Research project develops mobile quantum tokens with long storage time

Experimental physicist Prof. Kilian Singer (University of Kassel) is coordinating the research project in cooperation with the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH. It is being funded with 1.12 million euros as part of the "Grand Challenge of Quantum Communication" research competition. Until now, objects such as bank cards, transponders or transaction numbers have been used for the security of data transmissions as so-called security tokens, which can store and transmit information for the identification and authentication of users. "Unlike the common token, the quantum tokens developed in the project would be tamper-proof due to immutable physical laws of nature. This is because the key feature of the technology is that the quantum information contained on them cannot be copied without being altered," explains Prof. Singer. Quantum tokens would even protect digital infrastructures from attacks by powerful quantum computers. Possible future applications include authentication, secure data storage while maintaining privacy, secure distributed computing, digital signatures and forgery-proof documents.

To realize this, important key parameters of quantum physical systems must first be further improved. In the "DIamant-based quantum tokens (DIQTOK)" project, researchers are developing an essential component: a mobile quantum token that is usable at room temperature and also efficient to manufacture. The planned quantum token protocol could also achieve significantly longer storage times of several hours for quantum information. Until now, quantum information has often been irretrievably lost after only fractions of a second due to interactions with the environment. "With these properties, we could even make a quantum ID card. This would be a non-copyable mobile identification option secured by fundamental physical principles with a natural decay date," describes Prof. Singer.

DIQTOK optimizes a material system based on nitrogen defect centers in diamond and adapts it to specific requirements. Here, the researchers combine different experimental methods such as nitrogen implantation, electron beam lithography and laser-induced healing with computer-aided material design for the fabrication of the centers. These centers allow the quantum information to be stored and read in and out. Microwave and radio frequency pulse techniques are being further developed for the control of the quantum information, and thus for the realization of long storage times. For mobile use, the quantum token system is gradually being made smaller and smaller.

Contact:
Prof. Dr. Kilian Singer
University of Kassel
Experimental Physics I
Phone: +49 561 804-4235
E-mail: ks[at]uni-kassel[dot]de