My lunch companion sits down with a clamshell container. Physicist Sagar Lokhande is a graceful, careful man, and he settles his tall frame across the table from me. He pops open the clamshell.
“Wow. What is that called?”
He regards the imposing mound. “Loaded tater tots.” He pauses. “I’m trying to gain weight. I’m always trying to gain weight.”
“That looks like a good choice.”
Sagar, a postdoc at the University of Illinois, Urbana-Champaign, has come to the Kavli Institute for Theoretical Physics (KITP), in Santa Barbara, Calif., for a three-month program on “gravitational holography.” Here, some of the brightest physicists in the world push the boundaries of understanding how and where gravity and quantum physics will finally have to shake hands and declare some sort of truce. Odds in Vegas suggest this will happen near the boundary of a black hole.
Wearing my writer’s hat, I’m allowed to snoop about KITP’s prestigious ivory tower and ask all sorts of questions, including “Why physics?” When and how did each of these people know they would be called to this difficult, heady work? In the weeks before the pandemic would take over almost every conversation, I collected their reflections.
Sagar recalls precisely how it happened, when he was about 17. “One evening I was just laying down in my dorm room—I lived in student housing, away from my family—and I was looking at the lamp.” As he thought about the light filling the space around him, he was filled with an urge to understand everything about it, an exact description of its inner nature and its flight from the bulb.
Some of the leading theoretical physicists in the world walk the hallways here at KITP, pausing to sketch and dissect new ideas at the well-placed chalkboards. Juan Maldacena, a professor at the Institute for Advanced Study and winner of many physics prizes, including medals named for Galileo and Einstein, serves as a scientific advisor to the program on gravitational holography. He has previously said he was pulled to physics by an early fascination with electricity. I ask him for details from his childhood in Argentina. He tells me his father did engineering work in the elevator industry. But at home, “the washing machine kept breaking down, and my father and I would fix it.” He pauses and laughs. “Years later, my father said, ‘now your washing machine is too good. Now your son will not be interested in physics!’”
Some trace their start to disquieting childhood questions they could not shake. Veronika Hubeny, a professor at the University of California, Davis, and the founding director for the Center for Quantum Mathematics and Physics, recalls a particular question from her most tender years in Czechoslovakia. “I’d spend nights wondering, for instance, whether giants would have the same perception of time as dwarfs.” Mind you, she was contemplating mythical creatures and not different types of stars at that age. But her earnest and troubling question presaged a life contemplating the geometries that relate mass to space and time.
Cumrun Vafa, a highly decorated mathematical physicist at Harvard University, recipient of a Breakthrough Prize in Fundamental Physics, and a leading light in string theory, had a different sort of troubling childhood question. Vafa is coordinating a KITP program on the string “swampland.” He coined the term in 2005 to propose a way for physicists to wade into string theory’s 10272,000 possible solutions and rule some large acreage of them as “swampland,” physically inconsistent and unworthy for local planning commissions. He has previously shared that, as a second-grader in Iran, he looked at the moon and wondered why it did not fall to Earth like everything else. It was this very practical, Newton-like moment that helped physics set the hook for the young Vafa. I ask him if anyone answered it for him. He shakes his head but says that wasn’t important. “What bothered me was not that I couldn’t get a good answer but that it didn’t bother anyone else.”
Alejandra Castro, a professor of physics at the University of Amsterdam, is newer to the game but is as well-regarded in her black hole work as she is well-spoken. Compared to some of the origin stories, physics spoke to her somewhat later. “When I was a little girl, I wanted to be a flight attendant, because girls couldn’t be pilots,” she says. “I was always interested in traveling.” In high school, Alejandra’s mathematical skills became obvious but suggested a fixed direction. “If you’re good at math in Chile, you’re going to be an engineer,” she says. “My family is filled with engineers.”
But at age 17, a profile of astronomer María Teresa Ruiz opened a new path. “I discovered through this newspaper article that astronomers knew a lot of math and science and had the opportunity to go all over the world. I was like, oh that sounds fascinating.” She was off and running from that moment, but astronomy could not hold her. Once she discovered Einstein’s general relativity, she recognized her calling in theoretical physics.
I’m wrapping up lunch with Sagar Lokhande. I need to let him get back to his real work, and it’s his last day at KITP. Closing my laptop, as usual, summons something important. Sagar says he aims to maintain a childlike sense of wonder, that scrutiny of the lamp. But there’s something else pushing him too. Sagar shares that he’s the only person from his agricultural community in India, some 70 miles outside Mumbai, to ever leave India. He returns once per year. “At least 10 parents have come up to me and asked me to explain to their kids what it is I do,” he says. “This is a place where people would not usually study pure science.” Newspaper articles in his hometown follow his progress. He’s been on a somewhat lonely expedition, away from his family, but people are watching.
Sagar and his colleagues climb to the most difficult ledges of physics from an array of different routes and base camps. While the rest of us squint to glimpse them above, it’s easy to miss an occasional byproduct of their work: turning on lamps that can inspire others, far from the academic ledges, to question their own paths forward.