# Aron Wall wins Breakthrough New Horizons Prize for work on black holes and spacetime

Aron Wall employs concepts from across theoretical physics, from black holes to the holographic principle, in the quest to answer a fundamental question: What is spacetime?

Stanford research scientist Aron Wall has been awarded a 2019 Breakthrough New Horizons in Physics Prize for fundamental insights about quantum information, quantum field theory and gravity.

The $100,000 prize is given each year to up to three “promising junior researchers who have already produced important work,” according to the prize website. This year, Wall shares the prize with physicists Daniel Jafferis of Harvard University and Daniel Harlow of MIT. Wall has co-authored scientific papers with both of them. They will receive their prize at an award ceremony to be held Nov. 4.

“It’s very humbling to get an award like this, especially when I know so much of the great work that other people do,” said Wall, who is a part of the Stanford Institute for Theoretical Physics (SITP).

New Horizons prizes are one of three groups of Breakthrough Prizes in physics – the others are the $3 million Special Breakthrough Prize and the $3 million Breakthrough Prize. The Breakthrough Prizes also recognize researchers in mathematics and life sciences.

## A common thread

The selection committee of the New Horizons prizes considers a scientist’s entire body of work when doling out the awards. At first glance, Wall’s research seems to span an eclectic mix of interests that range from black hole thermodynamics to quantum information theory.

For his doctoral thesis at the University of Maryland, Wall proved a longstanding conjecture that black holes must obey the second law of thermodynamics, which has to do with irreversible processes in nature.

Wall later broadened his research focus toward the holographic principle, which is the idea that the information in a three-dimensional volume of space can somehow be encoded in a two-dimensional surface outside of it. An analogy is reconstructing all of the objects within a room using only the information contained in its floor, ceiling, and walls.

In 2017, Wall co-authored a paper that showed how to use quantum effects to connect two distant black holes to create a stable tunnel, or “wormhole,” between them. “This is the only known way to construct a traversable wormhole in string theory,” Wall said. “Unfortunately, the method we used for opening the wormhole automatically prevents you from using it for faster-than-light travel. You can still get through it, but it’s slower than if you go around the long way.”

As disparate as his research projects might seem, Wall said there is a common thread that unites them. “What ties most of my work together is that I’m trying to answer the question: What is spacetime made out of?” Wall said.

## Entangled webs

Over the past several years, physicists have begun thinking about spacetime in a radically different way. Instead of just an empty backdrop for the unfolding story of the universe, it’s more fruitful, they say, to treat spacetime as the flow of quantum information from one point to another.

Wall and others are growing increasingly convinced that thinking about spacetime in this way could be the key to developing a theory that can account for gravity using the principles of quantum mechanics—a decades-old dream in physics that dates back to Albert Einstein.

Black holes enter the picture because, according to Einstein’s theory of general relativity, they are gravitational distortions of spacetime. “A black hole is pure gravity,” Wall said. “There is no ‘stuff’ there anymore, so anything we learn about black holes must also be about spacetime.”

Traversable wormholes also come into play because Wall and others have demonstrated that using wormholes to travel between black holes is mathematically equivalent to quantum teleportation – the process by which quantum information is transmitted from one location to another using a pair of connected, or “entangled,” particles.

One intriguing possibility, first put forth by Leonard Susskind, the Felix Bloch Professor in Physics at Stanford, and Juan Maldacena of the Institute for Advanced Study in Princeton, New Jersey, is that if wormholes between black holes are identical to quantum entanglement, and spacetime works the same way as black holes, then quantum entanglement may be a fundamental aspect of spacetime itself.

Space as we know it may be an emergent property of the universe, a consequence of information flowing between entangled quantum bits, or “qubits,” connected by tiny wormholes.

“If this is right,” Wall said, “then the act of moving from point A to point B is fundamentally no different than quantum teleporting through a wormhole.”

## An early start

Wall, 34, grew up in the Bay Area and traces his lifelong fascination with physics to a specific childhood incident. At the age of 7, he checked out a children’s book about physics from the Mountain View Public Library. The chapters of the book were about things like force, pressure and energy, which seemed boring to the young Wall. But near the end, the book mentioned that physicists had recently discovered that subatomic particles such as protons and neutrons were made of even smaller particles, called quarks. “That surprised me because I’d never heard it before,” Wall recalled.

From that moment on, Wall’s reading list always included physics books like Stephen Hawking’s *A Brief History of Time*. He made charts of all the known elementary particles, collecting them the way that other kids collected baseball cards. In order to delve deeper into physics, Wall taught himself algebra in the fourth grade and calculus in middle school. By high school, he was taking college-level math courses.

Wall came to Stanford in 2017, where he has worked closely with the research group of __Patrick Hayden__, a professor of physics and an expert in quantum information theory at SITP.

Wall is also the recipient of the 2013 Bergmann-Wheeler Thesis Prize, the 2018 Philippe Meyer Prize in Theoretical Physics and the 2018 Young Scientist Prize for the International Commission on General Relativity & Gravitation.

In 2019, he will leave Stanford to become a lecturer (the British equivalent of an assistant professor) at Cambridge University in the United Kingdom.

## Media Contacts

Amy Adams, Stanford News Service: (650) 497-5908, amyadams@stanford.edu

Ker Than, School of Humanities and Sciences: (650) 723-9820, kerthan@stanford.edu