Quantum Communication

Quantum Communication

According to Einstein’s theory of relativity, it shouldn’t be possible. It’s called quantum teleportation, and it sounds like the stuff of science fi ction—using quantum mechanics to communicate over vast distances; ostensibly, it means using cutting-edge science to “teleport” information, but practically, it means using quantum mechanics to create perfect cryptography.

Of course, China has its reasons for putting this physics pipe dream to the top of the funding queue. The Chinese government, of late and for very obvious reasons, became very keen on information security a few years ago, needing something hack-proof to the point of absolute security. The answer is quantum-key distribution (QKD), data teleportation. The process uses photons—the stuff of light and so utterly indefi nable as to be both particle and wave at the same time—sent to a receiver. Based on the known fundamental principles of quantum mechanics, any eavesdropping, hacking, or interference with information sent from the source would show up to both sides. It’s the fragility of QKD that makes it so useful.

In 2010, in the hills north of Beijing near the Great Wall, China smashed US and European records for teleportation, sending their quantum information over 16 kilometers. At the time, it was a major breakthrough, with US and European experiments maxing out at a paltry 600 meters. Before that, in 2008, the biggest advance in the fi eld was sending a single photon refl ection from a satellite. In 2012, China outdid itself, with the University of Science and Technology from Shanghai teleporting their information 97 kilometers across Qinghai Lake. However, their time in the sun was not to last, with European researchers sending information across two islands in the Canary Islands 143 kilometers.

But, China is pulling no more punches; the race for quantum communication supremacy is on, and China’s grand ambitions put it in the lead. The University of Science and Technology started working on a quantum exchange from Beijing to Shanghai in April 2014, an ambitious project to say the least, and it’s already showing results. The man at the helm of China’s quantum communication in China is one Pan Jian-Wei, who told Nature that this new program is to “provide a test bed for quantum theories and new technologies”. The US is in talks to secure a 10,000-kilometer such system. In response, China plans to launch a quantum communications satellite in 2016, and all bets are on China to be fi rst in the quantum comms space race.

While all of these technologies are in the experimental stage, they do, in fact, work. Simply put, it isn’t teleportation in the sci-fi sense, in that no clone is created at the other end; indeed, the current system is simple binary, meaning it is more transported rather than teleported—albeit transported via subatomic particles’ quantum entanglement. The problems are complex; as Richard Feynman famously said, “if you think you understand quantum mechanics, you don’t understand quantum mechanics.”

But, China is now at the helm of a whole new world of science. Much of quantum mechanics remains a mystery, but with the funding, research, and genius of a newly motivated nation, quantum communication doesn’t seem like such a pipe dream anymore, with quantum computing and mass quantum communications systems a palpable reality. Indeed, China’s advances in the fi eld and the competition for quantum supremacy is an exciting race, one with no fi nish line.