Theoretical Physicist Ana Asenjo-Garcia Named a 2021 Packard Fellow

One of 20 early-career researchers selected for the fellowship, Asenjo-Garcia is exploring how light and matter interact at the quantum level.

Ellen Neff
October 14, 2021

Ana Asenjo-Garcia’s career has long followed the light. She started her career with eyes on the stars, but these days, she’s busy exploring the smallest scales of light—photons—and how they shape our world. Her work in quantum optics has earned her the recognition of the Packard Foundation, which today announced its 2021 list of Packard Fellows. Asenjo-Garcia is one of 20 early-career researchers to receive the prestigious award this year.  

She grew up in a small city in Spain and first developed her interest in physics as a teenager. “I liked the predictive power of physics combined with math,” she said, recalling time spent trying to solve problems of inclined planes, or how objects behave on ramps. After reading popular physics tomes, including those by Stephen Hawking, she was drawn to astrophysics as she entered college. But as an undergraduate at Complutense University in Madrid, she grew a closer connection to the science that underpins our daily lives: the physics that occurs within and between the atoms that make up us and the world with which we interact, rather than that of the cosmos.

During her masters and as a PhD student at the Institute of Photonic Sciences (ICFO) studying plasmonics—the study of how light interacts with metals—Asenjo-Garcia was introduced to the field of quantum optics. This is an area of physics that attempts to understand the properties of photons and characterize what happens when they interact with matter, such as atoms. It’s a research field that has produced amazing discoveries, such as lasers, and has promising applications for storing and processing information and taking precise measurements.

While experimental scientists are busy firing lasers at objects and adjusting magnetic fields, theorists like Asenjo-Garcia attempt to make sense of those observations. “I’m writing on the blackboard and trying to come up with the most minimal model that describes what they are seeing,” she says. She also proposes ideas for them to test in the lab. The mathematical tools exist to describe the world, she said: you just need to find the right ones.

“I strive to be a better scientist every day; it’s a process of learning, both about science and about yourself,” Ana Asenjo-Garcia said. “I really have a lot of fun in my job.”

Over a career that has taken her from Madrid, to Southern California, and now New York, Asenjo-Garcia has made notable discoveries about how ensembles, or groups, of atoms interact and exchange photons with one another. When you shine a laser on an atom, one of its electrons absorbs photons and gets excited; soon, however, this electron will decay back down to what’s known as its ground state, losing the energy the photons added. Conventionally, this dissipation and decay is considered to be a bad thing, but Asenjo-Garcia sees advantages.

When multiple atoms are close to each other, they start behaving collectively. In certain situations, Ansejo-Garcia has shown that groups of excited atoms can become entangled with one another and enter perpetual “dark states,” in which they never re-emit those added photons and become theoretically capable of storing information forever. More recently, she has been looking at the opposite behavior: the rapid decay of atoms in lattices. Due to correlations that develop as they decay, such atoms will release their energy in an intense and fast burst, which can be harnessed to produce new light sources, such as “superradiant” lasers.

“She has a novel way of looking at things,” said Dmitri Basov, Higgins Professor of Physics at Columbia. “That’s beginning to define Ana’s style. She’s not walking along well-defined paths: she’s a trail blazer.” Asenjo-Garcia is indeed bringing a unique way of thinking to physics at Columbia, and elsewhere. “Her results and my collaborations with her have stimulated entire new research directions in my group, and I know that the same is true of her interactions with other groups as well,” said Darrick Chang, her former postdoc advisor at ICFO in Barcelona. “That aspect makes her a very valued collaborator and colleague, on top of being one of the young leaders in her field.”

Asenjo-Garcia runs a research group in Columbia's physics department that now counts seven students and postdocs. As with atoms, the ensemble can be stronger than the individual. “I don’t know all the answers, and nor do they; we’re trying to help each other,” she said. “I am very privileged to have outstanding people to talk with about physics—now my students and postdocs, and before, my postdoctoral mentors. It is because of their help and support that I get to do this for a living.” She also benefits from frequent science discussions with her husband, who is also a physicist and has been extremely supportive of her career. “I strive to be a better scientist every day; it’s a process of learning, both about science and about yourself,” she said. “I really have a lot of fun in my job.”

Beyond research, she encourages her group and other graduate students to share their skills and love of science with kids in the community—she’s a first-generation college student herself, so she embraces opportunities to help motivate teenagers to pursue STEM careers. Last year, for example, she established a program to teach coding and physics to students at a nearby charter school, Democracy Prep Harlem High School, which is now fully run by graduate students in physics and astronomy. “Their response has been fantastic, and they are really the ones moving it forward,” she said. “I’m just there to help out when they need it.”  She is also involved with the Bridge to PhD Program, a mentoring program at Columbia for underrepresented STEM students, and is helping to develop new quantum courses.

With her Packard Fellowship, a five-year, $875,000 award, Asenjo-Garcia plans to keep exploring correlated quantum behavior in ever-larger groups of atoms. In the future, she is also curious to delve into the role of synchronization in biological systems, such as in groups of neurons, where coordination between many particles plays a crucial role in their functioning.

A few words of motivation? Push beyond your comfort zones. To blaze a trail, you need to take those detours that inevitably turn up whenever you embark on a new problem. As her former post-doc advisor Jeff Kimble of Caltech once said: “If you know what you’re doing, don’t do it.”