Lifeboat Foundation

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.

CAMBRDIGE, United Kingdom — “Quantum light” may sound like something out of a Marvel movie, but scientists say it may hold the real-world key to revolutionizing science as we know it. An international team says generating this high-energy light and controlling it can unlock a whole new realm in quantum computing.

Researchers from the University of Cambridge, as well as scientists in the United States, Israel, and Austria, have come up with a theory describing this new state of light. They say it has controllable quantum properties and a wide range of frequencies which reach X-ray levels. Harnessing this power could lead to advances in microscopy — or the ability to see incredibly small things normally invisible to the naked eye.

Continue reading “‘Quantum light’ breakthrough could revolutionize science at the atomic level” »

Quantum mechanics is simultaneously beautiful and frustrating.

Its explanatory power is unmatched. Armed with the machinery of quantum theory, we have unlocked the secrets of atomic power, divined the inner workings of chemistry, built sophisticated electronics, discovered the power of entanglement, and so much more. According to some estimates, roughly a quarter of our world’s GDP relies on quantum mechanics.

Yet despite its overwhelming success as a framework for understanding what nature does, quantum mechanics tells us very little about how nature works. Quantum mechanics provides a powerful set of tools for successfully making predictions about what subatomic particles will do, but the theory itself is relatively silent about how those subatomic particles actually go about their lives.

QuEra Computing, maker of the world’s first and only publicly accessible neutral-atom quantum computer—Aquila—today announces its research team has uncovered a method to perform a wider set of optimization calculations than previously known to be possible using neutral-atom machines.

The findings are the work of QuEra researchers and collaborators from Harvard and Innsbruck Universities: Minh-Thi Nguyen, Jin-Guo Liu, Jonathan Wurtz, Mikhail D. Lukin, Sheng-Tao Wang, and Hannes Pichler.

“There is no question that today’s news helps QuEra deliver value to more partners, sooner. It helps bring us closer to our objectives, and marks an important milestone for the industry as well,” said Alex Keesling, CEO at QuEra Computing. “This opens the door to working with more corporate partners who may have needs in logistics, from transport and retail to robotics and other high-tech sectors, and we are very excited about cultivating those opportunities.”

If life is common in our Universe, and we have every reason to suspect it is, why do we not see evidence of it everywhere? This is the essence of the Fermi Paradox, a question that has plagued astronomers and cosmologists almost since the birth of modern astronomy.

It is also the reasoning behind the Hart-Tipler Conjecture, one of the many (many!) proposed resolutions, which asserts that if advanced life had emerged in our galaxy sometime in the past, we would see signs of their activity everywhere we looked. Possible indications include self-replicating probes, megastructures, and other Type III-like activity.

Continue reading “Physicists Say Aliens May Be Using Black Holes as Quantum Computers” »

Researchers in the US developed a new energy-based benchmark for quantum advantage and used it to demonstrate noisy intermediate-scale quantum (NISQ) computers that use several orders of magnitude less energy than the world’s most powerful supercomputer. Quantum computing is a branch of computer science that focuses on the development of technologies based on quantum theory principles.

Quantum computing solves problems that are too complex for classical computing by utilizing the unique properties of quantum physics. The question of whether a quantum computer can perform calculations beyond the reach of even the most powerful conventional supercomputer is becoming increasingly relevant as quantum computers become larger and more reliable. This ability, dubbed “quantum supremacy,” marks the transition of quantum computers from scientific curiosity to useful devices. Scientists predict that Quantum computing is better than supercomputers as it performs tasks a million times faster. Quantum computers can handle complex calculations easily because they are built based on quantum principles that go beyond classical physics.

Quantum computers and supercomputers are extremely powerful machines used for complex calculations, problem solving, and data analysis. While both have the potential to revolutionize computing technology, they have significant speed and capability differences. In 2019, Google’s quantum computer performed a calculation that would take the world’s most powerful computer 10,000 years to complete. It is the seed for the world’s first fully functional quantum computer, which will be capable of producing better medicines, developing smarter artificial intelligence, and solving cosmic mysteries. Theoretical physicist John Preskill proposed a formulation of quantum supremacy, or the superiority of quantum computers, in 2012. He dubbed it the moment when quantum computers can perform tasks that ordinary computers cannot. To quickly crunch large amounts of data and achieve a single result, supercomputers employ a traditional computing approach with multiple processors.

Quantum Mechanics is the science behind nuclear energy, smart phones, and particle collisions. Yet, almost a century after its discovery, there is still controversy over what the theory actually means. The problem is that its key element, the quantum-mechanical wave function describing atoms and subatomic particles, isn’t observable. As physics is an experimental science, physicists continue to argue over whether the wave function can be taken as real, or whether it is just a tool to make predictions about what can be measured—typically large, “classical” everyday objects.

The view of the antirealists, advocated by Niels Bohr, Werner Heisenberg, and an overwhelming majority of physicists, has become the orthodox mainstream interpretation. For Bohr especially, reality was like a movie shown without a film or projector creating it: “There is no quantum world,” Bohr reportedly affirmed, suggesting an imaginary border between the realms of microscopic, “unreal” quantum physics and “real,” macroscopic objects—a boundary that has received serious blows by experiments ever since. Albert Einstein was a fierce critic of this airy philosophy, although he didn’t come up with an alternative theory himself.

For many years only a small number of outcasts, including Erwin Schrödinger and Hugh Everett populated the camp of the realists. This renegade view, however, is getting increasingly popular—and of course triggers the question of what this quantum reality really is. This is a question that has occupied me for many years, until I arrived at the conclusion that quantum reality, deep down at the most fundamental level, is an all-encompassing, unified whole: “The One.”