Posted on 09/04/2020 5:48:07 PM PDT by LibWhacker
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Experimental evidence of quasiparticles called anyons has been found by a team of scientists at Purdue University. Electrical interference in the experiment created a pattern which the researchers called a “pyjama plot”; jumps in the interference pattern were the signature of the presence of anyons. (Purdue University image/James Nakamura)
WEST LAFAYETTE, Ind. — New experimental evidence of a collective behavior of electrons to form "quasiparticles" called "anyons" has been reported by a team of scientists at Purdue University.
Anyons have characteristics not seen in other subatomic particles, including exhibiting fractional charge and fractional statistics that maintain a "memory" of their interactions with other quasiparticles by inducing quantum mechanical phase changes.
Postdoctoral research associate James Nakamura, with assistance from research group members Shuang Liang and Geoffrey Gardner, made the discovery while working in the laboratory of professor Michael Manfra. Manfra is a Distinguished Professor of Physics and Astronomy, Purdue's Bill and Dee O'Brien Chair Professor of Physics and Astronomy, professor of electrical and computer engineering, and professor of materials engineering. Although this work might eventually turn out to be relevant to the development of a quantum computer, for now, Manfra said, it is to be considered an important step in understanding the physics of quasiparticles.
A research paper on the discovery was published in this week's Nature Physics.
Scientists at Purdue have announced new experimental evidence of a collective behavior of electrons to form "quasiparticles" called "anyons." The team was able to demonstrate this behavior by routing the electrons through a specific maze-like etched nanostructure in a nanoscale device called an interferometer. (Purdue University image/James Nakamura) Nobel Prize-winning theoretical physicist Frank Wilczek, professor of physics at MIT, gave these quasiparticles the tongue-in-cheek name "anyon" due to their strange behavior because unlike other types of particles, they can adopt “any” quantum phase when their positions are exchanged.
Before the growing evidence of anyons in 2020, physicists had categorized particles in the known world into two groups: fermions and bosons. Electrons are an example of fermions, and photons, which make up light and radio waves, are bosons. One characteristic difference between fermions and bosons is how the particles act when they are looped, or braided, around each other. Fermions respond in one straightforward way, and bosons in another expected and straightforward way.
Anyons respond as if they have a fractional charge, and even more interestingly, create a nontrivial phase change as they braid around one another. This can give the anyons a type of "memory" of their interaction.
"Anyons only exist as collective excitations of electrons under special circumstances," Manfra said. “But they do have these demonstrably cool properties including fractional charge and fractional statistics. It is funny, because you think, 'How can they have less charge than the elementary charge of an electron?' But they do."
Manfra said that when bosons or fermions are exchanged, they generate a phase factor of either plus one or minus one, respectively.
"In the case of our anyons the phase generated by braiding was 2π/3," he said. “That's different than what's been seen in nature before."
Anyons display this behavior only as collective crowds of electrons, where many electrons behave as one under very extreme and specific conditions, so they are not thought to be found isolated in nature, Nakamura said.
"Normally in the world of physics, we think about fundamental particles, such as protons and electrons, and all of the things that make up the periodic table," he said. "But we study the existence of quasiparticles, which emerge from a sea of electrons that are placed in certain extreme conditions."
Because this behavior depends on the number of times the particles are braided, or looped, around each other, they are more robust in their properties than other quantum particles. This characteristic is said to be topological because it depends on the geometry of the system and may eventually lead to much more sophisticated anyon structures that could be used to build stable, topological quantum computers.
The team was able to demonstrate this behavior by routing the electrons through a specific maze-like etched nanostructure made of gallium arsenide and aluminum gallium arsenide. This device, called an interferometer, confined the electrons to move in a two-dimensional path. The device was cooled to within one-hundredth of a degree from absolute zero (10 millikelvin), and subjected to a powerful 9-Tesla magnetic field. The electrical resistance of the interferometer generated an interference pattern which the researchers called a “pyjama plot.” Jumps in the interference pattern were the signature of the presence of anyons.
"It is definitely one of the more complex and complicated things to be done in experimental physics," Chetan Nayak, theoretical physicist at the University of California, Santa Barbara told Science News.
Nakamura said the facilities at Purdue created the environment for this discovery to happen.
"We have the technology to grow the gallium arsenide semiconductor that's needed to realize our electron system. We have the nanofabrication facilities in the Birck Nanotechnology Center to make the interferometer, the device we used in our experiments. In the physics department, we have the ability to measure ultra-low temperatures and to create strong magnetic fields." he said. "So, we have all of the necessary components that allowed us to make this discovery all here at Purdue. That's a great thing about doing research here and why we've been able to make this progress."
Manfra said the next step in the quasiparticle frontier will involve building more complicated interferometers.
"In the new interferometers we will have the ability to control the location and number of quasiparticles in the chamber," he said. "Then we will be able to change the number of quasiparticles inside the interferometer on demand and change the interference pattern as we choose.”
My favorite tranny is the Porsche PDK tranny.
Leave it to the Germans to spell clutch with a k.
The universe is not only stranger than we imagine, it is stranger than we can imagine.
B. S. Haldane
The above is a variant of Haldane’s original: “The Universe is not only queerer than we suppose, but queerer than we can suppose.” I always thought this was either Einstein or Arthur Eddington.
Wow, what a coincidence....Following our softball game yesterday, a few of us were sitting around enjoying a couple of beers when that very topic came up........Weird....
You were a math major?
I never made it past math corporal.
I guess I have to salute you.
Well, my point is, (and don’t get the idea that I know what I am talking about), is that there is a finite number of binary synapses in the human brain. Even if you connect all the human brains, there is still a limit. God’s reality is FAR more complex that what we CAN comprehend, even if all synapses are firing productively. This is not a criticism of humans, it is recognition of the magnificence of God.
It’s funny. No matter how deep we delve, there is always something there that is more complicated. The complication always seems to expand faster than the understanding. Turtles all the way down....
Sure, we had this in the fifth grade, Kentucky in 1949... It's cake...
Fortunately, we appear to be on this journey eternally; so it’s going to be a pretty long, fun ride.
I had a hard lol at that one.
Some people don’t believe that ‘Mind’ is a product of nuts-and-bolts ‘Brain’, at all. They believe that there is only one Mind; and individual brains are just receivers of it.
It’s possible that some have more finely-tuned ‘receivers’ than others do - and that may be due to other influences than just material ones.
Have a great Labor Day everyone!!!
Nah, think of everything as a bunch of waves interacting with each other. The anyons are like generating “rogue waves”, peaks that “pop up” out of “nowhere”. Note that the article didn’t say anything about a different interpretation of quantum field theory, a newly found expression of it. These guys would never have released the results if the math didn’t check out.
Supposedly the hole rest of everything is made up of waves, E=MC**2.
Anyway, thats how I think about while sitting back and drinking a beer ;-)
Balderdash! How do they know what we actually thought?
Well, nowadays, a lot of people think - and believe - a lot of pretty strange stuff.
So maybe you’re correct :-)
“there is always something there that is more complicated”
and that beckons for more billions of dollars for a new particle accelerator.
maybe someday the scientists will figure it all out.
but then again, perhaps not:
Don’t salute me! Anybody can do what I did. All you have to do is WORK YOUR BOOTY OFF! And the more cartoons you watched as a child, the harder you have to work to get rid of those cartoonish misconceptions the boob tube bombarded you with and pounded into your brain. Same as today when it comes to watching the lamestream media, lol. Some things never change.
Sorry about the math corporal. It was doomed to failure from the very start. One has to wonder how many Gausses and Eulers and Newtons, etc., were turned off to math forever by it, never to give it another look.
That wasn’t Heisenberg; it was JBS Haldane.
Those quantum physicists all look the same to me...
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