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
OU-led team discovers rare, newborn tri-star system using ALMA
27.10.2016 | University of Oklahoma
First results of NSTX-U research operations
26.10.2016 | DOE/Princeton Plasma Physics Laboratory
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences