Work that demonstrates simultaneous control over transport and spin properties of cold atoms establishes a framework for exploring concepts of spintronics and solid-state physics
One of the more unexpected things that can be done with charge-neutral atoms is to use them to emulate the fundamental behaviour of electrons. In the past few years, the group of Tilman Esslinger at the Institute of Quantum Electronics in the Department of Physics of ETH Zurich has pioneered a platform in which atoms cooled to temperatures close to absolute zero are transported through one- and two-dimensional structures, driven by a potential difference.
An optical beam (red) introduces an effect equivalent to applying a magnetic field inside an optically defined structure in which the atoms move (green). Atoms in the energetically lower spin state (orange) can flow while atoms in a higher spin state (blue) are blocked.
(ETH Zurich/D-PHYS, adapted from doi: 10.1103/PhysRevLett.123.193605)
In this way defining phenomena occuring in mesoscopic electronic systems can be studied in great detail, not least quantized conductance. In a pair of papers published today in Physical Review Letters and Physical Review A, postdoc Laura Corman, former PhD student Martin Lebrat and colleagues in the Esslinger group report that they have mastered in their transport experiments control over another quantum property of the atoms --- their spin.
The team added to the transport channel a tightly focussed light beam, which induces local interactions that are equivalent to exposing the atoms to a strong magnetic field.
As a consequence, the degeneracy of the spin states is lifted, which in turn serves as the basis for an efficient spin filter: atoms of one spin orientation are repelled, whereas those of another orientation are free to pass (see the figure).
Importantly, even though the application of an additional light field leads to the loss of atoms, these dissipative processes do not destroy the quantization of conductance. The ETH researchers replicate this experimental finding in numerical simulation and substantiate its validity through an extension of the Landauer--Büttiker model, the key formalism for quantum transport.
The efficiency of the atomic spin filter demonstrated by the Esslinger group matches that of the best equivalent elements for electronic systems. This, together with the extraordinary 'cleanness' and controllability of the cold-atom platform, opens up exciting new perspectives for exploring the dynamics of quantum transport.
In particular, as the interaction between the atoms can be tuned, the platform provides access to spin transport of strongly correlated quantum systems. This regime is difficult to study otherwise, but is of considerable fundamental and practical interest, not least for applications in spintronic devices and to explore fundamental phases of matter.
Andreas Trabesinger | EurekAlert!
Simple experiment explains magnetic resonance
09.12.2019 | University of California - Riverside
Electronic map reveals 'rules of the road' in superconductor
09.12.2019 | Rice University
Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...
University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making
In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...
With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction
The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...
Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.
Fibroblasts kit - ready to heal wounds
Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.
In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
09.12.2019 | Earth Sciences
09.12.2019 | Information Technology
09.12.2019 | Life Sciences