PATRICK TUCKER, SEPTEMBER 3, 2015
US, China are betting millions on the promise of this newish field, but the real-world potential remains a mystery.
An assortment of super powers awaits the superpower that harnesses quantum science: unhackable communications, radars that see underground, supercomputers that make today’s biggest machines look like first-generation Ataris. But which of those goals are achievable in the near future, and at what cost?
Earlier this summer, the Pentagon announced a $45 million research effort into quantum networking. Meanwhile, China hopes to complete construction of the world’s largest quantum communication network and become the first nation to put a quantum communications satellite into orbit. But other military-funded research has suggested that quantum comms and cryptography may prove too complicated to warrant the effort, while quantum computing will remain out of reach for a decade or more. (Some argue that’s being very optimistic.)
All of this power, and all of this hype, emerges from a source almost unfathomably small: atomic and subatomic particles that behave differently than larger objects, especially at very cold temperatures. It’s enormously difficult even to study quantum objects; simply observing them generally changes their behavior.
The Holy Grail of applied quantum science is quantum computation, which is as different from regular computers as humans are from jellyfish. Whereas conventional computing uses electrical impulses running through transistors to manipulate bits, or binary values of one or zero, quantum machines track the strange behavior of ultracold atoms that can exist in two states at once — a one, a zero, or both. If you’ve got two qubits in the same so-called superposition, you have what’s called an entanglement gate. They’re atomically linked even if they’re miles apart. And this opens up the possibility of massive parallel calculating. What would you use that for? Think about cracking a code: you try one combination after another after another. But if you can try all the possible combos at once, you arrive at the solution instantly.





