Researchers used powerful XFELs to trigger strong inner-shell lasing, producing attosecond hard X-ray pulses. Filamentation and Rabi cycling helped explain these effects. Lasers, once confined to the realm of science fiction, are now widely used in research, medicine, and even everyday entertainm
CU Boulder scientists created a quantum device that uses cold atoms and lasers to track 3D acceleration. In a new study, physicists at the University of Colorado Boulder used a cloud of atoms cooled to extremely low temperatures to measure acceleration in three dimensions at the same time, achiev
The answer, it turns out, is yes. In a breakthrough experiment, scientists have observed signs of anyons in a one-dimensional ultracold gas for the first time. The research, published in Nature, involved teams from the University of Innsbruck, Université Paris-Saclay, and Université Libre de Bruxelles.
To reveal the presence of anyons, the scientists carefully injected and accelerated a mobile impurity into a tightly controlled gas of bosons at near absolute zero.
Absolute zero is the theoretical lowest temperature on the thermodynamic scale, corresponding to 0.00 K (−273.15 °C or −459.67 °F). At this point, atomic motion ceases entirely, and the substance no longer emits or absorbs thermal energy.
Researchers have developed a novel analytical model that reveals the kinetics of exciton dynamics in thermally activated delayed fluorescence (TADF) materials. Organic light-emitting diodes, or OLEDs, are photoluminescence devices that use organic compounds to generate light. Compared to traditio
Researchers found that natural polymers derived from okra and fenugreek are highly effective at removing microplastics from water. The same sticky substances that make okra slimy and give fenugreek its gel-like texture could help clean our water in a big way. Scientists have discovered that these
The world’s strangest trampoline doesn’t bounce—it swings sideways and even glides around corners. But no one can jump on it, because it’s less than a millimeter tall. Imagine a trampoline so tiny it’s just 0.2 millimeters wide, with a surface thinner than anything you’ve ever seen, only about 20
The ingestible capsule creates a drug depot in the stomach, slowly releasing its medication over time and removing the need for patients to take a daily dose. For many people living with schizophrenia, other psychiatric conditions, or chronic illnesses like hypertension and asthma, taking medicat
Researchers have demonstrated the slowing and subsequent reacceleration of a muon beam, increasing the potential of muon beams as a research tool.
About every second, the average human has a rare messenger from the edge of space passing through their body. Muons―similar to electrons but with 200 times the mass―are created naturally when cosmic ions strike the upper atmosphere, producing a shower of particles. Muons can also be created artificially, but these muon beams are very sparse compared to more conventional electron, proton, and ion beams. Over the past few decades, researchers have developed a way to make much denser beams [1, 2], but the difficulty of working with such beams has kept scientists from fulfilling their potential as a research tool. Now a team at the Japan Proton Accelerator Research Complex (J-PARC) has successfully demonstrated the capability to manipulate a dense muon beam, accelerating the muons in a radio-frequency device for the first time [3].
Multidimensional effects degrade the neutron yield and the compressed areal density of laser-direct-drive inertial confinement fusion implosions of layered deuterium–tritium cryogenic targets on the OMEGA Laser System with respect to 1D radiation-hydrodynamic simulation predictions. A comprehensive physics-informed 3D reconstruction effort is under way to infer hot-spot and shell conditions at stagnation from four x-ray and seven neutron detectors distributed around the OMEGA target chamber. Neutron diagnostics, providing measurements of the neutron yield, hot-spot flow velocity, and apparent ion-temperature distribution, are used to infer the mode-1 perturbation at stagnation. The x-ray imagers record the shape of the hot-spot plasma to diagnose mode-1 and mode-2 perturbations. A deep-learning convolutional neural network trained on an extensive set of 3D radiation-hydrodynamic simulations is used to interpret the x-ray and nuclear measurements to infer the 3D profiles of the hot-spot plasma conditions and the amount of laser energy coupled to the hot-spot plasma. A 3D simulation database shows that larger mode-1 asymmetries are correlated with higher hot-spot flow velocities and reduced laser-energy coupling and neutron yield. Three-dimensional hot-spot reconstructions from x-ray measurements indicate that higher amounts of residual kinetic energy are correlated with higher measured hot-spot flow velocities, consistent with 3D simulations.
This theoretical and numerical study investigates the impact of electrostatic stresses on the shape of charged water structures (grains) in weakly ionized plasmas. We developed an analytic model to predict the conditions under which a grain in a plasma is deformed. We find that electrostatic stresses can overcome the opposing surface tension stresses on nanometer-scale grains, causing initially spherical clusters to elongate and become ellipsoidal. The exact size limit of the grain for which electrostatic stress will dominate depends on the floating potential, surface tension, and local radius of curvature. Clusters larger than this limit are not affected by electrostatic stresses due to an insufficient number of electrons on the surface. The model is compared to Molecular Dynamics (MD) simulations performed with a calculated solvated electron potential on initially spherical grains of 2.5 nm radius charged with 0.5%–1% electrons. We find excellent agreement between MD simulations and the analytic theory. We also carried out Quantum Mechanics (QM) computations showing that the surface tension increases with decreasing size of the water molecule cluster and increases even more with the addition of solvated electrons. This increase in surface tension can hinder the elongation of the grains. Our QM computations also show that on the nanosecond time scale, the binding force of electrons to water molecule clusters is stronger than the electrostatic repulsion between adjacent electrons and thus the cluster behaves as an insulator. However, consideration of the very small conductivity of ice shows that on time scales of a fraction of a second, ice clusters behave as conductors, so their surface may be considered to be at an equipotential.