“Generating Pure Randomness”

**How to Turn a Quantum Computer Into the Ultimate Randomness Generator**

Excerpts and salient points ~

+ Randomness is crucial for almost everything we do with our computational and communications infrastructure. In particular, it’s used to encrypt data, protecting everything from mundane conversations to financial transactions to state secrets.

+ Genuine, verifiable randomness — think of it as the property possessed by a sequence of numbers that makes it impossible to predict the next number in the sequence — is extremely hard to come by.

*“We are really excited about it,” said John Martinis, a physicist at the University of California, Santa Barbara, who heads Google’s quantum computing efforts. “We are hoping that this is the first application of a quantum computer.”*

+ That could change once quantum computers demonstrate their superiority. Those first tasks, initially intended to simply show off the technology’s prowess, could also produce true, certified randomness.

+ Aaronson’s protocol to generate randomness is fairly straightforward. A classical computer first gathers a few bits of randomness from some trusted source and uses this “seed randomness” to generate the description of a quantum circuit. The random bits determine the types of quantum gates and the sequence in which they should act on the qubits. The classical computer sends the description to the quantum computer, which implements the quantum circuit, measures the qubits, and sends back the 50-bit output bit string. In doing so, it has randomly sampled from the distribution specified by the circuit.