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Category: particle physics

Why twisted bilayer graphene stops superconducting near high-dielectric substrates

Superconductors are materials that can conduct electricity with a resistance of zero. In so-called conventional superconductors, this occurs at low temperatures when electrons become bound into pairs, known as Cooper pairs.

In some other materials, however, superconductivity (SC) emerges via other electron pairing mechanisms that are still poorly understood. These materials, called unconventional superconductors, include twisted bilayer graphene (tBLG), a two-dimensional material created by stacking two single sheets of graphene on top of each other, one of which is rotated in relation to the other by a precise small angle.

One factor that plays a role in unconventional SC is the so-called dielectric constant. This is the measure of how well a material reduces the electric forces between charged particles.

A persistent quantum computing error finally explained

Scientists have discovered the cause of a persistent glitch that continues to disrupt superconducting quantum computers, even when they have built-in defenses. For all their advanced hardware, superconducting quantum computers are vulnerable to errors caused by ionizing radiation from space or the environment. Radiation particles interfere with the chip substrate (the silicon base the processor is built on), which leads to the creation of rogue particles (quasiparticles) that disrupt the qubits, the basic units of quantum computers.

To protect against this, scientists developed a technique called gap engineering. This involves creating an energy barrier in the superconducting material of the qubits, making it harder for these particles to reach sensitive parts of the device.

However, it is not foolproof. Even with this defense, radiation can still cause sudden widespread errors affecting many qubits at once (error bursts). But it was not clear why.

Hourglass nanographenes unlock strong, robust multi-spin entanglement

Researchers from the National University of Singapore (NUS) and collaborators have developed a predictive design strategy for creating graphene-like molecules with multiple interacting spins and enhanced resilience to magnetic perturbations, opening new avenues for molecular-scale quantum information technologies and next-generation spintronics.

The research team was led by Professor Lu Jiong from the NUS Department of Chemistry and the NUS Institute for Functional Intelligent Materials, together with Professor Wu Jishan from the NUS Department of Chemistry, and international collaborators, including key contributor Professor Pavel Jelínek from the Czech Academy of Sciences in Prague.

Magnetic nanographenes, which are molecules composed of fused benzene rings, are of growing interest for quantum technologies because they can host unpaired electrons, or spins, that may be used to store and process information. Unlike conventional magnetic materials based on metal atoms, these carbon-based systems offer chemical versatility and long spin coherence times. However, engineering a single molecule that contains multiple strongly coupled spins in a stable and controlled manner remains a major challenge.

Twisting atom-thin materials reveals new way to save computing energy

A recent study shows a new and potentially more energy-efficient way for information to be transmitted inside electronic systems, including computers and phones—without relying on electric currents or external magnetic fields.

In today’s electronics, information is transmitted by moving electrons through circuits, where ones and zeros are represented by high or low electrical signals. While this approach has enabled modern computing, the movement of electrical charge inevitably generates heat, leading to energy loss and limiting how much devices can be miniaturized and improved.

In the new study, published in Nano Letters, researchers at KTH Royal Institute of Technology and international collaborators demonstrate that simply twisting two layers of certain atom-thin magnetic materials allows magnetic signals to carry information instead of relying on electrical currents to do the work.

NASA Powers Down Voyager 1 Instrument As It Fights To Survive Deep Space

Voyager 1 is losing power, and NASA just shut down a decades-old instrument to keep it going. The sacrifice could help the spacecraft continue exploring interstellar space a little longer.

On April 17, engineers at NASA’s Jet Propulsion Laboratory (JPL) in Southern California transmitted commands to switch off an instrument on Voyager 1 known as the Low-energy Charged Particles experiment, or LECP. The spacecraft, which runs on nuclear power, is steadily losing energy, and shutting down this instrument is the most effective way to extend the mission of the first human-made object to reach interstellar space.

A 49-Year-Old Instrument Falls Silent

Small talk shapes big trends: Physics predicts how language patterns spread

A new model to predict how language changes over time has been developed by a statistical physicist at the University of Portsmouth. The model is a step towards understanding the “statistical physics of language,” a scientific theory which borrows ideas from the physics of interacting particles to explain how words, accents, and dialects spread, shift, and disappear across regions and generations, and how they might change in future. The research is published in the journal Physical Review E.

James Burridge, Professor of Probability and Statistical Physics, from the University’s School of Mathematics and Physics, said, Just as meteorologists use mathematical models to forecast tomorrow’s weather, the same kind of thinking can be applied to language.

Where you are affects how you speak and if you map how people use certain words, you see clear geographic patterns—just like a weather map. However, the physics of language is closer to crystals and magnets than the atmosphere.

Sean Carroll, CalTech, John’s Hopkins, Santa Fe Institute

One of the great intellectual achievements of the twentieth century was the theory of quantum mechanics, according to which observational results can only be predicted probabilistically rather than with certainty. Yet, after decades in which the theory has been successfully used on an everyday basis, most physicists would agree that we still don’t truly understand what it means. Sean Carroll will discuss the source of this puzzlement, and explain why an increasing number of physicists are led to an apparently astonishing conclusion: that the world we experience is constantly branching into different versions, representing the different possible outcomes of quantum measurements. This could have important consequences for quantum gravity and the emergence of spacetime.

Sean Carroll is a research professor at CalTech, Homewood Professor of Natural Philosophy at John’s Hopkins University, and Fractal Faculty at SFI. His research focuses on fundamental physics and cosmology, quantum gravity and spacetime, philosophy of science, and the evolution of entropy and complexity. He’s authored “Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime;” “The Big Picture;” “The Particle at the End of the Universe;” “From Eternity to Here;” and the textbook “Spacetime and Geometry.”

This laser turns metal into a star-like plasma in trillionths of a second

In a striking glimpse into extreme physics, scientists have captured the split-second chaos that unfolds when powerful laser flashes blast matter into a superheated plasma. By combining two cutting-edge lasers, researchers were able to track how copper atoms lose and regain electrons in trillionths of a second, creating and dissolving highly charged ions in a rapid, almost cinematic sequence.

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