The device uses lasers to accelerate electrons along an etched channel.
Category: computing – Page 720
False Alarm: The So-Called ‘Angel Particle’ Is Still a Mystery
A 2017 report of the discovery of a particular kind of Majorana fermion — the chiral Majorana fermion, referred to as the “angel particle” — is likely a false alarm, according to new research. Majorana fermions are enigmatic particles that act as their own antiparticle and were first hypothesized to exist in 1937. They are of immense interest to physicists because their unique properties could allow them to be used in the construction of a topological quantum computer.
A team of physicists at Penn State and the University of Wurzburg in Germany led by Cui-Zu Chang, an assistant professor of physics at Penn State studied over three dozen devices similar to the one used to produce the angel particle in the 2017 report. They found that the feature that was claimed to be the manifestation of the angel particle was unlikely to be induced by the existence of the angel particle. A paper describing the research appears on January 3, 2020 in the journal Science.
“When the Italian physicist Ettore Majorana predicted the possibility of a new fundamental particle which is its own antiparticle, little could he have envisioned the long-lasting implications of his imaginative idea.”
Decoder translates brain activity into speech
Neurological conditions or injuries that result in the inability to communicate can be devastating. Patients with such speech loss often rely on alternative communication devices that use brain–computer interfaces (BCIs) or nonverbal head or eye movements to control a cursor to spell out words. While these systems can enhance quality-of-life, they can only produce around 5–10 words per minute, far slower than the natural rate of human speech.
Researchers from the University of California San Francisco today published details of a neural decoder that can transform brain activity into intelligible synthesized speech at the rate of a fluent speaker (Nature 10.1038/s41586-019‑1119-1).
“It has been a longstanding goal of our lab to create technology to restore communication for patients with severe speech disabilities,” explains neurosurgeon Edward Chang. “We want to create technologies that can generate synthesized speech directly from human brain activity. This study provides a proof-of-principle that this is possible.”
Researchers build a particle accelerator that fits on a chip
The accelerator-on-a-chip demonstrated in Science is just a prototype, but Vuckovic said its design and fabrication techniques can be scaled up to deliver particle beams accelerated enough to perform cutting-edge experiments in chemistry, materials science and biological discovery that don’t require the power of a massive accelerator.
“The largest accelerators are like powerful telescopes. There are only a few in the world and scientists must come to places like SLAC to use them,” Vuckovic said. “We want to miniaturize accelerator technology in a way that makes it a more accessible research tool.”
Team members liken their approach to the way that computing evolved from the mainframe to the smaller but still useful PC. Accelerator-on-a-chip technology could also lead to new cancer radiation therapies, said physicist Robert Byer, a co-author of the Science paper. Again, it’s a matter of size.
Today, medical X-ray machines fill a room and deliver a beam of radiation that’s tough to focus on tumors, requiring patients to wear lead shields to minimize collateral damage.
On a hillside above Stanford University, the SLAC National Accelerator Laboratory operates a scientific instrument nearly 2 miles long. In this giant accelerator, a stream of electrons flows through a vacuum pipe, as bursts of microwave radiation nudge the particles ever-faster forward until their velocity approaches the speed of light, creating a powerful beam that scientists from around the world use to probe the atomic and molecular structures of inorganic and biological materials.
Now, for the first time, scientists at Stanford and SLAC have created a silicon chip that can accelerate electrons—albeit at a fraction of the velocity of that massive instrument—using an infrared laser to deliver, in less than a hair’s width, the sort of energy boost that takes microwaves many feet.
Remote connections? Detangling entanglement in quantum physics
Quantum computers, quantum cryptography and quantum (insert name here) are often in the news these days. Articles about them inevitably refer to entanglement, a property of quantum physics that makes all these magical devices possible.
Einstein called entanglement “spooky action at a distance,” a name that has stuck and become increasingly popular. Beyond just building better quantum computers, understanding and harnessing entanglement is also useful in other ways.
For example, it can be used to make more accurate measurements of gravitational waves, and to better understand the properties of exotic materials. It also subtly shows up in other places: I have been studying how atoms bumping into each other become entangled, to understand how this affects the accuracy of atomic clocks.
Neuroscientists Discover New Kind of Signal in the Human Brain
Scientists have uncovered a new kind of electrical process in the human brain that could play a key role in the unique way our brains compute.
Our brains are computers that work using a system of connected brain cells, called neurons, that exchange information using chemical and electric signals called action potentials. Researchers have discovered that certain cells in the human cortex, the outer layer of the brain, transmit signals in a way not seen in corresponding rodent cells. This process might be important to better understanding our unique brains and to improving programs that are based on a model of the human brain.
A computer made from DNA can compute the square root of 900
By Donna Lu
A computer made from strands of DNA in a test tube can calculate the square root of numbers up to 900.
Chunlei Guo at the University of Rochester in New York state and colleagues developed a computer that uses 32 strands of DNA to store and process information. It can calculate the square root of square numbers 1, 4, 9, 16, 25 and so on up to 900.
