 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 by Staff Writers Frankfurt, Germany (SPX) Jan 18, 2019
Imagine a disc made of an insulator with a conducting edge along which a current always flows in the same direction. "This makes it impossible for a quantum particle to be impeded, because the state of flowing in the other direction simply doesn't exist," explains Bernhard Irsigler, the first author of the study. In other words: in the edge state, the current flows without resistance. This could be used, for example, to increase the stability and energy efficiency of mobile devices. Research is also being done on how to use this to construct lasers that are more efficient. In recent years, topological insulators have also been produced in ultracold quantum gases in order to better understand their behaviour. These gases result when a normal gas is cooled down to temperatures between a millionth and billionth of a degree above absolute zero. This makes ultracold quantum gases the coldest places in the universe. If an ultracold quantum gas is also produced in an optical lattice made of laser light, the gas atoms arrange themselves as regularly as in the crystal lattice of a solid. However, unlike a solid, many parameters can be varied, allowing artificial quantum states to be studied. "We like to call it a quantum simulator because this kind of system reveals many things that take place in solids. Using ultracold quantum gases in optical lattices, we can understand the basic physics of topological insulators," explains co-author Jun-Hui Zheng. A significant difference between a solid and a quantum gas, however, is that the cloud-shaped gases do not have defined edges. So how does a topological insulator in an ultracold gas decide where its edge states are? The researchers in Professor Walter Hofstetter's research group at the Institute for Theoretical Physics at Goethe University answer this question in their study. They modelled an artificial barrier between a topological isolator and a normal isolator. This represents the edge of the topological insulator along which the conducting edge state forms. "We demonstrate that the edge state is characterized through quantum correlations that could be measured in an experiment using a quantum gas microscope. Harvard University, MIT and the Max-Planck-Institute for Quantum Optics in Munich all carry out these kinds of measurements," says Hofstetter. A quantum gas microscope is an instrument with which individual atoms can be detected in experiments. "For our work, it is critical that we explicitly take into account the interaction between the particles of the quantum gas. That makes the investigation more realistic, but also much more complicated. The complex calculations could not be carried out without a supercomputer. The close collaboration with leading European scientists within the context of the DFG Research Unit 'Artificial Gauge Fields and Interacting Topological Phases in Ultracold Atoms' is also of particular importance for us," Hofstetter adds.
Brilliant glow of paint-on semiconductors comes from ornate quantum physics Atlanta GA (SPX) Jan 18, 2019 LED lights and monitors, and quality solar panels were born of a revolution in semiconductors that efficiently convert energy to light or vice versa. Now, next-generation semiconducting materials are on the horizon, and in a new study, researchers have uncovered eccentric physics behind their potential to transform lighting technology and photovoltaics yet again. Comparing the quantum properties of these emerging so-called hybrid semiconductors with those of their established predecessors is about ... read more
|
|||||||||||||
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |
del.icio.us
Digg
Reddit
Google
