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Apart from a fairly unique first name, Samara Overvaag could strike one as a fairly ordinary 21-year-old college student. Her recreational interests center on video games and attending football games at South ��ֱ���� State. 

With long, blonde hair and a good Norwegian name, she fits the profile of many of the Scandinavian descendants who make up the ��ֱ����s. But when talking to this Future Innovator of America a little more, one realizes she is quite unique. Her passions also include research, and she wants to earn a doctorate in physics.

A double major in physics and mathematics, she can leave one stupefied when she starts describing her research project that involves negative kinetic energy and ghost systems.

“In this work, we consider a system with two scalar fields chosen such that they have opposite kinetic terms, thus introducing a ghost. We are interested in these ghost-ridden systems because they have been generally deemed unstable and physically unmeaningful in the past. 

“However, recent work shows that stable evolution is possible under certain conditions, which has inspired this study,” Overvaag said.

The title of her computational physics project is “A Numerical Study for the Stable Dynamics of Ghost-Ridden Systems with the Space-Time Finite Element Method.”

Negative kinetic energy creates ghosts

Her mentor is Jung-Han Kimn, an associate professor in mathematics at SDSU. He is partnering with Los Alamos National Laboratory scientist Hyun Lim, who did his bachelor’s and master’s degree under Kimn and later earned a doctorate in physics. Also part of the project is Jax Wysong, an SDSU master’s degree student under Kimn.

Wysong explained, “This research explores how to obtain stable solutions (stable evolutions of equations of motion) for situations that were previously thought to not have stable solutions. So, in one sense, this research is exciting because it is relatively new. Further down the line it might lead to a different way of thinking about negative energy and how systems with negative energy might theoretically evolve in time.”

It deals with invisible waves of energy, but that is not why the systems have ghosts. The ghosts come from negative kinetic energy, a concept not possible in classical mechanics because either something is moving and has positive kinetic energy or is not moving and has zero kinetic energy.

But in quantum mechanics, negative kinetic energy can exist as a mathematical concept related to the behavior of wavefunctions.

Overvaag said the ghost systems “have to do with how it is mathematically described. It’s really difficult to understand. I have little understanding of the physics around this. This is high-level physics. My work has focused more on the mathematical implementation side of things.”

Ten weeks at Los Alamos lab

Her work this summer was at Los Alamos National Laboratory, but it had nothing to do with ghost systems.

Overvaag was selected for a 10-week computational physics workshop, which is similar to summer research projects at a university only at a higher level. She and an undergraduate from North Carolina State were charged with implementing a new way to simulate friction between materials in one of Los Alamos’ multiphysics simulation codes.

In simple terms, the project involved a piston pushing into a tube of salt. They were given previous experimental and simulation data and asked to improve the simulation code.

The Los Alamos scientists want to be able to simulate contacting materials in their code simulations. “Each granule needs to be considered in a simulation like this,” Overvaag said. The friction factor is needed to analyze energy, and the Los Alamos friction model was unreliable, she said. “My partner and I created a new implement a code to simulate friction.”

In contrasting the difference between her Future Innovator and Los Alamos projects, Overvaag said the Los Alamos project “doesn’t feel as abstract. We can actually run simulations and see what is happening between materials and surfaces. They were similar in that we are using high-performance computing and parallel computing to run the simulations. I was able to translate that to this project and get things set up fairly quickly.

“Both projects were also math heavy. A lot of linear algebra was involved in both projects.”

‘Studious Jacks’ rates study locations

When Overvaag isn’t running simulations on high-performance computers, she can be found playing the video game “Fallout,” going to SDSU football games and studying, partially to keep up her GPA and partially to rate study locations on campus.

“I run a campus study location review page called ‘Studious Jacks’ on Instagram. I have a social media page where I review study locations on campus. I started that my sophomore year. I typically rate things based on atmosphere, such as lighting and quietness and resources available, such as printers, vending machines and outlets. I rate each factor on a 1-to-10 scale and gives the location an average rating.”

Her favorite location is the study areas in the math department because of the dry erase tables and boards as well as good lighting.

SDSU football: Look for the carrot bunch

As for football games, Overvaag is not a casual fan in a Jackrabbits T-shirt.

She and her friends don full-body carrot costumes and stand in the front of the student section. “It started with three (people) and has gotten up to seven. There are consistently three or four. Usually, my parents and grandparents will watch from home and look for us on TV. I’ve actually been on ESPN a couple times.”

Overvaag started the new Jackrabbits tradition for the 2024 season. They’ve also worn the $40 costumes for a few basketball games. “We’ve definitely got our money’s worth out of them,” she said.

Overvaag is slated to graduate in May and then will pursue graduate studies. Whether that will be at a school where she can still wear her carrot costume is yet to be determined.