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Category: computing

Radiation Imbalance: New Material Emits Better Than It Absorbs

A newly designed structure exhibits the largest-recorded emissivity–absorptivity difference, a property that could prove useful in energy-harvesting and cloaking devices.

Hot objects glow. From the warmth of a stovetop to the invisible heat radiating from a building’s roof, thermal radiation flows outward. But it also flows inward in a reciprocal manner. This means that at thermal equilibrium, an object’s ability to thermally emit light in one direction, described as emissivity, is equal to its ability to absorb the same light coming in from the other direction, known as absorptivity. But what if this rule could be violated?

In a new study, Zhenong Zhang and colleagues from Pennsylvania State University demonstrate this exciting possibility [1]. The researchers apply an external magnetic field to a layered material, creating a system that breaks Lorentz reciprocity—a common symmetry that relates electromagnetic inputs and outputs. They then show that this nonreciprocal system exhibits much higher emissivity than absorptivity in the same direction. The observed difference between emissivity and absorptivity is twice that observed in previous experiments, thus setting a new benchmark in the field. These results pave the way for future technologies such as thermal diodes, radiative heat engines, and infrared camouflage.

Quantum computers just beat classical ones — Exponentially and unconditionally

A research team has achieved the holy grail of quantum computing: an exponential speedup that’s unconditional. By using clever error correction and IBM’s powerful 127-qubit processors, they tackled a variation of Simon’s problem, showing quantum machines are now breaking free from classical limitations, for real.

Enhanced quantum computers and beyond: Exploring magnons with superconducting qubits

Devices taking advantage of the collective quantum behavior of spin excitations in magnetic materials—known as magnons—have the potential to improve quantum computing devices. However, using magnons in quantum devices requires an in-depth understanding of their nature and limitations. A new experimental technique uses superconducting qubits to sensitively characterize magnon behavior in previously unexplored regimes.

Researchers in the Grainger College of Engineering at the University of Illinois Urbana-Champaign have reported in the journal Physical Review Applied that highly excited magnon behavior in can be accurately characterized by coupling the material to a superconducting qubit via a microwave cavity. This setup allowed the researchers to characterize both the number of magnons and their lifetimes when thousands of excitations are present, a regime that has not been studied well.

“To be useful in quantum computing applications, limitations on magnon systems need to be understood properly,” said Sonia Rani, the study’s lead author. “The problem is that there isn’t a good theory for when certain effects become important, and if we should expect them to lead to detrimental effects.

Q&A: Companies are racing to develop the first useful quantum computer—ultracold neutral atoms could be the key

The race to build the first useful quantum computer is on and may revolutionize the world with brand new capabilities, from medicine to freight logistics.

Tech companies all want to take the crown, with Microsoft announcing the first of its kind quantum chip in February, only days before Google’s breakthrough on .

As the race heats up, companies are turning to a new ultracold solution—neutral atoms—which Swinburne University of Technology has been exploring and making discoveries in for two decades.

Major Graphene Breakthrough: Magnet-Free Spin Currents Could Supercharge Quantum Computing

Scientists at TU Delft have unlocked a key quantum effect in graphene without using any magnetic fields, paving the way for ultra-thin quantum circuits. By layering graphene on a special magnetic crystal, they created stable spin currents that travel along the edges of the material. These current

How key brain cells help replay and store memories during rest and sleep

How does the brain store knowledge so that you actually remember what you have learned the next day or even later? To find out, researchers at the University of Oslo disconnected one type of nerve cell in the brain of mice while the animals rested after having learned something new. This gave new answers to what actually happens when you remember earlier experiences for later use. The study is published in the journal Science Advances.

In the first phase of this experiment, were trained to recognize that an image with a particular pattern meant that they would be given a reward in the form of a sweet drink. Two different groups of mice were then put in front of a computer screen where they were able to see several images containing different patterns. In order to demonstrate that they remembered which image led to a reward, the mice had to lick a small “nozzle” that dispensed the drink.

While the mice performed this action, researchers at the University of Oslo monitored the activity in their using a special microscope. “It took some time before the mice understood which pattern triggered a reward. We could see what was happening with their neurons while they mastered the task,” says researcher Kristian K. Lensjø, who works at the Institute of Basic Medical Sciences and the Department of Biosciences at the University of Oslo.

A unified framework to model synaptic dynamics during the sleep–wake cycle

Conflicting results have been observed regarding changes in synaptic strength in the cerebral cortex during the sleep-wake cycle. This computational study provides a comprehensive understanding and unified framework about synaptic dynamics during the sleep-wake cycle.