Professor Larsenâ€™s work is in the general area of theoretical high energy physics with particular focus on quantum gravity. The mathematical implementation of this subject was traditionally known as superstring theory, but the modern and more complete theory is referred to as M-theory. Larsen is working on foundational aspects of M-theory, as well as on its applications to black holes and cosmology.

We have known since the 1970s that black holes are thermal objects. The internal structure responsible for this property was mysterious until recent discoveries in string theory. Larsen made pioneering contributions to this breakthrough and maintains an active research program aimed at uncovering further secrets from the quantum black hole.

The quantum effects of gravity dominate at tremendously small distances, equivalent to enormous energies. It may be that this physics controls the initial conditions of the universe, determined close to the apparent big bang singularity. It is also thought that quantum gravity, through the accumulative effects over large distances, is responsible for the cosmological constant, or dark energy, currently accelerating the universe. Larsen is exploring such cosmological applications with the ultimate goal of finding observable consequences of string theory.

**Selected Publications**

D-Branes and Strings as Noncommutative Solitons, (Jeff Harvey, Per Kraus, Finn Larsen, and Emil Martinec), *Jour. High. Ener. Phys.* **7,** 42 (2000).

String Theory in Magnetic Monopole Backgrounds, (David Kutasov, Finn Larsen and Robert Leigh), *Nucl. Phys. ***B 550,** 183-213 (1999).

Microstates of Four Dimensional Rotating Black Holes from Near Horizon Geometry, (Mirjam Cvetic and Finn Larsen), *Phys. Rev. Lett.* **82,** 484-487 (1999).

Internal Structure of Black Holes, (Finn Larsen and Frank Wilczek), *Phys. Lett ***B 375** 7-42 (1996).