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Researchers used quantum optics to advance state-of-the-art microscopy and illuminate a path to detecting material properties with greater sensitivity than is possible with traditional tools. More
Future wireless networks of the 6th generation (6G) will consist of a multitude of small radio cells that need to be connected by broadband communication links. In this context, wireless transmission at THz frequencies represents a particularly attractive and flexible solution. Researchers have now developed a novel concept for low-cost terahertz receivers. More
Inspired by the need for new and better therapies for neurodegenerative diseases, researchers are exploring the link between uncontrolled inflammation within the brain and the brain’s immune cells, known as microglia, which are emerging as a promising cellular target because of the prominent role they play in brain inflammation. The group highlights the design considerations and benefits of creating therapeutic nanoparticles for carrying pharmacological factors directly to the sites of the microglia. More
A recent study has shed new light on the Minoan system of fractions, one of the outstanding enigmas tied to the ancient writing of numbers. More
In physics, it is essential to be able to show a theoretical assumption in actual, physical experiments. For more than a hundred years, physicists have been aware of the link between the concepts of disorder in a system, and information obtained by measurement. However, a clean experimental assessment of this link in common monitored systems, that is systems which are continuously measured over time, was missing so far. More
Structural coloration is promised to be the display technology of the future as there is no fading – it does not use dyes – and enables low-power displays without strong external light source. However, the disadvantage of this technique is that once a device is made, it is impossible to change its properties so the reproducible colors remain fixed. Recently, a research team has successfully obtained vivid colors by using semiconductor chips – not dyes – made by mimicking the human brain structure. More
A fifth of carbon dioxide emissions come from multinational companies’ global supply chains, according to a new study that shows the scope of multinationals’ influence on climate change. More
Quantum bits, or qubits, can hold quantum information much longer now thanks to efforts by an international research team. The researchers have increased the retention time, or coherence time, to 10 milliseconds — 10,000 times longer than the previous record — by combining the orbital motion and spinning inside an atom. Such a boost in information retention has major implications for information technology developments since the longer coherence time makes spin-orbit qubits the ideal candidate for building large quantum computers.
They published their results on July 20 in Nature Materials.
“We defined a spin-orbit qubit using a charged particle, which appears as a hole, trapped by an impurity atom in silicon crystal,” said lead author Dr. Takashi Kobayashi, research scientist at the University of New South Wales Sydney and assistant professor at Tohoku University. “Orbital motion and spinning of the hole are strongly coupled and locked together. This is reminiscent of a pair of meshing gears where circular motion and spinning are locked together.”
Qubits have been encoded with spin or orbital motion of a charged particle, producing different advantages that are highly demanded for building quantum computers. To utilize the advantages of qubits, Kobayashi and the team specifically used an exotic charged particle “hole” in silicon to define a qubit, since orbital motion and spin of holes in silicon are coupled together.
Spin-orbit qubits encoded by holes are particularly sensitive to electric fields, according to Kobayashi, which allows for more rapid control and benefits scaling up quantum computers. However, the qubits are affected by electrical noise, limiting their coherence time.
“In this work, we have engineered sensitivity to the electric field of our spin-orbit qubit by stretching the silicon crystal like a rubber band,” Kobayashi said. “This mechanical engineering of the spin-orbit qubit enables us to remarkably extend its coherence time, while still retaining moderate electrical sensitivity to control the spin-orbit qubit.”
Think of gears in a watch. Their individual spinning propels the entire mechanism to keep time. It is neither the spin nor orbital motion, but a combination of them that takes the information forward.
“These results open a pathway to develop new artificial quantum systems and to improve the functionality and scalability of spin-based quantum technologies,” Kobayashi said.
This work was supported in part by the ARC Centre of Excellence for Quantum Computation and Communication Technology, the U.S. Army Research Office and the Tohoku University Graduate Program in Spintronics.
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Materials provided by Tohoku University. Note: Content may be edited for style and length. More
