**Abstract: **Quantum mechanics is important for determining the geometry of spacetime. We will review the role of quantum fluctuations that determine the large scale structure of the universe. In some model universes we can give an alternative description of the physics in terms of a theory of particles that lives on its boundary. This implies that the geometry is an emergent property. Furthermore, entanglement plays a crucial role in the emergence of geometry. Large amounts of entanglement are conjectured to give rise to geometric connections, or wormholes, between distant and non-interacting systems.

Refreshments at 3:15 in CP179.

**About the speaker**: Juan Maldacena is the leading string theorist of his generation. His 1998 discovery of the AdS/CFT correspondence set off a revolution in string theory, and has found applications in many areas of physics and mathematics. Maldacena's work since then has included groundbreaking work in particle physics, cosmology, and quantum gravity. He was awarded a MacArthur Fellowship in 1999, the 2007 APS Dannie Heineman Prize, the 2008 Dirac Medal, the 2012 Fundamental Physics Prize, and is a member of the National Academy of Sciences.

### About the van Winter Memorial Lecture in Mathematical Physics

The van Winter Memorial Lecture honors the memory of Clasine van Winter, who held a professorship in the Department of Mathematics and the Department of Physics and Astronomy from 1968 to her retirement in 1999. Professor Van Winter specialized in the study of multiparticle quantum systems; her contributions include the Weinberg-van Winter equations for a multiparticle quantum system, derived independently by Professor van Winter and Professor Steven Weinberg, and the so-called HVZ Theorem which characterizes the essential spectrum of multiparticle quantum systems. She died in October of 2000.