Quantum Computing -- December 21, 2022

In the current issue of The New Yorker (paywall), December 19, 2022, in the annals of technology, "The future of everything: how the quantum computer will change the world," Stephen Witt, pp. 22 - 27.

Like al New Yorker articles, this is a very, very long essay. It is perhaps the best essay I've read on quantum computing. 

The essay begins:

On the outskirts of Santa Barbara, California, between the orchards and the ocean, sits an inconspicuous warehouse, its windows tinted brown and its exterior painted a dull gray. The facility has almost no signage, and its name doesn’t appear on Google Maps. A small label on the door reads “Google AI Quantum.” Inside, the computer is being reinvented from scratch.

In September, Hartmut Neven, the founder of the lab, gave me a tour.

In the middle of the warehouse floor, an apparatus the size and shape of a ballroom chandelier dangled from metal scaffolding. Bundles of cable snaked down from the top through a series of gold-plated disks to a processor below. The processor, named Sycamore, is a small, rectangular tile, studded with several dozen ports. Sycamore harnesses some of the weirdest properties of physics in order to perform mathematical operations that contravene all human intuition. Once it is connected, the entire unit is placed inside a cylindrical freezer and cooled for more than a day. 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.

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.

Then, all of a sudden, on the fifth page of the essay:

In early 2020, scientists at Pfizer began producing hundreds of experimental pharmaceuticals intended to treat Covid-19.

That July, they synthesized seven milligrams of a research chemical labelled PF-07321332, one of twenty formulations the company produced that week. PF-07321332 remained an anonymous vial in a laboratory refrigerator until September, when experiments showed that it was effective at suppressing Covid-19 in rats.

The chemical was subsequently combined with another substance and rebranded as Paxlovid, a drug cocktail that reduces Covid-19-related hospitalizations by some ninety per cent.

Paxlovid is a lifesaver, but, with the assistance of a quantum computer, the laborious process of trial and error that led to its development might have been shortened.

“We are just guessing at things that can be directly designed,” the venture capitalist Peter Barrett, who is on the board of the startup PsiQuantum, told me.

“We’re guessing at things which our civilization entirely depends on—but that is by no means optimal.”

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.

But look at that, where I least expected to find a reference to Pfizer and there it popped up.