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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Deciphering decomposition pathways of high explosives with cryogenic X-ray Raman spectroscopy

We employed cryogenic X-ray Raman spectroscopy to investigate the early-stage decomposition of the high explosive molecule hexanitrohexaazaisowurtzitane (CL-20). By systematically varying the radiation dose under cryogenic conditions, we induced the decomposition of the molecule using ionizing radiation and observed the evolution of spectral features at the carbon, nitrogen, and oxygen K edges. Through extensive first-principles calculations, we identified key intermediates in the early stages of the decomposition process, resulting from C–C and C–N bond cleavage which leads to the opening of the internal cage structure. A detailed analysis of spectral trends and fingerprints provided evidence supporting N–NO 2 homolytic cleavage as the primary initial decomposition pathway. The combination of advanced core-level spectroscopy methods and state-of-the-art theoretical calculations enabled a comprehensive characterization of the molecular changes induced by controlled radiation dose exposures. In conclusion, our findings establish a benchmark for understanding the decomposition chemistry of high-explosive materials, offering important insights into their stability and reactivity under extreme conditions.

X-ray Raman spectroscopy↗
DOE OSTI2026

A critical review on additive manufacturing of refractory alloys from a data analytics perspective- beyond nickel-based superalloys

Refractory alloys (RAs) are promising materials due to their exceptional physicochemical properties, but most research remains at the laboratory scale. For broader adoption, advancements in manufacturing are essential. Because their high stability makes conventional methods like machining and casting difficult, additive manufacturing (AM) is emerging as an effective approach for fabricating refractory alloy components. However, AM's repeated non-equilibrium thermal cycles introduce undesired features (e.g. defects, anisotropic microstructures, and residual stresses), which are magnified due to RAs’ unique properties. This paper comprehensively reviews the state-of-the-art methods of AM for refractory alloys. It explores data analytics techniques to establish design rules based on multi-fidelity experimental and computational methods. Furthermore, it investigates integrated, collaborative efforts to harmonise standalone databases, information, knowledge, and predictive models at multi-physics, multi-stage, and multi-scale. Unlike the existing literature that focuses primarily on material systems or process fundamentals, this work provides an integrated perspective on AM of refractory alloys from a data analytics standpoint, highlighting the roles of integrated computational materials engineering (ICME), verification, validation, and uncertainty quantification (VV&UQ), and digital twin-driven qualification in overcoming data scarcity and accelerating rapid qualification.

Additive manufacturing↗
DOE OSTI2025

Dynamics of amphiphilic PEG–PDMS–PEG triblock copolymer assemblies

Here, the size and stability of micelles and vesicles determine the uptake capacity of guest molecules, thereby influencing potential applications in drug/gene delivery, bioreactors, and templates for nanoparticle synthesis. Polyethylene glycol (PEG) and polydimethylsiloxane (PDMS) are commonly used in these applications. We discovered that PEG-PDMS-PEG triblock copolymers can assemble into micelles and vesicles, making them valuable for dynamic studies to derive the bending elasticity, $κ_η$, which governs the stability these objects. We analyzed the structure using cryogenic transmission electron microscopy and small-angle neutron scattering. We investigated the dynamics through dynamic light scattering and neutron spin echo spectroscopy. By varying the number of repeating units in the hydrophilic block, we created micellar (PEG 28 -PDMS 15 -PEG 28 ) and vesicular systems (PEG 14 -PDMS 15 -PEG 14 ). For the vesicle, membrane rigidity was determined from experiments to be $κ_η$ =(16 ± 2) $k_BT$, where $k_BT$ is the thermal energy ($k_B$ Boltzmann’s constant and T is the temperature). According to Zilman and Granek's concept, membrane rigidity reflects height-height fluctuations within the membrane layer. Compared to polymers at the oil-water interface of a microemulsion, the membrane rigidity in polymersomes is over an order of magnitude higher, indicating significantly enhanced stability. This value closely aligns with that of liposomes, suggesting similar stability between polymersomes and liposomes.

Gupta, Sudipta [Louisiana State Univ., Baton Rouge↗
DOE OSTI2025

Leveraging Hamiltonian simulation techniques to compile operations on bosonic devices

Circuit quantum electrodynamics enables the combined use of qubits and oscillator modes. Despite a variety of available gate sets, many hybrid qubit-boson (i.e. qubit-oscillator) operations are realizable only through optimal control theory, which is oftentimes intractable and uninterpretable. We introduce an analytic approach with rigorously proven error bounds for realizing specific classes of operations via two matrix product formulas commonly used in Hamiltonian simulation, the Lie–Trotter–Suzuki and Baker–Campbell–Hausdorff product formulas. We show how this technique can be used to realize a number of operations of interest, including polynomials of annihilation and creation operators, namely (a) p (a † ) q for integer p, q. We show examples of this paradigm including obtaining universal control within a subspace of the entire Fock space of an oscillator, state preparation of a fixed photon number in the cavity, simulation of the Jaynes–Cummings Hamiltonian, and simulation of the Hong-Ou-Mandel effect. This work demonstrates how techniques from Hamiltonian simulation can be applied to better control hybrid qubit-boson devices.

bosonic qubits↗
DOE OSTI2025

Artificial intelligence for advanced functional materials: exploring current and future directions

This perspective addresses the topic of harnessing the tools of artificial intelligence (AI) for boosting innovation in functional materials design and engineering as well as discovering new materials for targeted applications in energy storage, biomedicine, composites, nanoelectronics or quantum technologies. It gives a current view of experts in the field, insisting on challenges and opportunities provided by the development of large materials databases, novel schemes for implementing AI into materials production and characterization as well as progress in the quest of simulating physical and chemical properties of realistic atomic models reaching the trillion atoms scale and with near ab initio accuracy.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Hybrid Oscillator-Qubit Quantum Processors: Instruction Set Architectures, Abstract Machine Models, and Applications

This tutorial offers a pedagogical guide to hybrid quantum processors that integrate discrete-variable (DV) qubits and continuous-variable (CV) oscillators. Aimed at computer scientists, engineers, and physicists, it provides an overview of the experimental, algorithmic, and architectural aspects of this novel and rapidly developing hardware model. Experimental realizations of this model include superconducting, trapped-ion, and neutral-atom platforms. By combining DV and CV components, hybrid oscillator-qubit processors enable a powerful new paradigm that offers complementary strengths for quantum control, error correction, computation, and simulation. Working toward the goal of a full-stack system connecting applications to CV-DV hardware, we define and formulate abstract machine models and instruction set architectures. These essential abstractions enable codesign of hardware and software, and resource estimation for exploring the potential of current and future hardware for computational and simulation tasks. Using these abstractions, we present both new and existing examples that illustrate the benefits of hybrid CV-DV processors relative to traditional DV-only hardware in computation as well as quantum simulation of physical models. Examples include algorithms for transferring states between DV and CV systems, performing the quantum Fourier transform, and simulation of lattice gauge theories. Relative to qubit-only hardware, the bosonic degrees of freedom natively available in hybrid architectures can substantially reduce the circuit complexity of simulations for physical models containing bosons. A key technique is the extension of quantum signal processing ideas to CV-DV systems. This work is intended to serve as a timely and comprehensive guide to this relatively unexplored yet promising approach to quantum computation and to provide a road map to guide future development.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Mechanical sensors for ultraheavy dark matter searches via long-range forces

Dark matter candidates with masses around the Planck scale are theoretically well-motivated, and it has been suggested that it might be possible to search for dark matter solely via gravitational interactions in this mass range. In this work, we explore the pathway towards searching for dark matter candidates with masses around the Planck scale using mechanical sensors while considering realistic experimental constraints, and develop analysis techniques needed to conduct such searches. These dark matter particles are expected to leave tracks as their signature in mechanical sensor arrays, and we show that we can effectively search for such tracks using statistical approaches to track-finding. We analyze a range of possible experimental setups and compute sensitivity projections for searches for ultraheavy dark matter coupling to the Standard Model via long-range forces. We find that while a search for Planck-scale dark matter purely via gravitational couplings would be exceedingly difficult, requiring ∼80 dB of quantum noise reduction with a 100 3 array of devices, there is a wide range of currently unexplored dark matter candidates which can be searched for with already existing or near-term experimental platforms.

Qin, Juehang [Rice Univ., Houston, TX (United Stat↗
DOE OSTI2025

Covariant Quantum Error-Correcting Codes with Metrological Entanglement Advantage

Here, we show that a subset of the basis for the irreducible representations of a tensor-product SU(2) rotation forms a covariant approximate quantum error-correcting code with transversal U(1) logical gates. Generalizing previous work on “thermodynamic codes” to general local spin and different irreducible representations using only properties of the angular momentum algebra, we obtain bounds on the code inaccuracy under generic noise on any known 𝑑 sites, under independent and identically distributed noise, and under heralded 𝑑-local erasures. We demonstrate that this family of codes protects a probe state with quantum Fisher information surpassing the standard quantum limit when the sensing parameter couples to the generator of the U(1) logical gate.

quantum error correction↗
DOE OSTI2026

Hyperfine spectroscopy and laser cooling of the fermionic isotopes 47 Ti and 49 Ti

Here, we report on magneto-optical trapping of the two fermionic isotopes of atomic titanium, 47 Ti and 49 Ti . Unlike the even mass-number isotopes, which were recently laser cooled, 47 Ti and 49 Ti have nonzero nuclear spins and, consequently, their atomic levels are split by hyperfine structure. Combining and comparing theoretical calculations and atomic beam-spectroscopy measurements, we determine the hyperfine structures and isotope shifts of the 3⁢𝑑 2 ⁢4⁢𝑠 2 𝑎 3 ⁢𝐹 4 → 3⁢𝑑 2 ⁢( 3 𝑃)⁢4⁢𝑠⁢4⁢𝑝⁢( 3 𝑃 𝑜 ) 𝑦 5 ⁢𝐷$^o_4$ optical-pumping transition at optical wavelength 391 nm and the 3⁢𝑑 3 ⁢(4𝐹)⁢4⁢𝑠 𝑎 5 ⁢𝐹 5 → 3⁢𝑑 3 ⁢( 4 𝐹)⁢4⁢𝑝 𝑦 5 ⁢𝐺$^𝑜_6$ laser-cooling transition at wavelength 498 nm. With this information, we produce magneto-optical traps of both 47 Ti and 49 Ti by applying two additional tones of light to repump atoms to the maximum-spin states on the laser-cooling transition. Directly loading from the atomic flux of a titanium sublimation pump, we produce 47 Ti and 49 Ti traps with 731(190) and 1142(240) atoms, and with lifetimes of 330⁢(15) and 310⁢(8)⁢ ms, respectively.

atomic spectra↗
DOE OSTI2026

Unified and Consistent Structure Growth Measurements from Joint ACT, SPT, and Planck CMB Lensing

We present the tightest cosmic microwave background (CMB) lensing constraints to date on the growth of structure by combining CMB lensing measurements from the Atacama Cosmology Telescope (ACT), the South Pole Telescope (SPT), and Planck. Each of these surveys individually provides lensing measurements with similarly high statistical power, achieving signal-to-noise ratios of approximately 40. The combined lensing band powers represent the most precise CMB lensing power spectrum measurement to date with a signal-to-noise ratio of 61 and an amplitude of A lens recon = 1.025 ± 0.017 with respect to the theory prediction from the best-fit CMB Planck-ACT cosmology. The band powers from all three lensing datasets, analyzed jointly, yield a 1.6% measurement of the parameter combination S 8 CMBL ≡ σ 8 ( Ω m / 0.3 ) 0.25 = 0.82 5 - 0.013 + 0.015 . Including dark energy spectroscopic instrument baryon acoustic oscillation (BAO) data improves the constraint on the amplitude of matter fluctuations to σ 8 = 0.829 ± 0.009 (a 1.1% determination). When combining with uncalibrated supernovae from Pantheon+, we present a 4% sound-horizon-independent estimate of H 0 = 66.4 ± 2.5 km s - 1 Mpc - 1 . The joint lensing constraints on structure growth and present-day Hubble rate are fully consistent with a Λ CDM model fit to the primary CMB data from Planck and ACT. While the precise upper limit is sensitive to the choice of data and underlying model assumptions, when varying the neutrino mass sum within the Λ CDM cosmological model, the combination of primary CMB, BAO, and CMB lensing drives the probable upper limit for the mass sum towards lower values, comparable to the minimum mass prior required by neutrino oscillation experiments.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Exponentially Reduced Circuit Depths Using Trotter Error Mitigation

Product formulas are a popular class of digital quantum simulation algorithms due to their conceptual simplicity, low overhead, and performance, which often exceeds theoretical expectations. Recently, Richardson extrapolation and polynomial interpolation have been proposed to mitigate the Trotter error incurred by the use of these formulas. This work provides a rigorous, general analysis of these techniques for computing time-evolved observables, simplifying the interpolation algorithm in the process, and shows that extrapolation generically improves the performance of product formulas for this task. We demonstrate that, to achieve error 𝜖 in a simulation of time 𝑇 using a 𝑝 ⁢th-order product formula with extrapolation, circuit depths of 𝑂⁡(𝑇 1+1/𝑝 ⁢polylog (1/𝜖)) are sufficient—an exponential improvement in the precision over product formulas alone. Furthermore, we prove that these algorithms achieve commutator scaling, and improve the 𝑇 complexity for the interpolation algorithm. By relaxing the requirement of performing exact Chebyshev interpolation, our simplified algorithm eliminates the need for fractional implementations of Trotter steps, reducing computational overhead. Finally, we show these techniques can be combined with the classical shadows method to estimate many time-evolved local observables. Taken together, our findings provide the strongest evidence yet for the utility of Trotter error-mitigation techniques in algorithmic applications.

quantum algorithms & computation↗
DOE OSTI2026

Spin reorientations in structurally metastable, disordered, and hexagonal Cr 7 ⁢Te 8

Vapor deposited two-dimensional Cr 7 ⁢Te 8 displays unusual temperature dependent Hall effect properties, including a room-temperature anomalous Hall effect, sign reversals of the Hall resistivity on cooling, and a peak in the Hall resistivity at low temperatures. The two-dimensional Cr 7⁢ Te 8 heterostructures that form the basis of these measurements are hexagonal in structure. We study the magnetic and structural properties of bulk Cr 7 ⁢Te 8 synthesized by quenching from 1000⁢°C with the goal of relating the magnetic, structural, and electronic properties. This quenched phase is metastable, hexagonal, and displays different magnetic properties from the slow-cooled and more thermodynamically stable monoclinic phase. High-resolution x-ray diffraction of the quenched hexagonal phase finds a first-order transition to a lower symmetry monoclinic phase on heating above ∼550 K. Magnetic susceptibility measurements of the quenched hexagonal phase reveal ferromagnetic ordering above room temperature, along with the two distinct transitions at ∼220 K and ∼70 K. Through neutron diffraction studies, we find the ∼220 K anomaly is a spin reorientation transition of the ferromagnetically aligned magnetic moments and the ∼70K feature represents a transition from a high-temperature ferromagnet to a low-temperature antiferromagnet. We suggest that these magnetic transitions are related to changes in the unit-cell dimensions and are connected to the temperature-dependent Hall resisitivity studied in two-dimensional heterostructures. This implies a link between structural, magnetic, and electronic properties in the “pseudo” two-dimensional chromium tellurides.

Chemical synthesis↗
DOE OSTI2025

Chiral microwave nonreciprocity demonstrated via Rayleigh and Sezawa modes supported in an Al 0.58 ⁢Sc 0.42 ⁢N/4⁢H–Si⁢C platform

Chirality plays a crucial role in the helicity mismatch between surface acoustic waves and magnetic spin waves, leading to nonreciprocal transmission of acoustic power for coupled magnetoacoustic modes. Acoustic modes with both longitudinal and shear strain exhibit elliptical particle displacements, making them chiral, and different acoustic modes can exhibit different helicities of this elliptical particle displacement. Here, we study chiral acoustic modes with different helicities supported on the same piezoelectric platform and their interaction with magnetic spin waves. Our study demonstrates that the nonreciprocal transmission of acoustic power is driven by the helicity mismatch effect and, specifically, that the handedness of the nonreciprocity is based on whether the surface acoustic wave has retrograde (Rayleigh mode) or prograde (Sezawa mode) elliptical particle displacement with respect to the propagation direction. We found the transmission nonreciprocity to be significant, with 7.3 dB/mm for the retrograde particle displacement (Rayleigh mode at 2.358 GHz) and 3.3 dB/mm for prograde particle displacement (Sezawa mode at 3.112 GHz). Furthermore, this work highlights that piezoelectric platforms can be engineered to support acoustic modes with opposite helicities to enable frequency-selective nonreciprocal radiofrequency and microwave components, such as isolators and circulators, through coupled acoustic spin wave interactions.

42 ENGINEERING↗
DOE OSTI2025

Pulling Order Back from the Brink of Disorder: Observation of a Nodal-Line Spin Liquid and Fluctuation Stabilized Order in K 2 ⁢IrCl 6

Competing interactions in frustrated magnets can give rise to highly degenerate ground states from which correlated liquidlike states of matter often emerge. The scaling of this degeneracy influences the ultimate ground state, with extensive degeneracies potentially yielding quantum spin liquids, while subextensive or smaller degeneracies yield static orders. A long-standing problem is to understand how ordered states precipitate from this degenerate manifold and what echoes of the degeneracy survive ordering. Here, we use neutron scattering to experimentally demonstrate a new “nodal-line” spin liquid, where spins collectively fluctuate within a subextensive manifold spanning one-dimensional lines in reciprocal space. Realized in the spin-orbit-coupled, face-centered-cubic iridate K 2 ⁢IrCl 6 , we show that the subextensive degeneracy is robust, but remains susceptible to fluctuations or longer-range interactions which cooperate to select a magnetic order at low temperatures. Proximity to the nodal-line spin liquid influences the ordered state, enhancing the effects of quantum fluctuations that in turn act to stabilize the sublattice magnetization through the self-consistent opening of a large spin-wave gap. Our results demonstrate how quantum fluctuations can act counterintuitively in frustrated materials: Even in a case where fluctuations are ineffective at selecting an ordered state from a degenerate manifold, at the brink of the nodal spin liquid, they can act to protect the ordered state and dictate its low-energy physics.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Interface magnetism and anomalous Hall effect in La 0.7 ⁢Sr 0.3⁢ Mn⁢O 3 /SrIr⁢O 3 bilayers

Epitaxial interfaces combining 3d and 5d transition metal oxides are a fertile playground to examine the interplay between topology and electron correlations. In this work, we explore magnetism and transport of bilayers combining ferromagnetic La 0.7⁢ Sr 0.3⁢ Mn⁢O 3 and the strong spin-orbit coupling material SrIr⁢O 3 . We have found an interfacial magnetic proximity effect driving an intrinsic contribution to the anomalous Hall effect of topological origin. The interfacial proximity interaction is enabled by the Mn-O-Ir bonding reconstruction and depends on layer sequence. While bilayers with the La 0.7⁢ Sr 0.3 ⁢Mn⁢O 3 on top featuring a robust Mn magnetism at the interface show the intrinsic AHE contribution, it is absent in bilayers with the inverted layer sequence (SrIr⁢O 3 layer on top) showing strongly suppressed magnetism at the interface. These results illustrate the leading role of interfacial atomic reconstructions on the interplay between topology and correlations at 3d/5d oxide interfaces. This finding may be of interest in future oxide topological spintronics and spin-orbitronics.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Two-population Rouse models for polymer segmental dynamics in nanocomposites

Segmental dynamics of polymer chains in a model nanocomposite of poly(ethylene oxide) and silica nanoparticles (NPs) was investigated using quasielastic neutron scattering. The dynamics can be accurately described with the Rouse model. The bulklike polymer far from the NP surface behaves as the neat polymer. However, the slower polymer in the interface close to the NP surface is described either with a second Rouse population with different relaxation time or using the suppressed Rouse model. These simple two-population models accurately reproduce the experimental data, with the suppressed Rouse model describing topological constraints, on average, every 12 beads with an interfacial thickness up to 13.5 beads, and the effect of the interface extending to a layer of thickness comparable to the end-to-end distance of the polymer. This modeling provides an explanation for the observed reinforcement in PNC even at low loadings, consistent with current understanding of the relevance of the interphase.

Composite materials↗
DOE OSTI2025

Nonresonant two-photon x-ray absorption in Cu

We present a real-space Green's function theory and calculations of two-photon x-ray absorption (TPA). Our focus is on nonresonant 𝐾-shell TPA in metallic Cu, which has been observed experimentally at intense x-ray free electron laser (XFEL) sources. The theory is based on an independent particle Green's function treatment of the Kramers-Heisenberg equation and an approximation for the sum over nonresonant intermediate states in terms of a static quadrupole transition operator. XFEL effects are modeled by a partially depleted 𝑑 band. This approach is shown to give results for 𝐾-shell TPA in quantitative agreement with XFEL experiment and with a Bethe-Salpeter equation approach. Furthermore, we also briefly discuss many-body corrections and TPA sum rules.

Approximation methods for many-body systems↗
DOE OSTI2026

Measurement of the 252 Cf ⁢(sf) prompt fission neutron spectrum utilizing 12 C ⁡(𝑛, 𝑛) and 9 Be ⁢(𝑛, 𝑛) neutron scattering reference measurements

The 252 Cf spontaneous fission (sf), prompt fission neutron spectrum (PFNS) is a fundamental quantity for nuclear physics measurements of neutron-emitting reactions. This energy distribution of neutrons emitted from fission has been considered a neutron data standard for decades and has been utilized as a reference for neutron detection efficiency, validation of Monte Carlo simulations, benchmarking of dosimetry standards, and more. A significant portion of the global collection of nuclear data on neutron-induced reactions is correlated with the 252 Cf ⁢(sf) PFNS. Despite the reliance on this quantity by the nuclear physics community, the historical collection of 252 Cf PFNS measurements display systematic disagreements that are not understood or easily explained. These experimental discrepancies could potentially bias the 252 Cf PFNS Standard evaluation. On top of this, these past experiments frequently employed correlated experimental measurement or analysis methods. The artificial intelligence (AI)/machine learning (ML)-informed californium chi-nuclear data experiment (AIACHNE) project was formed to (a) investigate these discrepancies utilizing AI/ML methods to identify outlying regions of literature data, assign these regions to features of the experiment itself, and perform an improved evaluation of the 252 Cf PFNS and (b) perform a new experimental measurement of this quantity designed to improve upon the existing literature database. Here, in this work, we report on the AIACHNE 252 Cf PFNS experiment utilizing a new analysis method uncorrelated with all previous measurements: neutron efficiency determinations based on elastic neutron scattering on 12 C and 9 Be . This new method provides an independent test of the existing literature data and evaluation of the 252 Cf ⁢(sf) PFNS. The method is described with detailed covariance quantification procedures, as well as a direct discussion of the sources of uncertainty described as requirements in the “Templates” series of papers. The 252 Cf ⁢(sf) PFNS reported in this work agrees well with the overall shape of the existing standard PFNS evaluation as well as many literature measurements, thus verifying the current evaluation utilizing new techniques. However, the results suggest that there are deficiencies in the angle-differential 12 C and 9 Be ⁢(𝑛, 𝑛) evaluated nuclear data, which produce unphysical structures in the reported result. While these structures are relatively minor, they become obvious because of the high statistical precision of the data and the expected smooth continuity of the 252 Cf ⁢(sf) PFNS.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗