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Category: computing – Page 14

Quantum computer simulates spontaneous symmetry breaking at zero temperature

For the first time, an international team of scientists has experimentally simulated spontaneous symmetry breaking (SSB) at zero temperature using a superconducting quantum processor. This achievement, which was accomplished with over 80% fidelity, represents a milestone for quantum computing and condensed matter physics.

The results are published in the journal Nature Communications.

The system began in a classical antiferromagnetic state, in which particles have spins that alternate between one direction and the opposite direction. It then evolved into a ferromagnetic quantum state, in which all particles have spins that point in the same direction and establish quantum correlations.

Faster topology optimization: An emerging industrial design technique gets a speed boost

With the rise of 3D printing and other advanced manufacturing methods, engineers can now build structures that were once impossible to fabricate. An emerging design strategy that takes full advantage of these new capabilities is topology optimization—a computer-driven technique that determines the most effective way to distribute material, leading to an optimized design.

Now, a research team including mathematicians from Brown University has developed a new approach that dramatically improves the speed and stability of topology optimization algorithms. The team, a collaboration between researchers at Brown, Lawrence Livermore National Laboratory and Simula Research Laboratory in Norway, detailed their work in two recently published papers in the SIAM Journal on Optimization and Structural and Multidisciplinary Optimization.

“Our method beats some existing methods by four or five times in terms of efficiency,” said Brendan Keith, an assistant professor of applied mathematics at Brown. “That’s a huge computational savings that could enable people to make designs more quickly and inexpensively, or to develop more complex designs with higher resolution.”

Terahertz instead of gigahertz — quantum material speeds up transistor switching by 1000 times

Researchers from Northeastern University in the United States have found a way to speed up electronics by a thousand times by replacement of silicon chips on quantum materials.

It is noted, that the new technology, through controlled heating and cooling, allows the quantum material to switch between the state of a conductor and an insulating material almost instantly. According to the researchers, such materials can replace silicon and lead to the emergence of electronic devices that are much faster and smaller.

«Processors currently operate in gigahertz. The speed of change that this will provide will allow you to move to terahertz», — explains the lead author of the study, professor of physics Alberto de la Torre.

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.