Landskepticism: or Why Effective Potentials Don't Count String Models

TL;DR

The paper argues that the string landscape is not an established feature and cannot be meaningfully defined without a rigorous cosmological framework based on the Big Bang and eternal inflation. It critiques the use of effective potentials in string theory, highlighting the limited validity of Wilsonian-like actions and the gravitational obstacles to naive vacuum counting. Through discussions of eternal inflation, CDL instantons, and AdS/CFT constraints, it shows that landscape constructions lack a coherent, universal quantum-gravity foundation and that initial conditions and global structure critically affect predictions. Consequently, anthropic reasoning and vacuum enumeration remain speculative without a robust theoretical framework, suggesting a need for a rigorous Big Bang/holographic approach to ground string cosmology.

Abstract

This paper is a synthesis of talks I gave at the Cargese Workshop in June 2004 and the Munich Conference on Superstring Vacua in November 2004. I present arguments which show that the landscape of string theory is not a well established feature of the theory, as well as a brief discussion of the phenomenological prospects of the landscape and the use of the anthropic principle.