Quantum computers are revealing an unexpected new theory of reality

A powerful new idea about how the laws of physics work could bring breakthroughs on everything from quantum gravity to consciousness, says researcher Chiara Marletto

Physics 14 April 2021

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Manshen Lo

QUANTUM supremacy” is a phrase that has been in the news a lot lately. Several labs worldwide have already claimed to have reached this milestone, at which computers exploiting the wondrous features of the quantum world solve a problem faster than a conventional classical computer feasibly could. Although we aren’t quite there yet, a general-purpose “universal” quantum computer seems closer than ever – a revolutionary development for how we communicate and encrypt data, for virtual reality, artificial intelligence and much more.

These prospects excite me as a theoretical physicist too, but my colleagues and I are captivated by an even bigger picture. The quantum theory of computation originated as a way to deepen our understanding of quantum theory, our fundamental theory of physical reality. By applying the principles we have learned more broadly, we think we are beginning to see the outline of a radical new way to construct laws of nature.

It means abandoning the idea of physics as the science of what’s actually happening, and embracing it as the science of what might or might not happen. This “science of can and can’t” could help us tackle some of the big questions that conventional physics has tried and failed to get to grips with, from delivering an exact, unifying theory of thermodynamics and information to getting round conceptual barriers that stop us merging quantum theory with general relativity, Einstein’s theory of gravity. It might go even further and help us to understand how intelligent thought works, and kick-start a technological revolution that would make quantum supremacy look modest by comparison.

Since the dawn of modern physics in …