`2023-03-21 15:45:00``2023-03-21 16:45:00``Colloquium- Pierre Heidmann (Johns Hopkins University)-Topological Stars from Quantum Gravity``Dr. Pierre Heidmann Johns Hopkins University Topological Stars from Quantum Gravity Location: 1080 Physics Research Building, Smith Seminar Room Faculty Hosts: Eric Braaten & Samir Mathur Abstract: In this colloquium, I will discuss new degrees of freedom of gravity as motivated by string theory. Although they are expected to be generically quantum mechanical, classes of such states are coherent enough to admit classical descriptions in Einstein gravity. I will explain how to describe them as novel ultra-compact geometries without horizon or singularity. These solitons of spacetime are referred to as Topological Stars. I will discuss their potential role in quantum gravity to resolve astrophysical black holes. Furthermore, in light of the emerging field of black hole astronomy, we will see how they can provide an interesting experimental window into the quantum aspects of gravity. Bio: I obtained my master degree in theoretical physics at ENS Paris in France. Then, I did my Ph.D. at IPhT CEA Saclay on the subject of black hole microstates in string theory and studied the fundamental nature of black holes in the supersymmetric paradigm. I am currently finishing a postdoctoral fellowship at Johns Hopkins University. My research focuses on understanding the fundamental degrees of freedom that make up black holes. More broadly, I am interested in the fundamental constituents and quantum aspects of gravity, and how they may translate into new observables for black hole astrophysics.``1080 Physics Research Building``OSU ASC Drupal 8``ascwebservices@osu.edu``America/New_York``public`

`2023-03-21 15:45:00``2023-03-21 16:45:00``Colloquium- Pierre Heidmann (Johns Hopkins University)-Topological Stars from Quantum Gravity``Dr. Pierre Heidmann Johns Hopkins University Topological Stars from Quantum Gravity Location: 1080 Physics Research Building, Smith Seminar Room Faculty Hosts: Eric Braaten & Samir Mathur Abstract: In this colloquium, I will discuss new degrees of freedom of gravity as motivated by string theory. Although they are expected to be generically quantum mechanical, classes of such states are coherent enough to admit classical descriptions in Einstein gravity. I will explain how to describe them as novel ultra-compact geometries without horizon or singularity. These solitons of spacetime are referred to as Topological Stars. I will discuss their potential role in quantum gravity to resolve astrophysical black holes. Furthermore, in light of the emerging field of black hole astronomy, we will see how they can provide an interesting experimental window into the quantum aspects of gravity. Bio: I obtained my master degree in theoretical physics at ENS Paris in France. Then, I did my Ph.D. at IPhT CEA Saclay on the subject of black hole microstates in string theory and studied the fundamental nature of black holes in the supersymmetric paradigm. I am currently finishing a postdoctoral fellowship at Johns Hopkins University. My research focuses on understanding the fundamental degrees of freedom that make up black holes. More broadly, I am interested in the fundamental constituents and quantum aspects of gravity, and how they may translate into new observables for black hole astrophysics. ``1080 Physics Research Building``Department of Physics``physics@osu.edu``America/New_York``public`Dr. Pierre Heidmann

Johns Hopkins University

**Topological Stars from Quantum Gravity**

*Location: 1080 Physics Research Building, Smith Seminar Room*

Faculty Hosts: Eric Braaten & Samir Mathur

**Abstract: **In this colloquium, I will discuss new degrees of freedom of gravity as motivated by string theory. Although they are expected to be generically quantum mechanical, classes of such states are coherent enough to admit classical descriptions in Einstein gravity. I will explain how to describe them as novel ultra-compact geometries without horizon or singularity. These solitons of spacetime are referred to as *Topological Stars*. I will discuss their potential role in quantum gravity to resolve astrophysical black holes. Furthermore, in light of the emerging field of black hole astronomy, we will see how they can provide an interesting experimental window into the quantum aspects of gravity.

**Bio: **I obtained my master degree in theoretical physics at ENS Paris in France. Then, I did my Ph.D. at IPhT CEA Saclay on the subject of black hole microstates in string theory and studied the fundamental nature of black holes in the supersymmetric paradigm. I am currently finishing a postdoctoral fellowship at Johns Hopkins University. My research focuses on understanding the fundamental degrees of freedom that make up black holes. More broadly, I am interested in the fundamental constituents and quantum aspects of gravity, and how they may translate into new observables for black hole astrophysics.