Who are the most respected research groups in QG now?

[marcus]

Yeah, it is California (perhaps I have an idealized image of this place, but at the very least it will be new and I think a good experience for me to live somewhere like this. If I was just comparing two identical PhDs one in Nott, one in CA I would definitely take the latter). Also yes the structured nature of the course, with it's graduate lectures also appeals to me (but of course this also means it will be almost double the length to completion). But I would sacrifice both location and course structure if I thought academically Nott was going to be better for me than the other gradschool (after all I can always do postdocs and things in nice locations later in life).

So to break it down, US gradschool:
Pros:
Location/Travel/Lifestyle
Graduate lectures
Cons:
Only mid 40's, is this kind of ranking good enough, respectable for career in ST?
5-6 Years in length, vs just 3 in the UK

Whereas Nottingham:
Pros:
Seems respectable to me, well known people like Krasnov/Barrett. Also conferences with the likes of Rovelli plenary speaker etc.
3 years in length
Cons:
Location doesn't excite me at all being from the UK myself anyway.
I worry about how I am going to learn advanced topics such as QFT/Gauge/Topology, without the rigorous lecture struct. Will it be just independant book reading alongside research etc.

Think that sums it up, my open questions are is a mid 40's US gradschool good enough to make it (by which I mean as I defined earlier) in ST? and in regard to Nottingham, will a UK PhD give me the support to learn advanced topics, given that I've never taken formal lectures in these before?

Cheers

Hi Azrael, up to now I don't think I've given you any definite advice, just given general views and info and tried to elicit some more detail. Now I will say I (since you have asked repeatedly for advice) that I think the US 5-year option is better suited to your needs.

I say this not because I think a string Phd is better than nonstring Phd at this point in time but because you have just these two specific options that you described and frankly you don't want to live in Nottingham. Wouldn't be happy there. You want the California coast.
And in 5 years the job market may have changed. So if you have a secure grad school berth for 5 years in a nice place go for it. Also you need those US grad level courses, you are not the independent self-study type.

But I have also more higher-level reasons besides immediate security and happiness.
Let's say that the "mid-40s" California school is UCSC which in physics ranks 45 in USNews listing.
It has Tom Banks, it has Tony Aguirre (in cosmology), it has Stefano Profumo (young, brilliant, fun particle physics and cosmology). It has a great older guy Joel Primack who both helped put together the Standard Particle Model in the 1970s and then moved into cosmology.

UCSC has name people who have shifted from particle over into astroparticle and cosmo---which is a smart move. And whose guidance is going to be smart and insider-wise. And whose recommendation letters are the kind that open doors. It is a very very good place. So even tho it ranks 45 with USNews, in physics, it is intrinsically distinguished.

So let's say you are talking about a UCSC option. Then don't worry, go where you feel secure and happy and be confident that a good PhD from there will get you started on a career.

Also UC grad schools have some leeway for changing research line. The stringy folks at UCSC are very close to the cosmology folks, some even could be seen as line crossers or as wearing two hats.

Stefano Profumo is teaching the basic grad level QFT course that you have to take. He likes bicycling and sailing on SFbay and outdoors stuff. He is into astroparticle and cosmology. You will inevitably get to know him because you have to take QFT.
If you have even one friend you can probably get out of straight string theory and into a more interdisciplinary line. String has applications to trying to understand dark matter and cosmology. Get into applications, and you already have an exit if the field goes bad.
They like interdisciplinary stuff at UCSC.

Tom Banks is even something of a shape-changer himself. More interesting and less predictable than the run-of-mill big string name.
He is a noted string/M person but has moved into cosmology and helped establish string cosmology as a line of research.

Tony Aguirre is co-director of a highprofile private research foundation called FQXi. He is inside as all get-out.

Now it is just speculative hypothesis that your mid-40 school is UCSC, which I just take as an example, because it is mid-40. Suppose not. Suppose some other institution on the California coast. The details may differ but the fundamental reasoning still applies.
Wherever it is, there are going to be some good aspects, so look on the brightside, stay flexible, work enthusiastically, and you can very well luck out. Plus who really knows what the picture will be 5 years out.

http://scipp.ucsc.edu/~profumo/
Research Interests:
Astro-particle Physics
Particle Dark Matter Searches and Model Building
High Energy Astrophysics
Theoretical High Energy Physics
Particle Physics Beyond the Standard Model
Models for the Generation of the Baryon Asymmetry in the Universe
Phenomenology of Supersymmetric and Extra-Dimensional Models

http://scipp.ucsc.edu/personnel/profiles/primack.html
"...In the 1970s, Primack helped to create what is now called the Standard Model of particle physics; for example, in 1972, with Ben Lee and Sam Trieman he did the first calculation of the mass of the charmed quark using renormalizable electroweak theory. Primack's recent research has concentrated on the nature of the dark matter that comprises most of the mass in the universe. He and Heinz Pagels were the first to suggest that the dark matter might be the lightest supersymmetric partner particle. He also investigated the possibility that some of the dark matter might be light neutrinos (hot dark matter). He and his students and other collaborators have analyzed many variants of CDM - especially CDM with less than a critical density of matter and a compensating cosmological constant (CDM) - and confronted the predictions of these models with a wide range of observational data..."

http://scipp.ucsc.edu/theory/banks.html

http://physics.ucsc.edu/people/faculty/aguirre.html

 

[MTd2]

Civilized, concerning the top universities, this is pointless, as well as citing any no-go theorem because they do not rule all possible situations, and you can always counter with a nice trick such as supersymmetry did to Coleman Mandula theorem to the trivial combination of poincare symmetries and internal ones.

Non stringy QG is peer reviewed, I don't know where you get that. As for reformulating everything every 6 months is simply not true. Besides if one can expose your ideas, work with other researchers, goes to conferences, be financially supported,this person can be sure that it has accomplished its primary objective to be a researcher "on the market".

Any way, what matter is experiments. The day CERN people like Tommaso Dorigo accepts these things as truth, I will take their word, otherwise, Cumrun Vafa and Edward Witten are just, crudely speaking, mathematicians working as physicists. If you want to speak in terms of status quo, Witten and Vafa are not as trustworthy as Tommaso Dorigo when it comes to real physics.

Concerning the strings on AdS, I don't really see the need for strings. The action used for every CFT interpreted as low effective action from strings, or their correction due to different ways of connecting string with N branes can be just seen as ad hoc assumption. As usual, it *seems* one can get anything out of strings. What is really working here is the mathematical method, which is: finding an action with inverse coupling in the AdS or CFT side that reproduces the other's sides physics. And then, proceed with calculations, afterall, one do not need AdS/CFT more than other than to simplify calculations.

I know what I told you won't convince you. Well, at least you should really rest becaue you know cannot do much to avoid the growth of non stringy QG. Just relax and enjoy the show :).

 

[Civilized]

Civilized, concerning the top universities, this is pointless, as well as citing any no-go theorem because they do not rule all possible situations, and you can always counter with a nice trick such as supersymmetry did to Coleman Mandula theorem to the trivial combination of poincare symmetries and internal ones.

But the yet-to-be-created trick you are counting on is nothing more than a fantasy at this point. There is no substance to support the possible existence of such a trick.

Non stringy QG is peer reviewed, I don't know where you get that.

Show me a peer-reviewed review paper published in the last 6 or 12 months.

If you want to speak in terms of status quo, Witten and Vafa are not as trustworthy as Tommaso Dorigo when it comes to real physics.

Of course this statement is a joke to me, but I don't except proof by authority in any case so it doesn't matter.

Concerning the strings on AdS, I don't really see the need for strings. The action used for every CFT interpreted as low effective action from strings, or their correction due to different ways of connecting string with N branes can be just seen as ad hoc assumption.

First of all, I already explained why we physically would expect the confining phase of an SU(n) gauge theory to be described by strings with super-high tension, so I don't know what you mean by "ad hoc", except in the sense that every hypothesis in science is "ad hoc" until it is put to proven use.

What is really working here is the mathematical method, which is: finding an action with inverse coupling in the AdS or CFT side that reproduces the other's sides physics. And then, proceed with calculations, afterall, one do not need AdS/CFT more than other than to simplify calculations.

Now I think I see the problem, and it has to do with the naive viewpoint that the CFT is what actually exists and the dual description in terms of AdS string theory is just a mathematical tool. This naive realist viewpoint is a major thing that separates mainstream researchers from crackpot amateurs who think it is possible or desirable to describe the things that really exist. Mature theorist realize that we are just building models to describe nature, and to say that one model 'exists' but that the completely equivalent dual model does not is to be participating in a discourse that is at a lower level than real physics research.

Well, at least you should really rest becaue you know cannot do much to avoid the growth of non stringy QG. Just relax and enjoy the show :).

I'm not worried about the growth of non-stringy QG, I am worried about students receiving misinformation that leads to the end of their studies in physics. At the university, I never mention non-string QG and neither does anyone else, it's only on this forum where non-string QG is vastly over represented as a legitimate field of physics research that I fear that students will become confused. I know people are going to call my comments off topic, but the main reason I'm in this thread is to combat the impression that "Who are the most respected research groups in QG now?" should be entirely about non-string non-standard research. In the mainstream QG is a subset of string theory, and so when I saw that the tone of the thread was contrasting string theory and QG I had to step into clean up the misinformation. According to the physics forums guideline we are trying to give students an accurate knowledge of mainstream physics, and this thread was working against that goal.

 

[MTd2]

Civilized, your hipocrisis civilized me. I ran out of arguments... You are totally right :).

 

[Civilized]

Civilized, your hipocrisis civilized me. I ran out of arguments... You are totally right :).

Although I suspect your post is sarcasm, that would really serve no purpose in a mature discussion forum, and so I am forced to conclude that you are entirely sincere.

 

[MTd2]

Although I suspect your post is sarcasm, that would really serve no purpose in a mature discussion forum, and so I am forced to conclude that you are entirely sincere.

You bet. Really powerful in you hypocrisis is. Leech of public money you are!

PS.: Just joking. You probably are some unemployed physicist with too much time in your hands. It is likely that said students are just your fantasy because no good physicist would have your kind of atitude in real life and still be able to keep a place at university. Unless you show that you are someone at a university, I don't believe you, neither in your fantasy university.

 

[Max™]

I'm just curious after seeing these bold statements about String models being the only way to do things.

Is there in fact a useful background independent formulation of String Theory which I've somehow missed in the last... god, decade and a half since I first read up on the subject?If there isn't... doesn't that bother you... just a little?Just noticed the bit about Lorentz violations... I'd say your post is very misleading to say the least. String Theory is a great tool. Reformulating equations and processes in various theoretical frameworks can often provide new insights into them. This is fantastic.

It is not the only way to do things, or the very idea of adS/CFT wouldn't make sense at all, and it is not the holy grail of modern physics just yet. Maybe after the LHC goes live, or the Tevatron beats them to the punch, and they finally prove a prediction of String Theory, you can claim it is the only functioning way to do these things.

http://xkcd.com/171/

The most important thing in science is to be honest, you are not being honest.

 

[Civilized]

Is there in fact a useful background independent formulation of String Theory which I've somehow missed in the last... god, decade and a half since I first read up on the subject? If there isn't... doesn't that bother you... just a little?

I assume by background dependent you mean that String Theory assumes the existence of spacetime as a smooth manifold. This doesn't bother me because I would prefer to have a tractable theory that fits well with the theories we already have as opposed to arbitrarily demanding that the universe should be composed of pre-geometry on the grounds that I know it must be so.

Just noticed the bit about Lorentz violations... I'd say your post is very misleading to say the least.

The LQG that was proposed by Rovelli and Smolin in 1990 was found to be Lorentz violating. Deformed special relativity is obviously Lorentz violating. My understanding is that there are new variants of LQG that are not Lorentz-violating, and that these are also not QFTs (but could be thought of as a generalization of QFT). If you know of a non-string model for quantum gravity that is a Lorentz covariant QFT, I would love to see. I'm still waiting for a peer-reviewed review paper on non-string QG that has been published in the last 12 months.

It [string theory] is not the only way to do things, or the very idea of adS/CFT wouldn't make sense at all, and it is not the holy grail of modern physics just yet.

I understand the logic you are using, if strings in AdS are dual to Conformal fields then why not do away with the strings and just talk about conformal fields. But AdS/CFT is not a quantum theory of gravity, the gravity in AdS is classical Einstein gravity. The comments about strings being the only game in town apply to quantum gravity in particular.

Maybe after the LHC goes live, or the Tevatron beats them to the punch, and they finally prove a prediction of String Theory, you can claim it is the only functioning way to do these things.

No, experimental confirmation can only rule theories out, in can never establish a theory as the only possible truth. To do that you need mathematics, you need impossibility proofs. Now of course impossibility proofs must be handled with care, since as someone pointed out it is always possible to escape the conclusion by failing to satisfy the premises. I am just saying that the current situation is such that failing to satisfy the premises is inconcievable: it means either being Lorentz-violating, being non-renormalizable, or being not a QFT.

You probably are some unemployed physicist with too much time in your hands. It is likely that said students are just your fantasy because no good physicist would have your kind of atitude in real life and still be able to keep a place at university. Unless you show that you are someone at a university, I don't believe you, neither in your fantasy university.

First of all, I'm guessing that English is not your first language. Secondly, you have extrapolated an elaborate ad hominem attack and it happens to be based on falsehoods. I am in fact employed doing research full time at one of the top 5 public schools in the US. My field of expertise is in the theory of quantum computing. Your right that I don't have any students, and that I don't have tenure, but I am far from unemployed --- although I am constantly moving from one short-term appointment to another just like most people who work in physics. The only way I can think of to "prove" this to you without revealing my identity is by showing that I have access to all the paid journal subscriptions that a university like mine typically has, but this would involve violating copyright and is unlikely to satisfy you anyway.

As for whether I have too much time on my hands, that may be so, but writing these posts takes almost no time or effort for me and is an alternative to having a blog to rant on (I prefer to be stimulated to discussion by other people than to stimulating myself to discussion on a blog).

Your right that most professors don't have my attitude, most of them ignore non-string QG altogether and lump it, as I said, into general crackpottery and avoid talking about it.

 

[MTd2]

Your right that most professors don't have my attitude, most of them ignore non-string QG altogether and lump it, as I said, into general crackpottery and avoid talking about it.

you have extrapolated an elaborate ad hominem attack and it happens to be based on falsehoods.

 

[Civilized]

you have extrapolated an elaborate ad hominem attack and it happens to be based on falsehoods.

The only thing I said about a specific person was "You're right", and I meant it sincerely. I also sincerely think that the exchange between you and I in this thread has been an accurate allegory which represents (granted, the extremes of) the exchange between the standard and non-standard physics communities, albeit accurate only in miniature.

I apologize for taking over the non-string QG party in this thread; I've made my point, and I'll leave the thread unless anyone else wants to discuss my assertions with me. I will continue to take issues with other threads where "Quantum Gravity" is discussed entirely in terms of non-standard physics, since this is supposed to be a forum where students come to learn about mainstream peer-reviewed science(btw, no one has responded to my request for a peer-reviewed non-string QG review paper from the last 12 months).

P.S. The criticism of string theory in the XKCD comic above applies to non-string QG to a much, much incomparably greater degree. This is, in fact, the whole problem with non-string QG. If people spent more time elucidating why these models don't contradict relativistic QFT, and elucidating them from the point of view of what us mainstreamers want to hear, answering our doubts before we have them instead of never, than we wouldn't be having this argument today on such ugly terms.

 

[Fra]

I am worried about students receiving misinformation that leads to the end of their studies in physics. At the university, I never mention non-string QG and neither does anyone else, it's only on this forum where non-string QG is vastly over represented as a legitimate field of physics research that I fear that students will become confused. thread is to combat the impression that "Who are the most respected research groups in QG now?" should be entirely about non-string non-standard research.

I've had teachers telling me to face that string theory is THE future of physics, and the of physics or no physics was pretty much string theory or no string theory and that if I am serious I must study string theory or no one will take me seriously. And this guy is a string theory professor. Unfortunately he only convinced about his own inability to see beyond it; which really was not my problem to fix, so he convinced me that I am not meant to do "s"cience, I'm way too stubborn.

I've also come to think that this issue with brainwashing students aren't really much of an issue. Those who are "easily confused" in these matters are perhaps not the best suitable anyway, so they might as well do whatever "they are told to do" as far as I am concerned. After all we're not talking about kids here, it's adults. My only concern today is my tax money.

From the point of view of Science (btw, about Christine and "S" see post#16; "S" vs "s" is wether you think successful science means solving the deep problems, or wether it means "getting hired and stick there")

From the point of view of "S"cience, regarding what is relevant research is clearly up to the individual researcher what he/she chooses to invest part of their life in. If we are talking about "relevance" from the commercial point of view, then we are talking about "s"cience.

/Fredrik

 

[cristo]

This thread has gone way off-topic. Whilst this thread clearly had a bias towards non-string QG to start, there is no excuse for derailing the thread into an argument between string and non-string parties. This helps no-one. Thus, this thread is done.