Artificial edge in an optical lattice (blue), filled with an ultracold quantum gas that consists of ‘spin-up’ particles (red) and ‘spin-down’ particles (green). Along the edge – and only there - 'spin-up' particles can only flow to the left, and ‘spin-down’ particles can only flow to the right. Credit: Bernhard Irsigler

FRANKFURT. Insulators that are conducting at their edges hold promise for interesting technological applications. However, until now their characteristics have not been fully understood. Physicists at Goethe University have now modelled what are known as topological insulators with the help of ultracold quantum gases. In the current issue of Physical Review Letters, they demonstrate how the edge states could be experimentally detected.

An atom is trapped in the resonator between two mirrors (left). A reflected light pulse gets entangled with the atom and may fly freely as a superimposed cat state (right). Bastian Hacker, Max Planck Institute of Quantum Optics (MPQ)

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state. In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken experiment is a cat that is simultaneously dead and alive. Since Schrödinger proposed his ‘cat paradox’, physicists have been thinking about ways to create such superposition states experimentally.

A 3D-printed ear: Empa researcher Michael Hausmann uses nanocellulose as the basis for novel implants. Empa

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing. It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains: «In viscous state cellulose nanocrystals can easily be shaped together with nother biopolymers into complex 3-dimensional structures using a 3D printer, such as the Bioplotter.” Once cross-linked, the structures remain stable despite their soft mechanical properties.

Physicist Martin Hauck fits a silicon carbide transistor into the measuring apparatus: researchers at FAU have discovered a method for finding defects at the interfaces of switches. FAU/Michael Krieger, Martin Hauck

 

Transistors are needed wherever current flows, and they are an indispensable component of virtually all electronic switches. In the field of power electronics, transistors are used to switch large currents. However, one side-effect is that the components heat up and energy is lost as a result. One way of combating this and potentially making considerable savings is to use energy-efficient transistors. Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have developed a simple yet accurate method for finding defects in the latest generation of silicon carbide transistors. This will speed up the process of developing more energy-efficient transistors in future. They have now published their findings in the renowned journal Communications Physics.*