Menu

Blog

Archive for the ‘particle physics’ category: Page 208

Jan 14, 2023

Quasicrystal with a “Flashy” Origin

Posted by in categories: climatology, particle physics

The meteorite and explosion-site quasicrystals were both uncovered by a team that includes Luca Bindi of the University of Florence, Italy, and Paul Steinhardt of Princeton University. In those previous cases, the materials were subjected to extremely high-pressure, high-temperature shock events—analysis of the meteorite sample revealed the temperature reached at least 1,200 °C and the pressure 5 GPa, while the New Mexico sample reached 1,500 °C and closer to 8 GPa. These transient, intense conditions contorted the materials’ atoms, forcing them to arrange into patterns unseen for usual laboratory conditions.

The explosion-site sample was found in a rock-like substance made of sand that had been fused together with copper wires from a measurement device that had been set up to monitor the atom-bomb test. As a trained geologist, Bindi was aware that similar substances—so-called fulgurites—are created when lightning strikes a beach or a sand dune. He wondered if lightning-fused samples might also contain quasicrystals, so he and the team set about collecting and analyzing the structures of as many fulgurites as they could lay their hands on.

Luck was on their side. In a fragment of a storm-created fulgurite from the Nebraskan Sand Hills—grass-stabilized sand dunes in northern Nebraska—the team found a micron-sized fragment of a quasicrystal with a previously unseen composition and pattern. Specifically, the newly discovered quasicrystal has a dodecagonal—12-fold symmetric—atomic structure. Such ordering is impossible in ordinary crystals, Bindi says, and is unusual even for quasicrystals (both the meteorite and explosion-site quasicrystals, as well as most lab-made ones, have fivefold symmetric patterns). “This was all more than [we] could have hoped for in such a long-shot search,” Steinhardt says.

Jan 13, 2023

Fukushima nuclear disaster: Japan to release radioactive water into sea this year

Posted by in categories: nuclear energy, particle physics

Japan says it will release more than a million tonnes of water into the sea from the destroyed Fukushima nuclear power plant this year.

After treatment the levels of most radioactive particles meet the national standard, the operator said.

The International Atomic Energy Agency (IAEA) says the proposal is safe, but neighbouring countries have voiced concern.

Continue reading “Fukushima nuclear disaster: Japan to release radioactive water into sea this year” »

Jan 13, 2023

Researchers create an optical tractor beam that pulls macroscopic objects

Posted by in categories: particle physics, tractor beam

Researchers have developed a way to use laser light to pull a macroscopic object. Although microscopic optical tractor beams have been demonstrated before, this is one of the first times that laser pulling has been used on larger objects.

Light contains both energy and momentum that can be used for various types of optical manipulation such as levitation and rotation. Optical tweezers, for example, are commonly used scientific instruments that use laser light to hold and manipulate tiny objects such as atoms or cells. For the last ten years, scientists have been working on a new type of optical manipulation: using to create an optical tractor beam that could pull objects.

Continue reading “Researchers create an optical tractor beam that pulls macroscopic objects” »

Jan 13, 2023

Visualizing a complex electron wavefunction using high-resolution attosecond technology

Posted by in categories: information science, particle physics, quantum physics

The early 20th century saw the advent of quantum mechanics to describe the properties of small particles, such as electrons or atoms. Schrödinger’s equation in quantum mechanics can successfully predict the electronic structure of atoms or molecules. However, the “duality” of matter, referring to the dual “particle” and “wave” nature of electrons, remained a controversial issue. Physicists use a complex wavefunction to represent the wave nature of an electron.

“Complex” numbers are those that have both “real” and “imaginary” parts—the ratio of which is referred to as the “phase.” However, all directly measurable quantities must be “real”. This leads to the following challenge: when the electron hits a detector, the “complex” phase information of the disappears, leaving only the square of the amplitude of the wavefunction (a “real” value) to be recorded. This means that electrons are detected only as particles, which makes it difficult to explain their dual properties in atoms.

The ensuing century witnessed a new, evolving era of physics, namely, physics. The attosecond is a very short time scale, a billionth of a billionth of a second. “Attosecond physics opens a way to measure the phase of electrons. Achieving attosecond time-resolution, electron dynamics can be observed while freezing ,” explains Professor Hiromichi Niikura from the Department of Applied Physics, Waseda University, Japan, who, along with Professor D. M. Villeneuve—a principal research scientist at the Joint Attosecond Science Laboratory, National Research Council, and adjunct professor at University of Ottawa—pioneered the field of attosecond physics.

Jan 12, 2023

Researchers devise a new way to control ‘3D’ effects in chemical reactions

Posted by in categories: chemistry, particle physics

Researchers have observed steric effects—the interactions of molecules depending on their spatial orientation (not just between their electrons involved in bonding)—in a chemical reaction involving non-polar molecules for the first time. The breakthrough opens the door to an entirely new way to control the products of chemical reactions.

A paper describing the research team’s findings was published in the journal Science on Jan. 12.

One of the central goals of chemistry is to develop new methods of controlling chemical reactions. For the most part, control of chemical reactions involves understanding of the interactions between the electrons of different atoms. These “electronic” effects govern many of the properties and behavior of chemicals and the changes they undergo during reactions.

Jan 12, 2023

Astronomers find a group of zombie stars 20 times hotter than the Sun

Posted by in categories: evolution, particle physics, space

Of course, all stars are hot compared with anything we’re used to here on Earth. But while the Sun’s surface chills at a steady 6,000 degrees Kelvin, these stars’ extreme temperatures range from 100,000 to 180,000 degrees.

These are “stars which are a little bit outside the canonical evolution,” Klaus Werner of the University of Tuebingen’s Kepler Centre for Astro and Particle Physics, a co-author of the paper, tells Inverse. “These stars are strange.”

Even among the ultra-hot white dwarfs known by the designation PG1159, the selection that cropped up in this survey lack the helium normally found in their atmosphere: instead, they’ve burned it all away, fusing it into a solar atmosphere of pure carbon and oxygen.

Jan 12, 2023

Mysterious Quantum Phenomenon Lets Us Peek Inside an Atom’s Heart

Posted by in categories: particle physics, quantum physics

Silently churning away at the heart of every atom in the Universe is a swirling wind of particles that physics yearns to understand.

No probe, no microscope, and no X-ray machine can hope to make sense of the chaotic blur of quantum cogs whirring inside an atom, leaving physicists to theorize the best they can based on the debris of high-speed collisions inside particle colliders.

Researchers now have a new tool that is already providing them with a small glimpse into the protons and neutrons that form the nuclei of atoms, one based on the entanglement of particles produced as gold atoms brush past each other at speed.

Jan 12, 2023

Quantum superposition begs us to ask, “What is real?”

Posted by in categories: particle physics, quantum physics, space

The world of the very, very small is a wonderland of strangeness. Molecules, atoms, and their constituent particles did not readily reveal their secrets to the scientists that wrestled with the physics of atoms in the early 20th century. Drama, frustration, anger, puzzlement, and nervous breakdowns abounded, and it is hard for us now, a full century later, to understand what was at stake. What happened was a continuous process of worldview demolition. You might have to give up believing everything you thought to be true about something. In the case of the quantum physics pioneers, that meant changing their understanding about the rules that dictate how matter behaves.

In 1913, Bohr devised a model for the atom that looked somewhat like a solar system in miniature. Electrons moved around the atomic nucleus in circular orbits. Bohr added a few twists to his model — twists that gave them a set of weird and mysterious properties. The twists were necessary for Bohr’s model to have explanatory power — that is, for it to be able to describe the results of experimental measurements. For example, electrons’ orbits were fixed like railroad tracks around the nucleus. The electron could not be in between orbits, otherwise it could fall into the nucleus. Once it got to the lowest rung in the orbital ladder, an electron stayed there unless it jumped to a higher orbit.

Clarity about why this happened started to come with de Broglie’s idea that electrons can be seen both as particles and waves. This wave-particle duality of light and matter was startling, and Heisenberg’s uncertainty principle gave it precision. The more precisely you localize the particle, the less precisely you know how fast it moves. Heisenberg had his own theory of quantum mechanics, a complex device to compute the possible outcomes of experiments. It was beautiful but extremely hard to calculate things with.

Jan 12, 2023

Scientists See Quantum Interference between Different Kinds of Particles for First Time

Posted by in categories: particle physics, quantum physics

In a first, physicists have now found interference between two dissimilar subatomic particles. Researchers made the observation at the Relativistic Heavy Ion Collider (RHIC), a colossal particle accelerator at Long Island’s Brookhaven National Laboratory. The finding broadens the way we understand entanglement and offers new opportunities to use it to study the subatomic world.

“With this new technique, we are able to measure the size and shape of the nucleus to about a tenth of a femtometer, a tenth of the size of an individual proton,” says James Daniel Brandenburg, a physicist at the Ohio State University and a member of RHIC’s STAR experiment, where the new phenomenon was seen. That’s 10 to 100 times more precise than previous measurements of high-energy atomic nuclei.

RHIC is designed to collide heavy ions, such as the nuclei of gold atoms. In this case, though, researchers were interested in near misses, not collisions. As the gold nuclei zing at near light speed through the collider, they create an electromagnetic field that generates photons. When two gold nuclei come close to one another but don’t collide, the photons may ping off the neighboring nuclei. These near misses used to be considered background noise, says STAR collaborator Raghav Kunnawalkam Elayavalli, a physicist at Vanderbilt University. But looking at the close-call events “opened up a whole new field of physics that initially was not accessible,” Kunnawalkam Elayavalli says.

Jan 12, 2023

‘A perfect little system’: Physicists isolate a pair of atoms to observe p-wave interaction strength for the first time

Posted by in categories: chemistry, particle physics, quantum physics

“Suppose you knew everything there was to know about a water molecule—the chemical formula, the bond angle, etc.,” says Joseph Thywissen, a professor in the Department of Physics and a member of the Centre for Quantum Information & Quantum Control at the University of Toronto.

“You might know everything about the molecule, but still not know there are waves on the ocean, much less how to surf them,” he says. “That’s because when you put a bunch of molecules together, they behave in a way you probably cannot anticipate.”

Thywissen is describing the concept in physics known as emergence: the relationship between the behavior and characteristics of individual particles and large numbers of those particles. He and his collaborators have taken a first step in understanding this transition from “one-to-many” particles by studying not one, not many, but two isolated, interacting particles, in this case potassium atoms.