Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog – Page 10

Get the latest international news and world events from around the world.

Log in for authorized contributors

Four superconducting cables link two large quantum processors into one

As quantum computers grow more ambitious, many researchers believe the best way forward is to build them in multiple interconnected parts. In these modular designs, separate quantum processors are linked so they can work together as one larger machine. For this to happen, however, connections must carry fragile quantum information without destroying it.

For superconducting processors, this means building reliable links around a meter (3.3 feet) long inside equipment chilled to just above absolute zero. A team at IBM Research has now achieved this for the first time: joining two large superconducting processors using four separate high-quality quantum links, all installed after both chips were already in place.

Their work is detailed in a new paper published on the arXiv preprint server.

Experiment supports theoretical foundation for potentially more error-resistant quantum computing

One approach to making information storage in quantum computing less prone to errors is known as topological quantum computing. It relies on special quantum states that are expected to be more resistant to local disturbances.

Physicists at the University of Cologne have now observed quantum states that behave as predicted in a material system considered promising for this approach.

Their findings, published under the title “Tunneling spectroscopy of topological insulator Josephson junctions” in Science Advances, support a theoretical description of how superconductivity interacts with the surface of a topological insulator.

Breaking the ice: Scientists use attracting particles to form an anti-spin ice

In a recent Nature Communications study, researchers have reported the realization of an anti-spin ice, a system that does the opposite of conventional spin ices by breaking the ice rule that governs them.

Spin ices are magnetic systems that mimic a rule found in water ice. In water ice, each oxygen atom keeps two hydrogen atoms close and two farther away. This is known as the ice rule. Because many arrangements satisfy this rule equally well, the hydrogen atoms in ice end up being disordered, meaning that there’s no repeating pattern.

This is a sign of geometric frustration, which occurs when competing interactions in a system can’t all be satisfied at once, leaving many equally good compromises.

Ultrathin kagome material opens a route to study unusual quantum states

How atoms are arranged inside materials can influence the behavior of electrons and the resulting electronic states. Kagome lattices, repeating arrangements of atoms forming triangles that share corners (with hexagonal spaces between them), have been linked with the emergence of unusual electronic states.

Researchers at Seoul National University, the Center for Complex Phase of Materials and other institutions recently realized a two-dimensional (2D) kagome material that could be used to investigate quantum physics phenomena. This material, presented in a paper published in Nature Physics, was found to retain a set of tunable electron states with nearly identical energies (i.e., a flat electronic band) in a single layer.

“A central theme in condensed matter physics is the emergence of new electronic behavior from the underlying lattice geometry and symmetry,” Mingu Kang, senior author of the paper, told Phys.org. “A well-known example is graphene, where the symmetry of its hexagonal lattice gives rise to massless Dirac electrons (m = 0). Another extensively studied example in theoretical physics is the kagome lattice, composed of corner-sharing triangles.”

Magnetic nanocomposites could help shrink the components that power computer chips

When you think about making computer chips better, you probably think about transistors. My colleagues and I focused on a less visible part of the problem: the components that deliver power to those transistors. A chip needs more than electricity. It needs electricity supplied at the right voltage, with fluctuations kept under control. Making the hardware that does this smaller is an important challenge—and one that led my colleagues and me to build tiny magnetic devices called stripline microinductors.

In our study, we fabricated these devices using a composite of nickel and iron oxide nanoparticles. Our measurements showed more than twice the inductance of comparable devices without a magnetic core. The broader question behind this work is how to bring useful magnetic materials into the small structures used in semiconductor manufacturing.

The research was conducted at the University of Florida with my coauthors Brenden M. Mears, Noah Morgan, Jennifer S. Andrew and David P. Arnold. Our study, now published in the Journal of Micromechanics and Microengineering, brought together expertise in materials synthesis, microfabrication and electrical characterization.

Exactly solvable model reveals how trapped light can create magnetic order in one-dimensional spin chains

A research team wanted to better understand how the forces between particles inside a material change. They discovered that by confining one-dimensional classical spin chains inside a mirror box cavity with light, they could force these magnetic particles to organize and undergo a phase transition. Their work provides the simplest exactly solvable examples showing that light can create new phase transitions with materials.

In 1925, Ernst Ising showed that a single one-dimensional chain of small magnetic particles with nearest-neighbor interactions does not exhibit a magnetic phase transition at finite temperatures. This is called the Ising chain.

However, scientists today know that magnetic phase transitions can occur in two or more dimensions, positioning the Ising model as a simple, crucial math tool for studying how large groups of interacting particles behave. In addition, scientists are using cavity systems where matter and light are trapped and strongly interact with each other, leading to the possible discovery of new phenomena in physics.

A smart window grows a silver shield to keep sunlight’s heat out

A window can admit welcome daylight but also let in unwanted heat, taxing air conditioning systems. Darkening the glass helps control glare, but the absorption of sunlight warms it. An ideal window would block more incoming heat while also letting trapped heat escape.

To address this challenge, researchers at the Chinese Academy of Sciences, Northeast Forestry University and collaborating institutions have developed a colorful smart window with a reflective silver layer that activates when a voltage is applied. The layer turns a tinted, see-through pane opaque, providing shade and privacy. A separate outer coating helps the window release heat to the outside of the building.

In outdoor tests, small structures covered by the prototype window stayed cooler than those covered by quartz glass or other commercial smart windows. The study, published in Nano Letters reveals a technology that manages daylight, privacy and heat at the same time.

Researchers Discover a New Way To Control Magnetism Without Changing a Material’s Chemistry

Neutron experiments have uncovered an unexpected connection between magnetic structure and electrical behavior.

A gentle squeeze can change the magnetic structure of certain crystals and alter their electrical behavior. Scientists at the Department of Energy’s Oak Ridge National Laboratory (ORNL) demonstrated this effect in altermagnets, an emerging class of magnetic materials being investigated for advanced electronics.

Using neutron beams to examine the materials at the atomic scale, the researchers found that mechanical strain could shift their magnetic organization and influence an electrical response associated with electron transport. The findings, published in back-to-back papers in Physical Review X and Advanced Materials, point to a possible method for controlling magnetic properties without altering a material’s chemical composition.

A Hidden Nanoscopic Effect Is Disrupting Some of the World’s Most Sensitive Sensors

Nanomechanical resonators are vital to precision sensing and emerging quantum technologies, but their extraordinary sensitivity comes with an unexpected vulnerability.

A nanomechanical device can lose much of its ability to sustain vibrations without ever touching another object. Researchers at EPFL have discovered that placing insulating materials just a few hundred nanometers from these tiny structures can dramatically increase energy loss, reducing their mechanical quality factor by as much as tenfold.

The findings, published in Nature Physics by scientists in the group of Tobias J. Kippenberg, identify a previously underappreciated limitation for ultrahigh-precision sensors and quantum technologies. The source of the problem is an electrical interaction that allows energy to escape across an otherwise empty gap.