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Category: computing – Page 596

New research, based on earlier results in mice, suggests that our brains are never at rest, even when we are not learning anything about the world around us.

Our brains are often likened to computers, with learned skills and memories stored in the of billions of . However, new research shows that memories of specific events and experiences may never settle down. Instead, the activity patterns that store information can continually change, even when we are not learning anything new.

Why does this not cause the to forget what it has learned? The study, from the University of Cambridge, Harvard Medical School and Stanford University, reveals how the brain can reliably access stored information despite drastic changes in the brain signals that represent it.

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MIT engineers develop a hybrid process that connects photonics with “artificial atoms,” to produce the largest quantum chip of its type.

MIT researchers have developed a process to manufacture and integrate “artificial atoms,” created by atomic-scale defects in microscopically thin slices of diamond, with photonic circuitry, producing the largest quantum chip of its type.

The accomplishment “marks a turning point” in the field of scalable quantum processors, says Dirk Englund, an associate professor in MIT’s Department of Electrical Engineering and Computer Science. Millions of quantum processors will be needed to build quantum computers, and the new research demonstrates a viable way to scale up processor production, he and his colleagues note.

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Further improvements in nuclear propulsion system efficiency beyond nuclear-electric (NEP) are possible. The fission process accelerates the fission fragments to velocities between 3–5% of the speed of light, far faster than the 0.027% achieved by NEP, which uses a conventional nuclear reactor to convert the kinetic energy of the fission fragments into heat, the heat into electricity, and the electricity back into Xe ion kinetic energy with eficiencies much less than 40%. In the fission fragment reactor, the high-speed fragments are used directly as the rocket exhaust after charge neutralization. Therefore the fission fragment rocket can produce a specific impulse (Isp) greater than one million seconds.[CR][CR]Previous concepts suRered from impractical or inadequate methods to cool the fission fuel. In this work the heating problem is overcome by dividing the solid fuel into small dust particles and thereby increasing the surface to volume ratio of the fuel. The small size of the fuel particle allows adequate cooling to occur by the emission of thermal radiation.

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July 13, 2020—Researchers at Columbia Engineering and Montana State University report today that they have found that placing sufficient strain in a 2-D material—tungsten diselenide (WSe2)—creates localized states that can yield single-photon emitters. Using sophisticated optical microscopy techniques developed at Columbia over the past three years, the team was able to directly image these states for the first time, revealing that even at room temperature they are highly tunable and act as quantum dots, tightly confined pieces of semiconductors that emit light.

“Our discovery is very exciting, because it means we can now position a emitter wherever we want, and tune its properties, such as the color of the emitted photon, simply by bending or straining the material at a specific location,” says James Schuck, associate professor of mechanical engineering, who co-led the study published today by Nature Nanotechnology. “Knowing just where and how to tune the single-photon is essential to creating quantum optical circuitry for use in quantum computers, or even in so-called ‘quantum’ simulators that mimic physical phenomena far too complex to model with today’s computers.”

Developing such as quantum computers and quantum sensors is a rapidly developing field of research as researchers figure out how to use the unique properties of quantum physics to create devices that can be much more efficient, faster, and more sensitive than existing technologies. For instance, quantum information—think encrypted messages—would be much more secure.

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But, he added, the method took about 10 minutes to produce 1,024 random strings, whereas current cryptographic processes would need far faster number generators.

The new technique’s first real-world use will come when it’s incorporated into NIST’s randomness beacon, a public source of randomness for researchers studying unpredictability, Bierhorst said.

But he added that he hopes the experimental setup could one day be shrunk enough to fit on a computer chip and help in the creation of “unhackable” messages.

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Researchers at ETH have measured the timing of single writing events in a novel magnetic memory device with a resolution of less than 100 picoseconds. Their results are relevant for the next generation of main memories based on magnetism.

At the Department for Materials of the ETH in Zurich, Pietro Gambardella and his collaborators investigate tomorrow’s memory devices. They should be fast, retain data reliably for a long time and also be cheap. So-called magnetic “random access memories” (MRAM) achieve this quadrature of the circle by combining fast switching via electric currents with durable data storage in magnetic materials. A few years ago researchers could already show that a certain physical effect – the spin-orbit torque – makes particularly fast data storage possible. Now Gambardella’s group, together with the R&D-center IMEC in Belgium, managed to temporally resolve the exact dynamics of a single such storage event – and to use a few tricks to make it even faster.

Magnetizing with single spins.

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In a new study, a group of researchers led by Prof. Lior Klein, from the physics department and the Institute of Nanotechnology and Advanced Materials at Bar-Ilan University, has shown that relatively simple structures can support an exponential number of magnetic states—much greater than previously thought. They have additionally demonstrated switching between the states by generating spin currents. Their results may pave the way to multi-level magnetic memory with an extremely large number of states per cell; it could also have application in the development of neuromorphic computing, and more. Their research appears as a featured article on the cover of a June issue of Applied Physics Letters.

Spintronics is a thriving branch of nano-electronics which uses the spin of the electron and its associated in addition to the electron charge used in traditional electronics. The main practical contributions of spintronics are in magnetic sensing and non-volatile magnetic data storage, and researchers are pursuing breakthroughs in developing magnetic-based processing and novel types of .

Spintronics devices commonly consist of magnetic elements manipulated by spin-polarized currents between stable magnetic states. When spintronic devices are used for storing data, the number of stable states sets an upper limit on capacity. While current commercial magnetic memory cells have two stable magnetic states corresponding to two memory states, there are clear advantages to increasing this number, as it will potentially allow increasing memory density and enable the design of novel types of memory.

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Researchers at MIT have developed a process to manufacture and integrate “artificial atoms” with photonic circuitry, and in doing so, are able to produce the largest quantum chip of its kind.

The atoms, which are created by atomic-scale defects in microscopically thin slices of diamond, allow for the scaling up of quantum chip production.

RELATED: 7 REASONS WHY WE SHOULD BE EXCITED BY QUANTUM COMPUTERS

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