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Category: computing

Electrons that lag behind nuclei in 2D materials could pave way for novel electronics

One of the great successes of 20th-century physics was the quantum mechanical description of solids. This allowed scientists to understand for the first time how and why certain materials conduct electric current and how these properties could be purposefully modified. For instance, semiconductors such as silicon could be used to produce transistors, which revolutionized electronics and made modern computers possible.

To be able to mathematically capture the complex interplay between electrons and atomic nuclei and their motions in a solid, physicists had to make some simplifications. They assumed, for example, that the light electrons in an atom follow the motion of the much heavier atomic nuclei in a crystal lattice without any delay. For several decades, this Born-Oppenheimer approximation worked well.

Error-correction technology to turn quantum computing into real-world power

Ripples spreading across a calm lake after raindrops fall—and the way ripples from different drops overlap and travel outward—is one image that helps us picture how a quantum computer handles information.

Unlike conventional computers, which process digital data as “0 or 1,” quantum computers can process information in an in-between state where it is “both 0 and 1.” These quantum states behave like waves: they can overlap, reinforcing one another or canceling one another out. In computations that exploit this property, states that lead to the correct answer are amplified, while states that lead to wrong answers are suppressed.

Thanks to this interference between waves, a quantum computer can sift through many candidate answers at once. Our everyday computers take time because they evaluate each candidate one by one. Quantum computers, by contrast, can narrow down the answer in a single sweep—earning them the reputation of “dream machines” that could solve in an instant problem that might take hundreds of years on today’s computers.

A wireless subdural-contained brain–computer interface with 65,536 electrodes and 1,024 channels

A flexible micro-electrocorticography brain–computer interface that integrates a 256 × 256 array of electrodes, signal processing, data telemetry and wireless powering on a single complementary metal–oxide–semiconductor substrate can provide stable, chronic in vivo recordings.

Diode-Like Behavior Arising from Antiferromagnetism

An antiferromagnet with a zigzag magnetic structure exhibits a diode effect that has potential applications in spintronics.

In a traditional diode, current flows in one direction only, thanks to an internal charge imbalance. Researchers have now shown a diode-like effect in an antiferromagnet with a zigzag magnetic structure [1]. The underlying mechanism is different from that in traditional diodes, as the zigzag pattern creates a combined magnetic and electric field that favors current flow in one direction. The strength of the diode effect in the antiferromagnet is relatively small, but rather than exploiting the effect to make a diode for conventional circuits, the team foresees possible applications in spintronics, devices that make use of electron spins.

A typical diode is a junction between two semiconductors having different charge carriers. The charge imbalance across this junction restricts current to flow in only one direction. Diode-like behavior can, in principle, occur in a single material, but it requires that the material’s internal structure is asymmetric in a particular way. This asymmetry should produce two effects: an internal electric field and an internal magnetic field. When those two fields are perpendicular to each other, they can exert a one-way force—called a toroidal moment—on electrons moving through the material, explains Kenta Sudo from Tohoku University in Japan.

Fault-tolerant quantum computing: Novel protocol efficiently reduces resource cost

Quantum computers, systems that process information leveraging quantum mechanical effects, could soon outperform classical computers on some complex computational problems. These computers rely on qubits, units of quantum information that share states with each other via a quantum mechanical effect known as entanglement.

Qubits are highly susceptible to noise in their surroundings, which can disrupt their quantum states and lead to computation errors. Quantum engineers have thus been trying to devise effective strategies to achieve fault-tolerant quantum computation, or in other words, to correct errors that arise when quantum computers process information.

Existing approaches work either by reducing the extra number of physical qubits needed per logical qubit (i.e., space overhead) or by reducing the number of physical operations needed to perform a single logical operation (i.e., time overhead). Effectively tackling both these goals together, which would enable more scalable systems and faster computations, has so far proved challenging.

Versatile mechanophore detects structural damage without false alarms from heat or UV

A newly designed robust mechanophore provides early warning against mechanical failure while resisting heat and UV, report researchers from Institute of Science Tokyo. They combined computational chemistry techniques with thermal and photochemical testing to show that their mechanophore scaffold, called DAANAC, stays inert under environmental stress yet emits a clear yellow signal when mechanically activated. This could pave the way for smart, self-reporting materials in construction, transportation, and electronics.

High-performance polymers, such as plastics and elastomers, are essential materials in modern life that are present in everything from airplane parts to bridges and electronics. Because sudden failures in these sectors can be extremely dangerous and costly, ensuring the safety and longevity of high-performance polymers is a critical challenge.

Since damage is often invisible at the molecular level until it is too late, scientists have been actively developing compounds known as “mechanophores.” These molecular sensors, which can be embedded into the bulk of a polymeric material, serve as an early warning system by chemically reacting to mechanical stress and producing visible light via fluorescence or other phenomena.

Metal–metal bonded molecule achieves stable spin qubit state, opening path toward quantum computing materials

Researchers at Kumamoto University, in collaboration with colleagues in South Korea and Taiwan, have discovered that a unique cobalt-based molecule with metal–metal bonds can function as a spin quantum bit (spin qubit)—a fundamental unit for future quantum computers. The findings provide a new design strategy for molecular materials used in quantum information technologies.

The study is published in the journal Chemical Communications.

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