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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Enhanced quantum efficiency from optical interference in alkali antimonide photocathodes: Modeling and experimental results

We present measurements of enhanced quantum efficiency (QE) in thin film alkali antimonide photocathodes from optical interference in the cathode-substrate multilayer. Modulations in the spectral response are observed over a range of visible wavelengths and are shown to increase the QE by more than a factor of two at specific wavelengths. We present a model describing the QE modulations based on the three step photoemission process incorporating cases of both constant density of states and density functional theory-derived density of states and show that the calculated results are in good agreement with the measurements. Model predictions demonstrate that QE can be enhanced by more than a factor of 5 by optimization of cathode and substrate layer thicknesses. Additionally, these calculations reveal that optical interference can yield higher quantum efficiencies in thin films compared to thick, optically dense films. We model the QE vs excitation wavelength of multiple alkali antimonide compounds at different thicknesses. We then discuss the advantages of this interference effect for electron accelerators.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Hyperspectral interference tomography of nacre

Significance We invented an optical technique—hyperspectral interference tomography—that rapidly and nondestructively extracts nanoscale structural information across large samples of nacre (mother-of-pearl) and other layered materials by combining multiangle and polarization-resolved hyperspectral imaging with optical-interference modeling. We investigated nacre in mollusk shells from two different species, red abalone and rainbow abalone, and discovered a previously unknown relationship between the age of the mollusk and the thickness of aragonite tablets in nacre. Hyperspectral interference tomography will have applications in climate science, since nacre tablet thickness in fossil shells is a proxy for ancient seawater temperature, and in bioinspired mechanics, because the layered structure of nacre inspires engineered materials with exceptional strength and toughness.

47 OTHER INSTRUMENTATION↗
DOE OSTI2026

Laser interference structuring of Cu for adhesive joining of HVAC equipment

Due to potential energy and cost savings benefits, adhesive joining has been recently considered for heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems. HVAC adhesive bonding requires cost-effective and adequate surface preparations of adherents. Here, this article investigates the use of abrasion, traditional single-beam laser, and a laser-interference technique as surface preparations of copper surfaces. Surface morphology is characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Effective submicrometer peak-to-valley structuring with a periodicity of ∼2.7μ⁢m was demonstrated for laser-interference processing. Single-lap shear tests were conducted for 89 joints made with bondline thicknesses of 0.15 and 0.3 mm. Data on process variables and measured variables included open-time, bond length, maximum load, displacement at failure, shear lap strength, and failure mode. A statistical analysis was conducted on each lot to determine the lower limit with 95% confidence intervals for displacements at failure and shear lap strengths. A comparison is presented between the properties of laser-structured joints with respect to those prepared by abrasion, which is considered the baseline surface preparation technique. Based on this comparison, one single-beam laser technique and two laser-interference techniques were shown to exhibit vastly superior performance over the joints made with abraded specimens.

Sabau, Adrian S. [Oak Ridge National Laboratory (O↗
DOE OSTI2023

Triple interference, non-linear Talbot effect and gravitization of the quantum

Recently we have discussed a new approach to the problem of quantum gravity in which the quantum mechanical structures that are traditionally fixed, such as the Fubini–Study metric in the Hilbert space of states, become dynamical and so implement the idea of gravitizing the quantum. Here, in this paper we elaborate on a specific test of this new approach to quantum gravity using triple interference in a varying gravitational field. Our discussion is driven by a profound analogy with recent triple-path interference experiments performed in the context of non-linear optics. We emphasize that the triple interference experiment in a varying gravitational field would deeply influence the present understanding of the kinematics of quantum gravity and quantum gravity phenomenology. We also discuss the non-linear Talbot effect as another striking phenomenological probe of gravitization of the geometry of quantum theory.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Light storage, retrieval, and controllable interference in an atomic tripod system

Highly efficient quantum memories are essential for advancing quantum information processing technologies, including scalable quantum computing and quantum networks. We experimentally demonstrate a light storage and retrieval protocol in a tripod system using an ensemble of laser-cooled 87 Rb atoms. The tripod system, which consists of three ground states and an excited state, offers rich dynamics: its use to coherently store and retrieve a weak probe pulse in the 87 Rb 𝐹 = 1 ground-state manifold leads to the interference of two spin-wave excitations during storage time that translate to an interference in the peak intensity of the retrieved probe pulse. Our work shows that these interferences, which manifest when varying the pulse sequence or energy level structure, can be controlled experimentally by varying the storage time, optical phase, and magnetic field strength. Theoretical simulations exhibit excellent agreement with the experimental results. In conclusion, this work demonstrates the rich dynamics and versatile capabilities of atomic tripod systems for light storage and retrieval, with key advantages over conventional Λ systems, highlighting the potential of atomic tripod systems for applications in quantum information processing, quantum synchronization, and atomic memory protocols.

Coherent control↗
DOE OSTI2026

Quantum Interference in Two-Atom Resonant X-ray Scattering of an Intense Attosecond Pulse

We theoretically investigate resonant x-ray scattering from two noninteracting Ne+ ions driven by an intense attosecond pulse using a nonrelativistic, QED-based time-dependent framework. Our model includes Rabi oscillations, photoionization, Auger decay, and quantum interference among elastic scattering and resonance fluorescence pathways. We analyze how the total scattering signal depends on pulse intensity, atomic configuration, and initial electronic state. We find that the total resonant scattering yield exceeds its nonresonant counterpart; the angular dependence of the signal qualitatively resembles a two-atom structure factor; and the visibility of interference fringes is sensitive to pulse area and the initial electronic state. Only a subset of final states reached via resonance fluorescence exhibits interference, determined by the indistinguishability of photon emission pathways. Fringe visibility is maximized in the linear scattering regime, where ionization is minimal and resonance fluorescence pathways can be largely indistinguishable. These results highlight optimal conditions for applying ultrafast resonant x-ray scattering to single-particle imaging.

Venkatesh, Akilesh↗
DOE OSTI2021

Dissecting subcycle interference in photoelectron holography

Multipath holographic interference in strong-field quantum tunnel ionization is key to revealing subangstrom attosecond dynamics for molecular movies. This critical subcycle motion is often obscured by longer timescale effects such as ring-shaped patterns that appear in above-threshold ionization (ATI). In the present work, we overcome this problem by combining two techniques in theory and experimental analysis: unit-cell averaging and time-filtering data and simulations. Together these suppress ATI rings and enable an unprecedented highly detailed quantitative match between strong-field ionization experiments in argon and the Coulomb-quantum orbit strong-field approximation (CQSFA) theory. Velocity map images reveal fine modulations on the holographic spiderlike interference fringes that form near the polarization axis. CQSFA theory traces this to the interference of three types of electron pathways. The level of agreement between experiment and theory allows sensitive determination of quantum phase differences and symmetries, providing an important tool for quantitative dynamical imaging in quantum systems.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2015

Temporal interferences driven by a single-cycle terahertz pulse in the photodetachment dynamics of negative ions

We present theory and calculations of a real-time-domain interferometry for the photodetachment dynamics of negative ions in the presence of a single-cycle terahertz pulse. The photoelectron can follow two or more classical trajectories to arrive at a detector simultaneously allowing the electron waves to interfere quantum mechanically. Both the in-phase and antiphase oscillations can be observed in the photoelectron interferences from negative hydrogen and fluorine ions depending on the pulse strength and the observing angle. Especially, a temporal-caustic bifurcation is observed when the detection angle is not in line with the pulse polarization direction. Furthermore, similar interferences and bifurcations are also expected in the angle-resolved energy spectrum, as a result of its approximate equivalence with the time-dependent electron flux at large distances.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Interference patterns from post-collision interaction in below-threshold photoexcitation Auger processes

In this work, we focus on the post-collision interaction in Auger processes where the photoelectron energy is near or below the ionization threshold. Time-dependent quantum and classical calculations are performed. When the photoelectron is more deeply bound, interference patterns can be seen in the angular and photoelectron energy distributions. These interference patterns are visible in quantum calculations, but not in purely classical calculations. A semiclassical analysis using actions from two-path trajectories gives the relative locations of the interference maxima very close to those from the full quantum calculations.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2019

Strong Aharonov-Bohm quantum interference in simply connected LaAlO 3 /SrTiO 3 structures

We report Aharonov-Bohm (AB) type quantum interference in simply connected devices created at the LaAlO 3 /SrTiO 3 interface using conductive atomic force microscope (c-AFM) lithography. The oscillations are multiperiodic functions of magnetic field strength, and they exhibit a substantial magnetic hysteresis with frequencies that depend on the magnetic sweep direction. The oscillation amplitude for the lowest two frequencies approaches $e^2/h$, consistent with the theoretical maximum for the AB effect, and harmonics up to third order are observable. Broadband quasiperiodic behavior is reported in a fraction of simply connected electron waveguide devices that exhibit magnetic asymmetries. Curiously, nanoscale ring devices that are multiply connected lack signatures of AB quantum interference. In this work, the interference phenomena are associated with an inhomogeneous magnetic landscape within theLaAlO 3 /SrTiO 3 nanostructures.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

Interference of Higgs diphoton signal and background in production with a jet at the LHC

The Higgs mass determination from diphoton events at the LHC can be affected by interference between the Higgs resonant and continuum background amplitudes with the same initial and final states. For the leading order gluon fusion process, this shift was previously found to exceed 100 MeV, with some dependence on the diphoton mass resolution and the methods used to extract and fit the peak from data. In this paper, I consider the mass shift for the process pp --> j\gamma\gamma\ that includes an additional central jet in the final state. For cuts on the transverse momentum of the jet of 25 GeV or more, the diphoton Higgs peak mass shift due to interference is found to be very small, due in part to less interference for the gluon-gluon initiated subprocess, and in part to a cancellation between it and the quark-gluon initiated subprocess.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

On-shell interference effects in Higgs boson final states

Top quark loops in Higgs production via gluon fusion at large invariant final state masses can induce important interference effects in searches for additional Higgs bosons as predicted in, e.g., Higgs portal scenarios and the minimal supersymmetric Standard Model when the heavy scalar is broad or the final state resolution is poor. Currently, the limit setting as performed by both ATLAS and CMS is based on injecting a heavy Higgs-like signal neglecting interference effects. In this study, we perform a study of such “on-shell” interference effects in pp → ZZ and find that they lead to a ≲O(30%) width scheme-dependent modification of the signal strength. Finally, including the continuum contributions to obtain, e.g., the full pp → ZZ → 4l final state, this modification is reduced to the 10% level in the considered intermediate mass range.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2 H – NbSe 2

We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe₂, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe₂. Thus, we demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe₂, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Interference in the g g → h → γ γ On-Shell Rate and the Higgs Boson Total Width

Here, we consider interference between the Higgs signal and QCD background in $gg\rightarrow h \rightarrow \gamma\gamma$ and its effect on the on-shell Higgs rate. The existence of sizable strong phases leads to destructive interference of about 2% of the on-shell cross section in the Standard Model. This effect can be enhanced by beyond the standard model physics. In particular, since it scales differently from the usual rates, the presence of interference allows indirect limits to be placed on the Higgs width in a novel way, using on-shell rate measurements. Our study motivates further QCD calculations to reduce uncertainties. We discuss potential width-sensitive observables, both using total and differential rates and find that the HL-LHC can potentially indirectly probe widths of order tens of MeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Two-Center Interference in the Photoionization Delays of Kr 2

Herein we present the experimental observation of two-center interference in the ionization time delays of Kr 2 . Using attosecond electron-ion-coincidence spectroscopy, we simultaneously measure the photoionization delays of krypton monomer and dimer. The relative time delay is found to oscillate as a function of the electron kinetic energy, an effect that is traced back to constructive and destructive interference of the photoelectron wave packets that are emitted or scattered from the two atomic centers. Our interpretation of the experimental results is supported by solving the time-independent Schrödinger equation of a 1D double-well potential, as well as coupled-channel multiconfigurational quantum-scattering calculations of Kr 2 . This work opens the door to the study of a broad class of quantum-interference effects in photoionization delays and demonstrates the potential of attosecond coincidence spectroscopy for studying weakly bound systems.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2026

Evidence of Spin-Interference Effects in Exclusive 𝐽/𝜓 → 𝑒 + ⁢𝑒 − Photoproduction in Ultraperipheral Heavy-Ion Collisions

Here, we report the first evidence of spin interference in exclusive 𝐽/𝜓 → 𝑒 + ⁢𝑒 − photoproduction in ultraperipheral heavy-ion collisions at STAR at $\sqrt{𝑠_{𝑁⁢𝑁}}$ = 200 GeV. In Au + Au collisions, a negative cos⁡(2⁢𝜙) modulation is found for 𝑝 𝑇 < 120 MeV/𝑐 with a significance of 3.2⁢𝜎, while the isobar data (Ru + Ru, Zr + Zr) show a consistent negative modulation with a significance of 1.9⁢𝜎, opposite in sign to that in 𝜌 0 → 𝜋 + ⁢𝜋 − photoproduction. This establishes for the first time that the interference sign is controlled by the spin structure of the final-state daughters, resolving the ambiguity present in the all-boson 𝜌 0 channel. The compact 𝐽/𝜓 probes gluon distributions at perturbative scales, resulting in a weaker modulation and providing stringent constraints on color glass condensate calculations. These findings demonstrate that spin-dependent interference in heavy vector mesons provides a new, experimentally accessible handle on gluon structure beyond traditional cross-section measurements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Interference Moral Hazard in Large Multihop Networks

Cooperation between network nodes is critical for supporting services in ad hoc networks. Cooperation, however, is an idealized assumption that may not always be present. This assumption can fail because of moral hazard, a scenario in part caused by misaligned incentives between the requesting node and supporting node. In this paper, we characterize a moral hazard that perversely incentivizes nodes to increase their routing payments by transmitting interference into the multi-hop network. We refer to this as the interference moral hazard (IMH) problem which is inherent to strategyproof mechanisms with low overpayments. We investigate IMH as a non-cooperative game played by network nodes on a random graph. For large networks, we show that IMH can be solved in the network design space. Finally, we provide sufficient conditions on the network distribution that guarantee an equilibrium path with interference-free play. This is achieved by 1) lower-bounding the number of nodes and 2) bounding the network density slightly above the 2-connectedness threshold and below a proposed upper-bound. Simulations suggest that density plays a fundamental role in IMH.

42 ENGINEERING↗
DOE OSTI2024

Electronic interactions in Dirac fluids visualized by nano-terahertz spacetime interference of electron-photon quasiparticles

Ultraclean graphene at charge neutrality hosts a quantum critical Dirac fluid of interacting electrons and holes. Interactions profoundly affect the charge dynamics of graphene, which is encoded in the properties of its electron-photon collective modes: surface plasmon polaritons (SPPs). Here, we show that polaritonic interference patterns are particularly well suited to unveil the interactions in Dirac fluids by tracking polaritonic interference in time at temporal scales commensurate with the electronic scattering. Spacetime SPP interference patterns recorded in terahertz (THz) frequency range provided unobstructed readouts of the group velocity and lifetime of polariton that can be directly mapped onto the electronic spectral weight and the relaxation rate. Our data uncovered prominent departures of the electron dynamics from the predictions of the conventional Fermi-liquid theory. The deviations are particularly strong when the densities of electrons and holes are approximately equal. The proposed spacetime imaging methodology can be broadly applied to probe the electrodynamics of quantum materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗