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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.

In fall of 2019, we demonstrated that the Sycamore quantum processor could outperform the most powerful classical computers when applied to a tailor-made problem. The next challenge is to extend this result to solve practical problems in materials science, chemistry and physics. But going beyond the capabilities of classical computers for these problems is challenging and will require new insights to achieve state-of-the-art accuracy. Generally, the difficulty in performing quantum simulations of such physical problems is rooted in the wave nature of quantum particles, where deviations in the initial setup, interference from the environment, or small errors in the calculations can lead to large deviations in the computational result.

In two upcoming publications, we outline a blueprint for achieving record levels of precision for the task of simulating quantum materials. In the first work, we consider one-dimensional systems, like thin wires, and demonstrate how to accurately compute electronic properties, such as current and conductance. In the second work, we show how to map the Fermi-Hubbard model, which describes interacting electrons, to a quantum processor in order to simulate important physical properties. These works take a significant step towards realizing our long-term goal of simulating more complex systems with practical applications, like batteries and pharmaceuticals.