I've just started a PhD in QCD phenomenology and Quarkonia. While I'm quite happy with the work at the moment, I suppose I do have a romanticised view of working in theory. How feasible is it for me to work on more formal theory projects during and following my PhD in the field?

Edit: I have changed the title to reflect the true nature of the question. "Making a switch from HEP PH to HEP TH after my PhD" -> "Working in HEP TH with a background primarily in HEP PH". This is not a duplicate of the switching question as I am looking for the relationship between 2 quite related fields and also how to work between them rather than "switch" per se

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    Can you spell out the acronyms please
    – user438383
    Nov 25, 2023 at 17:13
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    Currently, YQ is IC b/c of all the UAs. Nov 25, 2023 at 17:35
  • Please see the duplicate target above: phenomenology and formal theory in particular do not have a solid wall between them, so it should be easy to gradually switch as the article describes. That said: I'm sure you know how terrible the job market for hep-th is. Rather than moving deeper into theory, you are very likely to need to move toward applied / experimental positions that will build skills that will qualify you for a job other than a professorship.
    – cag51
    Nov 26, 2023 at 19:26
  • @cag51 I was looking for the very specific case of pheno to theory which is why I made a separate post. And yes, I know well how bad the market is for theory, thank you for the comment.
    – Allohn
    Nov 27, 2023 at 17:19
  • @user438383 The acronyms used are QCD: Quantum chromodynamics, HEP: High energy physics, PH: phenomenology, TH: theory.
    – Allohn
    Nov 27, 2023 at 17:19

2 Answers 2


In graduate school, you better follow the lines suggested to you by your supervisor. While your own initiative and your own ideas would be of a great value, try for the time being not to deviate much from the topics and specific problems offered to you by your advisor, because (s)he has a broader vision of things, and should know what research would be best to ensure for you a postdoctoral position after the defense.

After defense, you may start thinking if you indeed wish to continue in your specific field, or to switch your focus. Your choice should be based not only on your interests and tastes but also on the funding situation and availability of positions.

Given your (supposedly, solid) knowledge of quantum physics, you may, e.g. consider switching, in the future, to such an emerging subarea as Quantum Computing for QCD. While it is hard to predict the job market trend in 5 years, chances are that this subearea (and Quantum Computing in general) will be funded better than pure theory.

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    Thank you for the response! Yes, while I hope to continue in academia, I am absolutely building up my skills for possible employment in adjacent computing related roles.
    – Allohn
    Nov 27, 2023 at 17:26
  • @Allohn As an additional food for thought, my son started his PhD in QFT at a highly acknowledged department. However, after completing his MS requirements (and publishing three papers) he chose to receive his Masters, and to switch gears, leaving for a different school, to do his PhD in Quantum Computing. His background in Quantum Physics served him a good stead. He finished his PhD very quickly, and got a prestigious postdoctoral fellowship. Nov 28, 2023 at 6:06
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    I'll definitely be stewing on that! I'll have to find my own unique path so hearing lots of stories like that helps. Thank you
    – Allohn
    Nov 30, 2023 at 13:44

Generally, one can switch research focus and even, perhaps, subfield or even field, if you have a stable position from which to work. If you are a tenured professor in some aspect of physics then there is little to prevent you from examining and moving to another. It is helpful if you have colleagues in the new area so that you can easily get guidance, but that is available elsewhere if you work at it. Of course, you need to keep the department happy about your work but that doesn't necessarily imply being limited to one narrow area.

I switched focus a number of times over a long career, though not in physics.

But it is probably not possible to do so immediately after earning a doctorate as you will not yet have anything to show in the new field making it difficult to get hired.

What you can do during your doctorate depends on how intense it is and on the opinions/needs/desires of an advisor. There is probably some opportunity to dabble a bit but intense study is pretty hard even in one field.

If this is your plan, then you might consider either switching to the new field now or deciding to put it 'on the back burner' until you are fairly well established.

But it is always a good idea for an academic to look at new and different things and to take advantage of opportunities that arise if they seem interesting. Don't. Be. Bored.

  • Thank you for your comment! I suppose my desire comes more from an idealistic picture of what theory looks like compared to what I'm doing, but I am quite happy with what I'm doing. I'll keep your words to heart about keeping an open mind on topics but well into my career rather than as early on as I am.
    – Allohn
    Nov 27, 2023 at 17:28

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