Hundreds of researchers in a collaborative project called “It from Qubit” say space and time may spring up from the quantum entanglement of tiny bits of information
“All the world’s a stage…,” Shakespeare wrote, and physicists tend to think that way, too. Space seems like a backdrop to the action of forces and fields that inhabit it but space itself is not made of anything—or is it? Lately scientists have begun to question this conventional thinking and speculate that space—and its extension according to general relativity, spacetime—is actually composed of tiny chunks of information. These chunks might interact to create spacetime and give rise to its properties, such as the concept that curvature in spacetime causes gravity. If so, the idea might not just explain spacetime but might help physicists achieve a long-sought goal: a quantum theory of gravity that can merge general relativity and quantum mechanics, the two grand theories of the universe that tend not to get along. Lately the excitement of this possibility has engrossed hundreds of physicists who have been meeting every three months or so under the banner of a project dubbed “It from Qubit.”
The “it” in this case is spacetime, and the qubit (pronounced “cue-bit,” from “quantum bit”) represents the smallest possible amount of information—a computer “bit” on a quantum scale. The idea suggests the universe is built up from some underlying code, and that by cracking this code, physicists will finally have a way to understand the quantum nature of large-scale events in the cosmos. The most recent It from Qubit (IfQ) meeting was held in July at the Perimeter Institute for Theoretical Physics in Ontario, where organizers were expecting about 90 registrants. Instead, they got so many applications they had to expand to take 200 and simultaneously run five satellite sessions at other universities where scientists could participate remotely. “I think this is one of the most, if not the most, promising avenues of research toward pursuing quantum gravity,” says Netta Engelhardt, a postdoctoral researcher at Princeton University who is not officially involved in It from Qubit but who has attended some of its meetings. “It’s just taking off.”
Because the project involves both the science of quantum computers and the study of spacetime and general relativity, it brings together two groups of researchers who do not usually tend to collaborate: quantum information scientists on one hand and high-energy physicists and string theorists on the other. “It marries together two traditionally different fields: how information is stored in quantum things and how information is stored in space and time,” says Vijay Balasubramanian, a physicist at the University of Pennsylvania who is an IfQ principal investigator.
About a year ago the Simons Foundation, a private organization that supports science and mathematics research, awarded a grant to found the It from Qubit collaboration and finance physicists to study and hold meetings on the subject. Since then excitement has grown and successive meetings have drawn in more and more researchers, some official members of the collaboration funded by Simons and many others simply interested in the topic.
“The project is addressing very important questions, but very difficult questions,” says IfQ collaborator Beni Yoshida, a postdoctoral researcher at Perimeter. “Collaboration is necessary—it’s not like a single person can solve this problem.” Even scientists outside of the project have taken notice. “If the link with quantum information theory proves as successful as some anticipate, it could very well spark the next revolution in our understanding of space and time,” says string theorist Brian Greene of Columbia University, who is not involved in IfQ. “That’s a big deal and hugely exciting.”
Source: Clara Moskowitz
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