Using light to perform tasks beyond the reach of classical computers.
Category: quantum physics
Quantum friction causes light to slow down nanoworld movements
A research team in Bochum, Germany has unexpectedly found that light can slow down movements in the nanoworld. This is due to quantum friction, a phenomenon that has been poorly understood until now. The findings are published in the journal Nature.
Light is expected to heat particles up or set them in motion. However, the interdisciplinary team at Ruhr University Bochum, Germany, has now proven the opposite. In aqueous solution, fluorescent carbon nanotubes move much slower once they are irradiated with light. During this process, the diffusion constant decreases with light intensity, an effect linked to direct coupling between electrons in the solid and the molecules of the liquid.
“This discovery of light-induced quantum friction fundamentally changes our understanding of interfacial processes,” says researcher Sebastian Kruss, who led the work with Marialore Sulpizi and Martina Havenith.
One-way quantum synchronization could make quantum computers more reliable
Scientists at RIKEN have proposed a new way to make quantum systems synchronize in only one direction—like a one-way street for sound particles known as phonons. The breakthrough combines two quantum effects to create a form of one-way quantum synchronization that remains surprisingly stable even when exposed to manufacturing flaws and environmental noise, two major obstacles that have long hindered real-world quantum technologies.
Why we should all take quantum physics extremely personally
Physics is considered a cold, hard science – but it will transform your life if you view it with a bit more subjectivity, says Karmela Padavic-Callaghan
Electron matter waves gain ultrafast torque that flips handedness in femtoseconds
Many natural processes, ranging from magnetism to chemical reactions, entail the movement and rotation of particles at very small scales. In quantum mechanics, particles exhibit both particle-like and wave-like behaviors, and their states can be described mathematically using representations known as wavefunctions.
The reliable manipulation of wave-like properties of particles as small as atoms or single electrons could open new possibilities both for studying matter and for engineering materials with desirable characteristics. Notably, controlling the angular momentum, which is the quantum property related to rotational motion, of ultrasmall particles at ultrafast timescales has so far proved very challenging when only using conventional, laser-based approaches.
Researchers at Universität Konstanz recently devised a new approach to create electron beams with an ultrafast internal torque (i.e., twisting motion). Their proposed strategy, outlined in a paper published in Nature Physics, could be a promising tool for exploring material dynamics and quantum phenomena at atomic and subatomic scales.
Light rewrites magnetic memory in one pulse, opening path to lower-power AI chips
As artificial intelligence, cloud computing and digital services continue to expand, the world is facing a growing need for faster and more energy-efficient ways to store and process information. A team led by the National Institutes for Quantum Science and Technology (QST) has developed a new magnetic memory material that can be rewritten using laser light instead of electric current, a step that could help reduce power consumption in data centers and support future high-speed information systems.
The study is published in Applied Physics Letters.
The new material allows magnetic information to be switched by a single ultrashort laser pulse. Because light can reverse magnetic states much faster than electric current, the approach could deliver switching speeds roughly 1,000 times higher than those of conventional electrically driven magnetic memory while also reducing heat generation and energy loss.
Non-Hermitian Casimir effect of magnons
npj Spintronics has APC waivers available that can be allocated upon acceptance on an ad-hoc basis. For additional information, contact the Journal Publisher, Daniel Payne.
AI helps reveal large-scale quantum effects hidden in stacked atomic sheets
Quantum materials are a class of exotic materials with special properties that are governed by quantum mechanics rather than classical physics. Those properties—like superconductivity, entanglement and unusual forms of magnetism—often originate in the tiny repeating patterns of atoms inside crystals, but through clever engineering, they can be observed and controlled at a more human scale. Quantum materials are helping to power the quickly growing field of quantum computing and could find their way into future generations of energy-efficient electronics.
Designing new materials from the atomic scale up, however, requires intense modeling and simulation. Some materials may appear ordinary when viewed as small clusters of atoms, yet reveal new and useful properties when their atomic building blocks repeat and interact over larger distances. Researchers must be able to accurately predict behaviors at large scales in order to find materials with practical applications—otherwise, designing new materials is a slow and costly trial-and-error process.
In the past 50 years, supercomputers have helped materials scientists solve some of those thorny prediction problems, but two recent studies from the University of Washington demonstrate how newer computing techniques can help researchers sniff out promising quantum materials to pursue.
Majorana modes withstand disorder in atomic chains, boosting fault-tolerant quantum computing
Quantum computers—systems that process information and perform computations by leveraging the principles of quantum mechanics—could solve some tasks faster and more effectively than classical computers. While some studies have demonstrated the advantages of these computers for specific tasks, ensuring their reliable operation in real-world settings has proved challenging.
This is partly because quantum information units, or qubits, are known to be highly sensitive to environmental disturbances, such as fluctuations in temperature, electromagnetic fluctuations and magnetic fields. These environmental disturbances, collectively referred to as “noise,” can alter the qubit’s delicate quantum states, leading to computational errors.
In recent years, quantum physicists and engineers have proposed various strategies that could protect qubits from environmental disturbances and reduce quantum computing errors. One proposed solution is to rely on Majorana modes.