Through simple system studies, researchers are unearthing a new quantum state of matter

Nov 21, 2011

Researchers at the University of Pittsburgh have made advances in better understanding correlated quantum matter that could change technology as we know it, according to a study published in the Nov. 20 edition of Nature.

W. Vincent Liu, associate professor of physics in Pitt's Department of Physics and Astronomy, in with researchers from the University of Maryland and the University of Hamburg in England, has been studying topological states in order to advance computing, a method that harnesses the power of atoms and molecules for computational tasks. Through his research, Liu and his team have been studying orbital and nano-Kelvin cold atoms in optical lattices (a set of lasers) to better understand new quantum states of matter.

From that research, a surprising topological semimetal has emerged.

"We never expected a result like this based on previous studies," said Liu. "We were surprised to find that such a simple system could reveal itself as a new type of topological state—an insulator that shares the same properties as a quantum Hall state in solid materials."

Since the discovery of the quantum Hall effect by Klaus Van Klitzing in 1985, researchers like Liu have been particularly interested in studying topological states of matter, that is, properties of space unchanged under continuous deformations or distortions such as bending and stretching. The quantum Hall effect proved that when a magnetic field is applied perpendicular to the direction a current is flowing through a metal, a voltage is developed in the third perpendicular direction. Liu's work has yielded similar yet remarkably different results.

"This new is very reminiscent of quantum Hall edge states," said Liu. "It shares the same surface appearance, but the mechanism is entirely different: This Hall-like state is driven by interaction, not by an applied magnetic field."

Liu and his collaborators have come up with a specific experimental design of optical lattices and tested the topological semimetal state by loading very onto this "checkerboard" lattice. Generally, these tests result in two or more domains with opposite orbital currents; therefore the angular momentum remains at zero. However, in Liu's study, the atoms formed global rotations, which broke time-reversal symmetry: The momentum was higher, and the currents were not opposite.

"By studying these orbital degrees of freedom, we were able to discover liquid matter that had no origins within solid-state electronic materials," said Liu.

Liu says this liquid matter could potentially lead toward topological quantum computers and new quantum devices for topological quantum telecommunication. Next, he and his team plan to measure quantities for a cold-atom system to check these predicted quantum-like properties.

Explore further: Physicists discuss quantum pigeonhole principle

Provided by University of Pittsburgh

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User comments : 8

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axemaster
not rated yet Nov 21, 2011
Wow, this article was almost impossible to understand, and I've done experiments with the Hall effect before. Are there any editors who look at this stuff before it goes out?
Going
not rated yet Nov 21, 2011
University of Hamburg in England?
thermodynamics
not rated yet Nov 21, 2011
The reason this is not understandable is that it is very poorly written. For instance they say: "The quantum Hall effect proved that when a magnetic field is applied perpendicular to the direction a current is flowing through a metal, a voltage is developed in the third perpendicular direction." That is just the Hall effect. The quantum portion of it is that the current produced is quantized (specific values) under low temperature quantum conditions. They continue to chop parts of sentences out without adding all of the content. No wonder it is hard to follow.
Drumsk8
not rated yet Nov 21, 2011
University of Hamburg is GERMANY moron writers!
rah
1 / 5 (1) Nov 21, 2011
I understand ya! This article quantum show entirely shifted unexplained. So for the first time, it can be shown (redacted)Hall effect was produced in a nano quantum entangled state without the need for any rare earth magnets or funding evaporating said Professor Liu change physics! more Tsingtao?
Angus_P__Magilicutty
not rated yet Nov 21, 2011
I agree with the above. This sounds potentially important, but isn't there diagrams or analogies or SOMETHING that could illustrate the points made here better than this?
bugmenot23
5 / 5 (2) Nov 22, 2011
Original press release @ http://www.news.p...mPhysics

NBF article @ http://nextbigfut...-of.html
Nerdyguy
not rated yet Nov 22, 2011
I understand ya! This article quantum show entirely shifted unexplained. So for the first time, it can be shown (redacted)Hall effect was produced in a nano quantum entangled state without the need for any rare earth magnets or funding evaporating said Professor Liu change physics! more Tsingtao?


More Tsingtao?" haha

And I've got a feeling that the "original" press release bugmenot23 posted has just been updated at Pitt's site after numerous complaints about how bad it was. Hard to believe they got Hamburg wrong. Given that the researchers are working together. Oh, well, maybe it was written by an English major, lol.