Wednesday, 31 December 2008

2009

Another year in physics approaches. I'll begin the year with a visit to another dept. and a paper on noncommutativity, which is looking like it might shape up well. I would like to be able to stretch it into two papers, but that might not be feasible. That's January, and probably a chunk of Feb. taken up with.

In March it's another visit and back to QCD, and a paper for which the preliminary results have been sitting around for a couple of months, waiting for some serious attention. Lookinig forward to getting that one out for political reasons, but no-one is going to cite it, I can tell you that now.

Beyond that, no current plans. I suppose I could try the string field project -- recently had an idea for a paper based on my PhD, a subject I left behind years ago. Don't know if it's tractable, and if it is I don't know what it would reveal... it would be a hard sell, since no-one cared about my PhD. Well, a few guys in Japan did, but not in any serious way. Still, it might be nice to write a short paper and throw it at Int.J.Mod.Phys.A. Sigh.

Politically, I need another QCD paper before August. Even more importantly, I need a paper with someone in my current institute, which is going to be tricky. Hang on. Sending an e-mail about that now... ok, done, self promotion sucky uppy e-mail sent. I also need a referee from the current institute. Which will be impossible if I don't write a paper with someone. But being seemingly the only person doing analytic (as opposed to numerical) field theory in a group which is pronouncedly split between lattice and strings doesn't make that particularly easy. Shit shit shit.

Then, beginning in August, it's application time again. And seeing as I'm onto my second postdoc, this means writing big impressive research proposals and applying for 5 year and permanent positions semi-seriously.

HAHAHAHAH hah ah ah oh dear, I almost believed that for a moment. I'm screwed. There are so few jobs anyway, and no reason for anyone to give one to me. Ha. I'm 30 and shortly to be turfed out of my chosen career because I don't work on trendy bandwagon subjects. Oh dear. On that note, I need a bacon sandwich.

Sunday, 21 December 2008

An idiot.

My reviewer thinks that the following object is not Lorentz invariant:

p_\mu T^{\mu\nu} p_\nu

where p_\mu is the four vector momentum of a particle and T^{\mu\nu} is an energy momentum tensor.

And this prick probably has tenure.

UK Annual Theory Meeting, day 3.

Physics Highlights from the Tevatron -- Beate Heinemann

No deviation from the SM in diboson (WZ or ZZ) production. These investigations are important as they're sensitive to trilinear gauge boson couplings which are a direct consequence of the SM's SU(2) x U(1) gauge group. If there is something else going on, it might be seen here. 5.7\sigma significance.

Theory says that a CP violating phase \beta_s measured in B_s->J\psi\psi should be very small -- it can be measured at the LHC, but it's too small to be seen by the Tevatron -- unless there is some new physics going on. And indeed, the Tevatron seems to see something. This is early data, so will be watched closely.

Still no concensus on whether the
CDF results indicate new physics or a miscalculated background.

LHC Prospects -- Dave Charlton

This was depressing. I have three words written down on my pad:

"LHC: is fucked"

The machine will be cooled back down in Jult 2009. So you can kiss goodbye to any really interesting physics until 2010, I guess.

Harmony of Scattering Amplitudes: From QCD to Gravity -- Zvi Bern

Oh my word, this is an outttrraggeee.

After the three year old \cite{Bern, Kosower} introduction to MHV amplitudes \cite{Bern, Kosower} during which the word "harmony" was thrown about almost enough to make me vomit bile over the sleeping head of the chap in front, Bern spent his hour glorifying and citing himself and Kosower \cite{Bern, Kosower}. I actually don't care if what they're going is important, but I hate the approach -- consider some subset of loop diagrams which are "cut constructable", or otherwise handy to play with, do all your work on those and then claim that it applies to the whole theory. Oh shut up. This ad hoc approach yields a shed load of results, certainly, \cite{Bern, Kosower}, but it's never going to give you a genuine undersanding of the whole theory, despite what Bern claims. \cite\cite\cite\cite{Bern, Kosower}.

And, not once, not even god damned once, did Bern mention any of the work done by either the Durham or Southampton groups. Hello? Hello, Bern? You're at the UK theory meeting and you don't mention the papers of two of the larger groups in the country? Your arrogance appalls. Are you going to mention any UK contributions? Oh, the London guys. They get a nod at one point. Not even a mention of the seminal paper by Mansfield, who is at Durham and was sat in the bloody audience! Perhaps the citation count on that paper isn't high enough. That's what matters, after all, not content. Not like Bern and Kosower's papers. Oh no. They have big \cite{Bern, Kosower}, sorry, very big citation counts.

You make me sick.

UK Annual Theory Meeting, day 2 again.

Town Meeting

This meeting discusses the state of the UK theory community -- which, as might become apparent during this post, doesn't really exist. It's more a collection of people who don't like each other very much, resigned to either being in Oxbridge and therefore safe and happy in their jobs, or to being in a small group and having to fight and claw for a single postdoc every few years. The big groups don't care about the little groups, the little groups are bitter because the big groups take all the money.

There was again no official STFC representative at the town meeting (disgusting, despicable cowards). Ruth Gregory, who is on the PPAN board, acted as host and told us what she knew. Get yourselves a galss of something single malt, now.

6 of 19 rolling grant applications were not funded this round, and these were mostly from the smaller UK groups. STFC's line was "consolidating", I think. Sucking the nuts of Oxbridge would be my choice of words.

Georg Weiglein voiced a suspicion that this was part of a long term STFC objective to close down the smaller groups, but Ruth disagreed (phew).

The word is that over the next 5 years, there will be a 25% cut in the number of RA posts awarded -- so in five years time, there will be a total of 20 RA's funded. Ruth thinks this is very, very, likely to actually happen, barring some miracle. Oh god.

Even worse, STFC has been considering tieing the number of studentships awarded to the number of RA posts (so they control even more of a department's research direction). Given that there are going to be so few RAs, we're going to lose all our students too. Ohhhh god.

STFC's new "roadmap", called a "strategy" or some such feculant dribble, has just been announced. The document is open for consultation until March, and the message from Ruth is that we have to give STFC our feedback, loudly, but in a unified and non bitchy/backstabbing way (it's no use blaming Cambridge for stealing all the cash, as it will just give STFC a target to point their guns at, was the subtext, I think).

You might have heard the rumour that STFC had discovered an extra 9 million quid lying around. This is true, but no-one seems to know what the money should be used for. STFC has said that it will not be used for grant rounds which have already passed. There is a chance it will go to experiment, who are facing cuts at least as bad as theory, although Ruth says that we should make the case for it to come back to theory. YEY to that idea.

So, that's it. It's all bleak. We've been screwed by capitalisism and our vile PC culture of letting any bullshitting idiot walk into an important job and do it by spousing stolen, contentless, soundbits rather than thinking about all the people their decisions will affect.

So screw you, STFC.

UK Annual Theory Meeting, day 2.

There isn't much to report from this, the only full day of talks at the conference, as every presentation was pretty dire. Special mention must, however, go to:

Searching for B-mode polar anisotropies on large angular scales --George Efstathiou

We're treated to a 15 minute engineering porn flick on the cooling systems of the Planck satellite. No really. He means well, I think, but once again this is a staggering misinterpretation of what the meeting is about and misunderstanding of how the audience is composed. So it gets to the results, and there are lots of pretty pictures I don't understand. And why not? Well, at the end of the talk, some brave sod raises their hand and asks

"So what is a B-mode and why is it so important?"

That's right. He hadn't told us. It's in the title of his talk, and he hadn't told us what it bloody was. Arghhh.

This guy is an FRS and a professor at Cambridge, and he can't be bothered to do more than cannibalise a talk he's clearly given many times to specialists in his field. And this guy must be on the chair of a hundred commities, deciding the fate of postdocs and research groups, and he's lazy. Well that bodes well.

Physicists suck.

Friday, 19 December 2008

UK Annual Theory Meeting, day 1.

Neil Lambert --- Multiple Brane Dynamics: D-branes to M-branes.

Apparently string theory needs promoting again. Presumably at the behest of the organisers, the talk began with a 10 minute introduction to string theory which would not have taxed a PhD student. He began with the usual force unification picture, some trouser diagrams, and then ending with the string dualities and the hints of M-theory. All very old stuff.

There were some strange, to be honest sloppy, statements, such as the existence of 10 dimension being the "great prediction" of string theory -- this is clearly wrong. First, it's not a prediction of string theory, it's a requirement, and secondly, if we discover there are 6 hidden dimensions it neither proves nor disproves string theory. Sadly, no-one called him on this. Sigh.

There were some other statements I was unsure of -- apparently you still can't get the exact standard model as one of the plethora of string vacua, but I thought that perhaps Hui-He and collaborators had managed this some years ago. Unsure. Also, there is "great evidence that magnetic charges exist in nature, but they are very massive". Really? Can someone enlighten me? He's not talking about branes, is he?

After this dubious introduction, the talk turned to the Bagger--Lambert model. It was not thought possible, until recently, to be able to write down actions for (the low energy effective theory of) D-branes (2 and 5) in M--theory. The way around this is to take the symmetries of the theory to be generated not my Lie algebras, but by three algebras -- which just means you have a bracket [A,B,C] rather than [A,B], but where the bracket need not be totally antisymmetric. The nice example given was the space of M by N matrices, which are not a Lie algebra, but are a 3 algebra with the bracket [A,B,C]=AB^\dagger C-CB^\dagger A. A nice description of these 3--algebras is as a lie algebra with matter in the bi-fundamental, all packaged up into one object. Using this you can write down actions with the right symmetries of M--theory, but apparently you have to then do a bit more work to get actions which describe the branes you're interested in.

So yes, there were snippets of interesting information, but the talk would have benefited enormously from having a gentle introduction to M--theory and its branes, before progressing, rather than having a trivial introduction to string theory before leaping tall buildings.

Edward Shuryak -- Strongly coupled quark-gluon plasma.

RHIC has seen events involving sQGP (as in the title), I think. That's what I managed to pull out of the ultra-dense slides of this extremely busy talk. And then I lost interest, until half way through when there was a slide of diagrams which looked very much like the trajectories of a particle in an electromagnetic vortex (must check that), and then I lost interest until the conclusions. There were slides with pages of text taken from his research papers -- this is not the way to give a talk.

So, the conclusions -- QGP behaves like a very good liquid because of "magnetic bottle trapping", for T<1.4 Tc it is dominated by magnetic monopoles. But forget all that, the important point to take away is that QGP does not behave the way people expected it to. Apparently this chap is a candidate for a Nobel prize for discovering this, and it was nice to hear about this negative' result. But t was obvious. The people who first suggested that QGP was not going to agree with expectations will, of course, never get the credit. Why? Well, this comes down to the assumption that you lose confinement in QGP. And that's wrong. Why? Well, confinement means the absence of physical, colour charged states (to a field theorist) or a confining potential (to a lattice guy). The latter might well fail at high temp when you get QGP, you almost certainly have some other form of potential, but the former is a consequence of the global (non pert) properties of the Yang Mills configuration space, for example Gribov copies. None of this is altered by going to high temperature, so individual quarks and gluons aren't suddenly going to become observable.

But yeah, there we go. No-one listens to whispers.

Friday, 12 December 2008

This amused me -- it's an entry in "comments" field on version 2 of an arXived paper:

"A missing complex "i" is included in the field strength and the divergent contributions corrected accordingly. As a result the model turns out to be asymptotically free."

So casual. Beautiful.

Friday, 5 December 2008

Peer review

I've just been royally screwed by an editor at JHEP. I can't go into details without giving away who I am. I'm too fed up to detail the problems with peer review in physics these days. Actually I'm really depressed about the whole thing.

Thursday, 27 November 2008

Airport musings

"You have very little chance of getting at the truth, if you know in advance what the truth ought to be." -- Spencer (Robert. B. Parker).

Advice which many in the field need not. They massage their results until they arrive where they expected to, and they get cited for it.

So here I am sat in an airport waiting lounge. Was somewhat disappointed to find that either the arXiv hadn't updated on time, or that this place was refusing to refresh its cache, so I can't read the new abstracts. Meh.

It is important to market yourself, and your material, properly. Especially if you're a PhD student or Postdoc. You want people to read your abstract and think "wow", so that then hopefully they'll at least get through your introduction and conclusion before putting your paper to one side, rather than just letting it scroll off the top of the page as they persue the arXiv.

Of course, there is selling yourself, and then there is writing blatant crap. This morning I read this in a paper of a few years back. It isn't a direct quote -- I've cut out a few words to disguise its origin, but the statements are faithful representations of the original.

"There is no obstacle to formulating the theory for non-constant
F(x), but we shall concentrate on the case of constant F for simplicity.
Up to terms involving derivatives of F(x), our leading order results
are therefore also valid for varying F(x)."

Wow. Way to go dudes.

Wednesday, 26 November 2008

Talk on the LHC.

The incoming director general of Cern, Rolf-Dieter Heuer, gave a talk on the LHC, this week, in Dublin. You can now stream it from here.

I was told I couldn't attend, because by the time I tried to book a seat, 750 places had already been reserved and there was a waiting list of 400.

Well, a shame, I thought, but great that the public are obviously so interested.

Yeah, bull. Take a look at 2 mins 51 seconds of the above video, and you'll notice that the hall is half empty.

So, well done the RDS for shafting that one.

Friday, 14 November 2008

Try new "Group Theory"!

I'm not sure what it is about this place, but every seminar I go to involves some god awful group like PSL(2,4) and the word irrep' scattered liberally all over the place. Even the Masters and PhD students can't give a 20 minute seminar without something transforming in an irrep of something else. (Aside: the Russian Masters student has papers already. Wowzer.)

Now, before anyone blows a gasket, yes, we all know what irreps are and we all know that they're important. But don't you wish, sometimes, that the speaker would just write down the relevant field and the way it transforms? Don't you get the feeling that they're telling you "3*3=5+1+3" and then running out of the room with nothing else because, well, they can't be bothered to actually construct the fields of the theory they're talking about?

Example: anyone who's ever taken a course on string theory will be familiar with this phenomenon.

Lecture 1: you spend the obligatory hours trawling through the commutators of the modes, constructing the Hamiltonian and the spectra, identifing the tachyon and the photon, etc. It's not super exciting, but hey it's your first course in string theory and it's still pretty cool, because you can do everything explicitly and really its just like your QFT course. Importantly, you can see what's going on. Now, time to get fermions in the game.

Lecture 2:
Superstrings: 3+3=8+1. Sniff.

Lecture 3: N=4 SYM and the AdS-CFT correspondence in all its gory glory -- WOAHHH.

Wait. What happened there? What happened to all the supersymmetric stuff? Well, you've been told what representation it's in, what more do you want? You haven't written down a string, a single commutator, you haven't seen the spectrum, you're just told that there's a 2bar, a 4+1 bla bla bla, and now you should be able to understand all the gumph about conifolds and G2 and holography that the papers are full of.

Didn't it annoy you? It annoyed me. So, while group theory is important and funky and here to stay, don't you just feel sometimes that physics once saw an advert and thought yup, that's for me', and that advert said:

"Group Theory: for when you just can't be arsed to do it by hand."

Saturday, 8 November 2008

Gribov copies.

There's an interesting discussion on BRST going on over at Not Even Wrong. Someone mentioned Gribov copies, in which I have an interest, and I put my two pence worth in.

I think I inadvertently caused the discussion to split into two groups -- BRST and copies, and it ended with people apologising on the comments board. Rolls eys. Physicists apologizing for their views on physics -- if only the string theorists would go for that idea in a big way.

Anyway, I'll summarise my thoughts here.

Gribov copies have physical effects -- they do have something to do with confinement. This is really very easy to show -- see work by Bagan, McMullan and Lavelle. What they have shown is that although you can write down the wavefunction for a physical quark (so not simply the fermion in the Lagrangian, as that isn't anything physical) in perturbation theory, you cannot do so non-perturbatively. If you could, there would exist a globally well defined gauge fixing for Yang Mills, and there isn't, because we know there are copies.

Seeing this from a slightly different angle, your supposedly gauge invariant quark picks up a non--perturbative gauge dependence (and hence becomes unphysical) precisely through the action of the Gribov copies. In other words, you can have physical quarks in perturbation theory (weak coupling, which makes perfect sense since we have asymptotic freedom), but not non--perturbatively (strong coupling, when we expect the flux tube to form). Non-perturbatively, you can't have single quarks, but the above argument doesn't go through for multiquark states, so you can have mesons and hadrons -- well great, this is exactly what we see!

However, this doesn't give you the confinement scale or anything like it. For that you need dynamical, quantum, arguments, and probably non--perturbative arguments at that. So, just like every other approach to confinement, it doesn't go all the way, but it's a very simple, very physical argument.

The way most people are introduced to Gribov copies is, probably, as an overcounting in the path integral. That's not the fundamental origin of the copies, it's just a symptom of their existence. If there is some other, operator, picture in which the copies don't appear --as mentioned in the discussion linked above-- then either there is something amiss with that picture (it isn't capturing all the physics, in particular non-pert. physics) or there is something wrong with our understanding of that picture (which is probably easier to accept).

But then, I'm going up against Nakanishi -- and he invented the Nakanishi Lautrup field, compare: what have I done?, so you should probably take what I say with a pinch of salt.

Humility.

Wednesday, 15 October 2008

Peer review

Referee report dropped into my inbox this morning. Suffice to say our paper concerned a dimensionless object, let's call it O for object, which in the literature has a somewhat dubious, gauge dependent definition. So we gave a nice, sensible, gauge invariant definition for it.

The referee said "this is nonsense, they never explain what is wrong with the old units, and those units are certainly gauge invariant!".

Well. How to respond to that. Perhaps something like:

1. We explained exactly what was wrong with the old definitions of O.
2. O is dimensionless.
3. Sorry, in case that went over your head, O *doesn't have any units*. It is a pure number.
4. Units... gauge invariance? Sorry, what? No, really, what? Please, do explain. I'm waiting. No? No, I thought not. Go back to playing with your table top cold fusion. How's your website, by the way, www.my-own-theory- that-neutrinos-are-alive-and- cause-gravity-to-go-backwards.com ?

On a less facetious note, this example of, frankly, stupidity, raises an important point concerning peer review. This guy or gal now believes that I write rubbish papers. So I can kiss goodbye to any job for which this luddite holds any sway in the decision making process. Also, he is going to sit around with his chums, who presumably are at least partially connected to the field the paper is written for, and slag me and my physics off. My name is now dirt in some department, somewhere in the world (replace "some" with "another" if you like).

On the other hand, the peer anonymous review system means that I don't know who this crackpot is. I won't know now to avoid his papers, not apply for any jobs he might have, and I won't be able to laugh about him with my chums in conferences. Or get smashed during the conference dinner and tell him precisely what I think of his abilities.

Seriously -- this guy's incompetence is damaging my career. It isn't fair. And it's just not possible to get this point accross to the average journal editor, unless he happens to know you and that you aren't a cretin.

SIGH.

But what can we do? Our problem isn't the one they have in certain areas of pure maths, where there are fields so specialised that only six people in the world work on it, so everyone knows exactly who everyone else is and what they're doing. Our problem is that to make reviewing completely anonymous, we're going to have to either give up the arXiv (SHUDDER), make arXiv submission anonymous, or go back to the old ways of submitting to a journal and waiting until it's accepted before sending it around to people (meaning put it on the arXiv). Making arXiv submission anonymous seems the most sensible (until your paper is accepted), now that there's an endorsement system it should cut down on the crackpots. But is it really what we want?

There is another option. How important is journal publication these days? For the postdocs I know, it isn't -- what matters is the citation count on spires. It seems that the older chaps, who still hold the position of power, they are more likely to want to see that your papers are in good journals before they hire you. That's just the way things were done when they were coming up through the system.

Well, they'll be retiring soon... and if there are any jobs left in physics (STFC, I'm looking at you again), the young will be filling them up. People who communicate via e-mail and skype, not by waiting for the latest version of acta. physica. polonica. to be delivered by mountain pony. People who know if a paper is decent or not because they can download it and read it for themselves (or they can just count the cites and leap on the bloody bandwagon). Do they care what some random shadowy fool thinks of their paper when, if they have any sense, they'll give up any pretence of honesty and send their paper to a journal for which their chum is an editor and it will be accepted straight away.

Well. There we are.

Oh, should say, there was a second referee report which was overwhelmingly positive. Good show there.

Wednesday, 10 September 2008

The LHC is here. Ish.

Except it isn't really, is it. Although a round of applause for the chap who decided to tell the press that "beam circulation day" was the significant milestone they should all be slavering over. It worked -- it's certainly generated a lot of interest in the field, which is great, and rather cleverly this will help make the doubly-bitter pill of no Higgs and no SUSY somewhat easier for the public and the funding bodies to swallow in the future.

So yes, politically a very sensible move. But will any of this attention actually bring in funding to universities? Are we ever going to see another rolling grant? Can we employ another postdoc sometime in the next five years? STFC, are you listening?

STFC? Hello? Oh, you're at the LHC. Having champagne and nibbles. Right.

Saturday, 6 September 2008

LHC is coming...

...and all the string theorists will look up and shout "Cite us!", and we'll look down and whisper No.'

That should give you some idea of what to expect on this blog. Posting will commence in the new term.