An Amplifier That’s Quantum Quiet

An exotic new amplifier might be quiet enough for quantum computing

3 min read
An Amplifier That’s Quantum Quiet

14 December 2011—Quantum computers have the potential to solve seemingly intractable problems in no time flat. But a big stumbling block on the path to practical quantum computing is figuring out how to observe the tiny quantum signals that drive computation. In an advance that may make that observation easier, a group at Aalto University, in Finland, has created a new kind of microwave amplifier based on a mechanical resonator—essentially a nanometer-scale tuning fork.

“When you have microwave signals on the level of a single quantum, you can’t manipulate them with your bare hands—you need to amplify the signal,” says Francesco Massel, a postdoctoral researcher at Aalto who worked on the device. But today’s amplifiers boost those signals at a cost, sometimes drowning them out with noise from the amplifiers themselves. “Our device adds, at least in principle, the minimum possible amount of noise dictated by the laws of quantum mechanics,” says Massel.

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3 Ways 3D Chip Tech Is Upending Computing

AMD, Graphcore, and Intel show why the industry’s leading edge is going vertical

8 min read
Vertical
A stack of 3 images.  One of a chip, another is a group of chips and a single grey chip.
Intel; Graphcore; AMD
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A crop of high-performance processors is showing that the new direction for continuing Moore’s Law is all about up. Each generation of processor needs to perform better than the last, and, at its most basic, that means integrating more logic onto the silicon. But there are two problems: One is that our ability to shrink transistors and the logic and memory blocks they make up is slowing down. The other is that chips have reached their size limits. Photolithography tools can pattern only an area of about 850 square millimeters, which is about the size of a top-of-the-line Nvidia GPU.

For a few years now, developers of systems-on-chips have begun to break up their ever-larger designs into smaller chiplets and link them together inside the same package to effectively increase the silicon area, among other advantages. In CPUs, these links have mostly been so-called 2.5D, where the chiplets are set beside each other and connected using short, dense interconnects. Momentum for this type of integration will likely only grow now that most of the major manufacturers have agreed on a 2.5D chiplet-to-chiplet communications standard.

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