The launch of the world’s first quantum communication satellite couldn’t come at a more symbolic time for China. This year marks the 50th anniversary of the end of the Cultural Revolution – a period in which Mao Zedong’s social policies resulted in the forced migration of millions of people, the mass purges of party officials and intellectuals, and the starvation of hundreds of thousands of Chinese. Chinese officials have said that it was “the most severe setback and the heaviest losses suffered by the party, the country, and the people since the founding of the People’s Republic.”
The period since the Revolution, however, has been filled with sweeping economic reforms and innovations that have brought China both wealth and power. Next month’s scheduled launch of QUESS, the new Quantum Space Satellite program (or Quantum Experiments at Small Scale, as it is sometimes called), will cement their place at the forefront of technology and showcase China’s strength to the rest of the world.
The Satellite Makes Use of Einstein’s “Spooky” Physics
The satellite will test the physical properties of quantum entanglement. Quantum entanglement is a phenomenon in which grouped particles remain connected even if you try to mess with individuals in the group. When you perform an action on one particle it has an effect the other particles, even if they are separated by some distance. Einstein called it “spooky action at a distance,” because it seems like there is some spooky force moving both particles simultaneously whereas in reality you are manipulating just one particle. Scientists proved that quantum entanglement is real in November 2015, and now, just a few months later, China is using it to send secret messages.
The satellite will send encrypted messages from Beijing to the satellite 1000 km above to see if quantum entanglement works at huge distances. They will even test as far as from Vienna to Beijing. Pan Jian-Wei, he principal scientist on the QUESS project, told Nature, “Sure, in principle, quantum entanglement can exist for any distance. But we want to see if there is some physical limit. People ask whether there is some sort of boundary between the classical world and the quantum world: we hope to build some sort of macroscopic system in which we can show that the quantum phenomena can still exist.”
The QUESS Project May Lead to Unbreakable Security Codes
This has major implications for cryptography. Because particles linked by quantum entanglement cannot be described individually, they must be described using probabilities, or “quantum states.” Another quantum mechanical principle, called the Observer Effect, states that by observing a quantum state you change it. So when you send an encrypted message to a satellite using quantum entanglement, it is virtually un-hackable. Additionally, when the change in the quantum state after it is observed can be used to notify the ground station that someone (unsuccessfully) tried to hack the satellite. In theory, quantum keys are impossible to hack.
The QUESS project, if successful, will set China above the rest of the world in its security capabilities. The United States, Canada, Japan, and some EU countries are all racing to develop quantum communication networks as well, meaning satellite component manufacturing is increasing in importance globally. It is possible that we will live in world where un-hackable secrets become the norm. But what remains certain today is that China’s transformation from an impoverished and unstable nation to a formidable powerhouse whose breakneck-paced scientific research is transforming the security world is nothing short of remarkable.