Bianca Dittrich: Explorer Beyond Boundaries

Bianca Dittrich grew up in East Berlin, where the Wall wasn’t just a symbol — it was an omnipresent part of the landscape, hemming in her neighborhood on three sides. She could see it from her schoolyard. 

She was 12 when the Wall fell. The day after it was toppled, she walked with her family into West Berlin for the first time. 

That moment — symbolizing the sudden collapse of a seemingly immovable physical and political boundary — had a profound effect on Dittrich. 

She hasn’t stopped pushing boundaries since. 

Today, Dittrich’s work as a theoretical physicist involves confronting a different kind of wall: the one that divides general relativity and quantum mechanics. She’d like to bring down that wall, too. 

A longtime faculty member and Faculty Chair at Perimeter Institute, Dittrich is a leader in quantum gravity — a field that seeks to reconcile Einstein’s smooth spacetime with the probabilistic fuzziness of the quantum world. 

“Quantum gravity research is about finding a theory which describes all physics happening from the smaller scales like Planck scale… to the larger scale, basically the visible universe at 90 billion light years,” she explains. “We expect at the smaller scale that space and time are different from how we experience it… we expect that space and time will be quantum.”

The quest for a unified theory that can describe everything from the center of black holes to the beginning of the universe is what first drew Dittrich to physics. 

“I got interested in these big questions,” she recalls. “What is the universe made of? How does the universe work? How do black holes work?” 

As a teenager, she read Stephen Hawking’s A Brief History of Time and other popular science books that scratched at something deeper than curiosity  — an urge to understand the fundamental nature of reality.

 “That is one part, the philosophical questions,” she says. “And the second part is basically the elegance and effectiveness of physics. So you explain basically all natural phenomena, or almost all natural phenomena, by a few principles.”

Her path into Perimeter began in Germany, where she completed her PhD at the Max Planck Institute under Thomas Thiemann. She first came to Perimeter in 2003 as a visiting PhD student, returned as a postdoc in 2005, and joined the faculty in 2012. 

“It’s still a very cool place,” she says. “There’s lots of energy and discussions going on and lots of fun to be had at this place.”

What makes Perimeter different, she says, is the exchange of ideas across subfields that traditionally don’t overlap. 

“Quantum gravity is only done at a few places, and usually, if research is done, you find only people from a given approach,” she says. “Perimeter is indeed the largest research centre in the world in terms of quantum gravity. Because it's not only the quantum gravity researchers, but also quantum field theory, string theory, quantum foundations, even quantum matter — all interested in quantum gravity.”

Dittrich’s own approach focuses on loop quantum gravity and spin foam models — frameworks that treat spacetime as a quantum structure built from discrete chunks. 

A big unanswered challenge in the field is showing how these microscopic chunks can “glue together” to form a smooth spacetime on larger scales. “That is a… very hard task,” she says. 

“It’s basically much harder than what we have so far achieved in physics.” 

The hardness of the problems, she says, is a big part of the appeal. The more perplexing the challenge, the greater the satisfaction of solving it. 

In a recent breakthrough, Dittrich reformulated the dynamics of spin foam models to make them easier to compute — and, unexpectedly, more powerful. 

That work anchors her “Discretuum to Continuum” initiative at Perimeter, which aims to show how quantum geometry gives rise to the classical world we observe. The technical hurdles are immense. 

“The Planck scale is so small—way beyond what we can probe at particle accelerators,” Dittrich explains. “We hope we can probe it by having better cosmological probes, possibly via gravitational waves. But there’s still a large range of scales we don’t really understand.”

Even so, she remains optimistic. “I am optimistic, yes,” she says. “Many attempts possibly did fail because we were missing, for instance, computational tools. And that's what I hope we will improve a lot in the near future — that we can indeed construct the theory of quantum gravity.”

And if such a final theory proves elusive? It’s still worth the pursuit, she says. 

“Quantum gravity has driven innovation in physics in many ways. Gauge theories, which are now the basis of particle physics… Noether’s theorem was invented to explain gravity… even topological quantum field theories, which play a big role in condensed matter, were also invented in quantum gravity.” 

As Faculty Chair, she also helps guide the culture at Perimeter. “A big part of being a Faculty Chair is to try to bring people together and to make the institute work more effectively,” she says. 

Her hope is that the institute continues to grow while retaining the curiosity and creativity that drew her there in the first place. The same force that pushed her past the barriers of her childhood now drives her to explore the boundaries of physics — not to reinforce them, but to keep pushing forward. 

“I hope Perimeter Institute will still grow, keeping its innovative edge and cool edge. The hope for Perimeter Institute ‘is to make some history.’