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It’s a problem that few of us will likely ever face: once you’ve built your first homemade integrated circuit, what do you do next? If you’re [Sam Zeloof], the answer is clear: build better integrated circuits.

At least that’s [Sam]’s plan, which his new reactive-ion etching setup aims to make possible. While his Z1 dual differential amplifier chip was a huge success, the photolithography process he used to create the chip had its limitations. The chemical etching process he used is a bit fussy, and prone to undercutting of the mask if the etchant seeps underneath it. As its name implies, RIE uses a plasma of highly reactive ions to do the etching instead, resulting in finer details and opening the door to using more advanced materials.

[Sam]’s RIE rig looks like a plumber’s stainless steel nightmare, in the middle of which sits a vacuum chamber for the wafer to be etched. After evacuating the air, a small amount of fluorinated gas — either carbon tetrafluoride or the always entertaining sulfur hexafluoride — is added to the chamber. A high-voltage feedthrough provides the RF energy needed to create a plasma, which knocks fluorine ions out of the process gas. The negatively charged and extremely reactive fluorine ions are attracted to the wafer, where they attack and etch away the surfaces that aren’t protected by a photoresist layer.

Research from the McKelvey School of Engineering at Washington University in St. Louis has found a missing piece in the puzzle of optical quantum computing.

Jung-Tsung Shen, associate professor in the Department of Electrical & Systems Engineering, has developed a deterministic, high-fidelity two-bit quantum gate that takes advantage of a new form of light. This new logic gate is orders of magnitude more efficient than the current technology.

“In the ideal case, the fidelity can be as high as 97%,” Shen said.

Russian scientists have experimentally proved the existence of a new type of quasiparticle—previously unknown excitations of coupled pairs of photons in qubit chains. This discovery could be a step towards disorder-robust quantum metamaterials. The study was published in Physical Review B.

Superconducting qubits are a leading qubit modality today that is currently being pursued by industry and academia for quantum computing applications. However, the performance of quantum computers is largely affected by decoherence that contributes to a qubit’s extremely short lifespan and causes computational errors. Another major challenge is low controllability of large qubit arrays.

Metamaterial quantum simulators provide an alternative approach to quantum computing, as they do not require a large amount of control electronics. The idea behind this approach is to create artificial matter out of qubits, the physics of which will obey the same equations as for some real matter. Conversely, you can program the simulator in such a way as to embody matter with properties that have not yet been discovered in nature.

A quantum-computing startup announced Tuesday that its future quantum processor designs will differ significantly from its current offerings. Rather than building a monolithic processor as everyone else has, Rigetti Computing will build smaller collections of qubits on chips that can be physically linked together into a single functional processor. This isn’t multiprocessing so much as modular chip design.

The move is consequential for both Rigetti processors and quantum computing more generally.

The promise of 5G Internet of Things (IoT) networks requires more scalable and robust communication systems—ones that deliver drastically higher data rates and lower power consumption per device.

Backscatter radios—passive sensors that reflect rather than radiate energy—are known for their low-cost, low-complexity, and battery-free operation, making them a potential key enabler of this future although they typically feature low data rates and their performance strongly depends on the surrounding environment.

Researchers at the Georgia Institute of Technology, Nokia Bell Labs, and Heriot-Watt University have found a low-cost way for backscatter radios to support high-throughput communication and 5G-speed Gb/sec data transfer using only a single transistor when previously it required expensive and multiple stacked transistors.

3 mins. This is really fascinating. Several applications, including quantum computing. Need special diamonds that scientists now can produce.


Diamonds are dazzling physicists with their powerful quantum properties. A particular impurity — the nitrogen-vacancy (NV) centre — allows diamonds to be used for everything from geolocation to diagnosing disease. This animation takes a closer look at these NV centres, and the carefully crafted artificial diamonds that make them possible.

A new electrode that could free up 20% more light from organic light-emitting diodes has been developed at the University of Michigan. It could help extend the battery life of smartphones and laptops, or make next-gen televisions and displays much more energy efficient.

The approach prevents light from being trapped in the light-emitting part of an OLED, enabling OLEDs to maintain brightness while using less power. In addition, the electrode is easy to fit into existing processes for making OLED displays and light fixtures.

“With our approach, you can do it all in the same ,” said L. Jay Guo, U-M professor of electrical and computer engineering and corresponding author of the study.