Date of Award

Spring 2026

Degree Type

Thesis

Department

Physics and Astronomy

Director of Thesis

Varsha Kulkarni

Second Reader

Viacheslav Klimenko

Abstract

The fine-structure constant α is a dimensionless constant, defined as e²/(4πε₀ℏc) ≈ 1/137. On the order of human timescales, its value is very much unchanging, however, in recent years there has been extensive debate over whether or not the value of α has remained constant over cosmological timescales. With the natural corollary to a changing α being that either one or multiple of its constituent physical constants have also changed in value, observing a variation in the fine-structure constant would have vast ramifications for our understanding of the nature of the early universe and how it has evolved. While past experiments investigating potential α variations have been limited by the resolution of the spectrograph used (generally HIRES or UVES), the ESPRESSO spectrograph on the Very Large Telescope provides a 50% spectral resolution improvement, and with it an opportunity to more closely investigate past values of the fine-structure constant.

This thesis outlines three strategies for observing a possible temporal variation in the value of the fine-structure constant via absorption line spectroscopy with high-resolution data obtained from the ESPRESSO spectrograph. The techniques - alkali-doublet separation analysis, velocity plot analysis, and many-multiplet analysis via VPFIT - provide progressively better bounds on the value of Δα/α. Three systems at redshifts z = 1.692, 1.7765, and 1.839 are utilized in this experiment, which finds no significant change in the value of α over the past 10 billion years.

First Page

1

Last Page

25

Rights

© 2026, David Hoffman IV

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