Students and faculty gathered in the Nixon Lounge of Hawthorne-Longfellow Library on Thursday for a discussion of a new book by William R. Kenan Professor of Physics Thomas Baumgarte, “Numerical Relativity: Starting from Scratch.” This talk is part of the College’s Faculty New Book Launch Series.

Baumgarte’s book, which he co-authored with Stuart Shapiro, a professor of physics at the University of Illinois Urbana-Champaign, presents a concise and accessible introduction to the field of numerical relativity—a subfield of general relativity.

Baumgarte’s professional relationship with Shapiro has spanned over 30 years and began when Baumgarte took Shapiro’s course on general relativity at Cornell University in 1990.

“[Shapiro] is not only a master in his field, but also a very good teacher, and [I] fell in love with the subject,” Baumgarte said.

When he returned to Cornell to work under Shapiro as a graduate and postdoctoral student, Baumgarte taught Shapiro’s students about the emerging subfield of numerical relativity. It was through this work that Baumgarte discovered his passion for general relativity.

“I enjoyed [putting together lecture notes],” Baumgarte said of the opportunity. “It’s like putting together everything you know … it reminds me of these toys that toddlers really like, these sorting toys … fundamentally, it’s the exact same kind of enjoyment.”

He continued to develop these lecture notes—first into a review article, and then finally expanded into a complete textbook titled, “Numerical Relativity: Solving Einstein’s Equations on the Computer,” which Baumgarte and Shapiro published in 2010.

However, there have been a number of developments in the field of general relativity since 2010 that inspired Baumgarte and Shapiro to create an updated version of the text.

In 2015, gravitational waves were detected for the first time, and numerical relativity became an invaluable tool for interpreting these waves and their origins. Baumgarte also pointed to the wider availability of software that made it possible for the general public to download and run numerical relativity code, which sparked increased interest in the field.

“Not only is there broader interest in numerical relativity, but there is also the ability to participate,” Baumgarte said.

Additionally, Baumgarte’s experience teaching at summer schools taught him about the way in which students seek to learn about these topics.

“Really the students, maybe they want to see a derivation … but more likely they will actually benefit more from an exposition that appeals to analogy,” Baumgarte said.

“Numerical Relativity: Starting from Scratch” is a direct reflection of the increased interest and accessibility in the field of numerical relativity. After having such a positive experience co-authoring his first effort with Shapiro, Baumgarte felt it important to include Shapiro in his second project, as well.

“I truly believe that by writing a book with a co-author, the book will be better because there are two pairs of eyes looking at things … you can check each other’s writing, you can check each other’s math, and you can also have disagreements about ideas,” Baumgarte said. “Having those disagreements is a good thing because then you work it out, you find compromises … you end up with something that is better than what you would have found by yourself.”

The text is designed to be accessible to those who are interested in the subfield of numerical relativity but lack a background in physics. In addition to being less dense than its predecessor, “Starting from Scratch” contains a number of interactive, color-coded exercises derived from Baumgarte’s own research that allow readers to test their comprehension of the material.

“We call it ‘Starting from Scratch’ because it’s really for students or readers who do not have a detailed prior expertise in general relativity,” Baumgarte said. “We rely a lot on analogies … to motivate them.”

The library will hold its final book launch for the 2021-2022 academic year on April 7 to discuss “The Reparative Possibilities of Queer Young Adult Literature and Culture,” written by Assistant Professor of Gender, Sexuality and Women’s Studies Angel Daniel Matos.