The New Yorker has posted an excellent article about the race to build the world’s first viable quantum computer:
Classical computers speak in the language of bits, which take values of zero and one. Quantum computers, like the ones Google is building, use qubits, which can take a value of zero or one, and also a complex combination of zero and one at the same time. Qubits are thus exponentially more powerful than bits, able to perform calculations that normal bits can’t. But, because of this elemental change, everything must be redeveloped: the hardware, the software, the programming languages, and even programmers’ approach to problems.
On the day I visited, a technician—whom Google calls a “quantum mechanic”—was working on the computer with an array of small machine tools. Each qubit is controlled by a dedicated wire, which the technician, seated on a stool, attached by hand.
The quantum computer before us was the culmination of years of research and hundreds of millions of dollars in investment. It also barely functioned. Today’s quantum computers are “noisy,” meaning that they fail at almost everything they attempt. Nevertheless, the race to build them has attracted as dense a concentration of genius as any scientific problem on the planet. Intel, I.B.M., Microsoft, and Amazon are also building quantum computers. So is the Chinese government. The winner of the race will produce the successor to the silicon microchip, the device that enabled the information revolution.
A full-scale quantum computer could crack our current encryption protocols, essentially breaking the Internet. Most online communications, including financial transactions and popular text-messaging platforms, are protected by cryptographic keys that would take a conventional computer millions of years to decipher. A working quantum computer could presumably crack one in less than a day. That is only the beginning. A quantum computer could open new frontiers in mathematics, revolutionizing our idea of what it means to “compute.” Its processing power could spur the development of new industrial chemicals, addressing the problems of climate change and food scarcity. And it could reconcile the elegant theories of Albert Einstein with the unruly microverse of particle physics, enabling discoveries about space and time. “The impact of quantum computing is going to be more profound than any technology to date,” Jeremy O’Brien, the C.E.O. of the startup PsiQuantum, said recently. First, though, the engineers have to get it to work.
“Getting it to work is tricky, not least because currently “the processor relies on superconductivity, meaning that, at ultracold temperatures, its resistance to electricity all but disappears. When the temperature surrounding the processor is colder than the deepest void of outer space, the computations can begin.”
They are getting there, slowly. And when they do:
Fault-tolerant quantum computers should be able to simulate the molecular behavior of industrial chemicals with unprecedented precision, guiding scientists to faster results. In 2019, researchers predicted that, with just a thousand fault-tolerant qubits, a method for producing ammonia for agricultural use, called the Haber-Bosch process, could be accurately modelled for the first time. An improvement to this process would lead to a substantial decrease in carbon-dioxide emissions. Lithium, the primary component of batteries for electric cars, is a simple element with an atomic number of three. A fault-tolerant quantum computer, even a primitive one, might show how to expand its capacity to store energy, increasing vehicle range. Quantum computers could be used to develop biodegradable plastics, or carbon-free aviation fuel. Another use, suggested by the consulting company McKinsey, was “simulating surfactants to develop a better carpet cleaner.” “We have good reason to believe that a quantum computer would be able to efficiently simulate any process that occurs in nature,” Preskill wrote, a few years ago.
The world we live in is the macroscopic scale. It is the world of ordinary kinetics: billiard balls and rocket ships. The world of subatomic particles is the quantum scale. It is the world of strange effects: interference and uncertainty and entanglement. At the boundary of these two worlds is what scientists call the “nanoscopic” scale, the world of molecules. For the most part, molecules behave like billiard balls, but if you zoom in close enough you begin to notice quantum effects. It is at the nanoscopic scale that researchers expect quantum computing to solve its first meaningful problems, in pharmaceuticals and materials design, perhaps with just a few hundred fault-tolerant qubits. And it is in this discipline—quantum molecular chemistry—that analysts expect the first real money in quantum computing to be made. Quantum physics wins the Nobel. Quantum chemistry will write the checks.
This is a world of wondrous advances that will largely take place after I am gone. But it is exciting nonetheless for me. And also scary to think about, because the mischief and criminality that currently emanate from the intersection of capitalism and science under silicon-chip computer processing will be magnified unimaginably.
Whether quantum computing will help engender a world of greater community and cooperation, or a world where humanity is that much closer to destroying itself, remains to be seen.