Bret Underwood

Professor of Physics

Pacific Lutheran University

 I enjoy teaching a wide variety of courses, including introductory physics, Mathematical Physics, Experimental Physics, and Introduction to Quantum Mechanics.


My research interests are in the intersection of high energy physics, cosmology, and quantum information theory.

My Background

2023 - present: Professor of Physics, Pacific Lutheran University

2017 - 2023: Associate Professor of Physics, Pacific Lutheran University

2011 - 2017: Assistant Professor of Physics, Pacific Lutheran University

2008 - 2011: Postdoctoral Researcher, McGill University, Montreal, Canada

2003 - 2008: Ph.D. Theoretical Physics (2008), M.A. Physics (2005), University of Wisconsin-Madison

1999 - 2003: B.S. Physics, magna cum laude with distinction, Ohio State University

Teaching

My approach to teaching is to focus first on the learning goals for my students, and then determine the activities and assessments we will use to learn that material.

As a result, my courses tend to be highly interactive and require students to actively participate in class.

As an example, check out this spotlight on my teaching!

Some courses I have taught while at PLU include:

I tend to use a lot of demonstrations in this course, and we spend a lot of time practicing problem solving!

In this course, we focus a bit on preparing for learning the skills and techniques needed for upper-level physics courses.

This is a fun course introducing the concepts and content of special relativity and quantum mechanics! This course tends to be highly interactive.

This course is heavily focused on problem solving and application.

This sophomore/junior-level lab course is dedicated to teaching you essential skills for the physics laboratory.

A course in "applied vector calculus," this course allows us to practice advanced mathematics and the application of general laws in the field of electricity and magnetism.

This is much more of an applied course on electric and magnetic fields.

This interactive course focuses on the idea of mathematical modeling of physical systems, learning useful mathematical techniques along the way.

We dive deeper into actually doing quantum mechanics in this course.

I have taught a few independent study courses on General Relativity in the recent past. These courses usually end with an independent research project on cutting edge topics in General Relativity.


A central feature of many of my courses is that students watch videos and read material before class, so that they come to class prepared to apply what they have learned. 


Many of the videos I use are available on my YouTube Channel.


Research

Overview

I obtained my Bachelor of Science in Physics at the Ohio State University in 2003, completing a senior research project entitled "Renormalization of the n-dimensional Delta Function Potential" under the direction of Professor Robert Perry. In addition to gaining research experience, this project helped me learn quantum mechanics more deeply than I would have otherwise, and has helped me in my current teaching of quantum mechanics at PLU!

I began my graduate studies in 2003 at the University of Wisconsin-Madison, earning a Masters of Arts in Physics in 2005 and a Ph.D. in Theoretical Physics in 2008 as a student of Gary Shiu. My Ph.D. Thesis, entitled "Warped String Phenomenology: Topics in Cosmology and Particle Physics," focused on the interesting particle physics and cosmological implications of warped extra dimensions, which commonly appear in string theory models. I'm still passionate about connecting new ideas from the high energy physics community to cosmology and the study of the very early universe.

From 2008 - 2011 I was a postdoctoral researcher in theoretical high energy physics and cosmology at McGill University in Montreal. While there, I was a McGill Lorne Trottier and Institute of Particle Physics (IPP) Postdoctoral Fellow, and worked with students and faculty in the high energy group.


Publications

You can see a current list of all of my publications. Note that virtually all of these freely accessible -- just click on the "pdf" link!

Below are some highlights of my research interests, grouped by research topics.

Quantum Complexity and Quantum Information:

The concept of "complexity" is, ironically, straightforward to explain. Imagine a computer that takes an input, applies a series of calculations and produces a desired output. (An example: The input is the number 12. The calculations then produce an output which is the set of factors of 12, e.g. 1, 2, 3, 4, 6, and 12.) Computational complexity is the minimal number of calculation steps needed to produce the given output. "Quantum Complexity" is the same idea, but applied to quantum calculations. (Ok, that's oversimplifying quite a bit, but hopefully you get the idea!) I've been interested in exploring ideas around quantum complexity and quantum information, particularly as it applies to the early Universe.

Relevant Publications:

Constraints on Geometry from General Relativity and Beyond

General Relativity is our modern framework for explaining the structure of spacetime and gravity. In a series of papers, my collaborators and I have explored ways that geometry can have surprising constraints on allowed spacetimes. For example, we explored how it is not possible to embed certain types of expanding bubbles of spacetime within each other, how leading-order effects from theories such as string theory do not seem to cure the singularities found in the Big Bang or inside black holes, and how geometric constraints from extra dimensions restrict the possibility of having 3 large, expanding space-like dimensions with other space-like dimensions static and not expanding.

Relevant Publications:

Warped Effective Theories

Many high energy physics theories involve extra dimensions as part of their descriptions, most notably superstring theory (which requires 6 additional space dimensions!). In order for the extra dimensions to have escaped our notice, they must be "curled up" and small (there is technical way to do this, trust me). The study of physics like cosmology and particle physics in models with extra dimensions is often done by sort of "smearing" out the extra dimensions. But sometimes these extra dimensions can be highly curved and coupled to our dimensions; these are called "warped dimensions." In fact, almost every single interesting application of extra dimensions to physics requires the dimensions to be warped -- it's a pretty typical setup. Unfortunately, the physics and dynamics of these warped dimensions are not well-understood, despite their importance. I have spent quite some time thinking about these warped spaces.

Relevant Publications: