Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: particle physics – Page 488

“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.

Read more | >

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.

Read more | >

If you’ve been a grunt, then you probably have a love-hate relationship with body armor. You love having it in a firefight — it can save your life by stopping or slowing bullets and fragments — but you hate how heavy it is — it’s often around 25 pounds for the armor and outer tactical vest (more if you add the plate inserts to stop up to 7.62 mm rounds).

It’s bulky — and you really can’t move as well in it. In fact, in one firefight, a medic removed his body armor to reach wounded allies, earning a Distinguished Service Cross.

Imagine if the body armor were just another part of your clothes, like a light jacket. Imagine not having to haul around those extra 30 pounds. Well, troops may not have to imagine much longer. According to a release from the Advanced Science Research Center at the City University of New York, body armor could soon have the thickness of just two atoms. This is due to how graphene acts under certain conditions.

Read more | >

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.

Read more | >

A vacuum is generally thought to be nothing but empty space. But in fact, a vacuum is filled with virtual particle-antiparticle pairs of electrons and positrons that are continuously created and annihilated in unimaginably short time-scales.

The quest for a better understanding of vacuum physics will lead to the elucidation of fundamental questions in , which is integral in unraveling the mysteries of space, such as the Big Bang. However, the required to forcibly separate the virtual pairs and cause them to appear not as virtual particles but real particles would be 10 million times higher than current laser technology is capable of. This field intensity is the so-called Schwinger limit, named a half-century ago after the American Nobel laureate Julian Schwinger.

In 2018, scientists at Osaka University discovered a novel mechanism that they called a microbubble implosion (MBI). In MBIs, super-high-energy hydrogen ions (relativistic protons) are emitted at the moment when bubbles shrink to through the irradiation of hydrides with micron-sized spherical bubbles by ultraintense, .

Read more | >

A few millionths of a second after the Big Bang, the universe was so dense and hot that the quarks and gluons that make up protons, neutrons and other hadrons existed freely in what is known as the quark–gluon plasma. The ALICE experiment at the Large Hadron Collider (LHC) can recreate this plasma in high-energy collisions of beams of heavy ions of lead. However, ALICE, as well as any other collision experiments that can recreate the plasma, cannot observe this state of matter directly. The presence and properties of the plasma can only be deduced from the signatures it leaves on the particles that are produced in the collisions.

In a new article, presented at the ongoing European Physical Society conference on High-Energy Physics, the ALICE collaboration reports the first measurement of one such signature—the elliptic flow—for upsilon produced in lead–lead LHC collisions.

The upsilon is a bottomonium particle, consisting of a bottom (often also called beauty) quark and its antiquark. Bottomonia and their charm-quark counterparts, charmonium particles, are excellent probes of the quark–gluon . They are created in the initial stages of a heavy-ion collision and therefore experience the entire evolution of the plasma, from the moment it is produced to the moment it cools down and gives way to a state in which hadrons can form.

Read more | >

Metamaterials are artificial materials engineered to have properties not found in naturally occurring materials, and they are best known as materials for invisibility cloaks often featured in sci-fi novels or games. By precisely designing artificial atoms smaller than the wavelength of light, and by controlling the polarization and spin of light, researchers achieve new optical properties that are not found in nature. However, the current process requires much trial and error to find the right material. Such efforts are time-consuming and inefficient; artificial intelligence (AI) could provide a solution for this problem.

The research group of Prof. Junsuk Rho, Sunae So and Jungho Mun of Department of Mechanical Engineering and Department of Chemical Engineering at POSTECH have developed a design with a higher degree of freedom that allows researchers to choose materials and design photonic structures arbitrarily by using deep learning. Their findings are published in several journals including Applied Materials and Interfaces, Nanophotonics, Microsystems & Nanoengineering, Optics Express, and Scientific Reports.

AI can be trained with a vast amount of data, and it can learn designs of various and the correlation between photonic structures and their optical properties. Using this training process, it can provide a that makes a photonic structure with desired optical properties. Once trained, it can provide a desired design promptly and efficiently. This has already been researched at various institutions in the U.S. such as MIT, Stanford University and Georgia Institute of Technology. However, the previous studies require inputs of materials and structural parameters beforehand, and adjusting photonic structures afterwards.

Read more | >