Theoretical Physics Q and A site progress

The proposed Theoretical Physics stack exchange site has finished its definition phase and has now entered a commitment phase. What this means is that we need as many physicists as possible to agree (by signing up here) to participate in the beta and hopefully ask or answer 10 questions in the first 3 months. This shouldn’t be a huge time commitment, but it is really important to get as many research physicists as possible early on. The reason for this is that the democratic nature of Stack Exchange sites means that the direction of the site is set by the participants. Obviously there are a lot more people interested in some aspect of theoretical physics than there are people who have some level of expertise in the field, and so it is important to get as many TP grad students, postdocs and faculty involved at an early stage to insure that the site becomes a TP version of MathOverflow and CSTheory, rather than becoming a site for people to post their pet crackpot theories or discuss pop science topics.

To help convince you to sign up, below are a list of the top 5 examples of both on-topic and off-topic questions chosen during the definition phase.


  1. Are there entangled states which do not violate any Bell inequality?
  2. Are XXZ spinchains with uniform couplings exactly solvable?
  3. Has [specific toy model] been studied in the literature?
  4. What are the justifying foundations of statistical mechanics without appealing to the ergodic hypothesis?
  5. Within Twistor String Theory (ala Within), what is currently seen as the significance of the superconformal algebra realized on supertwistor space?


  1. Why is the sky blue during the day, red during sunrise and sunset and black at night?
  2. I have found an error in general relativity/quantum mechanics/the second law of thermodynamics. Can someone help me work out the maths?
  3. Is Dr. Quantum’s Double Slit Experiment video scientifically accurate?
  4. Why do hot things glow?
  5. What is the current thinking about Lisi’s “Exceptionally Simple Theory of Everything”?

8 Responses to “Theoretical Physics Q and A site progress”

  1. Earl Says:

    Are there entangled states which do not violate any Bell inequality?


    Me and Matty Hoban were talking about this problem just yesterday!

  2. Joe Fitzsimons Says:

    Then sign up! Matty hasn’t moved to Germany too, has he?

  3. Earl Says:

    I have just signed up! Although, I did not seem to be able to comment on any of the example questions…. is this because they are now in the “commitment” phase. Also did not seem to be able to suggest any more questions, or do much else other than sign up.

    Matty is still in the UK. I have been here for the last few days, and visited UCL. I fly back in a few hours.

  4. Joe Fitzsimons Says:

    Ah I see. Yes, the definition phase is over, though you can click on the “definition” tab to see what went on. Once the beta starts, then it works just like MathOverflow, but for that to happen you need 200 people to commit plus satisfy a few other metrics. Still, it’s at 7% now, so we’re making good progress.

  5. Anonymous Says:

    I support the proposal and would like to see it taking off but I am not a physicist (I am a mathematician). I don’t know if I can ask any good questions of the level you are expecting. So my questions is should I commit to the proposal?

  6. Joe Fitzsimons Says:

    Good question. I think the answer is that it is really up to you. If you are working in an interdisciplinary field that is also of interest to physicists, then I would think it makes sense to participate. If not, but the idea seems appealing to you, then go ahead and sign up. I’m sure there will be a lot of questions that are highly mathematical. I’m not worried about mathematician’s dragging down the level of the site, I’m worried about crackpots.

    On the other hand, of course, if you feel that you may not be able to contribute much, then perhaps you would prefer to wait for the public beta to gauge whether you wish to participate.

  7. Anonymous Says:

    Thanks Joe. I am interested in following theoretical physics questions and can follow discussions to some extent (on relativity, quantum physics/information/computing, and string theory) but I don’t think I can contribute much (asking good questions or answering research-level theoretical physics questions, which are not math questions and are not very board. My research area is not physics, I am mostly interested in mathematical models and tools used in theoretical physics). I will probably wait till you get into public beta.

  8. Alejandro Rivas-Micoud Says:

    From a neophyte: “Is time simply the means by which random chance “collapses” a wave probability for a specific segment of space/matter? In other words, is entropy simply the means by which gradually a set of probabilistic outcomes randomly occur throughout space? Thus making time a consequence of random chance gradually collapsing from its wave function into an observable state? The past as observed “collapsed” particles? The future as non observed probability waves? The present as observation of the collapse of a specific space/matter segment? Energy, the consequence of observation? Matter, the result of the action of time on space? In other words, if the future were known, then time would not exist?”

    Would love to hear any and all thoughts! :)

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