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Category: computing

A small prototype of a drone-based quantum network has successfully relayed a quantum signal over a kilometer of free space.

The airwaves are chock full of “classical” information from cell phones, radio stations, and Wi-Fi hubs, but one day those waves could be carrying quantum encrypted messages or data input for a quantum computer. A new experiment has used a pair of hovering drones to dole out quantum information to two ground stations separated by 1 km [1]. This demonstration could lead to a drone-based quantum network that could be positioned—and easily repositioned—over a city or rural area.

Quantum communication promises fully secure message sharing. For example, two users could exchange encrypted messages using “entangled” photons, pairs of particles with a unique quantum-mechanical relationship. For every pair, one photon would be sent to each of the users, who would be alerted to any eavesdropping by a loss of entanglement between the photons. One of the most common methods for sending such quantum encrypted messages relies on optical fibers (see Viewpoint: Record Distance for Quantum Cryptography). But in fibers, a large fraction of the photons scatter before reaching their destination. More photons can survive if quantum information is transmitted through the atmosphere, as in the quantum link established using a Chinese satellite in 2018 (see Focus: Intercontinental, Quantum-Encrypted Messaging and Video). However, satellites are expensive and difficult to adapt to changing demands on the ground.

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One of the obstacles for progress in the quest for a working quantum computer has been that the working devices that go into a quantum computer and perform the actual calculations, the qubits, have hitherto been made by universities and in small numbers. But in recent years, a pan-European collaboration, in partnership with French microelectronics leader CEA-Leti, has been exploring everyday transistors — that are present in billions in all our mobile phones — for their use as qubits.

The French company Leti makes giant wafers full of devices, and, after measuring, researchers at the Niels Bohr Institute, University of Copenhagen, have found these industrially produced devices to be suitable as a qubit platform capable of moving to the second dimension, a significant step for a working quantum computer. The result is now published in Nature Communications.

One of the key features of the devices is the two-dimensional array of quantum dot. Or more precisely, a two by two lattice of quantum dots. “What we have shown is that we can realize single electron control in every single one of these quantum dots. This is very important for the development of a qubit, because one of the possible ways of making qubits is to use the spin of a single electron. So reaching this goal of controlling the single electrons and doing it in a 2D array of quantum dots was very important for us,” says Fabio Ansaloni, former PhD student, now postdoc at center for Quantum Devices, NBI.

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A team of researchers at Columbia University has developed a way to allow DNA strands to store more data. In their study, published in the journal Science, the group applied a small amount of electricity to DNA strands to allow for encoding more information than was possible with other methods.

For several years, researchers have been looking for ways to increase data storage capacity—storage requirements are expected to exceed capacity in the near future as demand skyrockets. One such approach has involved encoding data into strands of DNA—prior research has shown that it is possible. In the early stages of such research, scientists manually edited strands to add characteristics to represent zeroes or ones. More recently, researchers have used the CRISPR gene editing tool. Most such studies used DNA extracted from the tissue of deceased animals. More recently, researchers have begun efforts to move the research to living animals because it will last longer. And not just in the edited strands—the information they contain could conceivably be passed on to offspring, allowing data to be stored for very long periods of time.

Back in 2017, another team at Columbia University used CRISPR to detect a certain signal—in their case, it was the presence of sugar molecules. Adding such molecules resulted in gene expressions of plasmid DNA. Over time, the editing process was improved as genetic bits were added to represent ones and zeroes. Unfortunately, the system only allowed for storing a few bits of data.

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“This is perhaps the hardest part of all DNA storage approaches. If you can get the cells to directly talk to a computer, and interface its DNA-based memory system with a silicon-based memory system, then there are lots of possibilities in the future.”

The work builds on a CRISPR-based cellular recorder Wang had previously designed for E. coli bacteria, which detects the presence of certain DNA sequences inside the cell and records this signal into the organism’s genome.

The system includes a DNA-based “sensing module” that produces elevated levels of a “trigger sequence” in response to specific biological signals. These sequences are incorporated into the recorder’s “DNA ticker tape” to document the signal.

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Chipmakers often place orders with contract manufacturers instead of fabricating chips in-house. It takes time to manufacture semiconductors while reconfiguring lines to accommodate varying specifications, making it difficult to turn out different chips at the same time.

TOKYO — The auto industry is facing a severe lack of semiconductors amid rising use of the chips in other products, like smartphones and communication base stations.

This has forced Germany’s Volkswagen as well as Japanese makers like Honda and Nissan to reduce production.

Toyota Motor has decided to reduce production of its Tundra pickup truck at its plant in the U.S. state of Texas due to the semiconductor shortage. The company has not released details on the size or time frame regarding the production cut but is looking into whether the lack of semiconductors will affect other vehicles.

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While many research teams worldwide are trying to develop highly performing quantum computers, some are working on tools to control the flow of heat inside of them. Just like conventional computers, in fact, quantum computers can heat up significantly as they are operating, which can ultimately damage both the devices and their surroundings.

A team of researchers at University Grenoble Alpes in France and Centre of Excellence—Quantum Technology in Finland has recently developed a single-quantum-dot heat valve, a that can help to control the flow of heat in single-quantum-dot junctions. This heat valve, presented in a paper published in Physical Review Letters, could help to prevent quantum computers from overheating.

“With the miniaturization of electronic components handling of excess heat at nanoscales has become an increasingly important issue to be addressed,” Nicola Lo Gullo, one of the researchers who carried out the study, told Phys.org. “This is especially true when one wants to preserve the quantum nature of a device; the increase in temperature does typically result in the degradation of the quantum properties. The recent realization of a photonic heat-valve by another research group ultimately inspired us to create a heat valve based on a solid-state quantum dot.”

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All the clean technologies that we need to combat climate change – whether that’s wind turbines, solar panels or batteries, they’re all really, really mineral intensive.

Cornwall, 1864. A hot spring is discovered nearly 450m (1485ft) below ground in the Wheal Clifford, a copper mine just outside the mining town of Redruth. Glass bottles are immersed to their necks in its bubbling waters, carefully sealed and sent off for testing. The result is the discovery of so great a quantity of lithium – eight or 10 times as much per gallon as had been found in any hot spring previously analysed – that scientists suspect “it may prove of great commercial value”.

But 19th-Century England had little need for the element, and this 50C (122F) lithium-rich water continued steaming away in the dark for more than 150 years.

Fast forward to autumn 2020, and a site nearby the Wheal Clifford in Cornwall has been confirmed as having some of the world’s highest grades of lithium in geothermal waters. The commercial use for lithium in the 21st Century could not be clearer. It is found not only inside smart phones and laptops, but is now vital to the clean energy transition, for the batteries that power electric vehicles and store energy so renewable power can be released steadily and reliably.

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