahead of the sign based binarization, and rely on the genetic algorithm (GA) to automatically search for the ideal AFs. These AFs can help extract extra information from the input data in the forward pass, while allowing improved gradient approximation in the backward pass. Fifteen novel AFs are identified through our GA-based search, while most of them show improved performance (up to 2.54% on ImageNet) when testing on different datasets and network models. Interestingly, periodic functions are identified as a key component for most of the discovered AFs, which rarely exist in human designed AFs. Our method offers a novel approach for designing general and application-specific BNN architecture.

59 BASIC BIOLOGICAL SCIENCES↗

A Contrast Calibration Protocol for X-ray Speckle Visibility Spectroscopy

X-ray free electron lasers, with their ultrashort highly coherent pulses, opened up the opportunity of probing ultrafast nano- and atomic-scale dynamics in amorphous and disordered material systems via speckle visibility spectroscopy. However, the anticipated count rate in a typical experiment is usually low. Therefore, visibility needs to be extracted via photon statistics analysis, i.e., by estimating the probabilities of multiple photons per pixel events using pixelated detectors. Considering the realistic X-ray detector responses including charge cloud sharing between pixels, pixel readout noise, and gain non-uniformity, speckle visibility extraction relying on photon assignment algorithms are often computationally demanding and suffer from systematic errors. In this paper, we present a systematic study of the commonly-used algorithms by applying them to an experimental data set containing small-angle coherent scattering with visibility levels ranging from below 1% to ∼60%. We also propose a contrast calibration protocol and show that a computationally lightweight algorithm can be implemented for high-speed correlation evaluation.

47 OTHER INSTRUMENTATION↗

Derivation of physical equations for high-speed laser welding using large language models

It is challenging to formulate complex physical phenomena that occur in a manufacturing process, particularly when the available data are limited, rendering conventional data-driven approaches ineffective. This study aims to predict humping onset in high-speed laser welding by introducing a novel framework, namely text-to-equations generative pre-trained transformer (T2EGPT). This method leverages the capabilities of large language models (LLMs), in combination with sparse experimental data and enriched literature data, to derive an interpretable and generalizable equation for predicting humping initiation. By capturing key correlations among physical parameters, T2EGPT generates a compact and dimensionless expression that accurately predicts hump formation. The equation reveals that humping arises from the interplay between inertia-driven backward melt flow and capillary-driven surface stabilization, where inertial forces drive molten metal backward and capillary forces resist surface deformation. Furthermore, compared to traditional data-driven models, T2EGPT demonstrates enhanced predictive accuracy and cross-material transferability. More broadly, this study highlights the potential of LLMs to integrate textual information with data-driven discovery, enabling the extraction of physical laws in data-scarce scientific domains.

36 MATERIALS SCIENCE↗

Understanding slurry formulations to guide solution-processing of solid electrolytes

Scalable processing of thin solid electrolytes is crucial for engineering solid-state batteries with practical energy densities. To leverage existing battery production infrastructure, pathways for solution processing of solid electrolyte films must be investigated. Here, roll-to-roll compatible film preparation of aluminum-doped lithium lanthanum zirconate oxide was studied. Four slurry configurations accounting for different solvent properties and solid loadings were evaluated to investigate the ternary interactions within the dispersions. Rheological and coating stability analyses were carried out on the processed slurries. The analysis and characterization indicated that improved component interactions within the ethanol/toluene system result in homogenized distribution of the particles, binder, and plasticizer, and enable the extraction of free-standing thin films with thicknesses of 20 μm and large area (>15 in. 2 ). The drawbacks and opportunities of several protocols for high temperature sintering of the dried green films were investigated. This study highlights the importance of engineering dispersions during the development of processing protocols for solid electrolytes and provides guidelines for the best practices that can be leveraged for solution processing–based fabrications for a wide range of solid electrolyte materials.

25 ENERGY STORAGE↗

Efficiency droop contributors in InGaN green light emitting diodes

Here, efficiency droop contributors (i.e., inherent Auger–Meitner recombination, polarization-induced effects, thermal effects, and light extraction) in InGaN green light emitting diodes (LEDs) are decoupled and quantified. First, a modified ABC model is developed, and external quantum efficiency measurements are taken under constant and pulsed currents (⁠ EQE Constant and EQE Pulsed ⁠, respectively). The LED internal quantum efficiency with and without thermal effects (⁠ IQE$^{ABC}_{Constant}$ and IQE$^{ABC}_{Pulsed}$⁠, respectively) is extracted using the modified model. Then, using Raman spectroscopy, the LED junction temperature is extracted. Finally, using the optical-electrical model (OEM), the polarization- and temperature-independent LED internal quantum efficiency (⁠ IQE OEM ) is calculated from the modified ABC model and the extracted junction temperature. By comparing external (⁠ EQE Constant ⁠) and the three internal quantum efficiencies (⁠ IQE$^{ABC}_{Constant}$, IQE$^{ABC}_{Pulsed}$⁠, and IQE OEM ), the impacts of inherent Auger–Meitner recombination, polarization-induced effects, thermal effects, and light extraction on the efficiency droop are decoupled and quantified. It is found that inherent Auger–Meitner recombination-induced droop is approximately 49% of the total efficiency droop in commercial green LEDs, while polarization-induced effects contribute about 35%, and thermal droop accounts for nearly 16%. Lastly, these findings suggest, to quash the green gap, it is critical to search for materials and device designs with low inherent Auger–Meitner coefficients and polarization fields, respectively.

42 ENGINEERING↗

Early Alarm: Robust Event Analysis for Power Systems using 1-D Fully Convolutional Network

This work presents a novel deep learning model for early, accurate, and robust detection, recognition, and temporal localization of multi-type events in large-scale power systems. The proposed method develops a unified 1-D fully convolutional network (FCN) model that takes time series of raw frequency signals measured from a power system as input, extracts distinguishing features, and predicts at every temporal point in the time series if an event is happening and what the type of the event is. Compared to existing methods, the proposed model eliminates the necessity for hand-crafted feature extraction or complicated data pre-processing, can flexibly handle input signals of arbitrary length, and precisely infer the event occurrence time. Most importantly, the model is intentionally trained with incomplete patterns, such that it is more robust to partial features of an event which is common in real-world online recognition, resulting in early alarm for power system failures. Extensive experimental results demonstrate that the proposed method achieves superior performance to the state-of-the-art, and also shows strong robustness to noise and system oscillations.

Li, Chengcheng↗

Electronic structure theory with molecular point group symmetries on quantum annealers

Quantum computation has the potential to revolutionize quantum chemistry through major speedups in computation times and an exponential reduction in computational resources. Here, we combine the symmetry-adapted Jordan–Wigner encoding based on the full Boolean symmetry group $\mathbb{Z}$$^{k}_{2}$ with our new implementation of the Xia–Bian–Kais (XBK) method for improving the efficiency of electronic structure theory calculations on quantum annealers, particularly by reducing the number of qubits needed to achieve the same accuracy. By providing a more extensive symmetry-adapted encoding (SAE) than previous work, we are able to simulate molecules larger than those previously reported that have been studied using methods developed for quantum annealers and without using an active space. We calculated the potential energy surfaces of H 2 , LiH, He 2 , H 2 O, O 2 , N 2 , Li 2 , F 2 , CO, BH 3 , NH 3 , and CH 4 , with the largest molecule in the STO-6G basis set requiring 16 qubits with our SAE, and compared them with full configuration interaction results. The application of SAE to the XBK method provides an exponential reduction in the size of the Hilbert space and scales well with the size of the problem. It does not introduce significant additional errors for even or large values of a key variational parameter that determines the number of ancilla qubits used in the XBK method’s Hamiltonian embedding, or for certain molecules such as He 2 and H 2 O. Here, we provide an explanation for this behavior and a recommendation on the usage of our method. In addition, we briefly discuss the potential of extracting electronic excited states from our method.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

Measurement of the $\textrm{t}\overline{\textrm{t}}\textrm{H}$ and tH production rates in the H → $\textrm{b}\overline{\textrm{b}}$ decay channel using proton-proton collision data at $\sqrt{s}$ = 13 TeV

An analysis of the production of a Higgs boson (H) in association with a top quark-antiquark pair ($\textrm{t}\overline{\textrm{t}}\textrm{H}$) or a single top quark (tH) is presented. The Higgs boson decay into a bottom quark-antiquark pair (H → $\textrm{b}\overline{\textrm{b}}$) is targeted, and three different final states of the top quark decays are considered, defined by the number of leptons (electrons or muons) in the event. The analysis utilises proton-proton collision data collected at the CERN LHC with the CMS experiment at $\sqrt{s}$ = 13 TeV in 2016–2018, which correspond to an integrated luminosity of 138 fb −1 . The observed $\sqrt{s}$ production rate relative to the standard model expectation is 0.33 ± 0.26 = 0.33 ± 0.17(stat) ± 0.21(syst). Additionally, the $\textrm{t}\overline{\textrm{t}}\textrm{H}$ production rate is determined in intervals of Higgs boson transverse momentum. An upper limit at 95% confidence level is set on the tH production rate of 14.6 times the standard model prediction, with an expectation of ${19.3}_{-6.0}^{+9.2}$. Finally, constraints are derived on the strength and structure of the coupling between the Higgs boson and the top quark from simultaneous extraction of the $\textrm{t}\overline{\textrm{t}}\textrm{H}$ and tH production rates, and the results are combined with those obtained in other Higgs boson decay channels.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Cold air quench control of local crystallization environment in fully air-processed carbon-based perovskite solar cells

Carbon-based perovskite solar cells (C-PSCs) present a low-cost route to efficient photovoltaic technology. Gas quenching is an essential process commonly used for solvent extraction in scalable module fabrication using solution processes, but film quality remains highly sensitive to the localized environmental processing temperature, especially during intermediate phase transitions before perovskite film high temperature annealing. In this study, we introduce a cold air quench strategy to precisely control the local crystallization temperature that simultaneously promotes uniform crystallization and facilitates strain relaxation in fully air-processed C-PSCs. It is found that implementing dry air at 10 °C as the quenching gas yields a champion power conversion efficiency (PCE) of 20.52 %, with preferential (110) orientation and reduced, homogenized in-plane strain. This newly developed technique of a cost-effective low temperature air quenching process also enhances carrier lifetime, reduces interface recombination, and improves charge extraction. Furthermore, this work presents cold air quenching as a scalable, economic method to control perovskite crystallization and strain in C-PSC fabrication, advancing the industrial viability of high-performance perovskite modules.

14 SOLAR ENERGY↗

Revealing the short-range structure of the mirror nuclei 3 H and 3 He

When protons and neutrons (nucleons) are bound into atomic nuclei, they are close enough to feel significant attraction, or repulsion, from the strong, short-distance part of the nucleon-nucleon interaction. These strong interactions lead to hard collisions between nucleons, generating pairs of highly energetic nucleons referred to as short-range correlations (SRCs). SRCs are an important but relatively poorly understood part of nuclear structure, and mapping out the strength and the isospin structure (neutron-proton (np) versus proton-proton (pp) pairs) of these virtual excitations is thus critical input for modelling a range of nuclear, particle and astrophysics measurements. Two-nucleon knockout or 'triple coincidence' reactions have been used to measure the relative contribution of np-SRCs and pp-SRCs by knocking out a proton from the SRC and detecting its partner nucleon (proton or neutron). These measurements have shown that SRCs are almost exclusively np pairs, but they had limited statistics and required large model-dependent final-state interaction corrections. Here we report on measurements using inclusive scattering from the mirror nuclei hydrogen-3 and helium-3 to extract the np/pp ratio of SRCs in systems with a mass number of three. In this work we obtain a measure of the np/pp SRC ratio that is an order of magnitude more precise than previous experiments, and find a marked deviation from the near-total np dominance observed in heavy nuclei. This result implies an unexpected structure in the high-momentum wavefunction for hydrogen-3 and helium-3. Understanding these results will improve our understanding of the short-range part of the nucleon-nucleon interaction.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Entanglement phase transitions in random stabilizer tensor networks

Here we explore a class of random tensor network models with “stabilizer” local tensors which we name random stabilizer tensor networks (RSTNs). For RSTNs defined on a two-dimensional square lattice, we perform extensive numerical studies of entanglement phase transitions between volume-law and area-law entangled phases of the one-dimensional boundary states. These transitions occur when either (a) the bond dimension D of the constituent tensors is varied or (b) the tensor network is subject to random breaking of bulk bonds, implemented by forced measurements. In the absence of broken bonds, we find that the RSTN supports a volume-law entangled boundary state with bond dimension D ≥ 3 where D is a prime number, and an area-law entangled boundary state for D = 2. Upon breaking bonds at random in the bulk with probability p, there exists a critical measurement rate p c for each D ≥ 3 above which the boundary state becomes area-law entangled. To explore the conformal invariance at these entanglement transitions for different prime D, we consider tensor networks on a finite rectangular geometry with a variety of boundary conditions, and extract universal operator scaling dimensions via extensive numerical calculations of the entanglement entropy, mutual information, and mutual negativity at their respective critical points. Our results at large D approach known universal data of percolation conformal field theory, while showing clear discrepancies at smaller D, suggesting a distinct entanglement transition universality class for each prime D. We further study universal entanglement properties in the volume-law phase and demonstrate quantitative agreement with the recently proposed description in terms of a directed polymer in a random environment.

36 MATERIALS SCIENCE↗

Optical tweezer measurements of asymptotic nonlinearities in complex fluids

This article presents micro-medium-amplitude oscillatory shear (μMAOS), a method to measure the frequency-dependent micromechanical properties of soft materials in the asymptotically nonlinear regime using optical tweezers. For this work, we have developed a theoretical framework to extract these nonlinear mechanical properties of the material from experimental measurements and also proposed a physical interpretation of the third-order nonlinearities measured in single-tone oscillatory tests. We validate the method using a well-characterized surfactant solution of wormlike micelles, and subsequently employ this technique to demonstrate that the cytoplasm of a living cell undergoes strain softening and shear thinning when locally subjected to weakly nonlinear oscillatory deformations.

59 BASIC BIOLOGICAL SCIENCES↗

PBjam: A Python Package for Automating Asteroseismology of Solar-like Oscillators

Asteroseismology is an exceptional tool for studying stars using the properties of observed modes of oscillation. So far the process of performing an asteroseismic analysis of a star has remained somewhat esoteric and inaccessible to nonexperts. In this software paper we describe PBjam, an open-source Python package for analyzing the frequency spectra of solar-like oscillators in a simple but principled and automated way. The aim of PBjam is to provide a set of easy-to-use tools to extract information about the radial and quadropole oscillations in stars that oscillate like the Sun, which may then be used to infer bulk properties such as stellar mass, radius, age, or even structure. Asteroseismology and its data analysis methods are becoming increasingly important as space-based photometric observatories are producing a wealth of new data, allowing asteroseismology to be applied in a wide range of contexts such as exoplanet, stellar structure and evolution, and Galactic population studies.

79 ASTRONOMY AND ASTROPHYSICS↗

AIRS Data Subsetting Service at the Goddard Earth Sciences (GES) DISC/DAAC

The AIRS mission, as a combination of the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), brings climate research and weather prediction into 21st century. From NASA' Aqua spacecraft, the AIRS/AMSU/HSB instruments measure humidity, temperature, cloud properties and the amounts of greenhouse gases. The AIRS also reveals land and sea- surface temperatures. Measurements from these three instruments are analyzed . jointly to filter out the effects of clouds from the IR data in order to derive clear-column air-temperature profiles and surface temperatures with high vertical resolution and accuracy. Together, they constitute an advanced operational sounding data system that have contributed to improve global modeling efforts and numerical weather prediction; enhance studies of the global energy and water cycles, the effects of greenhouse gases, and atmosphere-surface interactions; and facilitate monitoring of climate variations and trends. The high data volume generated by the AIRS/AMSU/HSB instruments and the complexity of its data format (Hierarchical Data Format, HDF) are barriers to AIRS data use. Although many researchers are interested in only a fraction of the data they receive or request, they are forced to run their algorithms on a much larger data set to extract the information of interest. In order to better server its users, the GES DISC/DAAC, provider of long-term archives and distribution services as well science support for the AIRS/AMSU/HSB data products, has developed various tools for performing channels, variables, parameter, spatial and derived products subsetting, resampling and reformatting operations. This presentation mainly describes the web-enabled subsetting services currently available at the GES DISC/DAAC that provide subsetting functions for all the Level 1B and Level 2 data products from the AIRS/AMSU/HSB instruments.

Vicente, Gilberto A.↗