An Ode to my Physics Ph.D.

On Five Years in Physics and the Transition to Machine Learning

Image from Unsplash.

One year ago, I defended my doctoral dissertation. The room was colloquially called “the fishbowl” owing to the windows that line its walls, allowing passers by to peer in. It was 4pm on a Friday afternoon, the only time all of my committee members could attend. After the inevitable AV hiccups, I presented to friends, family, and physicists for roughly an hour on “The Surprising Persistence of Symmetry Protected Topology”. Then, a brief private session with my defense committee, digging into the technical details of my research projects to probe the depth of my understanding. At 5:30, I walked out of the room with my Doctorate of Philosophy in Physics.

I calmly descended two flights of stairs and stepped outside into the sunny, bright air of a late Friday afternoon in Palo Alto to find my parents and best friends waiting to congratulate me with a bottle of champagne. My calm exterior crumbled and I began to cry.

That day — that moment — represented a culmination. It was a culmination of five years of coursework, teaching, and research; of long days struggling to parse impenetrable equations and long nights responding to questions in referee reports; of countless aha! moments, most of which turned out to be wrong; and of the omnipresent fear that I wasn’t going to make it.

Standing on the patio of Stanford’s Durand building with my parents, roommates, and partner, I was overcome with joy, gratitude, and especially relief. For at least a moment, I could set aside the self-doubt and unrelenting existential dread. For one sparing moment, I could be proud of myself.

At the same time, this moment was unmistakably bittersweet: it marked the end of my time devoted to physics. I did not know what post-Ph.D. life had in store for me, but I did know that physics would no longer be a guiding force.

Stanford campus, where I completed my Ph.D. in Physics. Image courtesy of Unsplash.

Before even starting the Ph.D. I knew academia was not the path for me. Within my cohort of budding physicists, this was a rather peculiar sentiment. Now, most of my classmates have graduated and others as well have left the academy. But for most this was not their original intent. From the outset, I had resolved to go into industry after the degree. In fact, this is largely why I chose to pursue my graduate studies in the San Francisco Bay Area!

I knew this day was coming. But I wasn’t prepared to face the reality.

Physics has been a part of my life for as long as I can remember. So many of my decisions have been driven by my obsession with concepts like symmetry, order, universality, and emergence.

This obsession led me to study physics, mathematics, and philosophy as an undergrad (as a side note, this means I have a bachelors in physics and philosophy, and a doctor of philosophy in physics, which I always thought was fun!); to work with Stephen Wolfram at Wolfram Research; and to pursue a Ph.D. in condensed matter theory, a subfield of physics concerned with how the interplay between order and symmetry can result in new phases of matter.

More importantly, for years I’ve thought of myself as a physicist. Physics wasn’t just the subject I studied or an umbrella for ideas I found endlessly fascinating; it was a part of my identity. Physics has informed the way I approach new problems and the way I engage with physical reality. It has shaped how I see the world and my place in it.

For many aspiring physicists, the doctoral defense marks one’s emergence onto the scene. Antiquated though it may be, the doctorate serves as proof of membership in the community of academic scholars; a validation that years of “training” in the subject matter, motifs, and minutiae of a discipline have paid off.

For me, this moment also represented a departure. I was leaving physics, and over the next few months I would face an identity crisis as I transitioned from “physicist” to “recovering physicist”.

I spent much of the following month scouring the internet, within and beyond my personal and professional networks, looking for others who had recently made the transition from theoretical physics to industry. I reached out to everyone I could, across industries, roles, and stages of career, and was pleasantly surprised by how receptive and responsive most people were.

The bigger surprise came from listening to their stories. Most of the ex-physicists in industry whom I spoke with were satisfied with where they were in their careers by the five year mark post-Ph.D. — and some far earlier on than that. But when reflecting on their journeys, the prevailing sentiment everyone expressed was a combination of frustration, disappointment, humility, and regret.

In physics, it is common to be told that from physics, you can go on to do anything. People look around and see an ex-quantum physicist in finance; a researcher from CERN who is now the head of AI research at a tech company; a once-upon-a-time string theorist now masquerading as an oceanographer, and they think physics prepares you for everything, all at once. “They” are not wrong, but this picture is deceptive.

Sure, there are ex-physicists all over the place. And sure, the “physics mindset” is an invaluable foundation for more than a few careers. Speaking from my own experience, and from the conversations I had with others, however, I think it is less about the preparation that physics gives the person, and more about the person who is drawn to physics.

No matter what field you are trying to transition into, there are people who have spent years studying and honing their craft. Physics is not a substitute for skills, and it certainly is not a substitute for knowledge. In fact, there is no substitute for putting in the time. And most companies, it turns out, hire for skills — especially during a recession.

This is where the aforementioned humility comes in. Despite publishing papers in prestigious journals, bathing in oceans of mathematical equations, and learning how to approach ambiguous research problems, so many physicists entering industry had trouble finding a job.

Image courtesy of Unsplash.

One friend told me of his six-month endeavor to secure employment, during which he applied to more than one hundred openings before finally receiving an offer. Others expressed shame that the only jobs they were even given interviews for were well below their education level. And when they started working, many were frustrated by their belief that they would have been just as capable of doing said job before their doctoral studies.

To succeed, I heard again and again, you had to start from scratch. One quote from an ex-string theorist friend working in machine learning sums it all up:

“I don’t think of myself as a physicist. I look back at my time in physics like a hazy dream”

When I started applying for jobs in earnest, in the middle of mass layoffs and hiring freezes, the dominant emotional tones that I felt were anxiety and frustration, with more than a tinge of self-loathing.

I was interested in climate tech, but all of the jobs that looked interesting were either in the process of being cut, given the economic outlook, or were jobs for which I was not qualified.

I was also interested in machine learning, and this was the one area that seemed to be immune to hiring freezes, so I decided to focus my efforts there. I didn’t have trouble with Leetcode questions, brain teasers, or white-board problems, so when I was able to get an interview I often made it to the final round. But I kept receiving rejections because I did not have strong enough software engineering skills. Looking back on this, I completely understand what they meant, and why I did not end up receiving these offers.

I grew anxious that I wasn’t going to be able to find a job. I grew increasingly frustrated with the job search process. At the same time I was upset with myself for having put myself in this position by spending five years in a Ph.D. program for a field I had no intention of continuing to work in afterwards. I could have done anything, yet I chose to study symmetry, topology, and emergence.

I had stopped calling myself a physicist, but I did not have anything to replace it with yet. Of course, defining oneself by one’s occupation is its problem — one which I am still very much working through.

In October, right when my anxiety was starting to turn into despair, things turned around. I received a few offers in rapid succession, from companies which valued my non-traditional experience and skillset.

Leap of faith. Image courtesy of Unsplash.

I was fortunate to find a home at an incredible series A startup, Voxel51, where I accepted a position as a Machine Learning Engineer & Developer Evangelist. The team at Voxel51 took a chance on me — they hired me as a machine learning engineer in spite of my limited software engineering experience and exposure to machine learning; they hired me to join their developer relations efforts even though I was new to the concept of developer relations itself!

Looking back, I think why Voxel51 hired me, and why the position worked out both boil down to three reasons:

Mission alignment: Voxel51’s mission is to bring clarity and transparency to the world’s data. For almost a decade I’ve undertaken efforts to make concepts, ideas, and research results in physics accessible (personal blog, Yale Scientific Magazine, Physics World, …). The physics itself is not transferable, but the spirit of my efforts closely aligned with the company’s mission.Learning is central: part of being a developer evangelist is constantly learning and exploring new technologies, and machine learning is moving so fast these days that everyone needs to keep learning to stay up to date. As a result, learning was (and is!) a central component of the job. Together, Voxel51 and I have been able to turn a potential weakness (gaps in my knowledge) into a strength by creating educational content derived from my journey!Startup mindset: when large companies hire, they are often looking for someone to perform a very specific set of tasks. Consequently, they are looking for someone with a very specific set of skills and experiences. In a startup, everyone has to wear multiple hats, and there are many ways an individual can create value. It’s not always so cut and dry, but in general I’ve seen people with non-traditional skill-sets — including Ph.D.s — thrive in the flexible, often ambiguous, and ever-changing environment of a startup.

I’ve been at Voxel51 for almost nine months, and I’ve already learned so much. I’ve learned about software engineering, computer vision, and generative AI; and I’ve learned about marketing, developer relations, and community management. I’ve also learned a lot about myself: what types of work excite me, how I collaborate with others, and how to balance work with life (still a work in progress). I’ve learned as much in the past year as I learned in any single year of grad school. And I’m still learning so much!

A year removed from the physics Ph.D., the resentment is finally starting to subside. I was so upset with myself for spending five years conducting physics research that I missed the bigger picture. I didn’t pursue a Ph.D. in physics to get ahead in my career. I chose to undertake the Ph.D. because I love physics, and I wanted the opportunity to dig deeper into fundamental questions about our universe. The fact that I was able to do so is a luxury — one for which I am exceedingly grateful.

I’m grateful to my advisor for funding me and allowing me to pursue projects that interested me, and I’m grateful for the mentorship I received from postdocs and professors. I published peer-reviewed papers, contributing (if ever-so-slightly) to the vast body of scientific knowledge. I gained both a deeper and broader grasp of physics. And I met so many cool people doing tremendous work within and beyond physics.

There’s also so much more that I’m grateful for which indirectly resulted from pursuing the Ph.D. in physics. I interned as a Ph.D. Quantum Resident at Google X; I joined Physics World as a Student Contributor; I had my first real experience with entrepreneurship; I lived with my best friends for three years; and I met my partner.

I still see myself as a recovering physicist, but now I also see what I’ve taken along with me. At one point, studying physics was my dream, and I got to live that dream. I will always love physics.

I’ve entered a new phase of my career, and I love what I’m doing now as well. The more time I spend away from physics, the more interested I become in a wider array of topics and ideas. I find myself compelled by the pursuit of excellence, the process of learning itself, and the desire for real, tangible impact.

It’s okay to not be a forever physicist. It’s okay to have a new dream.

Thank you, Physics.

Yours always,


Jacob Marks

Stanford Physics Ph.D. ‘2022

An Ode to my Physics Ph.D. was originally published in Towards Data Science on Medium, where people are continuing the conversation by highlighting and responding to this story.


Oh hi there 👋
It’s nice to meet you.

Sign up to receive awesome content in your inbox, every month.

We don’t spam!

Leave a Comment

Scroll to Top