Vacuum Selection on the String Landscape

TL;DR

This paper explores non-anthropic methods for selecting the universe's initial vacuum state from the string landscape, questioning the relevance of initial conditions and proposing eternal inflation and noncritical string theory as alternative explanations for the observed cosmological constant.

Contribution

It introduces a perspective that initial conditions may be irrelevant, emphasizing eternal inflation and noncritical string theory to explain the small cosmological constant.

Findings

All vacua are possible initial conditions in the landscape.

Eternal inflation can generate all vacua.

Noncritical string theory relates CC values to departures from equilibrium.

Abstract

I examine some non-anthropic approaches to the string landscape. These approaches are based on finding the initial conditions of the universe using the wavefunction of the multiverse to select the most probable vacuum out of this landscape. All approaches tackled so far seems to have their own problems and there is no clear cut alternative to anthropic reasoning. I suggest that finding the initial conditions may be irrelevant since all possible vacua on the landscape are possible initial state conditions and eternal inflation could generate all the other vacua. We are now left to reason out why we are observing the small value of the cosmological constant (CC). I address this issue in the contest of noncritical string theory in which all values of the cosmological constant on the landscape are departures from critical equilibrium state.