Physicist Sean Carroll Talks Uncertainty and Advances in Quantum Mechanics at Harvard Science Book Talk

California Institute of Technology professor Sean M. Carroll discussed recent advances and unsolved questions in the field of quantum mechanics, addressing a packed lecture hall Wednesday evening.

Harvard philosophy professor Edward J. Hall introduced Carroll, who researches theoretical physics. Carroll gave his talk as part of a promotion for his new book, “Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime.”

In his introduction, Hall highlighted Carroll’s ability to communicate his work to a general audience.

“I think his brilliance as an expositor comes not just from the fact that he knows the physics cold, and not just from the fact that he’s quite skilled in the use of thought experiments to draw out the implications of the physics, but from a motivation that he brings to the study of physics,” Hall said.

Carroll began his remarks by citing a lack of understanding of quantum mechanics among the general population, and a lack of motivation among physicists to understand quantum mechanics at a higher level.

“Professional physicists use quantum mechanics, as it’s the center of all of modern physics,” Carroll said. “And yet, they haven’t done all the work, not only to explain it to the rest of the world, but to even understand it in its own right.”

Carroll also discussed specific and current technical issues in modern quantum mechanics. He said there are many questions associated with the Schrödinger equation — a mathematical formula thought to govern most of the field of quantum mechanics — that remain unsolved.

“There are, these days, perfectly good answers to all these questions,” Carroll said. “Sadly, there is more than one set of perfectly good answers to these questions, and we don’t know which is right.”

Carroll concluded the talk by discussing the “many worlds hypothesis,” the idea that multiple worlds exist concurrently. The hypothesis is one of several concepts Carroll explores in his book, which is aimed at explaining physics to readers without a scientific background.

“The world is not duplicating, like in a Xerox machine, it’s being subdivided. It’s being differentiated,” he said. “But the width, weight, or the thickness of the universe is conserved over time.”

“I hope, if nothing else, this talk has lowered your amount of incomprehension when it comes to quantum mechanics,” he added.

After the lecture, several attendees noted Carroll’s ability to communicate complex ideas straightforwardly.

“He made it quite simple, easier to grasp, and that was his specialty,” Prabidhik Kc ’23 said. “I really liked it, and then some topics I really wanted to understand, I got to learn about today.”

Artist and Massachusetts College of Art and Design professor Barbara Bosworth also praised Carroll’s ability to synthesize information.

“I think it’s important to learn and talk about all sorts of things about the universe,” Bosworth said. “Sean is just someone who’s able to put that in a really understandable format.”

Albert X. Zhu ’23 said he admired Carroll’s efforts to further understand the intricacies of quantum mechanics.

“Even though — as Professor Carroll said — it’s probably almost impossible to understand it completely, it’s in our best interest to figure out as much as we can to understand the fundamentals of how our world operates,” Zhu said.