Analog cosmology with two-fluid systems

• Main Author: Fifer, Zachary
• Format: Dissertation
• Language: English
• Published: University of Nottingham 2022
• Subjects: QB Astronomy; QC170 Atomic physics. Constitution and properties of matter

Analog models in physics utilize a conceptual metaphore and a mathematical similarity to describe one system in terms of another. In this thesis, we will present the work that has been done regarding a time-dependent analog examining classical fluid interface waves in order to test predictions from cosmology. We will first detail theoretical work regarding interface waves in a strong-gradient magnetic field, conceived to simulate cosmological inflation, and constituting the first proposal for analog cosmology using interface waves. Motivated by this proposal we will then shift our focus towards parametric resonance, a process by which interface waves are exponentially amplified when coupled to an oscillating gravitational field. We outline an experiment designed to study the effective field theory of the interface, subject to parametric amplification. In this, we demonstrate that it is possible to conduct hundreds of nearly identical experiments while carefully controlling and monitoring the mechanical, optical, chemical, and environmental conditions with previously unachievable levels of precision. Our measurements of the exponential growth and damping rates for the interface waves are believed to be the most precise ever reported. The precise repetitions in the experiment further allow us to comment on the distribution of initial state at sub-micrometer amplitudes, introduce a classical two-mode squeezing model to characterize the linear statistical evolution of the model, and we present preliminary results characterizing the degree of nonlinearity in the system. Our results show that it is possible to control and interact with two-fluid systems to the accuracy needed to mimic and investigate in depth cosmological processes in a controlled laboratory environment. At the heart of this thesis is the desire to gain a deeper understanding of effective or emergent field theories. Our vision is to establish a fluid interface metrology approach to drive theoretical developments in both, the effective field theories in fluids and cosmology alike.