Phys.org March 22, 2019 Researchers in Germany performed high-harmonic generation measurements from silicon and quartz to demonstrate that the polarization states of the harmonics are not only determined by crystal symmetries, but can be dynamically controlled, as a consequence of the intertwined interband and intraband electronic dynamics. Using symmetry-dynamics duality they generated coherent circularly polarized harmonics from elliptically polarized pulses. The method is versatile and expected to find important applications in future studies of novel quantum materials such as strongly correlated materials, topological insulators, and magnetic materials… read more. Open Access TECHNICAL ARTICLE
Tag Archives: S&T Germany
One transistor for all purposes
Nanowerk March 19, 2019 Until now, organic semiconductors have failed to achieve high performance in highly integrated sub-100 nm transistors. Using a vertical field-effect transistor design with a channel length of only 40 nm and a footprint of 2 × 80 × 80 nm2, researchers in Germany show that high electrical performance with organic polymers can be realized when using electrolyte gating. These organic transistors combine high on-state current densities of above 3 MA cm−2, on/off current modulation ratios of up to 108 and large transconductances of up to 5,000 S m−1. These structures show promise for use in artificial neural networks, where they could operate as memristive devices with sub-100 fJ […]
Turning an organic molecule into a coherent two-level quantum system
Phys.org March 18, 2019 Researchers in Germany have demonstrated that an organic molecule placed into an optical microcavity behaves as a coherent two-level quantum system. This allows the observation of 99% extinction of a laser beam by a single molecule, saturation with less than 0.5 photons and non-classical generation of few-photons super-bunched light. They demonstrated that their molecule-microcavity system could interact with single photons generated by a second molecule in a distant laboratory. The research is an important step towards linear and nonlinear quantum photonic circuits based on organic platforms…read more. TECHNICAL ARTICLE
Nanocoating makes lightweight metal foams bone-hard and explosion-proof
Phys.org March 15, 2019 The metal foams currently available are suitably lightweight, but the production process is complicated and expensive, and the structures are still too weak and not resilient enough for many applications. Inspired by bone, researchers in Germany used aluminium or polymer foam as the initial lattice substrate to manufacture highly stable, porous metallic foams. They developed a proprietary procedure for coating the individual struts that make up the open-cell interior lattice. As a result, the exterior of the foam is stronger, more stable, light and the withstands extreme loads. They found polyurethane foams have a low density, […]
Invisible tags: Physicists write, read and erase using light
Nanowerk February 1, 2019 Researchers in Germany introduced organic luminescent molecules plastic foils. In the beginning, these molecules are in an inactive, dark state. By locally using ultraviolet irradiation, it is possible to turn the dark state into an active, luminescent one. By mask illumination or laser writing, activated patterns can be printed and the imprinted information can be read. Ultraviolet radiation induces a chemical reaction which efficiently removes the oxygen from the layer activating the luminescent molecules. By illuminating with infrared light, the tag is erased completely, and new data can be written into it. The deactivation process is […]
Graphene on the way to superconductivity
Science Daily November 9, 2018 Previously researchers at MIT showed that it is possible to generate a form of superconductivity in a system of two layers of graphene under very specific conditions using a complex method. Researchers in Germany have developed a simpler technique by heating silicon carbide crystal until silicon atoms evaporate from the surface, leaving first a single-layer of graphene on the surface, and then a second layer of graphene. The two graphene layers are not twisted against each other but lie exactly on top of each other. They argue that their two-dimensional flat band model and the […]
Multi-functional quantum bits for future computers
Eurekalert October 29, 2018 Researchers in Germany are working on Scalable Rare Earth Ion Quantum Computing Nodes (SQUARE) within the framework of the Quantum Technology Flagship funded by the European Commission. SQUARE is aimed at establishing rare earth ions that can be addressed separately as basic building blocks for scalable quantum technologies. In particular, it is planned to demonstrate functional elements of a multi-qubit quantum register that can be read out optically and to realize building blocks of a quantum network. Their work was presented at a recent conference in Germany… read more.
Artificial intelligence controls quantum computers
Science Daily October 25, 2018 Researchers in Germany show how a network-based “agent” can discover complete quantum-error-correction strategies, protecting a collection of qubits against noise. These strategies require feedback adapted to measurement outcomes. To find strategies without human intervention they developed two-stage learning with teacher and student networks and a reward quantifying the capability to recover the quantum information stored in a multiqubit system. Beyond its immediate impact on quantum computation, the work more generally demonstrates the promise of neural-network-based reinforcement learning in physics… read more. TECHNICAL ARTICLE
Biological invisibility cloak: Elucidating cuttlefish camouflage
Science Daily October 18, 2018 Among all animals, cuttlefish, squid and octopuses control their appearance by the direct action of neurons onto expandable pixels, numbered in millions, located in their skin. Researchers in Germany peered into the brain of the cuttlefish and its camouflage control system. They derived minimal rules that may explain skin morphogenesis. They found that chromatophores (specialized skin cells) systematically change colors over time. The study opens a large range of new questions and opportunities in field of cognitive computational neuroscience; help define the precise link between brain activity and behavior and help identify the cellular rules […]
Space-borne quantum source to secure communication
Phys.org October 1, 2018 Researchers in Germany developed a remarkably stable yet powerful quantum source which can generate 300,000 entangled photon pairs per second when the light from a laser beam hits a non-linear crystal. The twinned light particles enable sensitive messages to be securely encrypted. The two photons’ polarization remains entangled no matter how far apart they may be. This allows two communicating parties to produce and share keys and immediately detect if a third-party attempts to intercept their communication. If an unauthorized party tampers with the message, the two photons disentangle to reveal that a hacking attempt is […]