Emanuele Berti and David Kaplan, both professors in the William H. Miller III Department of Physics and Astronomy, were named Simons Investigators in Physics by the Simons Foundation. Simons Investigators are outstanding theoretical scientists who receive a stable base of research support from the foundation, enabling them to undertake the long-term study of fundamental questions.
Berti is a theoretical physicist who specializes in gravitational physics and gravitational-wave astronomy. His research interests include the structure, stability, dynamics, and formation of black holes and neutron stars; gravitational-wave signatures of modified theories of gravity and physics beyond the Standard Model; using gravitational waves to understand black hole binary astrophysics and cosmology; and preparing for the challenge of detecting gravitational waves in space with LISA (Laser Interferometer Space Antenna).
With the Simons funding, he plans to train Johns Hopkins students and postdocs in gravitational-wave physics and astronomy. "The models we use to detect gravitational waves from merging black holes and neutron stars are not perfect," Berti says. His group will work to improve these models, along with the ability to look for physics beyond general relativity. The group will use data from current gravitational-wave detectors to understand how astrophysical binaries of black holes and neutron stars form in the universe. The group will also explore the spectacular science enabled by future gravitational-wave detectors on the ground using the Cosmic Explorer and Einstein Telescope, and in space with LISA. These detectors will be much more sensitive, allowing researchers to use gravitational waves as messengers from the early universe.
Kaplan is also a theoretical physicist who discovers possible theoretical extensions to the standard models of particle physics and cosmology and finds novel ways to test them experimentally. He has discovered models of a naturally small cosmological constant and Higgs mass, classical solutions for firewalls in general relativity, and causal modifications of quantum mechanics. He has also found testable models of dark matter, dark energy, and dark radiation. He has proposed algorithms to discover both heavy and long-lived particles at colliders, as well as techniques for discovering dark matter and new elementary forces using new technologies in novel ways. The Simons funding will allow Kaplan to continue worldwide collaborations exploring some of the fundamentals of theoretical physics that could have dramatic physical consequences in cosmology. As Kaplan researches how gravity and quantum field theory interact, he has come to believe there may be deviations in quantum field theory itself. Discovering how general relativity emerges from a quantum theory has revealed the presence of an additional term in general relativity.
"In that sense, we're saying that there's a correction to Einstein's laws," Kaplan says. "And that correction, if it's there, would look like there is some dark matter in the universe that we can't interact with. That's what we're very excited and curious about and wanting to see if this is really true, and what the consequences of that are."