Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantum Simulator for Complex Electronic Materials

05.12.2008
Researchers from MPQ, Mainz, Cologne and Jülich simulate complex electronic insulator with ultracold atoms in artificial crystals of light

The design of new materials with specific properties is a difficult and important challenge in physics and chemistry. Nobel Prize winner Richard P. Feynman in 1982 therefore suggested to build a "quantum simulator" in order to understand and predict the properties of complex materials by simulating them using an artificial, but highly controllable different quantum system. In the latest issue of the journal Science a team of scientists led by Prof. Immanuel Bloch, director at MPQ and chair of physics at the Johannes Gutenberg Universität of Mainz show how to simulate the properties of electrons in a real crystal by using ultracold atoms trapped in an artificial crystal formed by interfering laser beams - a so called optical lattice. The researchers from the University of Mainz, the University of Cologne and the Forschungszentrum Jülich succeeded in demonstrating one of the most dramatic effects of the electron-electron repulsion: When the interactions between the electrons get too strong, a metal can suddenly become insulating. The resulting so-called Mott-insulator is probably the most important example of a strongly correlated state in condensed matter physics, and it is a natural starting point for the investigation of quantum magnetism. In addition, high temperature superconductivity is found to arise in close proximity to it.


An artists impression of the fermionic Mott insulating state: Due to the dominating repulsive interaction every lattice site is occupied by exactly one atom. The different colors indicate different spin states. Universität Mainz

"Atoms in an optical lattice are a nearly perfect quantum simulator for electrons in a solid, as they offer a very flexible model-system in a clean and well-controlled environment" explains Ulrich Schneider from the University of Mainz. Investigating complex materials and high temperature superconductors is difficult because of the presence of disorder and many competing interactions in the real crystalline materials. "This makes it difficult to identify the role of specific interactions and, in particular, to decide whether repulsive interactions between fermions alone can explain high temperature superconductivity" says Prof. Bloch.

In the experiment, a gas of potassium atoms is first cooled down to almost zero temperature. Subsequently, an optical lattice is created by overlapping several laser beams. To the atoms, the resulting standing-wave laser field appears as a regular crystal of tens of thousands of individual micro-traps, similar to an array of optical tweezers. The ultracold atoms, which assume the role of electrons in real solids, will line up at the nodes of this standing-wave field.

By investigating the behaviour of the atoms under compression and increasing interaction strength, and thereby measuring their compressibility, the experimentalists have been able to controllably switch the system between metallic and insulating states of matter and find evidence for a Mott-insulating phase within the quantum gas of fermionic atoms. In such a Mott insulating phase, the repulsive interactions between the atoms force them to order one-by-one into the regular lattice structure.

The observation of the fermionic Mott-insulator in the context of optical lattices opens up a new possibility to simulate and study strongly correlated states and related phenomena. This is affirmed by the excellent agreement achieved in comparing the experiment with theoretical calculations of modern condensed matter theory performed in Cologne and Jülich, which included extensive simulations on the Jülich based supercomputer system JUGENE. [I.B.]

Original publication:

U. Schneider, L. Hackermüller, S. Will, Th. Best, and I. Bloch,
T.A. Costi, R.W. Helmes, D. Rasch, and A. Rosch
"Metallic and Insulating Phases of Repulsively Interacting Fermions in a 3D Optical Lattice"

Science, 5th December 2008

More information and picture gallery:
www.quantum.physik.uni-mainz.de/bec
Contact:
Prof. Dr. Immanuel Bloch
Max-Planck-Institut für Quantenoptik
Hans-Kopfermann-Str. 1
D-85748 Garching, Deutschland
Phone: (+ 49 89) 32905 - 238
Fax: (+ 49 89) 32905 - 760
E-mail: immanuel.bloch[a]
Johannes Gutenberg-Universität Mainz
Staudingerweg 7
D 55128 Mainz
Phone: (+49 6131) 39-26234 / 22279
Fax: (+49 6131) 39-25179
E-mail: Bloch[a]Uni-Mainz.DE

Dr. Olivia Meyer-Streng | idw
Further information:
http://www.quantum.physik.uni-mainz.de
http://www.mpq.mpg.de
http://www.uni-mainz.de

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>