Category Physics

Experimental device of quantum cryptography system. Credit: ITMO University

A novel approach to the construction of quantum communication systems for secure data exchange. The experimental device based on the results of the research is capable of transmitting single-photon quantum signals across distances of 250km or more, which is on par with other cutting edge analogues. Information security is becoming more and more of a critical issue. Contrary to algorithm-based encryption, systems that protect information by making use of quantum physics, can make data transmission immune to hacker attacks in the future. Information in a quantum channel is carried by single photons that change irreversibly once an eavesdropper attempts to intercept them...

These are nine biological-solar (bio-solar) cells connected into a bio-solar panel. The panel has generated the most wattage of any existing small-scale bio-solar cells – 5.59 microwatts Credit: Seokheun “Sean” Choi

For the 1st time ever, researchers connected 9 biological-solar (bio-solar) cells into a bio-solar panel. Then they continuously produced electricity from the panel and generated the most wattage of any existing small-scale bio-solar cells – 5.59 microwatts. “Once a functional bio-solar panel becomes available, it could become a permanent power source for supplying long-term power for small, wireless telemetry systems as well as wireless sensors used at remote sites where frequent battery replacement is impractical,” said Assistant Professor Seokheun “Sean” Choi.

“This research...

Experimental and calculated structure of the Fermi surface and band dispersion of PtSn4.

Physicists have discovered a topological metal, PtSn4 (platinum and tin), with a unique electronic structure that may someday lead to energy efficient computers with increased processor speeds and data storage. The electrons in topological quantum materials can travel close to speed of light thanks to unique property Dirac dispersion. Up until now, only isolated points, called Dirac points, with relatively small numbers of conduction electrons, were known to exist in such materials. In PtSn4, the scientists not only discovered a high density of conduction electrons, but also large number of closely positioned Dirac points forming extended lines or Dirac node arcs.

Kaminski and his ARPES equipment.

“Thi...

Applying a magnetic field to PdCoO2, a non-magnetic metal, made it conduct 70% more electricity, even though basic physics principles would have predicted the opposite. Credit: Eiri Ono/Kyoto University

Applying a magnetic field to a non-magnetic metal made it conduct 70% more electricity, even though basic physics principles would have predicted the opposite. Insights from pure mathematics are lending new insights to material physics, which could aid in development of new devices and sensors. “We never expected that magnetoresistance could be lowered even further in the compound we tested, because in theory it should have increased,” says Kyoto University study author Shingo Yonezawa.

Applying a magneticfield to metals affects how well they are able to conduct electricity...