Critical Reviews of Causal Patch Measure over the Multiverse

TL;DR

This paper critically reviews the causal patch measure in the multiverse, examining its basis in black hole complementarity and its ability to address cosmological problems, while also discussing potential challenges to its validity.

Contribution

It offers a critical analysis of the causal patch measure, highlighting its similarities to black hole complementarity and discussing possible counterexamples that challenge its assumptions.

Findings

Relates causal patch measure to black hole complementarity.

Addresses the measure's success in solving the Boltzmann brain problem.

Identifies potential counterexamples challenging the measure's validity.

Abstract

In this talk, the causal patch measure based on black hole complementarity is critically reviewed. By noticing the similarities between the causal structure of an inflationary dS space and that of a black hole, we have considered the complementarity principle between the inside and the outside of the causal horizon as an attractive way to count the inflationary multiverse. Even though the causal patch measure relieves the Boltzmann brain problem and stresses physical reality based on observations, it could be challenged by the construction of counterexamples, both on regular black holes and charged black holes, to black hole complementarity.