Showing posts with label Physical Review Letters Journal. Show all posts
Showing posts with label Physical Review Letters Journal. Show all posts

Tuesday, November 16

Strange Particles Called ANYONS



Researchers Show New Strategy for Detecting Non-Conformist Particles Called Anyons

By observing how strange particles called anyons dissipate heat, researchers have shown that they can probe the properties of these particles in systems that could be relevant for topological quantum computing.A team of Brown University researchers has shown a new method of probing the properties of anyons, strange quasiparticles that could be useful in future quantum computers.

In research published in the journal Physical Review Letters, the team describes a means of probing anyons by measuring subtle properties of the way in which they conduct heat. Whereas other methods probe these particles using electrical charge, this new method enables researchers to probe anyons even in non-conducting materials. That’s critical, the researchers say, because non-conducting systems have far less stringent temperature requirements, making them a more practical option for quantum computing.

“We have beautiful ways of probing anyons using charge, but the question has been how do you detect them in the insulating systems that would be useful in what’s known as topological quantum computing,” said Dima Feldman, a physics professor at Brown and study co-author. “We show that it can be done using heat conductance. Essentially, this is a universal test for anyons that works in any state of matter.”

Anyons are of interest because they don’t follow the same rules as particles in the everyday, three-dimensional world. In three dimensions, there are only two broad kinds of particles: bosons and fermions. Bosons follow what’s known as Bose-Einstein statistics, while fermions follow Fermi-Dirac statistics. 

Generally speaking, those different sets of statistical rules mean that if one boson orbits around another in a quantum system, the particle’s wave function — the equation that fully describes its quantum state — does not change. On the other hand, if a fermion orbits around another fermion, the phase value of its wave function flips from a positive integer to a negative integer. If it orbits again, the wave function returns to its original state.

Anyons, which emerge only in systems that are confined to two dimensions, don’t follow either rule. When one anyon orbits another, its wave function changes by some fraction of an integer. And another orbit does not necessarily restore the original value of the wave function. Instead, it has a new value — almost as if the particle maintains a “memory” of its interactions with the other particle even though it ended up back where it started.

That memory of past interactions can be used to encode information in a robust way, which is why the particles are interesting tools for quantum computing. Quantum computers promise to perform certain types of calculations that are virtually impossible for today’s computers. A quantum computer using anyons — known as a topological quantum computer — has the potential to operate without elaborate error correction, which is a major stumbling block in the quest for usable quantum computers.  TO READ MORE ABOUT ANYONS, CLICK HERE...

Sunday, November 14

Dark Matter Creates Dark Matter From Regular Matter


An international team of physicists is proposing an addition to dark matter theory. In their paper published in the journal Physical Review Letters, the group is suggesting that dark matter came from regular matter and that dark matter is able to create more dark matter from regular matter.

The existence of a material described as dark matter has been proposed by physicists to explain certain behaviors observed by researchers—the way light bends as it makes its way from far away places to telescopes here on Earth, is just one example. 

But some parts of the theory have yet to be worked out, such as how did the amount of dark matter believed to exist today come into being? The team on this new effort has come up with a theory to answer that question.

The theorists begin by citing prior research which suggests that some amount of dark matter was created as part of the 'thermal bath'—where primordial plasma made of regular matter begat dark matter particles—but not the amount that is believed to exist today. 

They suggest that at some point dark matter particles began making more dark matter particles out of regular particles. And the new dark matter particles were also able to create new dark matter particles out of regular particles.  READ MORE...