By Michael Blanding
In addition to her work on quantum error correction, Asst. Prof. of Physics Archana Kamal has received another grant of $360,000 from the Department of Energy that lifts her gaze from the tiniest of quantum forces to the furthest reaches of the universe. For this research, she collaborates with UMass Lowell Asst. Prof. of Physics Nishant Agarwal, who also happens to be her husband.
A high-energy physicist with a background in theoretical cosmology, Agarwal had long contemplated the origins of the known universe, stretching back from its beginnings before the Big Bang to the expansion immediately after that scattered matter in every direction.
“There is reasonable evidence that in the early universe, there were quantum fluctuations in the spacetime fabric that caused some disturbances, and then gravity was able to bring these disturbances together to form galaxy clusters,” Agarwal says. Some of those fluctuations, he adds, remain in what scientists call the cosmic microwave background. “Essentially it’s like an overglow or remnant radiation from after the Big Bang,” he says.
That radiation isn’t uniform throughout the sky, lending credence to the theory of these long-ago quantum fluctuations. However, that theory is still not definitive. Together, Agarwal and Kamal are using techniques from quantum information physics to look for vestiges of quantum coherences in the early universe that might still be preserved. “We think there must have been some quantum-to-classical transition, where the quantumness disappeared and classical mechanics were sufficient to describe the universe at later times,” says Agarwal.
“So how did this universe, which started out as a quantum baby, become the classical universe of today?” asks Kamal. “Maybe we can get inspiration from quantum information concepts to actually think about how these kind of quantum-to-classical transitions happen.”
Since they started the research a few years ago with their collaborator from Penn State University, the project has grown to include researchers from about 10 other universities. As for Kamal and Agarwal, their different perspectives, stretching from the smallest particles to the largest galaxies, allow them to zoom in and out of phenomena in their discussions. “Our dinner conversations are very interesting,” Kamal says.