Transport properties such as thermal or electrical conductivity are of great importance for technical applications of materials. In particular the electrical conductivity stems from the behaviour of the electrons in the solid and is very difficult to predict. This is true especially in the case of strongly correlated electrons, when the position and the dynamics of each single electron is strongly influenced by the behaviour of all other electrons.
Figure 1: A system of fermionic atoms in an optical lattice (top) is brought out of equilibrium and exhibits different dynamics for non-interacting (left) and interacting atoms (right). Grafik: MPQ
Ultracold atoms in optical lattices can be used as model systems that allow the study of analogues processes in a clean and well controlled environment where all relevant parameters can be manipulated by external lasers and magnetic fields. Scientists in the group of Professor Immanuel Bloch (Ludwig-Maximilians-Universität Munich and Max Planck Institute of Quantum Optics, Garching) in collaboration with the theory group of Prof. Achim Rosch (University of Cologne) have now demonstrated that the dynamics of a system of ultracold potassium atoms, trapped in an optical lattice, depend surprisingly strongly on the particle interaction strength (Nature Physics 8, 213-218 (2012), DOI: 10.1038/NPHYS2205). Investigations of this kind give new insights into properties like electrical conductivity, superconductivity or magnetism, and may help to develop materials with ‘tailored’ properties.So-called optical lattices are generated by superimposing several laser beams. The resulting periodic structure of light resembles the geometry of simple solid state crystals. In fact, atoms trapped in such an artificial lattice, at a temperature of a few nano-Kelvin above absolute zero, experience forces similar to the ones that act on electrons in solid state systems. However, concerning their dynamics, only fermionic atoms behave exactly the same way as electrons, which are fermions as well. These particles have to differ in at least one quantum property if they happen to be at the same place at the same time. Bosonic particles, on the other hand, prefer to gather in exactly the same quantum state.
Dr. Olivia Meyer-Streng | Max-Planck-Institut
New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center
Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Interdisciplinary Research
20.10.2017 | Materials Sciences
20.10.2017 | Earth Sciences