The generation of coherent extreme ultraviolet and X-ray photons by high harmonic generation from solid targets relies on the formation of a steep electron density gradient tuned by the leading edge of a relativistically intense laser pulse interacting with a bulk, solid-density target.
Light is one aspect of the Universe that, for most people, holds a deep and noticeable value in everyday life, helping them to navigate, learn from, and connect with the world around them. Yet it's not particularly difficult to imagine life without it. After all, many nonhuman animals live in lightless environments. However, as Gideon Koekoek, an associate professor of physics in the research group Gravitational Waves and Fundamental Physics
This system is truly extraordinary. We are seeing the radio equivalent of a laser halfway across the universe. This galaxy acts as a lens, the way a water droplet on a window pane would, because its mass curves the local space-time. So we have a radio laser passing through a cosmic telescope before being detected by the powerful MeerKAT radio telescope.
A core question we want to understand is where did matter come from. And then, if you know about antimatter, it's natural to ask, why is that not here? The process is not understood and we are hunting for clues as to why it happened, says Dr Christian Smorra, a physicist on the Baryon Antibaryon Symmetry Experiment (Base) at Cern.
This system is truly extraordinary. We're seeing the radio equivalent of a laser halfway across the universe. Fundamentally, masers and lasers are focused beams of light in the same frequency. In the realm of astrophysics, these can arise from clouds of dust being excited into a higher energy state from the light emitted by other sources, like stars and black holes.
The sun is putting on a show. On Sunday the star unleashed several strong and bright solar flares, including one of the most powerful eruptions seen in decades. Far from the steadily glowing orb we sometimes picture, the sun's surface is made up of roiling plasma thrown about by twisting magnetic fields. When these fields snap, they can throw out huge bursts of energy and charged particles into spacea solar flare.
Stellar activity such as solar storms and plasma turbulence from a star near a transmitting planet can broaden otherwise ultra-narrow signals. That spreads the power of any such transmission across more frequencies, the institute's scientists say, which makes it more difficult to detect using traditional narrowband searches.
A bright star in a nearby galaxy has essentially vanished. Astronomers believe that it died and collapsed in on itself, transforming into the eerie cosmic phenomenon known as a black hole. "It used to be one of the brightest stars in the Andromeda galaxy," says Kishalay De, an astronomer with Columbia University and the Flatiron Institute. "Today, it is nowhere to be seen, even with the most sensitive telescopes."
Each time we've looked at the Universe in a fundamentally new way, we didn't just see more of what we already knew what was out there. In addition, those novel capabilities allowed the Universe to surprise us, breaking records, revolutionizing our view of what was out there, and teaching us information that we never could have learned without collecting that key data.
Y.W. designed the experimental protocols, performed experiments, analysed the data and wrote the manuscript. Y.H., X.K., D.C., J.X.X. and W.Z. performed experiments and edited the manuscript. Y.C. and S.P. edited the manuscript. M.J., X.P. and J.D. proposed the experimental concept, designed experimental protocols and proofread and edited the manuscript. All authors contributed with discussions and checking the manuscript. Corresponding authors Correspondence to Min Jiang or Xinhua Peng.
Now say you want to run some modest AI stuff. That's a bigger job, so let's scale up our cubical computer with edges twice as long as before. That would make the volume eight times larger (2 3), so we could have eight times as many processors, and we need eight times as much power input-2,400 watts. However, the surface area is only four times (2 2) larger, so the radiative power would be about 4,000 watts.
an electron within a molecule gets excited to a higher-energy state, the electron de-transitions back to the lower energy state, where it emits light of a very specific wavelength in the process. Then, pumped or injected energy re-excites an electron within that very same molecule back into that higher-energy state, over and over.
