I'm aware that the idea of undertaking two separate PhDs has been widely discussed in this forum, with the general consensus advising against it. However, I'm specifically interested if it's possible to pursue two PhDs in physics in distinct subfields at a US/UK university, assuming I have a genuine desire to specialize in both fields.

Here's my background:

As a current master's student on the verge of completing my program, I'm gearing up to embark on my PhD journey later this year at the same institution where I completed my undergraduate studies. My initial specialization will be in Field A, a subject I've had the pleasure of exploring for the past three years under the guidance of my professor.

However, during my master's program, I was introduced to Field B. I've found this area to be incredibly fascinating, perhaps even more so than Field A. Unfortunately, it's currently challenging for me to delve into Field B due to my lack of background in many mathematical areas. I think I'm only confident to start my PhD in Field A at this moment.

Moreover, my undergraduate institution lacks professors conducting research in Field B, which further complicates matters. This has led me to contemplate the possibility of pursuing a second physics PhD in Field B upon completing the program I'm about to begin in Field A.

I'm also aware that there are individuals who have managed to transition between different areas of interest in physics post-PhD, sidestepping the need for a second degree by opting for postdoctoral studies. However, considering the significant distinction between Fields A and B, I'm uncertain about the practicality of such a route in my case.


2 Answers 2


It is very unlikely to find an institution in the US that will allow you to obtain a degree in the same field again. If you are interested in both fields A and B and absolutely insist on being trained in both, then you need to find an institution that can support you in both fields. If you publish in Physics A and in Physics B, then you could/would be considered an expert in both, regardless of your thesis.

Life involves making choices and each choice closes possibilities. You should ask what you can do with both Physics A and Physics B. If you find a good answer to this, then you probably have found a way to make this come true in your life. If you cannot come up with a good answer then you just need to decide.

  • Thanks very much! :)
    – IGY
    May 11, 2023 at 13:41

Even if it were allowable, I don't see why it would be desirable. I'm a public policy phd student, but at day's end this is a masquerade. I'm really an econometrician who uses public policy to ask and attempt to answer interesting questions. I have multiple interests, yet I cannot specialize in all of them. So, I network. I have contacts... Sounds like you need coworkers in these different fields you're interested in. I'll explain.

I have friends who are in criminology. So, when I wanna do a crim paper, I work with them. When I wanna do meta-analysis, I work with my coworkers who do that. When I wanna do razor's edge econometrics work, I work with my friends/other colleagues in 'metrics. In other words, even if you don't become The Ultimate Brain in both subfields you do like, you can still both study and do very meaningful work in all these fields. Presumably physics is slightly different due to structural reasons, but the basic principles I speak of should still apply.

  • Thanks so much!!
    – IGY
    May 11, 2023 at 13:41

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