How Google’s Quantum Computer Could Change the World

https://www.wsj.com/articles/how-googles-quantum-computer-could-change-the-world-1508158847[wsj.com]

That potential is a result of exponential growth. Adding one bit negligibly increases a classical chip’s computing power, but adding one qubit doubles the power of a quantum chip. A 300-bit classical chip could power (roughly) a basic calculator, but a 300-qubit chip has the computing power of two novemvigintillion bits—a two followed by 90 zeros—a number that exceeds the atoms in the universe.

But this sort of comparison works only for specific computational tasks. Comparing bits to qubits is facile because quantum and classical computers are fundamentally different machines. Unlike classical computers, quantum computers don’t test all possible solutions to a problem. Instead, they use algorithms to cancel out paths leading to wrong answers, leaving only paths to the right answer—and those algorithms work only for certain problems. This makes quantum computers unsuited for everyday tasks like surfing the web, so don’t expect a quantum iPhone. But what they can do is tackle specific, unthinkably complex problems like simulating new molecules to engineer lighter airplane parts, more effective drugs and better batteries.

Not everyone is eager for large-scale, accurate quantum computers to arrive. Everything from credit-card transactions to text messaging is encrypted using an algorithm that relies on factorization, or reverse multiplication. An enormous number—several hundred digits long—acts as a lock on encrypted data, while the number’s two prime factors are the key. This so-called public-key cryptography is used to protect health records, online transactions and vast amounts of other sensitive data because it would take a classical computer years to find those two prime factors. Quantum computers could, in theory, do this almost instantly.

Companies and governments are scrambling to prepare for what some call Y2Q, the year a large-scale, accurate quantum computer arrives, which some experts peg at roughly 2026. When that happens, our most closely guarded digital secrets could become vulnerable.

Last year the National Security Agency issued an order that U.S. national-security employees and vendors must, “in the not-too-distant future,” begin overhauling their encryption to guard against the threat posed by quantum computers. Because national-security information must be protected for decades, the agency says new encryption needs to be in place before these machines arrive. Otherwise, the NSA warns, code-breaking quantum computers would be “devastating” to national security.

China building world’s biggest quantum research facility

Construction work is expected to finish in 2 ½ years with a budget of 76 billion yuan (~$11.5B).

“Our plan is that by 2020, or maybe as soon as next year, to achieve ‘quantum supremacy’ with calculation power one million times to all existing computers around the world combined,” Pan was quoted as saying by Anhui Business Daily, which is run by the provincial government.