Archive for the ‘particle physics’ category: Page 2

Jan 4, 2020

Clusters of gold atoms form peculiar pyramidal shape

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

Clusters composed of a few atoms tend to be spherical. They are usually organized in shells of atoms around a central atom. This is the case for many elements, but not for gold! Experiments and advanced computations have shown that freestanding clusters of twenty gold atoms take on a pyramidal shape. They have a triangular ground plane made up of ten neatly arranged atoms, with additional triangles of six and three atoms, topped by a single atom.

The remarkable tetrahedral structure has now been imaged for the first time with a scanning tunnelling microscope. This high-tech microscope can visualise single atoms. It operates at extremely low temperatures (269 degrees below zero) and uses quantum tunnelling of an electrical current from a sharp scanning metallic tip through the cluster and into the support. Quantum tunnelling is a process where electrical current flows between two conductors without any physical contact between them.

The researchers used intense plasmas in a complex vacuum chamber setup to sputter gold atoms from a macroscopic piece of gold. “Part of the sputtered atoms grow together to small particles of a few up to a few tens of atoms, due to a process comparable with condensation of water molecules to droplets,” says Zhe Li, the main author of the paper, currently at the Harbin Institute of Technology, Shenzhen. “We selected a beam of clusters consisting of exactly twenty gold atoms. We landed these species with one of the triangular facets onto a substrate covered with a very thin layer of kitchen salt (NaCl), precisely three atom layers thick.”

The study also revealed the peculiar electronic structure of the small gold pyramid. Similar to noble gas atoms or aromatic molecules, the cluster only has completely filled electron orbitals, which makes them much less reactive than clusters with one or a few atoms more or less.

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Jan 2, 2020

There’s a Giant Mystery Hiding Inside Every Atom in the Universe

Posted by in categories: particle physics, space

No one really knows what happens inside an atom. But two competing groups of scientists think they’ve figured it out. And both are racing to prove that their own vision is correct.

Here’s what we know for sure: Electrons whiz around “orbitals” in an atom’s outer shell. Then there’s a whole lot of empty space. And then, right in the center of that space, there’s a tiny nucleus — a dense knot of protons and neutrons that give the atom most of its mass. Those protons and neutrons cluster together, bound by what’s called the strong force. And the numbers of those protons and neutrons determine whether the atom is iron or oxygen or xenon, and whether it’s radioactive or stable.

Jan 2, 2020

The Universe May Be Flooded with a Cobweb Network of Invisible Strings

Posted by in categories: particle physics, quantum physics

During one of these phase transitions (which happened when the universe was less than a second old), the axions of string theory didn’t appear as particles. Instead, they looked like loops and lines — a network of lightweight, nearly invisible strings crisscrossing the cosmos.

This hypothetical axiverse, filled with a variety of lightweight axion strings, is predicted by no other theory of physics but string theory. So, if we determine that we live in an axiverse, it would be a major boon for string theory.

How can we search for these axion strings? Models predict that axion strings have very low mass, so light won’t bump into an axion and bend, or axions likely wouldn’t mingle with other particles. There could be millions of axion strings floating through the Milky Way right now, and we wouldn’t see them.

Jan 2, 2020

Laser-heated nanowires produce micro-scale nuclear fusion

Posted by in categories: nanotechnology, nuclear energy, particle physics

Nuclear fusion, the process that powers our sun, happens when nuclear reactions between light elements produce heavier ones. It’s also happening — at a smaller scale — in a Colorado State University laboratory.

Using a compact but powerful laser to heat arrays of ordered nanowires, CSU scientists and collaborators have demonstrated micro-scale nuclear fusion in the lab. They have achieved record-setting efficiency for the generation of neutrons — chargeless sub-atomic particles resulting from the fusion process.

Their work is detailed in a paper published in Nature Communications (“Micro-scale fusion in dense relativistic nanowire array plasmas”), and is led by Jorge Rocca, University Distinguished Professor in electrical and computer engineering and physics. The paper’s first author is Alden Curtis, a CSU graduate student.

Dec 31, 2019

Physicists Just Achieved The First-Ever Quantum Teleportation Between Computer Chips

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

As 2019 winds to a close, the journey towards fully realised quantum computing continues: physicists have been able to demonstrate quantum teleportation between two computer chips for the first time.

Put simply, this breakthrough means that information was passed between the chips not by physical electronic connections, but through quantum entanglement – by linking two particles across a gap using the principles of quantum physics.

We don’t yet understand everything about quantum entanglement (it’s the same phenomenon Albert Einstein famously called “spooky action”), but being able to use it to send information between computer chips is significant, even if so far we’re confined to a tightly controlled lab environment.

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Dec 31, 2019

A day in the life of an accelerator designer

Posted by in category: particle physics

Physicist Tor Raubenheimer explores the world by climbing rocks and designing particle accelerators.

Dec 29, 2019

Molecules Found in Ginger Remodel the Microbiome

Posted by in category: particle physics

So maybe ginger is actually good for you:

Small RNA-containing particles in ginger root are found to promote the growth of beneficial bacteria and alleviate colitis in mouse guts.

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Dec 28, 2019

Researchers Teleport Information Between Two Computer Chips for the First Time

Posted by in categories: computing, internet, nanotechnology, particle physics, quantum physics

For the first time, researchers and scientists from the University of Bristol, in collaboration with the Technical University of Denmark (DTU), have achieved quantum teleportation between two computer chips. The team successfully developed chip-scale devices that are able to harness the applications of quantum physics by generating and manipulating single particles of light within programmable nano-scale circuits.

Unlike regular or science fiction teleportation which transfer particles from one place to another, with quantum teleportation, nothing physical is being transported. Rather, the information necessary to prepare a target system in the same quantum state as the source system is transmitted from one location to another, with the help of classical communication and previously shared quantum entanglement between the sending and receiving location.

In a feat that opens the door for quantum computers and quantum internet, the team managed to send information from one chip to another instantly without them being physically or electronically connected. Their work, published in the journal Nature Physics, contains a range of other quantum demonstrations. This chip-to-chip quantum teleportation was made possible by a phenomenon called quantum entanglement. The entanglement happens between two photons (two light particles) with the interaction taking place for a brief moment and the two photons sharing physical states. Quantum entanglement phenomenon is so strange that physicist Albert Einstein famously described it as ‘spooky action at a distance’.

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Dec 27, 2019

Information teleported between two computer chips for the first time

Posted by in categories: computing, internet, particle physics, quantum physics

Scientists at the University of Bristol and the Technical University of Denmark have achieved quantum teleportation between two computer chips for the first time. The team managed to send information from one chip to another instantly without them being physically or electronically connected, in a feat that opens the door for quantum computers and quantum internet.

This kind of teleportation is made possible by a phenomenon called quantum entanglement, where two particles become so entwined with each other that they can “communicate” over long distances. Changing the properties of one particle will cause the other to instantly change too, no matter how much space separates the two of them. In essence, information is being teleported between them.

Hypothetically, there’s no limit to the distance over which quantum teleportation can operate – and that raises some strange implications that puzzled even Einstein himself. Our current understanding of physics says that nothing can travel faster than the speed of light, and yet, with quantum teleportation, information appears to break that speed limit. Einstein dubbed it “spooky action at a distance.”

Dec 27, 2019

Viewpoint: Shooting Ahead with Wakefield Acceleration

Posted by in category: particle physics

A method for accelerating particles, called wakefield acceleration, has notched up its output energy, bringing it closer to its goal of shrinking the size of accelerator facilities.

The field of plasma wakefield acceleration is picking up speed. This method, which was first proposed in 1979 [1], creates a collective motion of plasma particles, generating an accelerating field in its wake. The amplitude of this accelerating field is not limited, as it is in conventional acceleration techniques that use radio frequency pulses. The implication is that wakefield acceleration has the potential to work over much smaller lengths, which would allow a reduction in the size (and cost) of accelerator facilities. There exist different methods for generating wakefields, and now researchers are reporting significant progress for two of these techniques. One method using laser-driven wakefields has generated 8-GeV electrons, a new energy record that doubles the previous record [2].

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