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Category: quantum physics – Page 654

Faster technique for resetting quantum circuits proposed

Rebooting a quantum computer is a tricky process that can damage its parts, but now two RIKEN physicists have proposed a fast and controllable way to hit reset.

Conventional computers process information stored as bits that take a value of zero or one. The potential power of quantum computers lies in their ability to process ‘qubits’ that can take a value of zero or one—or be some fuzzy mix of both simultaneously.

“However, to reuse the same circuit for multiple operations, you have to force the qubits back to zero fast,” says Jaw Shen Tsai, a quantum physicist at the RIKEN Center for Quantum Computing. But that is easier said than done.

Quantum dots boost perovskite solar cell efficiency and scalability

Perovskites are hybrid compounds made from metal halides and organic constituents. They show great potential in a range of applications, e.g. LED lights, lasers, and photodetectors, but their major contribution is in solar cells, where they are poised to overtake the market from their silicon counterparts.

One of the obstacles facing the commercialization of solar is that their power-conversion efficiency and operational stability drop as they scale up, making it a challenge to maintain in a complete solar cell.

The problem is partly with the cell’s electron-transport , which ensures that the electrons produced when the cell absorbs light will transfer efficiently to the device’s electrode. In perovskite solar cells, the electron-transport layer is made with mesoporous titanium dioxide, which shows low electron mobility, and is also susceptible to adverse, photocatalytic events under ultraviolet light.

243-Year-Old Impossible Puzzle Solved Using Quantum Entanglement

Over 240 years ago, famous mathematician Leonhard Euler came up with a question: if six army regiments each have six officers of six different ranks, can they be arranged in a square formation such that no row or column repeats either a rank or regiment?

After searching in vain for a solution, Euler declared the problem impossible – and over a century later, the French mathematician Gaston Tarry proved him right. Then, 60 years after that, when the advent of computers removed the need for laboriously testing every possible combination by hand, the mathematicians Parker, Bose, and Shrikhande proved an even stronger result: not only is the six-by-six square impossible, but it’s the only size of square other than two-by-two that doesn’t have a solution at all.

First fully programmable quantum computer based on neutral atoms

Most quantum computers are based on superconductors or trapped ions, but an alternative approach using ordinary atoms may have advantages.

Back in 2016, we told you about the iBubble, an underwater drone that autonomously follows and films scuba divers. Well, it now has a more capable industrial-use big brother, known as the Seasam.

Quantum Physicists Find Paradoxical Material a Mashup of Three Different Phases at Once — “This Is Uncharted Territory”

‘Geometric frustration’ can cause the electrons in materials with atoms arranged in a triangular pattern to organize in three competing ways simultaneously, reveals a new computational study led by researchers at the Flatiron Institute.

Materials that look like mosaics of triangular tiles at the atomic level sometimes have paradoxical properties, and quantum physicists have finally found out why.

Using a combination of cutting-edge computational techniques, the scientists found that under special conditions, these triangular-patterned materials can end up in a mashup of three different phases at the same time. The competing phases overlap, with each wrestling for dominance. As a result, the material counterintuitively becomes more ordered when heated up, the scientists reported in Physical Review X.

Research demonstrates a new technique for improving long-distance quantum key distribution in a real-world field

An experiment, performed by Istituto Nazionale di Ricerca Metrologica (INRIM) on 200 km of the Italian Quantum Backbone, in collaboration with Toshiba Europe, shows that coherent laser interferometry considerably improves the performances of quantum key distribution protocols in long-distance, real-world networks. The study has been published in Nature Communications.

Quantum Key Distribution (QKD) protocols enable cryptographic keys to be shared between distant parties with an intrinsic security guaranteed by the laws of quantum mechanics. This is made possible by the transmission of single photons, the elementary particles of which light is made of.

The interest for this subject extends well beyond the scientific community, and has now a strong strategic and commercial relevance. The European Commission, within the “European Quantum Communication Infrastructure” intitative, aims at integrating quantum key distribution technologies into specific services throughout the European Union within the next 10 years, and INRIM will take part in the design of this infrastructure with the OQTAVO project.

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