What They Learned: Jack Crump ’23

Jack Crump’s thesis journey helped him realize the type of research he enjoys, leading him to continue a similar line of work as he pursues his PhD in physics.

Combining a range of interests he developed and different techniques he learned at Haverford made Jack Crump’s senior thesis “a challenging but rewarding project.”

A physics major and astronomy, math, and German minor, he investigated some of the approximations and assumptions that are connected with astronomical tests of possible time-variation in the fundamental charge of a single electron. Models in which this phenomenon occurs may be a sign of new particle physics (e.g. string-theory inspired scenarios), and would change the way we understand the laws of nature. He found that there is no significant change to the observables when energy conservation is included in the matter field when energy goes into the scalar field. 

“Experimental data from quasar absorption spectra and theoretical motivations coming from string theory prompt the idea that the fine-structure constant (α) is changing over time and space,” he writes in his abstract. He then details the models, techniques and parameters he analyzed.

His advisor, Assistant Professor of Physics and Astronomy Daniel Grin, introduced him to the fine-structure theory and helped him guide his research after Crump found unanswered questions in the existing research. Grin was also essential as Crump navigated the physics knowledge he needed for his work. They worked together to make sense of the results Crump would get during his research.

Crump’s thesis journey helped him realize the type of research he enjoys: a combination of theoretical and computational work. He will continue a similar line of work as he pursues a Ph.D. in physics at the University of Minnesota, Twin Cities.

“The biggest thing I learned from my thesis,” says Crump, “was how to tackle a huge project and work on something for about a year. A lot of our assignments in school are short term or maybe about a month in length, but I started my work on my thesis in the summer of 2022 so it takes a different kind of approach to work on something that long term. I also learned how to read through the literature and know how to find what I needed. I think that my scientific writing also got a lot better over the course of the project as I practiced. My biggest takeaway from the project is that there is always more that you can do to improve understanding on a topic. That makes it great if you need to find a thesis topic, but can also make it hard to know when to stop and be happy with what you have done.”

As for implications for his research, he says his work was focused on investigating some of the approximations and assumptions used in the varying fine-structure constant theory in the past. “One of my results,” he concludes, “was that an added complication to the theory of including energy conservation in the matter field when energy goes into the scalar field (which is the field that changes the fine-structure constant) does not make a significant change to the observables. I also worked a lot on trying to understand one of the parameters in the theory (zeta). I made some progress there and opened up a couple avenues of future research, but a lot more work needs to be done. In order to have a chance at determining if this theory for a varying fine-structure constant matches reality, it needs to be understood much better. That is how I hope my work can help future researchers.” 

“What They Learned” is a blog series exploring the thesis work of recent graduates.