by Staff Writers
Barcelona, Spain (SPX) Sep 23, 2020
While in a three-dimensional world, all particles must be either fermions or bosons, it is known that in fewer dimensions, the existence of particles with intermediate quantum statistics, known as anyons, is possible. Such fascinating objects are strongly believed to exist as emerging quasiparticles in fractional quantum Hall systems, but despite great efforts, experimental evidence of anyons has remained very limited.
Since quantum statistics is defined through the behavior of the phase of the wave function, when two identical particles are exchanged, early attempts of anyon detection have been based on interferometric measurements using Fabry-Perot interferometry or beamsplitter experiments.
So far, there have been many efforts to improve the experimental evidence of anyons by searching for ways to study the FQH effect and understand its underlying physics in highly controllable quantum systems such as cold atoms or photonic quantum simulators.
There are studies that have shown that light-matter interactions can create and trap fractional quasiparticles in atomic gases or electronic systems and measure, through time-of-light imaging, signatures of fractional statistics carried by the total angular momentum of a fractional quantum Hall system.
In a recent study published in Physical Review Letters, ICFO researchers Tobias Grass, Niccolo Baldelli, and Utso Bhattacharya, led by ICREA Prof. at ICFO Maciej Lewenstein, and in collaboration with Bruno Julia-Diaz, from the University of Barcelona, describe a new approach towards anyon detection, which is a crucial element for increasing our knowledge of exotic quantum matter.
Contrary to earlier detection schemes, the study authored by the researchers opens up a new possibility which requires neither particle exchange nor interferometry. Instead, the authors suggest to trace the behavior of the anyons by binding impurity particles to them. Specifically, the average angular momentum of a single impurity is shown to take characteristic values that are possibly fractional.
For a system of multiple impurities, the total angular momentum should then depend on how these effective single-impurity levels are filled. Strikingly, the value obtained by the authors corresponds neither to the filling of a Fermi sea nor to the condensation of a bosonic mode. Instead, the impurity angular momentum interpolates between these limiting cases, and the fractional statistical parameter of the anyons can be straightaway inferred from this interpolation.
Their detection scheme only requires density measurements and might be applicable to Abelian quantum Hall phases in electronic materials as well as in photonic or atomic quantum simulators.
The authors discuss also possible generalizations towards non-Abelian anyons. Since the impurities realize a non-interacting gas of anyons, their work also poses the possibility of studying the intricate thermodynamics of anyonic systems.
Why there is no speed limit in the superfluid universe
Lancaster UK (SPX) Sep 22, 2020
Physicists from Lancaster University have established why objects moving through superfluid helium-3 lack a speed limit in a continuation of earlier Lancaster research. Helium-3 is a rare isotope of helium, in which one neutron is missing. It becomes superfluid at extremely low temperatures, enabling unusual properties such as a lack of friction for moving objects. It was thought that the speed of objects moving through superfluid helium-3 was fundamentally limited to the critical Landau v ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2021 - 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.|