THOMAS CORBETT and PETER W. SINGER
A tenfold leap in a key aspect of quantum communications is just one of several recent breakthroughs by Chinese research teams that have major implications for the future of computing and communications.Quantum communications systems pass information using quantum bits: particles that exist in two states until they are observed. If an enemy observes these qubits—that is, intercepts a message—they lose this quality of “superposition.” The information they carry is lost and, as a bonus, the interception is easily detected. (Imagine dipping a cup into a stream of water; any attempt leaves traces.) But the intended recipients can interpret the information because they are being sent something called quantum keys. The inability to send enough of these keys has been a bottleneck in the pursuit of practical quantum communications.
Now a team of Chinese scientists at the University of Science and Technology of China has reported a breakthrough: a tenfold increase in the rate of stable quantum-key distribution. Led by the decorated USTC researcher Pan Jianwei and MIT-trained Xu Feihu, the team managed to push 115.8 megabytes of encrypted data per second over a 10-kilometer fiber-optic channel, shattering by over ten times the previous record of around 10 Mb/s. This breakthrough enables systems to handle vastly more data, larger files, and more users.
Another challenge for quantum systems, though, is that any increase in distance or bandwidth begins to introduce a large quantity of errors and decoherence. This is a result of the delicate superposition of the qubits, which frequently introduces unacceptable error rates and computational bottlenecking. Although these errors can be corrected by using extra qubits, this takes more computing power. It can even introduce more errors; the correcting qubits themselves are also delicate.
However, another Chinese team, led by Yu Dapeng of the Shenzhen Institute of Quantum Science and Engineering as well as researchers from Tsinghua and Fuzhou Universities, are also making progress on this problem. In March, the team announced a new system for real-time error correction in quantum systems. Their approach corrects for the added error potential of the extra qubits, improves the stability of information storage, and requires fewer resources, allowing quantum systems to realize a net-positive for resource intensity.
Beyond quantum communications













