embodying the Platonic ideal of a genius. Conversant in ancient Greek by age 6, the Hungarian made significant mathematical advances in his teens. Then, as an adult, he invented game theory and helped design the atomic bomb and the modern computer.
Along the way, as a young man in 1932, von Neumann rewrote the rules of quantum mechanics, formulating the strange new theory of particles and their fluctuating, probabilistic behavior in the mathematical language used today. Then he went further. He developed a framework known as “operator algebras” to describe quantum systems in a more powerful but more abstract way. Unlike his earlier work on quantum theory, this framework was hard to understand and did not catch on widely in theoretical physics. It was literally a century ahead of its time.
Over the past few years, however, more physicists have been dusting off von Neumann’s ideas. His operator algebras are now helping them see their way around the most mysterious quantum system yet: the substructure of space and time.
Even before von Neumann did his work, Albert Einstein’s theories of relativity merged space and time into a four-dimensional fabric known as “space-time.” Einstein showed that the force of gravity is generated by curves in this fabric. But physicists know that the fabric can’t be the whole story. Dying stars puncture it, creating intensely warped regions called black holes where the equations of general relativity break down. And even in calmer parts of space-time, when you zoom in to the smallest scales, quantum fluctuations seem to shred it apart.
Many theoretical physicists therefore believe that space-time will go the way of water, metals, and so many other substances before it; what seems like a smooth and simple medium will turn out to be made of a complicated collection of primitive quantum entities. For decades, theorists have wondered about those entities and how the space-time fabric emerges from them.
These physicists are now gaining a deeper understanding of space-time’s quantum weave. They’re developing new ways of predicting what happens in extreme regions where space-time as we know it unravels, as well as identifying the conditions that normally allow it to hang together. At the heart of the progress has been von Neumann’s abstruse research.
“People have been kind of scared of it,” said Antony Speranza, a physicist at the University of Amsterdam. But “it does seem to give you these algebraic tools for seeing that a space-time is emerging.”
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