Why go to graduate school in theoretical physics? If you are thinking about doing so, and particularly if you reside in North America or Europe, my recommendation would be: don’t do it! Find a career where your quantitative/analytical-thinking/programming skills are in demand, so that — relative to your chances within academia — you’ll likely find much higher standards of professionalism and more plentiful opportunities to grow.
In the US, your chances of getting admitted into a given physics graduate school would be curtailed if you indicate interest in pursuing theoretical as opposed to experimental physics. (There are usually many more people wishing to do theory than experiment.) This is why theory-inclined applicants misrepresent themselves, stating they wish to do experiment instead. (I am, in fact, quite curious how many current theoretical physics faculty lied on their graduate school statements.) However, once you do get in, you’ll be told that you are free to “explore your interests”. This is euphemism for the physics departments’ unwillingness to take any responsibility to help match you to the mentor of your indicated interests — despite judging you, often more harshly, based on it. International applicants should take particular note of this: you are essentially entering a wild lottery, going across the world thinking you are going to pursue your passion in theoretical physics when your fate may turn out very differently. In the current climate of over supply of graduate students and under supply of both jobs and genuinely good research problems (especially in high energy theory), there is little incentive for potential advisors to seek out students to mentor/nuture, let alone take them based on their merit. Instead, the personalities of both student and faculty play an outsized role; and the process of advisor-seeking often feels much more like a dating game.
♦ While I was a postdoc at U of MN Duluth (UMD), which does not award PhD degrees, one of the top MS students of the faculty who hired me had written 5 papers by time he was applying to PhD programs. Knowing the competitive nature of the admission process, however, I encouraged him to visit his top choices to deliver talks on his research. Given his track record, caliber, and experience, I told him he should not shy away from directly and aggressively approaching potential advisors to start working with them as soon as possible. The reader may not be surprised to hear — for, otherwise I would not be writing about this! — my advice was not taken; and while this student did get into a decent program he hadn’t found an advisor nearly a year into his tenure as a PhD student. I did hear from his former UMD classmate, this student did eventually find a mentor, but not within his original field of interest.
♦ Another ex-student of my research supervisor at UMD, whom I had co-mentored rather closely, spent 2+ years working with him — writing a robust numerical Python code to solve a class of Euclidean Quantum Field Theories — only to end up falling out with his advisor. He did end up writing his MS Project on the same topic, but with a completely different faculty. As I understood it, his supervisor falsely claimed all the 2+ years’ of work by the student was “trivial”. The only plausible explanation I have been able to come up with is that, due to his well-known conflict with the only other research-active theorist in the Department and out of his own pride, my then-supervisor did not want his students to only complete an MS degree with a Project. Rather he required them to produce something publishable (the student did not produce enough for a paper) in order to graduate from his theory group.
♦ What happens when an advisor produces an ill conceived, misguided project for his PhD student? Answer: his student struggles mightily with it, displaying great competence and scrupulousness — with little substantive aid from the advisor himself — only to end up wasting 2+ years and facing poor job prospects. Zero consequences for the advisor, as far as I can tell, other than padding his CV and grant applications with the paper the student did still manage to produce despite the trying circumstances.
♦ If you work with a senior and/or famous faculty, you may notice they publish very frequently and easily. This is at least partly because of the social-political dynamics of theoretical physics — it often takes just several conversations or so (especially if it involves junior people) for senior/famous folks to get their names on papers. Moreover, if you are senior/famous, it is easy to find junior scientists to explain things to you… Whereas, as already alluded to, as a graduate student you may have to struggle on your own with the technical implementation of your advisor’s ideas — and the burden of failure often falls entirely upon your shoulders.
♦ I took a year off after obtaining my MS degree to properly search for a graduate school to pursue my interests in theoretical cosmology, gravitation and field theory. During my visits to various schools I ran into quite a number of unhappy graduate students. One of them brought me inside a conference room, closed the door, and proceeded to warn me: if I ever came here, I should make sure not to work with this student’s advisor! The advisor is the sort that would barely write a single paper with his graduate student; and then leave them to find their own projects to work on. In theoretical physics, finding your own project as a graduate student is usually not only very difficult, it is a very poor strategy if one wishes to mature as a scientist. Unfortunately, this student’s experience is not an uncommon phenomenon.
♦ I obtained my MS degree in Physics from Yale. One of my classmates there was an international scholar who had graduated valedictorian from a small but elite school in the US. Like my UMD research supervisor’s top student mentioned above, however, he struggled to find an advisor that matched his research interests. He had to quit Yale, took a break from school, and eventually returned to his undergraduate alma mater to complete his PhD degree. The last time I heard from him, he was a physics and math private tutor in Texas. I suppose it is not too unreasonable to assert: a person of his abilities does not need to travel across the Atlantic (he’s European) to waste his time getting the most advanced degree possible in theoretical physics just to become a private tutor in a land so distant from home. (As a side note: I do personally know of at least 1-2 other PhD classmates of mine who have gone on to become high school teachers — a respectable profession, of course; but not one requiring a doctorate in theoretical physics. This side remark is not one about poor mentorship per se, but about the dearth of job opportunities.)
♦ When I was at Yale I came to appreciate that high energy theory was in the decline due to the severe lack of guidance from experiment: as of this writing, there are still no discoveries in particle physics that can illuminate the way forward for theorists working to extend the Standard Model to account for Dark Matter and other mysteries. I decided to turn my attention towards cosmology. I was temporarily relieved that the high energy theory group had just hired a new cosmologist; and I quickly made sure to approach him to indicate my interest in working with him. The way things worked at Yale, I was supposed to find an internship of sorts with a potential advisor during my first summer there. But the cosmologist told me he would be away and thus cannot take me. It turned out he was around, and even took on an undergraduate student. I repeated my interest in working with him during the following Fall. He asked me what classes I was taking and I happily told him I was auditing a Numerical Methods course offered by the Astronomy Department. This cosmologist was a heavily numerical one, and I had taken the initiative to pick up some numerical/programming skills. He told me he would take me “over all other students at Yale” but also did remark that numerical analysis was a very “portable skill,” a puzzling comment that I only understood later on. As far as Life itself was concerned, I guess I was still in kindergarten then, not recognizing that when a faculty is repeatedly vague with you, that most likely indicates a “No”. After more than 1+ years of pinning my hopes upon that cosmologist, I finally learned he — as brand new faculty at Yale — was taking his one and only student from a completely different institution. Only during Spring of my second year at Yale did the cosmologist reveal he was not inclined to take Yale students because he was worried they have a tendency to become quants right after graduation. When discussing this with my white American classmate later on, he then informed me he had overheard conversations between faculty that they believed Chinese graduate students have a tendency to go into finance directly after obtaining their PhD.
I had thought that this student the cosmologist had taken from another institution must be extraordinary — well trained in cosmology and quantum field theory perhaps. During the student’s first year at Yale, however, he had to take a cosmology reading course with his advisor and quantum field theory with mine. And, he did not do spectacularly in the latter. (I know, because I was his TA; I am glad to report, on the other hand, the top student in that QFT course is now a faculty at an elite US institution.)
At Yale, if you do not find an advisor by the end of the second year of graduate school,
you’re fucked your support will cease completely. After graduating from Kindergarten into Elementary School of Life, I proceeded to pursue the cosmologist’s next-door neighbor out of panic — despite hearing he had already taken a student. Now, a dating advice: you should be very wary of partners who are ready to find a new fling at the slightest temptation. (Did I mention advisor seeking is like dating?) My experiences with this advisor employer, whom I worked with for a whole year before taking a year off from school, can easily fill a blog post or two. Suffice to say, theoretical high energy physicists aren’t the nicest lot. A gravitation theorist once told me he chose not to do particle theory because of its hard-nosed culture; I find the latter to be an understatement.
These examples merely illustrate a single aspect of the deeply flawed reward structure that exists within the academia I am familiar with: the extraordinarily low standards of mentorship within the theoretical physics community. Unfortunately, nowadays, Western academia — including physics/astrophysics — enjoys emphasizing the need for “diversity,” but given how left-leaning illiberal/biased it has grown, however, I fear this just translates into an obsession with identity politics that is highly hypocritical and destructive.