What I wish I knew before a Physics PhD

My physics PhD took up 22% of my life, and I hope I learned a lot during it. If I had to pick one thing that would have materially changed how I approached it: a physics PhD is judged by the volume and quality of the publications you produce. Classes, volunteer work, extracurriculars are essentially irrelevant to the task at hand. If you’re serious about physics, optimize (volume of publications) × (quality per publication). Everything you do should boost one or the other.

01On the economics of the decision

Theoretical physics PhDs bear enormous opportunity costs. The time isn’t free — you could be doing another kind of research, learning a trade, or being paid handsomely to move numbers around a screen. They carry many of the intellectual challenges of medicine without the impact of relieving a child’s suffering, and many of the challenges of engineering without owning valuable IP. Time spent on this instead of anything else needs to be accounted for.

Motivations change. When you start, your focus is on expanding horizons — curiosity, new experiences, growth. When you finish, much of your focus is on becoming rooted — family, career, a personal brand. There are real tidal forces between the ideal program when you begin and the ideal one when you finish.

High supply and low demand for theoretical physics PhDs means a low price of labor. Being smart doesn’t mean the market values your contribution. And building an alternative career requires skills a PhD doesn’t develop — the modern economy values teamwork, quick decisions, and clear communication, none of which thrive in a monastic working style.

Finishing a PhD can be a red flag for startup entrepreneurship. Your 20s are perfect for startup dynamics; finishing first tends to lower, not raise, your odds. The most successful startups based on PhD research usually had the students drop out before completion.

02On physics itself

Physics is an experimental science and the best work is done in experiment, not theory. A mediocre experimentalist contributes vastly more than an outstanding theorist. And formal methods are for chumps — you won’t beat a 60-year-old Russian master at asymptotic series, but you can beat him with intelligent numerics sampling billions of examples. If you aren’t using computers early, you’re doing it wrong.

03On being a good PhD

Treat your research like a job: show up on time, write clear presentations, read the relevant work, find the people who can get you over the sticky bits, and care enough to do it well. Bad employee behavior translates directly into bad research. Alignment with your advisor is built over a long time — if you want early graduation or first authorship, build the case for why it’s in their interest too. Generalists don’t publish much; specialize quickly or run out the clock with something shallow.

04What I’d do again

Productive goofing off paid enormous dividends. My unstructured time went to Chinese, economics, and programming — three things I use every day, and more profitable than my formal education during the PhD. Going to a name-brand school helped even more once I left physics; alumni networks can make or break a first job search. And I took a deliberate, two-year job search to figure out what I actually wanted to do.