Date of Award


Document Type

Honors Thesis (Colby Access Only)


Colby College. Physics and Astronomy Dept.


Robert T. Bluhm


The aim of Physics is to provide a mathematical description of the physical universe and its underlying laws. Currently, the greatest problem lies in uniting the four fun- damental forces: gravitation, electromagnetism, strong interaction, and weak interac- tion. Various methods have been utilized in an attempt to provide a solution, however it is still impossible. The largest difficulty in developing a unified theory has been uniting relativity and quantum physics. Separately, both fields have been extremely successful, however no viable quantum theory of gravity is known. Approaches that look at quantum effects in the context of a gravity have revealed several issues that arise. In particular, the question of how to define a quantum vacuum, in the context of a curved background, has received much attention in the recent years. In this thesis, I will look at the approach to Quantum Field Theory through Classical Field Theory, working with scalar, vector, and tensor fields. I will then quantize a scalar field in a flat spacetime and define the vacuum state. Finally, I will look at quan- tum fields in the background of an expanding universe and show that our previously defined vacuum state is no longer the “true” vacuum.


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Vacuum, Field theory, Quantum Field Theory, Relativity, Gravity, Quantum Mechanics, Classical Field theory, Ambiguity, Unified theory