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Category: particle physics – Page 504

The phenomenon known as “tunneling” is one of the best-known predictions of quantum physics, because it so dramatically confounds our classical intuition for how objects ought to behave. If you create a narrow region of space that a particle would have to have a relatively high energy to enter, classical reasoning tells us that low-energy particles heading toward that region should reflect off the boundary with 100% probability. Instead, there is a tiny chance of finding those particles on the far side of the region, with no loss of energy. It’s as if they simply evaded the “barrier” region by making a “tunnel” through it.

It’s very important to note that this phenomenon is absolutely and unquestionably real, demonstrated in countless ways. The most dramatic of these is sunlight— the Sun wouldn’t be able to fuse hydrogen into helium without quantum tunneling— but it’s also got more down-to-earth technological applications. Tunneling serves as the basis for Scanning Tunneling Microscopy, which uses the tunneling of electrons across a tiny gap between a sharp tip and a surface to produce maps of that surface that can readily resolve single atoms. It’s also essential for the Josephson effect, which is the basis of superconducting detectors of magnetic fields and some of the superconducting systems proposed for quantum computing.

So, there is absolutely no debate among physicists about whether quantum tunneling is a thing that happens. Physicists get a bit twitchy without something to argue over, though, and you don’t have to dig into tunneling (heh) very far to find a disputed question, namely “How long does quantum tunneling take?”

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O.o!

A team of scientists recently determined certain quantum particles can regenerate after they’ve decayed. This has grand implications for the future of humanity, quantum computing, and intergalactic graffiti.

Theoretical physicists from the Technical University of Munich and the Max Planck Institute conducted simulation experiments to determine that certain quasiparticles are essentially immortal. Per the second law of thermodynamics nothing lasts forever, but these quantum particle fields can reassemble themselves after decaying – just like the phoenix from Greek mythology.

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A team of fusion researchers succeeded in proving that energetic ions with energy in mega electron volt (MeV) range are superiorly confined in a plasma for the first time in helical systems. This promises the alpha particle (helium ion) confinement required for realizing fusion energy in a helical reactor.

The deuterium-tritium reaction in a high-temperature plasma will be used in fusion reactors in the future. Alpha particles with 3.5 MeV energy are generated by the fusion reaction. The alpha particles transfer their energy to the plasma, and this alpha particle heating sustains the high-temperature plasma condition required for the fusion reaction. In order to realize such a plasma, which is called a burning plasma, the in the MeV range must be tightly confined in the plasma.

Numerical simulations predicted the favorable results of MeV ion in a plasma in helical systems that have the advantage of steady-state operation in comparison with tokamak systems. However, demonstration of MeV ion confinement by experiment had not been reported. Recently, the study was greatly advanced by an MeV ion confinement experiment performed in the deuterium operation of the Large Helical Device (LHD), which is owned by National Institute for Fusion Science (NIFS), National Institutes of Natural Sciences (NINS), in Japan. In deuterium plasmas, 1 MeV tritons (tritium ions) are created by deuteron-deuteron fusion reactions. The tritons have the similar behavior with generated in a future burning plasma.

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By Will Knight

A super-powered neutrino generator could in theory be used to instantly destroy nuclear weapons anywhere on the planet, according to a team of Japanese scientists.

If it was ever built, a state could use the device to obliterate the nuclear arsenal of its enemy by firing a beam of neutrinos straight through the Earth. But the generator would need to be more than a hundred times more powerful than any existing particle accelerator and over 1000 kilometres wide.

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Making a replicator from this could make something that could create almost anything :3.

The first type of molecule that ever formed in the universe has been detected in space for the first time, after decades of searching. Scientists discovered its signature in our own galaxy using the world’s largest airborne observatory, NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, as the aircraft flew high above the Earth’s surface and pointed its sensitive instruments out into the cosmos.

When the universe was still very young, only a few kinds of atoms existed. Scientists believe that around 100,000 years after the big bang, helium and hydrogen combined to make a molecule called helium hydride for the first time. Helium hydride should be present in some parts of the modern universe, but it has never been detected in space — until now.

SOFIA found modern helium hydride in a planetary nebula, a remnant of what was once a Sun-like star. Located 3,000 light-years away near the constellation Cygnus, this planetary nebula, called NGC 7027, has conditions that allow this mystery molecule to form. The discovery serves as proof that helium hydride can, in fact, exist in space. This confirms a key part of our basic understanding of the chemistry of the early universe and how it evolved over billions of years into the complex chemistry of today. The results are published in this week’s issue of Nature.

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Scientists at the University of Illinois have discovered a new way to make water, and without the pop. Not only can they make water from unlikely starting materials, such as alcohols, their work could also lead to better catalysts and less expensive fuel cells.

“We found that unconventional metal hydrides can be used for a chemical process called oxygen reduction, which is an essential part of the process of making water,” said Zachariah Heiden, a doctoral student and lead author of a paper accepted for publication in the Journal of the American Chemical Society, and posted on its Web site.

A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you can’t simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.

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“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.

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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.

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