Causal Sets and an Emerging Continuum

TL;DR

This paper discusses how most non-manifoldlike causal sets are suppressed in the gravitational path integral, advancing the understanding of how continuum spacetime might emerge from discrete causal set theory.

Contribution

It presents recent results showing strong suppression of non-manifoldlike causal sets in the gravitational path integral, a step toward emergent continuum spacetime.

Findings

Non-manifoldlike causal sets are strongly suppressed in the path integral.

Most causal sets do not resemble continuum spacetimes.

Progress towards understanding the emergence of continuum spacetime from causal sets.

Abstract

Causal set theory offers a simple and elegant picture of discrete physics. But the vast majority of causal sets look nothing at all like continuum spacetimes, and must be excluded in some way to obtain a realistic theory. I describe recent results showing that almost all non-manifoldlike causal sets are, in fact, very strongly suppressed in the gravitational path integral. This does not quite demonstrate the emergence of a continuum -- we do not yet understand the remaining unsuppressed causal sets well enough -- but it is a significant step in that direction.