TASI Lectures on Holographic Space-Time, SUSY and Gravitational Effective Field Theory

TL;DR

This paper challenges traditional notions of vacuum in quantum gravity, proposing a holographic space-time framework that leads to a non-singular quantum Big Bang cosmology with de Sitter future and approximate supersymmetry.

Contribution

It introduces holographic space-time as a new quantum mechanical approach to quantum gravity, linking solutions to different quantum systems and deriving cosmological implications.

Findings

Different gravitational solutions correspond to different quantum systems.

Holographic space-time models are exactly super-Poincare invariant in asymptotically flat space.

The formalism predicts a non-singular quantum Big Bang with de Sitter future and specific supersymmetry properties.

Abstract

I argue that the conventional field theoretic notion of vacuum state is not valid in quantum gravity. The arguments use gravitational effective field theory, as well as results from string theory, particularly the AdS/CFT correspondence. Different solutions of the same low energy gravitational field equations correspond to different quantum systems, rather than different states in the same system. I then introduce {\it holographic space-time} a quasi-local quantum mechanical construction based on the holographic principle. I argue that models of quantum gravity in asymptotically flat space-time will be exactly super-Poincare invariant, because the natural variables of holographic space-time for such a system, are the degrees of freedom of massless superparticles. The formalism leads to a non-singular quantum Big Bang cosmology, in which the asymptotic future is required to be a de Sitter space, with cosmological constant (c.c.) determined by cosmological initial conditions. It is also approximately SUSic in the future, with the gravitino mass $K \Lambda^{1/4}$.