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Category: particle physics – Page 555

In 1935, when both quantum mechanics and Albert Einstein’s general theory of relativity were young, a little-known Soviet physicist named Matvei Bronstein, just 28 himself, made the first detailed study of the problem of reconciling the two in a quantum theory of gravity. This “possible theory of the world as a whole,” as Bronstein called it, would supplant Einstein’s classical description of gravity, which casts it as curves in the space-time continuum, and rewrite it in the same quantum language as the rest of physics.

Bronstein figured out how to describe gravity in terms of quantized particles, now called gravitons, but only when the force of gravity is weak — that is (in general relativity), when the space-time fabric is so weakly curved that it can be approximated as flat. When gravity is strong, “the situation is quite different,” he wrote. “Without a deep revision of classical notions, it seems hardly possible to extend the quantum theory of gravity also to this domain.”

His words were prophetic. Eighty-three years later, physicists are still trying to understand how space-time curvature emerges on macroscopic scales from a more fundamental, presumably quantum picture of gravity; it’s arguably the deepest question in physics. Perhaps, given the chance, the whip-smart Bronstein might have helped to speed things along. Aside from quantum gravity, he contributed to astrophysics and cosmology, semiconductor theory, and quantum electrodynamics, and he also wrote several science books for children, before being caught up in Stalin’s Great Purge and executed in 1938, at the age of 31.

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March 2 (UPI) — Forty years after scientists first theoretically predicted the existence of a three-dimensional skyrmion, scientists have observed the particle in the lab.

The particle, observed cold quantum gas, isn’t a normal particle composed of electrons, protons and electrons. It is a quantum particle, the energy signature created by the interactions between a particle and the surrounding system.

In this instance, the quantum particle is a tangled knot of magnetic moments in the quantum gas.

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Scientists at Amherst College and Aalto University have created, for the first time a three-dimensional skyrmion in a quantum gas. The skyrmion was predicted theoretically over 40 years ago, but only now has it been observed experimentally.

In an extremely sparse and cold , the physicists have created knots made of the magnetic moments, or spins, of the constituent atoms. The knots exhibit many of the characteristics of , which some scientists believe to consist of tangled streams of . The persistence of such knots could be the reason why ball lightning, a ball of plasma, lives for a surprisingly long time in comparison to a lightning strike. The new results could inspire new ways of keeping plasma intact in a stable ball in fusion reactors.

‘It is remarkable that we could create the synthetic electromagnetic knot, that is, quantum ball lightning, essentially with just two counter-circulating electric currents. Thus, it may be possible that a natural ball lighting could arise in a normal ,’ says Dr Mikko Möttönen, leader of the theoretical effort at Aalto University.

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Scientists create ‘quantum ball lightning’ in the lab in breakthrough that could pave the way for stable fusion reactors…

In the new research, led by scientists at Amherst College and Aalto University, the team created a three-dimensional skyrmion in an extremely cold quantum gas.

The three-dimensional particle consists of knots made from the spin fields of a Bose-Einstein condensate – or, atoms cooled to a point just above absolute zero.

According to the researchers, this bizarre tangle may share some of the characteristics of ball lightning.

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A team of astronomers led by Prof. Judd Bowman of Arizona State University unexpectedly stumbled upon “dark matter,” the most mysterious building block of outer space, while attempting to detect the earliest stars in the universe through radio wave signals, according to a study published this week in Nature.

The idea that these signals implicate dark matter is based on a second Nature paper published this week, by Prof. Rennan Barkana of Tel Aviv University, which suggests that the signal is proof of interactions between normal matter and dark matter in the early universe. According to Prof. Barkana, the discovery offers the first direct proof that dark matter exists and that it is composed of low-mass particles.

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What is inside an atom between the nucleus and the electron? Usually there is nothing, but why could there not be other particles too? If the electron orbits the nucleus at a great distance, there is plenty of space in between for other atoms. A “giant atom” could be created, filled with ordinary atoms. All these atoms form a weak bond, creating a new, exotic state of matter at cold temperatures, referred to as Rydberg polarons.

A team of researchers has now presented this state of matter in the journal Physical Review Letters. The theoretical work was done at TU Wien (Vienna) and Harvard University, the experiment was performed at Rice University in Houston (Texas).

Two special fields of atomic physics, which can only be studied in extreme conditions, have been combined in this research project: Bose-Einstein condensates and Rydberg atoms. A Bose-Einstein condensate is a state of matter created by atoms at ultracold temperatures, close to absolute zero. Rydberg atoms are those in which one single electron is lifted into a highly excited state and orbits the nucleus at a very large distance.

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Black holes don’t just sit there munching away constantly on the space around them. Eventually they run out of nearby matter and go quiet, lying in wait until a stray bit of gas passes by.

Then a black hole devours again, belching out a giant jet of particles. And now scientists have captured one doing so not once, but twice — the first time this has been observed.

The two burps, occurring within the span of 100,000 years, confirm that supermassive black holes go through cycles of hibernation and activity.

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Antimatter is notoriously tricky to store and study, thanks to the fact that it will vanish in a burst of energy if it so much as touches regular matter. The CERN lab is one of the only places in the world that can readily produce the stuff, but getting it into the hands of the scientists who want to study it is another matter (pun not intended). After all, how can you transport something that will annihilate any physical container you place it in? Now, CERN researchers are planning to trap and truck antimatter from one facility to another.

Antimatter is basically the evil twin of normal matter. Each antimatter particle is identical to its ordinary counterpart in almost every way, except it carries the opposite charge, leading the two to destroy each other if they come into contact. Neutron stars and jets of plasma from black holes may be natural sources, and it even seems to be formed in the Earth’s atmosphere with every bolt of lightning.

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Oganesson (Og) is the heaviest chemical element in the periodic table, but its properties have proved difficult to measure since it was first synthesised in 2002.

Now an advanced computer simulation has filled in some of the gaps, and it turns out the element is even weirder than many expected.

At the atomic level, oganesson behaves remarkably differently to lighter elements in several key ways – and that could provide some fundamental insights into the basics of how these superheavy elements work.

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