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The Computer Chip That Never Forgets

Melding spin-based logic and memory could lead to low-power, instant-on electronics

15 min read
The Computer Chip That Never Forgets
Illustration: Chad Hagen

In 1945, mathematician John von Neumann wrote down a very simple recipe for a computer. It would contain two key components: a central processing unit to perform calculations and logical operations, and a memory bank to store instructions and data.

Our computers and microprocessor-equipped gadgets still follow this basic recipe. But under the hood, of course, they are far more complex. No existing form of memory is good at everything. So to move instructions and data as fast as possible, engineers have had to compromise. Today’s computers use a smorgasbord of different memory technologies, exploiting the best parts of each.

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A Transistor for Sound Points Toward Whole New Electronics

“Topological” acoustic transistor suggests circuits with dissipationless flow of electricity or light

3 min read
Model of a honeycomb lattice

Model of a honeycomb lattice that serves as the basis for a "transistor" of sound waves—whose design suggests new kinds of transistors of light and electricity, made from so-called topological materials. Electrons in a topological transistor, it is suspected, would flow without any resistance.

Hoffman Lab/Harvard SEAS

Potential future transistors that consume far less energy than current devices may rely on exotic materials called "topological insulators" in which electricity flows across only surfaces and edges, with virtually no dissipation of energy. In research that may help pave the way for such electronic topological transistors, scientists at Harvard have now invented and simulated the first acoustic topological transistors, which operate with sound waves instead of electrons.

Topology is the branch of mathematics that explores the nature of shapes independent of deformation. For instance, an object shaped like a doughnut can be deformed into the shape of a mug, so that the doughnut's hole becomes the hole in the cup's handle. However, the object couldn't lose the hole without changing into a fundamentally different shape.

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Taking Cosmology to the Far Side of the Moon

New Chinese program plans to use satellites in lunar orbit to study faint signals from early universe

3 min read
crescent moon
Darwin Fan/Getty Images

A team of Chinese researchers are planning to use the moon as a shield to detect otherwise hard-to-observe low frequencies of the electromagnetic spectrum and open up a new window on the universe. The Discovering the Sky at the Longest Wavelengths (DSL) mission aims to seek out faint, low-frequency signals from the early cosmos using an array of 10 satellites in lunar orbit. If it launches in 2025 as planned, it will offer one of the very first glimpses of the universe through a new lens.

Nine “sister” spacecraft will make observations of the sky while passing over the far side of the moon, using our 3,474-kilometer-diameter celestial neighbor to block out human-made and other electromagnetic interference. Data collected in this radio-pristine environment will, according to researchers, be gathered by a larger mother spacecraft and transmitted to Earth when the satellites are on the near side of the moon and in view of ground stations.

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Fix DFM hotspots in P&R with sign-off confidence
Fix DFM hotspots in P&R with sign-off confidence

This paper introduces the Aprisa low power solution and innovative low-power methodology to quickly converge on low-power-optimized power, performance, and area.