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Archive for the ‘particle physics’ category: Page 495

Aug 28, 2018

Scientists observe decay of Higgs boson particle into two bottom quarks

Posted by in category: particle physics

Aug. 28 (UPI) — Particle physicists have finally witnessed the decay of a Higgs boson particle into two bottom quarks.

Models predict Higgs boson particles decay into two bottom quarks 60 percent of the time. Bottom quarks, or b quarks, are the second heaviest of the six types of quarks.

Scientists have struggled to directly observe the predicted decay. Several types of proton-proton collisions can produce bottom quarks, making it difficult to link quarks produced by particle collisions with decaying Higgs boson particles.

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Aug 24, 2018

Research team finds evidence of matter-matter coupling

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

After their recent pioneering experiments to couple light and matter to an extreme degree, Rice University scientists decided to look for a similar effect in matter alone. They didn’t expect to find it so soon.

Rice physicist Junichiro Kono, graduate student Xinwei Li and their international colleagues have discovered the first example of Dicke cooperativity in a matter-matter system, a result reported in Science this week.

The discovery could help advance the understanding of spintronics and , Kono said. On the spintronics side, he said the work will lead to faster information processing with lower power consumption and will contribute to the development of spin-based quantum computing. The team’s findings on quantum magnetism will lead to a deeper understanding of the phases of matter induced by many-body interactions at the atomic scale.

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Aug 24, 2018

Pushing the plasma density limit

Posted by in categories: nuclear energy, particle physics

For decades, researchers have been exploring ways to replicate on Earth the physical process of fusion that occurs naturally in the sun and other stars. Confined by its own strong gravitational field, the sun’s burning plasma is a sphere of fusing particles, producing the heat and light that makes life possible on earth. But the path to a creating a commercially viable fusion reactor, which would provide the world with a virtually endless source of clean energy, is filled with challenges.

Researchers have focused on the tokamak, a device that heats and confines turbulent plasma fuel in a donut-shaped chamber long enough to create fusion. Because plasma responds to magnetic fields, the torus is wrapped in magnets, which guide the fusing plasma particles around the toroidal chamber and away from the walls. Tokamaks have been able to sustain these reactions only in short pulses. To be a practical source of energy, they will need to operate in a steady state, around the clock.

Researchers at MIT’s Plasma Science and Fusion Center (PSFC) have now demonstrated how microwaves can be used to overcome barriers to steady-state tokamak operation. In experiments performed on MIT’s Alcator C-Mod tokamak before it ended operation in September 2016, research scientist Seung Gyou Baek and his colleagues studied a method of driving current to heat the plasma called Lower Hybrid Current Drive (LHCD). The technique generates plasma current by launching microwaves into the tokamak, pushing the electrons in one direction—a prerequisite for steady-state operation.

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Aug 22, 2018

Ancient Starlight Just Helped Confirm the Reality of Quantum Entanglement

Posted by in categories: particle physics, quantum physics

Quantum entanglement is the theory that particles can be connected in such a way that measuring one particle can instantaneously convey information about that measurement to the other particle, regardless of the distance between them. It almost sounds like magic, which is probably why it received a healthy dose of criticism from the physics community when the theory was first proposed nearly 100 years ago.

Albert Einstein was a particularly vocal critic of entanglement, which he famously described as “spooky action at a distance.” Part of Einstein’s beef with the quantum mechanics crowd was that he believed that particles have definite qualities that exist before they are measured and that two particles distant in space and time can’t affect one another instantaneously since they are limited by the speed of light—a viewpoint known as local realism.

Under quantum mechanics, however, the properties of a particle don’t exist independently of measurement used to determine those properties. Moreover, when it comes to entangled particles, the measurement of one particle will instantaneously influence the properties of the other entangled particle. This means that the values of these properties will be highly correlated—so highly correlated, in fact, that the degree of coincidence in their values can’t really be explained without recourse to quantum mechanics.

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Aug 20, 2018

Light from ancient quasars helps confirm quantum entanglement

Posted by in categories: particle physics, quantum physics

Last year, physicists at MIT, the University of Vienna, and elsewhere provided strong support for quantum entanglement, the seemingly far-out idea that two particles, no matter how distant from each other in space and time, can be inextricably linked, in a way that defies the rules of classical physics.

Take, for instance, two particles sitting on opposite edges of the universe. If they are truly entangled, then according to the theory of quantum mechanics their physical properties should be related in such a way that any measurement made on one particle should instantly convey information about any future measurement outcome of the other particle—correlations that Einstein skeptically saw as “spooky action at a distance.”

In the 1960s, the physicist John Bell calculated a theoretical limit beyond which such correlations must have a quantum, rather than a classical, explanation.

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Aug 18, 2018

A group of physicists are questioning our understanding of how quarks — a type of elementary particle — arrange themselves under extreme conditions

Posted by in category: particle physics

A group of physicists are questioning our understanding of how quarks — a type of elementary particle — arrange themselves under extreme conditions. And their quest is revealing that elements beyond the edge of the periodic table might be fair weirder than we thought.

Deep in the depths of the periodic table there are monsters made of a unique arrangement of subatomic particles. As far as elements go, they come no bigger than oganesson – a behemoth that contains 118 protons and has an atomic mass of just under 300.

That’s not to say protons and neutrons can’t be arranged into even bigger clumps and still remain somewhat stable for longer than an eye blink. But for all practical purposes, nobody has discovered it yet.

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Aug 18, 2018

Researchers Build Quantum Transistor Using a Single Atom

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

The sub-microscopic switch can also operate at room temperature, marking a major breakthrough.

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Aug 15, 2018

This one particle could solve five mega-mysteries of physics

Posted by in categories: cosmology, particle physics

Forget the Higgs: theorists have uncovered a missing link that explains dark matter, what happened in the big bang and more. Now they’re racing to find it.

By Michael Brooks

911? It’s an emergency. The most important particle in the universe is missing. Florian Goertz knows this isn’t a case for the police, but he is still waiting impatiently for a response. This 911 isn’t a phone number, but a building on the northern edge of the world’s biggest particle accelerator.

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Aug 15, 2018

Researchers suggest phonons may have mass and perhaps negative gravity

Posted by in categories: mathematics, particle physics

A trio of physicists with Columbia University is making waves with a new theory about phonons—they suggest they might have negative mass, and because of that, have negative gravity. Angelo Esposito, Rafael Krichevsky and Alberto Nicolis have written a paper to support their theory, including the math, and have uploaded it to the xrXiv preprint server.

Most theories depict waves as more of a collective event than as physical things. They are seen as the movement of molecules bumping against each other like balls on a pool table—the energy of one ball knocking the next, and so on—any motion in one direction is offset by motion in the opposite direction. In such a model, sound has no mass, and thus cannot be impacted by . But there may be more to the story. In their paper, the researchers suggest that the current theory does not fully explain everything that has been observed.

In recent years, physicists have come up with a word to describe the behavior of at a very small scale—the phonon. It describes the way sound vibrations cause complicated interactions with molecules, which allows the sound to propagate. The term has been useful because it allows for applying principles to sound that have previously been applied to actual particles. But no one has suggested that they actually are particles, which means they should not have mass. In this new effort, the researchers suggest the phonon could have negative , and because of that, could also have negative gravity.

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Aug 14, 2018

Researcher accurately determines energy difference between two quantum states

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

A kiwi physicist has discovered the energy difference between two quantum states in the helium atom with unprecedented accuracy, a ground-breaking discovery that contributes to our understanding of the universe and space-time and rivals the work of the world’s most expensive physics project, the Large Hadron Collider.

Our understanding of the universe and the forces that govern it relies on the Standard Model of particle physics. This model helps us understand space-time and the fundamental forces that hold everything in the universe in place. It is the most accurate scientific theory known to humankind.

But the Standard Model does not fully explain everything, for example it doesn’t explain gravity, dark matter, dark energy, or the fact that there is way more matter than antimatter in the universe.

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