A5044003926- Laser-Matter Interactions and Applications
- Orbital Angular Momentum in Optics
- Laser-Plasma Interactions and Diagnostics
- Advanced Fiber Laser Technologies
- Advanced Chemical Physics Studies
- Advanced Condensed Matter Physics
- Atmospheric chemistry and aerosols
- Topological Materials and Phenomena
- Organic and Molecular Conductors Research
- Atmospheric Ozone and Climate
- Atomic and Molecular Physics
- Advanced Electron Microscopy Techniques and Applications
- High-pressure geophysics and materials
- Mass Spectrometry Techniques and Applications
- Physics of Superconductivity and Magnetism
- Advanced X-ray Imaging Techniques
- Electronic and Structural Properties of Oxides
- Theoretical and Computational Physics
- Advanced biosensing and bioanalysis techniques
- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Iron-based superconductors research
- DNA and Nucleic Acid Chemistry
- Laser-Ablation Synthesis of Nanoparticles
- Random lasers and scattering media
SLAC National Accelerator Laboratory
2022-2025
Linac Coherent Light Source
2022-2025
Stanford University
2022-2024
Fermi National Accelerator Laboratory
2024
Joint Institute for Laboratory Astrophysics
2017-2023
University of Colorado Boulder
2017-2021
University of Colorado System
2020-2021
National Institute of Standards and Technology
2021
Saarland University
2016-2018
Temple University
2013-2016
We present a novel latent embedding model for learning compatibility function between image and class embeddings, in the context of zero-shot classification. The proposed method augments state-of-the-art bilinear by incorporating variables. Instead single map, it learns collection maps with selection, which map to use, being variable current image-class pair. train ranking based objective penalizes incorrect rankings true given image. empirically demonstrate that our improves various...
Pulses with a twist and torque Structured light beams can serve as vortex carrying optical angular momentum have been used to enhance communications imaging. Rego et al. generated dynamic pulses by interfering two incident time-delayed different orbital momenta through the process of high harmonic generation. A controlled time delay between allowed extreme-ultraviolet beam exhibit time-dependent momentum, called self-torque. Such could potentially be manipulate nanostructures atoms on...
Altermagnets are an emerging elementary class of collinear magnets. Unlike ferromagnets, their distinct crystal symmetries inhibit magnetization while, unlike antiferromagnets, they promote strong spin polarization in the band structure. The corresponding unconventional mechanism time-reversal symmetry breaking without electronic spectra has been regarded as a primary signature altermagnetism but not experimentally visualized to date. We directly observe structure altermagnetic RuO 2 by...
Abstract Crystal lattice fluctuations, which are known to influence phase transitions of quantum materials in equilibrium, also expected determine the dynamics light-induced changes. However, they have only rarely been explored these dynamical settings. Here we study time evolution fluctuations paraelectric SrTiO 3 , mid-infrared drives shown induce a metastable ferroelectric state. Crucial physics is competition between polar instabilities and antiferrodistortive rotations, equilibrium...
The extreme nonlinear optical process of high-harmonic generation (HHG) makes it possible to map the properties a laser beam onto radiating electron wave function and, in turn, emitted x-ray light. Bright HHG beams typically emerge from longitudinal phased distribution atomic-scale quantum antennae. Here, we form transverse necklace-shaped array linearly polarized emitters, where orbital angular momentum conservation allows us tune line spacing and divergence ultraviolet soft combs. on-axis...
We present a method of producing ultrashort pulses circularly polarized extreme ultraviolet (EUV) light through high-harmonic generation (HHG).HHG is powerful tool for generating bright laser-like beams EUV and soft x-ray with pulse durations, which are important many spectroscopic imaging applications in the materials, chemical, nano sciences.Historically HHG was restricted to linear polarization; however, recent advances making it possible precisely control polarization state emitted...
A central paradigm of nonequilibrium physics concerns the dynamics heterogeneity and disorder, impacting processes ranging from behavior glasses to emergent functionality active matter. Understanding these complex mesoscopic systems requires probing microscopic trajectories associated with irreversible processes, role fluctuations entropy growth, timescales on which responses are ultimately maintained. Approaches that illuminate in model may enable a more general understanding other...
Using x-ray photoelectron diffraction (XPD) and angle-resolved photoemission spectroscopy, we study intensity changes related to in the geometric electronic structure kagome metal CsV_{3}Sb_{5} upon transition an unconventional charge density wave (CDW) state. The XPD patterns reveal presence of a chiral atomic CDW phase. Furthermore, using circularly polarized x-rays, have found pronounced nontrivial circular dichroism angular distribution valence band phase, indicating chirality structure....
We identify a class of over-parameterized deep neural networks with standard activation functions and cross-entropy loss which provably have no bad local valley, in the sense that from any point parameter space there exists continuous path on is non-increasing gets arbitrarily close to zero. This implies these sub-optimal strict minima.
We demonstrate temporally multiplexed multibeam ptychography implemented for the first time in EUV, by using a high harmonic based light source. This allows simultaneous imaging of different sample areas, or same area at times incidence angles. Furthermore, we show that this technique is compatible with wavelength multiplexing spectroscopic imaging, taking full advantage temporal and spectral characteristics sources. enables increased data throughput simple experimental implementation photon...
Hypergraph matching has recently become a popular approach for solving correspondence problems in computer vision as it allows the use of higher-order geometric information. can be formulated third-order optimization problem subject to assignment constraints which turns out NP-hard. In recent work, we have proposed an algorithm hypergraph first lifts fourth-order and then solves via corresponding multilinear form. This leads tensor block coordinate ascent scheme guarantee providing monotonic...
The photophysical behavior of pyrrolocytosine (PC), a fluorescent base analogue cytosine, has been investigated using theoretical approaches. similarities between the PC and cytosine structures allow to maintain pseudo-Watson-Crick base-pairing arrangement with guanine. Cytosine, similar other natural nucleobases, is practically non-fluorescent, because ultrafast radiationless decay occurring through conical intersections. displays much higher fluorescence quantum yield than making it an...
We report ultrafast x-ray scattering experiments of the quasi-1D charge density wave (CDW) material (TaSe_{4})_{2}I following infrared photoexcitation. From time-dependent diffraction signal at CDW sidebands we identify a 0.11 THz amplitude mode derived primarily from transverse acoustic high-symmetry structure. our measurements determine that this interacts with valence indirectly through another collective mode, and system in has composite nature supporting multiple dynamically active...
We report the development of a new three-dimensional (3D) momentum-imaging setup based on conventional velocity map imaging to achieve coincidence measurement photoelectrons and photo-ions. This uses only one detector (microchannel plates (MCP)/phosphor screen) but voltages electrodes are pulsed push both electrons ions toward same detector. The ion-electron is achieved using two cameras capture images separately. time-of-flight read out from MCP digitizer. demonstrate this system by...
The kagome superconductor CsV3Sb5 hosts a variety of charge density wave (CDW) phases, which play fundamental role in the formation other exotic electronic instabilities. However, identifying precise structure these CDW phases and their intricate relationships remain subject intense debate, due to lack static probes that can distinguish with identical spatial periodicity. Here, we unveil out-of-equilibrium competition between two coexisting 2 × CDWs harnessing time-resolved X-ray...
Significance Highly excited states of neutral molecules behave qualitatively differently than the lower that are commonly studied in photochemistry. Such involved ionospheric and astrochemical phenomena, as well detonation processes. However, highly poorly understood due to experimental theoretical challenges probing their complex dynamics. Here, we apply vacuum-UV femtosecond laser sources an imaging photoelectron–photoion coincidence spectrometer directly probe surprisingly fast 25-fs...
Warm dense matter (WDM) represents a highly excited state that lies at the intersection of solids, plasmas, and liquids cannot be described by equilibrium theories. The transient nature this when created in laboratory, as well difficulties probing strongly coupled interactions between electrons ions, make it challenging to develop complete understanding regime. In work, exciting isolated ∼8 nm copper nanoparticles with femtosecond laser below ablation threshold, we create uniformly WDM....
Abstract Carboxylic acids are important combustion intermediates, especially regarding the of oxygenates such as ethyl esters. The purpose this study is to discern unimolecular decomposition pathways one carboxylic acid, propionic using microreactor flow experiments with line‐tunable photoionization mass spectrometry and infrared spectroscopy, along high‐level electronic structure calculations (CCSD(T)/cc‐pV∞Z//M06‐2X/cc‐pVTZ level theory) master equation theory. Microreactor were performed...