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Category: particle physics

Exotic physics can happen when quantum particles come together and talk to each other. Understanding such processes is challenging for scientists, because the particle interactions can be hard to glimpse and even harder to control. Moreover, modern computer simulations struggle to make sense of all the intricate dynamics going on in a large group of particles. Luckily, atoms cooled to near zero temperatures can provide insight into this problem.

Lasers can make mimic the physics seen in other systems—an approach that is familiar terrain for atomic physicists. They regularly use intersecting laser beams to capture atoms in a landscape of rolling hills and valleys called an optical lattice. Atoms, when cooled, don’t have enough energy to walk up the hills, and they get stuck in the valleys. In this environment, the atoms behave similarly to the electrons in the crystal structure of many solids, so this approach provides a straightforward way to learn about interactions inside real materials.

But the conventional way to make optical lattices has some limitations. The wavelength of the laser light determines the location of the hills and valleys, and so the distance between neighboring valleys—and with that the spacing between atoms—can only be shrunk to half of the light’s wavelength. Bringing atoms closer than this limit could activate much stronger interactions between them and reveal effects that otherwise remain in the dark.

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Researchers at Colorado State University (CSU) have broken the efficiency record for nuclear fusion on the micro-scale. Using an ultra-fast, high-powered tabletop laser, the team’s results were about 500 times more efficient than previous experiments. The key to that success is the target material: instead of a flat piece of polymer, the researchers blasted arrays of nanowires to create incredibly hot, dense plasmas.

We have nuclear fusion to thank for our very existence – without it, the Sun wouldn’t have fired up in the first place. Inside that inferno, hydrogen atoms are crushed and through a series of chain reactions, eventually form helium. In the process, tremendous amounts of energy are released. Theoretically, if we can harness that phenomenon we could produce an essentially unlimited supply of clean energy, and although breakthroughs have been made in recent years, nuclear fusion energy remains tantalizingly out of reach.

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You probably scratched your head last year if you read about time crystals, likely 2017’s most esoteric, widely covered popular science story. Even if you understood how they worked, you might not have known what use they could have. Time crystals, systems of atoms that maintain a periodic ticking behavior in the presence of an added electromagnetic pulse, have now piqued the interest of one well-funded government agency: the Department of Defense.

The DoD’s Defense Advanced Research Projects Agency, or DARPA, announced a new program to fund research on these systems. More generally, the new DRINQS program will study exactly what its acronym stands for: “Driven and Nonequilibrium Quantum Systems.” But why?

“The applications could be for atomic clocks, where you have an ensemble of atoms you’re vibrating to extract time information,” Ale Lukaszew, program manager in DARPA’s defense sciences offices, told Gizmodo. “There might be applications related to measuring things with exquisite sensitivity in time and magnetic field domains. Not a lot of these applications are open for discussion.” In other words, time crystal-based military technology is classified.

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The European Space Agency created the world’s first thruster which allows satellites to remain in orbit for years longer than they currently do. The secret? The thruster runs on particles of air in the atmosphere.

Others have tried to improve the staying power of satellites before, but most are still limited by the amount of fuel they can carry. The new ion thruster “breathes” the rare air particles in the top of the atmosphere, allowing the satellites to remain without immediate need for refueling.

The thruster was developed by an ESA team and built by SITAEL, a private company in Italy. The air particles bounce away from satellites normally, but the thruster collects them and gives them an electric charge, after which they are ejected to provide thrust that counteracts atmospheric drag.

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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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