Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

Ph.D. in Physics

First Advisor

Luca Bombelli

Second Advisor

Luca Bombeilli

Third Advisor

Alakabha Datta

Relational Format



Causal set theory is an approach to quantum gravity which replaces the continuous spacetime manifold with a discrete set of points and a partial order. In this work, I will focus on causal sets embeddable in two-dimensional manifolds, and define an action based on chains which in the continuum limit replicates the Einstein-Hilbert action; furthermore, I will propose a variational principle based on this action and numerically show it can distinguish nonflat manifoldlike causal sets from the most common type of nonmanifoldlike causal sets. I will then supplement this action with a boundary term similar to the Gibbons-Hawking-York boundary term completing the treatment of two-dimensional causal sets. Finally, I will explore quantum scalar fields on causal sets though the back reaction on the causal set due to the stress-energy tensor of the scalar field is ignored (this is analogous to what is done in quantum field theory in the continuum) via a simple model of a particle detector travelling on a "geodesic" in the causal set.



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