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Results for “quantum diffraction”

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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Direct Monitoring of Conical Intersection Passage via Electronic Coherences in Twisted X-Ray Diffraction

Quantum coherences in electronic motions play a critical role in determining the pathways and outcomes of virtually all photophysical and photochemical molecular processes. However, the direct observation of electronic coherences in the vicinity of conical intersections remains a formidable challenge. Here we propose a novel time-resolved twisted x-ray diffraction technique that can directly monitor the electronic coherences created as the molecule passes through a conical intersection. We show that the contribution of electronic populations to this signal is canceled out when using twisted x-ray beams that carry a light orbital angular momentum, providing a direct measurement of transient electronic coherences in gas-phase molecules.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Path integral molecular dynamics: A high-fidelity approach to quantum dynamics of electrons

We investigate electron transport in the uniform electron gas using ring-polymer molecular dynamics (RPMD). Working in the weakly coupled, non-degenerate regime, we use RPMD to probe how the onset of quantum diffraction effects at high temperature reshapes electron–electron collisions and leads to a classical-to-quantum crossover in macroscopic transport properties. Static thermodynamics obtained with RPMD are consistent with the weak-coupling equation of state, confirming correct quantum Boltzmann sampling. Real-time transport extracted from mean square displacements exhibits the expected ballistic-to-diffusive transition and a systematic reduction of the electronic self-diffusivity as quantum effects strengthen, due to quantum diffraction modifying electron–electron collisions. Direct ring-polymer scattering simulations reveal diffractive “softening” of binary deflections, providing a micro-to-macro link between collision physics and diffusion. The present study establishes RPMD as a quantitative, trajectory-based tool for electron transport across the classical–quantum crossover and furnishes benchmarks for improving Coulomb-log interpolation models. We outline extensions to multi-component plasmas and a path to incorporate Fermi–Dirac statistics within path-integral dynamics.

Electronic transport↗
DOE OSTI2019

Quantum phase-sensitive diffraction and imaging using entangled photons

We propose a quantum diffraction imaging technique whereby one photon of an entangled pair is diffracted off a sample and detected in coincidence with its twin. The image is obtained by scanning the photon that did not interact with matter. We show that when a dynamical quantum system interacts with an external field, the phase information is imprinted in the state of the field in a detectable way. The contribution to the signal from photons that interact with the sample scales as ∝ I p 1 / 2 , where I p is the source intensity, compared with ∝ I p of classical diffraction. This makes imaging with weak fields possible, providing high signal-to-noise ratio, avoiding damage to delicate samples. A Schmidt decomposition of the state of the field can be used for image enhancement by reweighting the Schmidt modes contributions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2026

Quantum kinetic modeling of KEEN waves in a warm-dense regime

We report the first fully kinetic, quantum study of kinetic electrostatic electron nonlinear (KEEN) waves, showing that quantum diffraction systematically erodes the classical trapping mechanism, narrows harmonic locking to the fundamental, and hastens post-drive decay. Electrons are evolved with a second-order Strang-split 1D1V Wigner–Poisson solver that couples conservative semi-Lagrangian WENO advection to an analytic Fourier space update for the non-local Wigner term, while ions remain classical. We focus on collisionless dynamics in a weakly coupled regime, providing a controlled baseline before collisional extensions. Short, frequency-tuned ponderomotive pulses drive KEEN formation in a uniform Maxwellian plasma; as the dimensionless quantum parameter H rises from the classical limit to values relevant to warm-dense matter, doped semiconductors, and 2D electron systems, the drive threshold increases, higher harmonics are damped, trapped electron vortices diffuse, and the subplasma electrostatic energy relaxes to a lower stationary level, as confirmed by continuous wavelet analysis. These microscopic changes carry macroscopic weight. Ignition-scale capsules now compress matter to regimes where the electron de Broglie wavelength rivals the Debye length, making classical kinetic descriptions insufficient. By extending KEEN physics into this quantum domain, our results offer a potential diagnostic of non-equilibrium electron dynamics for next-generation inertial-confinement designs and high-energy-density platforms, indicating that predictive fusion modeling may benefit from the integration of kinetic fidelity with quantum effects.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Precision ultranarrow-linewidth resonance excitation (PURE) preparation of a molecular beam of nitric oxide molecules for inelastic scattering with argon

We recently reported a novel technique that utilizes narrow-linewidth lasers to selectively excite molecules into a pure quantum state with a well-resolved, tunable distribution of velocities [O. A. Krohn and D. W. Chandler, J. Phys. Chem. Lett. 15(50), 12455–12463 (2024)]. We refer to the preparation of molecules by this technique as precision ultranarrow-linewidth resonant excitation (PURE) preparation. Here, in this study, we pair this PURE preparation methodology with active frequency stabilization of the quantum cascade laser that drives the excitation. In doing so, highly velocity-resolved packets of molecules are possible, with the limitations of this velocity resolution set by the stability of the laser locking and the spectral linewidth of the transition. We show that side-of-fringe locking to a Doppler-broadened absorption spectrum of our target molecule is sufficiently stable for PURE preparation of molecules for long timescales (several hours) with highly resolved velocity spreads (σ < 3 m/s). To demonstrate the scientific utility of this new capability, we present differential cross sections from scattering between a neat molecular beam of argon and a velocity-selected beam of nitric oxide (NO) in a pure quantum state. We observe well-resolved quantum diffraction oscillations in the forward-scattered collisions as well as general trends consistent with prior characterized collisions of NO + Ar.

Krohn, Olivia A. [Sandia National Laboratories (SN↗
DOE OSTI2019

Neutron Time-of-Flight Measurements of Charged-Particle Energy Loss in Inertial Confinement Fusion Plasmas

Neutron spectra from secondary 3 H(d,n)α reactions produced by an implosion of a deuterium-gas capsule at the National Ignition Facility have been measured with order-of-magnitude improvements in statistics and resolution over past experiments. Furthermore, these new data and their sensitivity to the energy loss of fast tritons emitted from thermal 2 H(d,p) 3 H reactions enable the first statistically significant investigation of charged-particle stopping via the emitted neutron spectrum. Radiation-hydrodynamic simulations, constrained to match a number of observables from the implosion, were used to predict the neutron spectra while employing two different energy loss models. This analysis represents the first test of stopping models under inertial confinement fusion conditions, covering plasma temperatures of k B T ≈ 1–4 keV and particle densities of n ≈ (12–2) × 10 24 cm –3 . Under these conditions, we find significant deviations of our data from a theory employing classical collisions whereas the theory including quantum diffraction agrees with our data.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Tracking Thermal Transport in Colloidal Quantum Dot Films Using in Situ Time-Resolved X-ray Diffraction

Colloidal quantum dots (QDs) and their thin films are increasingly used in electronic and photonic devices replacing traditional bulk semiconductors. However, thermal properties of QDs remain underexplored relative to device development efforts. This study shows the use of time-resolved X-ray diffraction as a contact-free method to probe the thermal response of QDs in environments representative of the active layer in QD optoelectronic devices, providing in situ insights for future thermal management strategies. Through the extraction of Debye–Waller factors on a subnanosecond time scale, we directly capture the heating and cooling of core/shell CdSe/CdS QDs following pulsed optical excitation. In a QD thin film that actively provides optical gain, the thermal conductivity is found to be as low as 0.13 W m –1 K –1 , because of the poor heat flow between close-packed QD solids. For QDs dispersed in liquids, interfacial thermal conductance dominates thermal relaxation, with a conductance of 15 MW m –2 K –1 .

36 MATERIALS SCIENCE↗
DOE OSTI2018

Controllable diffraction pattern in semiconductor quantum well based on quantum coherence

In this paper, we study properties of diffraction of a weak probe field interacting with a symmetric semiconductor quantum well that is coherently manipulated by a standing wave. Based on the theory of quantum coherent and of light diffraction, we can obtain distribution of the diffraction spectra of the probe field. We consider the influences of Kerr nonlinear effect on the diffraction pattern, and studies show the distribution of diffraction pattern can be controlled through choosing appropriate physical parameters of system. Kerr nonlinear effect can enhance the brightness of central pattern and improve the transmission efficiency of the incident beam. A controllable diffraction pattern has potential applications in some areas, such as design of quantum diffractive optical elements, grating imaging system, precision measurement and so on.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Sub‐Diffraction Correlation of Quantum Emitters and Local Strain Fields in Strain‐Engineered WSe 2 Monolayers

Strain-engineering in atomically thin metal dichalcogenides is a useful method for realizing single-photon emitters (SPEs) for quantum technologies. Correlating SPE position with local strain topography is challenging due to localization inaccuracies from the diffraction limit. Currently, SPEs are assumed to be positioned at the highest strained location and are typically identified by randomly screening narrow-linewidth emitters, of which only a few are spectrally pure. In this work, hyperspectral quantum emitter localization microscopy is used to locate 33 SPEs in nanoparticle-strained WSe 2 monolayers with sub-diffraction-limit resolution (≈30 nm) and correlate their positions with the underlying strain field via image registration. In this system, spectrally pure emitters are not concentrated at the highest strain location due to spectral contamination; instead, isolable SPEs are distributed away from points of peak strain with an average displacement of 240 nm. These observations point toward a need for a change in the design rules for strain-engineered SPEs and constitute a key step toward realizing next-generation quantum optical architectures.

2D material↗
DOE OSTI2018

Strain annealing of SiC nanoparticles revealed through Bragg coherent diffraction imaging for quantum technologies

The crystalline strain properties of nanoparticles have broad implications in a number of emerging fields, including quantum and biological sensing in which heterogeneous internal strain fields are detrimental to performance. Here we used synchrotron-based Bragg coherent x-ray diffraction imaging (BCDI) to measure three-dimensional lattice strain fields within individual 3C-SiC nanoparticles, a candidate host material for quantum sensing, as a function of temperature during and after annealing up to 900 degrees C. We observed pronounced homogenization of the initial strain field at temperatures above 500 degrees C, and we find that the surface layers and central volumes of the nanoparticles reduce strain at similar rates, suggesting a uniform healing mechanism. Thus, we attribute the observed strain homogenization to activation of mobile point defects that annihilate and improve the overall quality of the crystal lattice. This work also establishes the feasibility of performing BCDI at high temperatures (up to 900 degrees C) to map structural hystereses relevant to the processing of quantum nanomaterials.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

Effects of nuclear structure and quantum interference on diffractive vector meson production in ultra-peripheral nuclear collisions

Here we study diffractive vector meson production in ultra-peripheral collisions (UPCs) of heavy nuclei, utilizing a theoretical framework based on the Color Glass Condensate (CGC) formalism. We focus on Au + Au, U + U, Ru + Ru, Zr + Zr, and Pb + Pb collisions, examining the transverse momentum dependence of vector meson production cross-sections and co s(2ΔΦ)asymmetries in the decay product distributions to explore the role of nuclear geometry. The angular modulation is due to the linear polarization of the incoming photons and quantum interference effects. We extract nuclear radii and find them to be consistent with experimental data from the STAR collaboration. The amplitudes of the cos(2ΔΦ)modulation in the cross-section and the extracted radii depend on the nuclear geometry. This dependence is dominated by the geometry-dependent variation of the minimum impact parameter required for ultra-peripheral collisions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

The quantum evolutions of the diffractive transverse-momentum dependent gluon distribution

Using the Colour Glass Condensate description of electron-nucleus collisions at high energy, we study the diffractive production of a pair of jets with transverse momenta much larger than the nuclear saturation momentum Q s . At leading order in the QCD coupling, the di-jet cross-section exhibits transverse-momentum dependent (TMD) factorisation, with a gluon diffractive TMD distribution (DTMD) which is controlled by gluon saturation and describes the transverse-momentum imbalance between the produced jets. The next-to-leading corrections generate the various quantum evolutions of the diffractive gluon distribution. We focus on the Collins-Soper-Sterman (CSS) evolution which describes the change in the gluon DTMD when increasing the “hard scale” (the typical transverse momentum of the di-jets). We consider two different representations for this equation, one in transverse-momentum space, the other one in transverse-coordinate space. They are not fully equivalent with each other (despite being related by a Fourier transform) because of the respective boundary conditions. These conditions encode the essential physics of gluon saturation together with the effects of two other types of quantum evolution: the BK/JIMWLK evolution over the rapidity gap (“inside the Pomeron”) and the DGLAP evolution outside the rapidity gap (“within the diffractive system”). We demonstrate that, due to gluon saturation, one can compute both the boundary conditions and the CSS solutions mostly from first principles, without the need for a non-perturbative Sudakov. We numerically find a good agreement between the CSS solutions in the two aforementioned representations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Scanning X-Ray Diffraction Microscopy for Diamond Quantum Sensing

An understanding of nano- and microscale crystal strain in chemical-vapor-deposition diamond is crucial to the advancement of diamond quantum technologies. In particular, the presence of such strain and its characterization presents a challenge to diamond-based quantum sensing and information applications-as well as for future dark-matter detectors, where the directional information about incoming particles is encoded in crystal strain. Here, we exploit nanofocused scanning x-ray diffraction microscopy to quantitatively measure crystal deformation from defects in diamond with high spatial and strain resolution. The combination of information from multiple Bragg angles allows stereoscopic three-dimensional modeling of strain-feature geometry; the diffraction results are validated via comparison to optical measurements of the strain tensor based on spin-state-dependent spectroscopy of ensembles of nitrogen-vacancy centers in the diamond. Finally, our results demonstrate both strain and spatial resolution sufficient for directional detection of dark matter via x-ray measurement of crystal strain and provide a promising tool for diamond growth analysis and improvement of defect-based sensing.

42 ENGINEERING↗
DOE OSTI2023

Deterministic nanoscale quantum spin-defect implantation and diffraction strain imaging

Abstract Local crystallographic features negatively affect quantum spin defects by changing the local electrostatic environment, often resulting in degraded or varied qubit optical and coherence properties. Few tools exist that enable the deterministic synthesis and study of such intricate systems on the nano-scale, making defect-to-defect strain environment quantification difficult. In this paper, we highlight state-of-the-art capabilities from the U.S. Department of Energy’s Nanoscale Science Research Centers that directly address these shortcomings. Specifically, we demonstrate how complementary capabilities of nano-implantation and nano-diffraction can be used to demonstrate the quantum relevant, spatially deterministic creation of neutral divacancy centers in 4H silicon carbide, while investigating and characterizing these systems on the ≤ 25 nm scale with strain sensitivities on the order of 1 × 10 − 6 , relevant to defect formation dynamics. This work lays the foundation for ongoing studies into the dynamics and deterministic formation of low strain homogeneous quantum relevant spin defects in the solid state.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Ligand-conjugated quantum dots for fast sub-diffraction protein tracking in acute brain slices

Semiconductor quantum dots (QDs) have demonstrated utility in long-term single particle tracking of membrane proteins in live cells in culture. To extend the superior optical properties of QDs to more physiologically relevant cell platforms, such as acute brain slices, we examine the photophysics of compact ligand-conjugated CdSe/CdS QDs using both ensemble and single particle analysis in brain tissue media. We find that symmetric core passivation is critical for both photostability in oxygenated media and for prolonged single particle imaging in brain slices. We then demonstrate the utility of these QDs by imaging single dopamine transporters in acute brain slices, achieving 20 nm localization precision at 10 Hz frame rates. Finally, these findings detail design requirements needed for new QD probes in complex living environments, and open the door to physiologically relevant studies that capture the utility of QD probes in acute brain slices.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Conformational diversity of 1-phenylpiperidin-4-one in the gas phase

Conformational preferences of substituted, saturated cyclic ketones may deviate from those of their parent analogues. 1-Phenylpiperidin-4-one was found to exist in several forms differing by not only position (axial or equatorial) of the aryl-substituent but also by a configuration of the piperidine cycle itself: chair-Eq, chair-Ax and twist-Tw. Here, the ratios of the co-existing species contributions in gas phase predicted by various quantum chemical calculations were confirmed by synchronous gas-phase electron diffraction and mass spectrometric experiments carried out for the vapor at 337 K demonstrating a best fit with the B3LYP-D3/cc-pVTZ combination: Eq:Ax:Tw=55(13):22(9):23(10) vs. 40:35:25.

1-phenylpiperidin-4-one↗