MOSCOW -- Russian scientists are beginning to produce quantum technology advances by attracting the best and brightest to the fledgling Russian Quantum Center (RQC). Only a few months past its second year of operation, the RQC is still in startup mode but has begun to produce results.
In the poster session at the International Conference on Quantum Technologies here, two presentations stood out. In one, a plug-and-play quantum key distribution system was demonstrated with superconducting single-photon detectors.
First proposed by Nicholas Gisim, founder of ID Quantique (the world's first successful quantum technology company), quantum key distribution systems enable uncrackable encryption techniques. Any attempt to eavesdrop on the transmission will collapse the wave function of the quantum bit (q-bit), thus destroying the information in it. RQC scientists say they have improved on the technique by creating a bidirectional tuning system that makes long-distance quantum key distribution systems plug-and-play tools.
"Our quantum key distribution system is not only plug and play but also has demonstrated the longest distance -- over 100 kilometers -- when compared to available commercial systems," said Yury Kurochkin, an RQC scientist. (ID Quantique has demonstrated longer distances in the lab using similar techniques.)
The new system works by encoding a q-bit on a single photon, which is sent down a 101.7km (63-mile) single-mode optical. Ordinarily, a tedious tuning step is required next to compensate for polarization distortion in the quantum channel, but the RQC scientists compensate automatically by reflecting the single photon with a Faraday mirror back to its source, where it is detected with a Mach-Zehnder interferometer. High-speed field programmable gate arrays at both ends handle the fine-tuning step automatically.
Elena Kuznetsova, an RQC scientist, stands before a poster paper outlining a new technique for transferring quantum information encoded on single photons to atoms, where they can be processed in a quantum computer.
Also at the poster session, RQC scientists demonstrated a new technique for transferring the quantum information encoded on single photons (such as those sent down Kurochkin's plug-and-play quantum channel) to atoms, where they can processed in a quantum computer.
"Quantum information encoded on atoms is very sensitive to environmental interference," Elena Kuznetsova, another RQC scientist, said at the session. "We are proposing a new technique that traps the atoms in a nanoscale cavity inside a photonic crystal, where they can be more efficiently processed."
After her education in the US, Kuznetsova became a post-doctoral researcher at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. She recently returned to Russia to join the RQC. Her atom-trapping technique for processing q-bits is still a theoretical design, but now that she has become an RQC scientist, she is improving its specifications and hopes to demonstrate the technique experimentally soon.