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Students Find Their Research Niche in Physics PhD Program

By Sarah Hojsak

Riya Shah, Weixiang Yu and Justin Gambrell are doctoral students in Drexel University's Physics program

Physics PhD students (left to right) Riya Shah, Weixiang Yu and Justin Gambrell


August 30, 2022

With five different areas of study—astrophysics, biophysics, particle physics, condensed matter and physics education research—Drexel’s physics PhD program gives students the flexibility to pursue unique, individualized research based on their own personal interests and career goals.

“Doctoral research in physics touches on so many big questions,” according to Associate Professor of Physics and Associate Dean of Graduate Education Michelle Dolinski, PhD. “Everything from our fundamental understanding of the universe to how we can improve education and health outcomes for people today.”

We spoke to three of these doctoral students about the research they are doing and what motivates them. While their areas of expertise differ, they share one thing in common: the impact they hope to make in the field of physics—and in the world.


In her academic career so far, Riya Shah has earned two degrees in two different areas of physics—and she’s not finished yet.

After completing a bachelor’s degree in astrophysics at the University of California, Berkeley, Shah decided to shift her focus when she came to Drexel. She recently completed an MS in biophysics and will begin researching particle physics as she transitions into the PhD program with “post-master’s” status this fall.

“I wanted to see if I was interested in other sorts of physics, so I figured during my master's I would try to explore another field that I’m not used to,” Shah said.

Starting with a master’s degree is an ideal option for students who are not 100% sure they want to pursue a PhD. Had Shah decided not to continue into the PhD program, she still would have entered the job market with a master’s degree in hand. Now, she’ll join the PhD program as a third-year student.

“After my two years I knew I definitely wanted to continue on and pursue a PhD,” Shah explained. “I already knew the people at Drexel and my professors and classmates, so it made sense to continue the PhD at Drexel.”

For Shah, the appeal of academia lies in the freedom it allows her to explore her interests. As she begins working toward her PhD, Shah will focus her research on neutrinos—nearly massless subatomic particles—specifically those detected at the IceCube Neutrino Observatory in Antarctica.

“By the time I’m finished my PhD, I will have published papers in three different fields,” Shah said. “I have a paper from undergrad in astronomy, and I have a paper in biophysics, and then I [will] have paper in particle physics. People will be like, ‘Is this the same girl?’”


NASA’s recently released images from the James Webb Space Telescope have allowed scientists and everyday people alike to see the universe more clearly than ever before. It’s a particularly exciting time to be studying astrophysics—although PhD student Weixiang Yu would argue that it’s always an exciting time to be studying astrophysics.

Yu studies supermassive black holes, which can be as heavy as one billion times the mass of our sun. He was drawn to the subject because black holes, according to Yu, are crucial to our understanding of the fundamental laws and evolution of our universe.

"We think we all live in a three-dimensional world, but actually the world is four-dimensional,” Yu said. “I was attracted by the idea of reality that is based on a four-dimensional space-time.”

Not long ago, the existence of black holes was only a theoretical prediction. Recent breakthroughs of the Event Horizon Telescope have allowed scientists to make images of black holes and determine some of their basic properties, like age, size and mass.

“My research focuses on studying the properties of supermassive black holes through monitoring how gas falls into the black holes and the electromagnetic radiation it produces during the process,” Yu explained. “By modeling the amount of radiation being produced as a function of time, we can also infer how big, how heavy and how ‘hungry’ it is.”

Yu was first drawn to astrophysics as an undergraduate at the University of Illinois Urbana Champaign, where he was introduced to the upcoming Legacy Survey of Space and Time (LSST) project at the Vera Rubin Observatory in Chile. He came to Drexel for graduate school to be at a university that was a participant in the project, which is expected to make unprecedented discoveries as early as 2024.

There is still much to learn about black holes, and Yu plans to keep advancing his research after he earns his PhD and continues his career in academia. Yu advises students considering a PhD program to make sure they are driven by a strong passion for the subject they want to study and warns that it involves sacrifices in financial security and work-life balance.

“Think thoroughly before you make the decision,” Yu cautioned. “You need to be prepared to struggle, but be prepared to enjoy at the same time—because you enjoy what you’re doing.”


Justin Gambrell always knew he wanted to pursue a career in education. He majored in physics—which had been a favorite subject of his in high school—as an undergraduate at Michigan State University and found a home in the Physics Education Research Lab there.

Physics Education Research, or PER, is the study of teaching and learning in physics and can encompass everything from curriculum reform to neuroimaging studies of physics students. Drexel’s PER track within the PhD program allows Gambrell to continue to explore his interests in physics and education. His research examines the importance of teaching computation in introductory undergraduate physics courses.

Computation was a pivotal part of Gambrell’s own physics education, but not all institutions include it in the curriculum.

“There's not really a widely accepted idea of what we want to learn from computation,” Gambrell said. “My research is trying to narrow down what computation in introductory physics entails, and how might we assess students for that [knowledge].”

Gambrell says computation personally helped him understand the less concrete aspects of physics.

“Mechanics, like projectile motion and gravity, made sense to me,” Gambrell explained. “But once we got into electricity and magnetism and quantum mechanics, these are less visible and not necessarily things we experience in our everyday lives, so having computation to help visualize what is actually happening at the microscopic scale was very helpful.”

Some institutions may be resistant to curriculum reform in this area because they assume adding something new to the curriculum would mean removing something else, or because they lack the time to implement the changes. Gambrell argues this doesn’t have to be the case, and wants to make it easier for educators to do what is best for their students.

“My hope is that by doing this research, I can help make it easier for educators to add computation to their curriculum, or, if they already have computation added in their curriculum, give them a way to see if their students are learning what we want them to learn as a physics community,” Gambrell said.

“I just want to help people, and because this is something that helped me, I want to try and help others in the same way.”