Researchers in Florence and Innsbruck have simulated a physical phenomenon in an atomic quantum gas that can also be observed at the edge of some condensed matter systems: chiral currents. The scientists have published the experiment, which will open new doors for the study of exotic states in condensed matter, in the journal Science.
Condensed matter physics remains a field of study with many puzzles to solve. New studies have become possible due to advances in experimental quantum physics.
In particular, ultracold atoms in optical lattices and an environment that is fully tunable and controllable represent an ideal system for studying the physics of condensed matter problems. One of these phenomena can be observed in connection with the quantum Hall effect:
When certain materials are subjected to a strong magnetic field, the electrons cannot move in a singular circular direction at the edges anymore but repeatedly bounce against the edge, where they are reflected. This corresponds to skipping trajectories. As a macroscopic consequence so called chiral currents, which move in the opposite direction at the opposite edges, can be observed at the boundaries of such two-dimensional materials.
“You could compare it to a river where the fish swim towards the right on one bank and towards the left on the other bank,” explains theoretical physicist Marcello Dalmonte from the Institute for Theoretical Physics at the University of Innsbruck and a member of Peter Zoller’s research group at the Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences.
Already ten years ago, Peter Zoller’s research team proposed a way to simulate chiral currents with neutral atoms. This idea combined with the synthetic dimension approach, put forward by the Barcelona group at ICFO, was picked up and implemented by physicists at the European Laboratory for Nonlinear Spectroscopy (LENS) in Florence collaborating with theoretical physicists in Innsbruck.
In their experiment, the scientists confined an ultracold gas of ytterbium atoms in an optical lattice generated by laser beams. As it is difficult to reproduce the structure of two-dimensional condensed matter systems, the physicists use a new approach: They used a one-dimensional chain of atoms and produced the second dimension synthetically. The dynamics along the synthetic dimension are generated by laser-induced hopping between two or three internal spin states.
“From a theoretical perspective this hopping into different internal spin states represents the same concept as the geometrical hopping of electrons at the edges of a condensed matter system,” explains Marcello Dalmonte. Together with Marie Rider and Peter Zoller, Marcello Dalmonte laid the theoretical groundwork for the experiment and suggested how to observe this phenomenon.
The observations published in Science show that the particles move mostly to the right at one edge and to the left on the other edge. “This behavior is very similar to chiral currents known in condensed matter physics,” says Dalmonte. This simulation of exotic effects opens up new ways for the researchers to study other new physical phenomena, for example, in connection with quantum Hall effects, the study of anyons in atomic systems. These exotic quasi particles are suggested to being suitable as the main building block for topological quantum computers.
The researchers are supported, among others, by the Austrian Science Fund (FWF), the European Research Council (ERC) and the European Union.
Publikation: Observation of chiral edge states with neutral fermions in synthetic Hall ribbons. M. Mancini, G. Pagano, G. Cappellini, L. Livi, M. Rider, J. Catani, C. Sias, P. Zoller, M. Inguscio, M. Dalmonte, L. Fallani. Science, Vol. 349 no. 6255 pp. 1510-1513
Institute for Theoretical Physics
Universtity of Innsbruck and
Institute for Quantum Optics and Quantum Information
Austrian Academy of Sciences
Tel.: +43 512 507 4792
Dr. Christian Flatz
Tel.: +43 512 507 32022
Mobil: +43 676 872532022
http://www.uibk.ac.at/th-physik/qo/ - Quantum Optics Theory Group
http://www.uibk.ac.at/th-physik/ - Institute for Theoretical Physics, Universtity of Innsbruck
http://iqoqi.at/ - Institute for Quantum Optics and Quantum Information
http://Austrian Academy of Sciences
http://www.lens.unifi.it/ - European Laboratory for Nonlinear Spectroscopy (LENS)
Dr. Christian Flatz | Universität Innsbruck
From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison
Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News