The Love Hypothesis by Ali Hazelwood

As a third year Ph.D.  candidate, Olive Smith doesn’t believe in lasting romantic relationships, but her best friend does, and that’s what got her into this situation. Convincing Anh that Olive is dating and well on her way to happily ever after was always going take more than hand-wavy Jedi mind tricks: Scientist require proof. So, like any self-respecting biologist, Olive panics and kisses the first man she sees. 

Paperback edition