Some people like company. Others prefer to be alone. The same holds true for the particles that constitute the matter around us: Some, called bosons, like to act in unison with others. Others, called fermions, have a mind of their own.
Different as they are, both species can show "collective" behavior -- an effect similar to the wave at a baseball game, where all spectators carry out the same motion regardless of whether they like each other.
Scientists generally believed that such collective behavior, while commonplace for bosons, only appeared in fermions moving in unison at very long wavelengths. Now, however, collective behavior has been discovered at short wavelengths in one Fermi system, helium-3.
A team led by Professor Eckhard Krotscheck -- a physicist who recently joined the University at Buffalo from the Johannes Kepler University in Linz, Austria -- predicted the existence of the behavior using theoretical tools. Independently, but practically at the same time, a French team observed the collective behavior.
A paper detailing both the theoretical and experimental discoveries appears today in the journal Nature.
Krotscheck said the scientists' success in developing accurate theoretical predictions lay, in part, in the fact that they focused on mathematical tools instead of trying to reproduce experiments.
"Knowing how nature ticks at a microscopic scale, we set out to develop a robust theory that was capable of dealing with a wide range of situations and systems," Krotscheck said. "We demanded that our mathematical description is accurate for both fermions and bosons, in different dimensions, and for both coherent and incoherent excitations. Only after we were done, we looked at experiments."
Krotscheck's colleagues on the study include Henri Godfrin, Matthias Meschke and Ahmad Sultan of the Institut NÃ©el, CNRS, and UniversitÃ© Joseph Fourier in France; Hans-Jochen Lauter of the Institut Laue-Langevin in France and Oak Ridge National Laboratory; and Helga Bohm and Martin Panholzer of the Institute for Theoretical Physics at Johannes Kepler University in Austria. Meschke also belongs to the Low Temperature Laboratory of Aalto University in Finland.
Charlotte Hsu | EurekAlert!
Rosetta’s comet contains ingredients for life
30.05.2016 | Universität Bern
Present-day measurements yield insights into clouds of the past
27.05.2016 | Paul Scherrer Institut (PSI)
A biological and energy-efficient process, developed and patented by the University of Innsbruck, converts nitrogen compounds in wastewater treatment facilities into harmless atmospheric nitrogen gas. This innovative technology is now being refined and marketed jointly with the United States’ DC Water and Sewer Authority (DC Water). The largest DEMON®-system in a wastewater treatment plant is currently being built in Washington, DC.
The DEMON®-system was developed and patented by the University of Innsbruck 11 years ago. Today this successful technology has been implemented in about 70...
Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.
The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...
In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.
In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...
Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices
Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.
When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene
In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...
24.05.2016 | Event News
20.05.2016 | Event News
19.05.2016 | Event News
30.05.2016 | Materials Sciences
30.05.2016 | Materials Sciences
30.05.2016 | Trade Fair News