Lifeboat Foundation

Quantum computing has entered a bit of an awkward period. There have been clear demonstrations that we can successfully run quantum algorithms, but the qubit counts and error rates of existing hardware mean that we can’t solve any commercially useful problems at the moment. So, while many companies are interested in quantum computing and have developed software for existing hardware (and have paid for access to that hardware), the efforts have been focused on preparation. They want the expertise and capability needed to develop useful software once the computers are ready to run it.

For the moment, that leaves them waiting for hardware companies to produce sufficiently robust machines—machines that don’t currently have a clear delivery date. It could be years; it could be decades. Beyond learning how to develop quantum computing software, there’s nothing obvious to do with the hardware in the meantime.

But a company called QuEra may have found a way to do something that’s not as obvious. The technology it is developing could ultimately provide a route to quantum computing. But until then, it’s possible to solve a class of mathematical problems on the same hardware, and any improvements to that hardware will benefit both types of computation. And in a new paper, the company’s researchers have expanded the types of computations that can be run on their machine.

It is truly an exciting time for the world of computing. Imagine being able to complete complex computing tasks in just a matter of hours, or even minutes, instead of waiting for days on end. L Venkata Subramaniam, a Quantum Distinguished Ambassador at IBM, tells AIM that this dream could become a reality thanks to the incredible power of quantum computing.

“Quantum naturally works in a higher dimensional space where data is better viewed or separated, or you can understand more about the data. Therefore, it is easier to work in quantum on AI problems,” said Subramaniam.

Quantum computing can also be effective in working with fundamental models, such as ChatGPT. Certain early observations suggest that quantum computing can achieve comparable results to classical AI using less training data and has the potential to accelerate the training process for AI models.

A new technical paper titled “A high-fidelity quantum matter-link between ion-trap microchip modules” was published by researchers at University of Sussex, Universal Quantum Ltd, University College London and University of Bristol.

“As quantum computers grow, we will eventually be constrained by the size of the microchip, which limits the number of quantum bits such a chip can accommodate. As such, we knew a modular approach was key to make quantum computers powerful enough to solve step-changing industry problems. In demonstrating that we can connect two quantum computing chips – a bit like a jigsaw puzzle – and, crucially, that it works so well, we unlock the potential to scale-up by connecting hundreds or even thousands of quantum computing microchips,” states Professor Winfried Hensinger, Professor of Quantum Technologies at the University of Sussex and Chief Scientist and Co-founder at Universal Quantum.

Quantum dots are semiconductor particles measuring just a few nanometres across, which are now widely studied for their intriguing electrical and optical properties.

Through new research published in EPJ B (“Third-order nonlinear susceptibility in CdS/Cdx1Zn 1-x1 S/ZnS multilayer spherical quantum dot,”), Kobra Hasanirokh at Azarbaijan Shahid Madani University in Iran, together with Luay Hashem Abbud at Al-Mustaqbal University College, Iraq, show how quantum dots containing spherical defects can significantly enhance their nonlinear optical properties.

By fine-tuning these defects, researchers could tightly control the frequency and brightness of the light emitted by quantum dots.

A team led by Professor Andrea Morello has just demonstrated the operation of a new type of quantum bit, called ‘flip-flop’ qubit, which combines the exquisite quantum properties of single atoms, with easy controllability using electric signals, just as those used in ordinary computer chips.

“Sometimes new qubits, or new modes of operations, are discovered by lucky accident. But this one was completely by design,” says Prof. Morello. “Our group has had excellent qubits for a decade, but we wanted something that could be controlled electrically, for maximum ease of operation. So we had to invent something completely new.”

Prof. Morello’s group was the first in the world to demonstrate that using the spin of an electron as well as the nuclear spin of a single phosphorus atom in silicon could be used as ‘qubits’ – units of information that are used to make quantum computing calculations. He explains that while both qubits perform exceptionally well on their own, they require oscillating magnetic fields for their operation.

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Stephen Hawking was one of the greatest scientific and analytical minds of our time, says NASA’s Michelle Thaller. She posits that Hawking might be one of the parents of an entirely new school of physics because he was working on some incredible stuff—concerning quantum entaglement— right before he died. He was even humble enough to go back to his old work about black holes and rethink his hypotheses based on new information. Not many great minds would do that, she says, relaying just one of the reasons Stephen Hawking will be so deeply missed. You can follow Michelle Thaller on Twitter at @mlthaller.

Continue reading “What Stephen Hawking would have discovered if he lived longer | NASA’s Michelle Thaller | Big Think” »

In quantum mechanics, the unitary nature of time evolution makes it intrinsically reversible, given control over the system in question. Remarkably, there have been several recent demonstrations of protocols for reverting unknown unitaries in scenarios where even the interactions with the target system are unknown. These protocols are limited by their probabilistic nature, raising the fundamental question of whether time-reversal could be performed deterministically. Here we show that quantum physics indeed allows for this by exploiting the non-commuting nature of quantum operators, and demonstrate a recursive protocol for two-level quantum systems with an arbitrarily high probability of success. Using a photonic platform, we achieve an average rewinding fidelity of over 95%. Our protocol, requiring no knowledge of the quantum process to be rewound, is optimal in its running time, and brings quantum rewinding into a regime of practical relevance.

Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

UK researchers have developed a novel technique that could enable the development of quantum computers operating on million qubits.

Experts are divided on whether practical applications are just around the corner.