Holography for closed universes & Non-supersymmetric branes, bordism, and fractional charges.

CMSA EVENTS: CMSA Geometry and Quantum Theory Seminar

When: October 28, 2025
4:15 pm - 6:15 pm
Where: Science Center 507
Address: 1 Oxford Street, Cambridge, MA 02138, United States
Speaker: Elliott Gesteau (CMSA) | Sanjay Raman (Harvard)

Elliott Gesteau

Title: Holography for closed universes

Abstract: Recent advances in holography and black hole physics have prompted a number of new puzzles related to the physics of closed universes, which can be argued to have a one-dimensional Hilbert space of states from various perspectives. In this talk I will review this new set of puzzles, with an emphasis of the mathematical questions that they seem to raise.

Sanjay Raman

Title: Non-supersymmetric branes, bordism, and fractional charges.

Abstract: We dive a little deeper into the non-supersymmetric brane configurations studied in Kaidi-Tachikawa-Yonekura (2024). We study the gravitational analogues of the branes in the aforementioned paper, relating them to relative defects predicted by the Cobordism Conjecture, and we argue for the existence of objects carrying fractional heterotic string and M2-brane charge.