Lifeboat Foundation

Abstract: The large, error-correcting quantum computers envisioned today could be decades away, yet experts are vigorously trying to come up with ways to use existing and near-term quantum processors to solve useful problems despite limitations due to errors or “noise.”

A key envisioned use is simulating molecular properties. In the long run, this can lead to advances in materials improvement and drug discovery. But not with noisy calculations confusing the results.

Now, a team of Virginia Tech chemistry and physics researchers have advanced quantum simulation by devising an algorithm that can more efficiently calculate the properties of molecules on a noisy quantum computer. Virginia Tech College of Science faculty members Ed Barnes, Sophia Economou, and Nick Mayhall recently published a paper in Nature Communications detailing the advancement.

A device that eavesdrops on the quantum whispers of atoms could form the basis of a new type of quantum computer.

Researchers at the Center for Theoretical Physics of Complex Systems (PCS), within the Institute for Basic Science (IBS, South Korea), and colleagues have reported a novel phenomenon, called Valley Acoustoelectric Effect, which takes place in 2-D materials, similar to graphene. This research is published in Physical Review Letters and brings new insights to the study of valleytronics.

In acoustoelectronics, surface acoustic waves (SAWs) are employed to generate electric currents. In this study, the team of theoretical physicists modelled the propagation of SAWs in emerging 2-D materials, such as single-layer molybdenum disulfide (MoS₂). SAWs drag MoS₂ electrons (and holes), creating an electric current with conventional and unconventional components. The latter consists of two contributions: a warping-based current and a Hall current. The first is direction-dependent, is related to the so-called valleys—electrons’ local energy minima—and resembles one of the mechanisms that explains photovoltaic effects of 2-D materials exposed to light. The second is due to a specific effect (Berry phase) that affects the velocity of these electrons travelling as a group and resulting in intriguing phenomena, such as anomalous and quantum Hall effects.

The team analyzed the properties of the acoustoelectric current, suggesting a way to run and measure the conventional, warping, and Hall currents independently. This allows the simultaneous use of both optical and acoustic techniques to control the propagation of charge carriers in novel 2-D materials, creating new logical devices.

An international research team has studied how photons travel in the plane of the world’s thinnest semiconductor crystal. The results of the physicists’ work open the way to the creation of monoatomic optical transistors — components for quantum computers, potentially capable of making calculations at the speed of light.

“If you rearrange the atoms in coal, you get diamond. If you rearrange the atoms in sand, you get silicon. How atoms are arranged is fundamental to all material aspects of life,” says Ralph Merkle, currently senior research chair at the Institute for Molecular Manufacturing. He’s a large, pear-shaped man who, as he speaks, waves his arms far more energetically than his physique would imply. He modulates his tone dramatically for effect, often humorous.

Those words kick off day 2 at the Singularity University Executive Program. The curriculum divides roughly into three days of intensive classroom introductions to critical tech domains, three days of visits to Silicon Valley companies, and two days of workshops devoted to specific industries, plus a final day to wrap up. On Saturday I settled gingerly into a lightly padded metal chair for highly compressed, sometimes super technical, up-to-the-minute overviews of artificial intelligence, robotics, networking, computing, and quantum computing. (Forecast: sunny! With patchy clouds and fog.) That took until dinner time with only a quick break for lunch, which was filled with presentations by graduates of SU’s nine-week summer program.

You’ve read your last complimentary article this month. To read the full article, SUBSCRIBE NOW. If you’re already a subscriber, please sign in and and verify your subscription.

The fine art of adding impurities to silicon wafers lies at the heart of semiconductor engineering and, with it, much of the computer industry. But this fine art isn’t yet so finely tuned that engineers can manipulate impurities down to the level of individual atoms.

As technology scales down to the nanometer size and smaller, though, the placement of individual impurities will become increasingly significant. Which makes interesting the announcement last month that scientists can now rearrange individual impurities (in this case, single phosphorous atoms) in a sheet of graphene by using electron beams to knock them around like croquet balls on a field of grass.

The finding suggests a new vanguard of single-atom electronic engineering. Says research team member Ju Li, professor of nuclear science and engineering at MIT, gone are the days when individual atoms can only be moved around mechanically—often clumsily on the tip of a scanning tunneling microscope.

Three experiments have vetted quantum Darwinism, a theory that explains how quantum possibilities can give rise to objective, classical reality.

When one atom emits light, they do so in a separate package called a photon. When this light is measured, this discrete or granular nature leads to small brightness fluctuations because two or more photons never emit simultaneously.

Physicists in the US have discovered a material that could qualify as the first known three-dimensional example of a quantum spin liquid — an exotic theoretical phase of matter.

Quantum spin liquids were first predicted by scientists back in the 1970s. While researchers have studied them for decades, these phases largely remain a theoretical concept, although that’s not the same as saying they don’t exist.

To confuse you further, quantum spin liquids aren’t actually liquids, but a kind of solid, magnetic matter that exhibits a strange form of behaviour at the subatomic particle level, specifically in terms of its electrons.