Archive for the ‘particle physics’ category: Page 9

Jul 26, 2021

Qubit Spin Ice: Emergent Magnetic Monopoles Isolated Using Quantum-Annealing Computer

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

Project offers new step toward study of emergence, ‘materials by design,’ and future nanomagnets.

Using a D-Wave quantum-annealing computer as a testbed, scientists at Los Alamos National Laboratory have shown that it is possible to isolate so-called emergent magnetic monopoles, a class of quasiparticles, creating a new approach to developing “materials by design.”

“We wanted to study emergent magnetic monopoles by exploiting the collective dynamics of qubits,” said Cristiano Nisoli, a lead Los Alamos author of the study. “Magnetic monopoles, as elementary particles with only one magnetic pole, have been hypothesized by many, and famously by Dirac, but have proved elusive so far.”

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Jul 25, 2021

Nanocatalytic Spontaneous Ignition and Self-Supporting Room-Temperature Combustion

Posted by in categories: nanotechnology, particle physics

Circa 2005 o,.o.

Stable and reproducible spontaneous self-ignition and self-supporting combustion have been achieved at room temperature by exposing nanometer-sized catalytic particles to methanol/air or ethanol/air gas mixtures. Without any external ignition, structurally supported platinum nanoparticles instantaneously react with the gas mixtures. The reaction releases heat and produces CO2 and water. Such reactions starting at ambient temperature have reached both high (]600 °C) and low (a few tenths of a degree above room temperature) reaction temperatures. The reaction is controlled by varying the fuel/air mixture. Catalytic activity could be dramatically changed by reducing particle size and changing particle morphology.

Jul 25, 2021

Remarkable Photo of a Single Atom Wins Science Photography Contest

Posted by in categories: particle physics, science

Ever wonder what an atom looks like?

A remarkable photography of a single atom by Ph.D. student David Nadlinger has won the EPSRC science photography contest. The atom photo was captured using a long exposure while the atom emitted light from a laser in a vacuum chamber.

Jul 24, 2021

Visualization of gaseous iodine adsorption on single zeolitic imidazolate framework-90 particles

Posted by in category: particle physics

Zeolitic imidazolate frameworks are promising as high-capacity iodine adsorbents. Here the authors image the gaseous I2 adsorption on single ZIF-90 particles, clarifying the inter-particle heterogeneity in adsorption reactivity and performance improvement after introduction of linker defects.

Jul 24, 2021

Quantum control of a nanoparticle optically levitated in cryogenic free space

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

Quantum control of an optically levitated nanoparticle with a mass of just one femtogram is demonstrated in a cryogenic environment by feedback-cooling the motion of the particle to the quantum ground state.

Jul 23, 2021

Physicists Show That a Quantum Particle Made of Light and Matter Can Be Dragged by a Current of Electrons

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

A pair of studies in Nature show that a quasiparticle, known as a plasmon polariton, can be pulled with and against a flow of electrons, a finding that could lead to more efficient ways of manipulating light at the nanoscale.

Jul 23, 2021

Antimatter from laser pincers

Posted by in categories: cosmology, particle physics

In the depths of space, there are celestial bodies where extreme conditions prevail: Rapidly rotating neutron stars generate super-strong magnetic fields. And black holes, with their enormous gravitational pull, can cause huge, energetic jets of matter to shoot out into space. An international physics team with the participation of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has now proposed a new concept that could allow some of these extreme processes to be studied in the laboratory in the future: A special setup of two high-intensity laser beams could create conditions similar to those found near neutron stars. In the discovered process, an antimatter jet is generated and accelerated very efficiently. The experts present their concept in the journal Communications Physics.

The basis of the new concept is a tiny block of plastic, crisscrossed by micrometer-fine channels. It acts as a target for two lasers. These simultaneously fire ultra-strong pulses at the block, one from the right, the other from the left — the block is literally taken by laser pincers. “When the laser pulses penetrate the sample, each of them accelerates a cloud of extremely fast electrons,” explains HZDR physicist Toma Toncian. “These two electron clouds then race toward each other with full force, interacting with the laser propagating in the opposite direction.” The following collision is so violent that it produces an extremely large number of gamma quanta — light particles with an energy even higher than that of X-rays.

The swarm of gamma quanta is so dense that the light particles inevitably collide with each other. And then something crazy happens: According to Einstein’s famous formula E=mc2, light energy can transform into matter. In this case, mainly electron-positron pairs should be created. Positrons are the antiparticles of electrons. What makes this process special is that “very strong magnetic fields accompany it,” describes project leader Alexey Arefiev, a physicist at the University of California at San Diego. “These magnetic fields can focus the positrons into a beam and accelerate them strongly.” In numbers: Over a distance of just 50 micrometers, the particles should reach an energy of one gigaelectronvolt (GeV) — a size that usually requires a full-grown particle accelerator.

Jul 23, 2021

Can consciousness be explained by quantum physics? Research is closer to finding out

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

One of the most important open questions in science is how our consciousness is established. In the 1990s, long before winning the 2020 Nobel Prize in Physics for his prediction of black holes, physicist Roger Penrose teamed up with anaesthesiologist Stuart Hameroff to propose an ambitious answer.

They claimed that the brain’s neuronal system forms an intricate network and that the consciousness this produces should obey the rules of quantum mechanics —the theory that determines how tiny particles like electrons move around. This, they argue, could explain the mysterious complexity of human consciousness.

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Jul 20, 2021

Revealing a Pauli Crystal

Posted by in categories: particle physics, quantum physics

A novel, high-resolution fluorescence imaging technique reveals a pattern, known as a Pauli crystal, that can emerge in a cloud of trapped, noninteracting fermions.

Bring two particles together and, in general, they will interact. For example, two electrons will repel each other through electrostatic forces, or two atoms may form a molecule through electrostatic and van der Waals forces. Noninteracting particles, however, can also affect another’s behavior in a way that depends on the spin of both particles. In particular, fermionic particles, which have half-integer spin, obey the Pauli exclusion principle, which states that two fermions can never occupy the same quantum state. Two electrons in an atom, for instance, can never occupy the same quantum state. As a result, noninteracting particles can form self-organized structures. However, these structures, called Pauli crystals, have not been previously observed. Now using ultracold atoms, Marvin Holten from the University of Heidelberg, Germany, and colleagues have experimentally realized and imaged a Pauli crystal [1].

Jul 20, 2021

New Protein Folding AI Just Made a ‘Once In a Generation’ Advance in Biology

Posted by in categories: biological, information science, mapping, particle physics, robotics/AI

The tool next examines how one protein’s amino acids interact with another within the same protein, for example, by examining the distance between two distant building blocks. It’s like looking at your hands and feet fully stretched out, versus in a backbend measuring the distance between those extremities as you “fold” into a yoga pose.

Finally, the third track looks at 3D coordinates of each atom that makes up a protein building block—kind of like mapping the studs on a Lego block—to compile the final 3D structure. The network then bounces back and forth between these tracks, so that one output can update another track.

The end results came close to those of DeepMind’s tool, AlphaFold2, which matched the gold standard of structures obtained from experiments. Although RoseTTAFold wasn’t as accurate as AlphaFold2, it seemingly required much less time and energy. For a simple protein, the algorithm was able to solve the structure using a gaming computer in about 10 minutes.

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