Quantum information science and technology (QIST) is a central emerging area in technology policy. QIST includes technologies we already know and use: lasers, magnetic resonance imaging, and atomic clocks. Quantum computing is a new horizon for QIST. It has attracted multi-billion-dollar investments as researchers, companies, and governments race to develop the first scalable, fault-tolerant quantum computers – computers that can solve currently impossible problems, from abstract mathematics to chemical engineering. These technologies pose new risks to our cybersecurity infrastructure, with data privacy and national security implications. With such high stakes, quantum computing deserves close attention from policymakers. SIIA has developed The Quantum Moment, a new white paper that provides both a working framework accessible to policy makers and highlights issues and proposals for the development of quantum computing. What is a Quantum Computer, anyway? In a 1981 paper, the eminent physicist Richard Feynman asked, “What kind of computer are we going to use to simulate physics?” Simulating physics is important for everything from learning about the universe to building planes to developing new drugs. But there’s a problem: as the simulation gets more complicated, the simulation overwhelms the capabilities of classical computers. Classical computers, as Feynman puts it, “would require exponentially explosive growth.” Douglass Adams’ The Hitchhiker’s Guide to the Galaxy provides the possibility of a “computer as big as all creation,” a comical stand-in for the size of a classical computer Feynman is suggesting. The Math Bit: If we want to simulate quantum mechanics, then we have to simulate probabilities. Feynman stipulates a threshold for the minimal probabilities that we care about in our simulation; call the number of possible states N, and the number of particles R. We need to represent N states of R particles, which would NR representations. Feynman points out that R is going to