Electrical engineers in the accelerator physics group at TU Darmstadt have developed a design for a laser-driven electron accelerator so small it could be produced on a silicon chip. It would be inexpensive and with multiple applications. The design, which has been published in Physical Review Letters, is now being realised as part of an international collaboration.
IMAGE: The driving laser field (red) ‘shakes’ electrons in graphene at ultrashort time scales, shown as violet and blue waves. A second laser pulse (green) can control this wave and thus determine the direction of current. (Image credit: FAU/Christian Heide)
Being able to control electronic systems using light waves instead of voltage signals is the dream of physicists all over the world. The advantage is that electromagnetic light waves oscillate at petaherz frequency. This means that computers in the future could operate at speeds a million times faster than those of today. Scientists at Friedrich-Alexander University (FAU; Erlangen-Nurenberg, Germany) have now come one step closer to achieving this goal as they have succeeded in using ultra-short laser impulses to precisely control electrons in graphene. The scientists published their results in Physical Review Letters.
Current control in electronics that is one million times faster than in today’s systems is a dream for many. Ultimately, current control is one of the most important components as it is responsible for data and signal transmission. Controlling the flow of electrons using light waves instead of voltage signals, as is now the case, could make this dream a reality. However, up to now, it has been difficult to control the flow of electrons in metals as metals reflect light waves and the electrons inside them cannot be influenced by these light waves.
Every action creates an equal and opposite reaction. It’s perhaps the best known law of physics, and Guido Fetta thinks he’s found a way around it.
According to classical physics, in order for something—like a spaceship—to move, conservation of momentum requires that it has to exert a force on something else. A person in roller skates, for example, pushes off against a wall; a rocket accelerates upward by propelling high-velocity combusted fuel downward. In practice, this means that space vessels like satellites and space stations have to carry up to half their weight in propellant just to stay in orbit. That bulks up their cost and reduces their useful lifetime.
A team of researchers from the Earthquake Research Institute, Department of Civil Engineering and Information Technology Center at the University of Tokyo, and the RIKEN Center for Computational Science and RIKEN Center for Advanced Intelligence Project in Japan were finalists for the coveted Gordon Bell Prize for outstanding achievements in high-performance computing. Tsuyoshi Ichimura together with Kohei Fujita, Takuma Yamaguchi, Kengo Nakajima, Muneo Hori and Lalith Maddegedara were praised for their simulation of earthquake physics in complex urban environments.
Two possibilities: Either the image captures two massive galactic clusters in the process of colliding, or NASA is covering up the existence of a starship so big it’s several million light years long.
Humanity’s current understanding of physics may suggest faster-than-light travel is impossible, but researchers here on Earth can still observe happening in places much too far away to ever actually visit (and generally only what they looked like in the distant past). One of them is a galactic collision that, at least from our planetary vantage point, looks an awful lot like a craft going where no man has ever gone before.
NASA released the above composite image of the galaxy cluster Abell 1033 some 1.62 billion light years away this week, showing wisps of gas that appear to be arranged in the shape of Star Trek’s USS Enterprise. NASA wrote that the image was captured by the Chandra X-ray Observatory, an X-ray telescope that detects superheated gases, as well as the Low-Frequency Array, which detects radio emissions.