From Quantum Spam to Quantum Minds: Why the ‘Best’ Revolution in Physics Is Only Getting Started

Physicist Paul Davies looks back at the past century of quantum mechanics—the most disruptive theory in the history of modern science.

The use of the word “quantum” has become rather hackneyed. There are quantum computers, quantum sensors, and even quantum refrigerators; the list is endless. I mean, what’s next—quantum washing machines?

If all the quantum spam has left you exhausted, Paul Davies’s new book, Quantum 2.0: The Weird Physics Driving a New Revolution in Technology, might help. Yes, the title has the q-word, but for the best possible reason. Starting with a brief rundown of what “quantum” actually means, the book lays out in plain language how quantum mechanics changed science in the past century—and how it will continue to do so going forward.

Paul Davies is a theoretical physicist and the director of the Beyond Center for Fundamental Concepts in Science at Arizona State University. A renowned science communicator, he has authored more than 20 books on topics from the origin of life to the nature of time.

Gizmodo spoke to Davies about navigating the so-called quantum noise and how best to understand what quantum mechanics has contributed to our understanding of the universe. The following conversation has been lightly edited for grammar and clarity.

Gayoung Lee, Gizmodo: So the book’s title is Quantum 2.0. That implies there was a Quantum 1.0. What was Quantum 1.0? What was the turning point that brought us to Quantum 2.0?

Paul Davies: Very good question. The technical term for the branch of quantum physics we’re talking about is quantum mechanics, which began in 1925. This is the most successful scientific theory ever, because it explained the nature of matter all the way from subatomic particles right up to stars.

It also led to some very familiar technology that underpins much of the modern world, for example, the laser, microchips, MRI machines, and nuclear power—your cell phone is packed full of quantum gizmos.

All of this stemmed from what we’re calling “Quantum 1.0,” which is the quantum mechanics developed 100 years ago. With the centenary last year, UNESCO declared 2025 to be the International Year of Quantum Science and Technology. It’s very clear that there is a whole new quantum revolution that is bursting upon us.

And the distinction is really the following: With Quantum 2.0, it’s possible to manipulate individual particles—electrons or photons, for example—and to sculpt their quantum states so that information is actually encoded in the individual particles themselves and not in the bigger devices, like transistors or gates.

Gizmodo: With this revolution, today it seems like everyone is attaching “quantum” to things. What does that really mean? What makes something “quantum”?

Davies: Well, if it’s not a commercial trick—and it generally is—then, in the past, people usually wouldn’t say, “You must go for a quantum MRI scan,” but that uses quantum mechanics. Or you wouldn’t say, “We’re going to build a quantum nuclear power station,” although that uses quantum principles.

With Quantum 2.0, “quantum” usually is a signature of something exploiting the subatomic world. It’s not just a gimmick. It means manipulating quantum physics in some non-trivial ways by utilizing concepts such as entanglement or [superposition].

Gizmodo: Strictly speaking, quantum effects influence everything in the universe. But they’re also often in conflict with observable reality. It seems that scientists don’t know exactly how the two are connected. Yet, if Quantum 2.0 is here, it means we’re using these obscure ideas to create tangible things.

Davies: Quantum mechanics is full of paradoxes and weird concepts that just don’t mesh with the everyday world. In everyday life, we have things like tables and chairs that we assume really exist independently of us measuring them or looking at them. But down at the atomic level, that isn’t the case.

A particle like an electron simply does not have a full set of properties before measurement. If you ask, well, before the measurement, did the particle really have both a position and a motion? The answer is that you cannot say. Even nature doesn’t know what properties the particle had.

The big difficulty is interfacing that shadowy world of the quantum, where things don’t exist in definite, well-defined states, with the everyday world, where everything seems a single concrete reality. Even after 100 years, physicists are squabbling over how to interpret that. It remains an outstanding problem for the next generation of physicists.

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Gizmodo: Your book offers many examples of how quantum science has left its mark on science. Is there any particular one you’d like to highlight?

Davies: There’s a whole chapter in the book on quantum biology. One of the founders of quantum mechanics, Erwin Schrödinger, realized in 1925 that within a few years, quantum mechanics could explain the nature of matter all the way from subatomic particles up to stars. But living matter seemed to have its own laws. To a physicist, life looks like a miracle.

In 1943, Schrödinger gave a series of lectures called “What Is Life?” He hoped that the powerful nature of quantum mechanics might explain the strangeness of living matter. But he was also open to the possibility that there may be something beyond quantum mechanics—some new kind of physical law, he said—prevailing in living matter.

In recent years, people [are considering] effects like superposition and entanglement, or possibly even quantum information processing, going on in living organisms. I myself am a little bit skeptical, but it’s intriguing. Might life’s apparently miraculous capabilities ultimately be an exploitation of some sort of profound type of quantum mechanics?

Gizmodo: At the start of the book, you write that quantum is the “science that gave us AI.” How exactly did quantum mechanics give us AI?

[F S26 Davies Quantum 9780226849324 Jkt Apl]

The international edition cover of Davies’s latest book. © The University of Chicago Press

Davies: There are two sides to this. One is AI as we know it, but the other is the possibility of what I call quantum artificial intelligence, which would be an even greater leap and even more disruptive.

Let’s answer your original question. AI is really just the outcome of doing a very large number of very rapid information processing on a very large scale. If you sat down and tried to work out the number of quantum devices involved in AI, there would be hundreds of components that fundamentally depend upon quantum mechanics through its principles.

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