## Date of Award

8-23-2024

## Degree Type

Dissertation

## Degree Name

Doctor of Philosophy (PhD)

## Department

Physics

## Advisor(s)

Jay Hubisz

## Keywords

Cosmology;High energy physics;Holography;Open Quantum systems;Phenomenology;Quantum Computing

## Subject Categories

Physical Sciences and Mathematics | Physics

## Abstract

Open quantum systems (OQS) are ubiquitous in various fields of physics, such as high energy physics, cosmology, atomic and molecular physics, and quantum optics. In some cases, there is a natural separation between the system and the environment, like the presence of a horizon in inflationary cosmology. In other cases, like field theories coupled to thermal baths or at finite chemical potential, it is not practical to simulate the large number of degrees of freedom making up the bath. The system of interest can be described by an effective theory upon integrating out the environment degrees of freedom. In certain cases, the effective theory is well-approximated by non-hermitian Hamiltonians, which generically have a sign problem. The work presented in this thesis explores OQS in two contexts: 1. Study the phenomenology of inflationary cosmology in holographic models, showing their viability and the measurable signatures they leave on the cosmic microwave background (CMB). 2. Use the OQS formalism developed in quantum information science (QIS) to construct algorithms to study the real-time dynamics of dissipative many-body quantum systems using quantum computers, which offer an avenue to get around the sign problem.

## Access

Open Access

## Recommended Citation

Sambasivam, Bharath, "Open Quantum Systems in High Energy Physics" (2024). *Dissertations - ALL*. 1984.

https://surface.syr.edu/etd/1984