Thursday, June 29, 2006

Flashes of Brilliance

Somewhere in between chasing wild geese and my own tail I seem to have a couple of spare minutes in which to write a brief update. As thunder rumbles outside I sit here, awake only from coffee and adrenalin fumes as all other power sources were used up some time ago. I was thinking last night of writing a post about how amazing it was that even though Beijing is supposed to be so polluted I've been remarkably healthy these last eight months. How ironic then that I sit here slightly feverish sipping on vile TCM. All in the line of work however.

Within a matter of minutes the sky has turned from a misty grey to a browny black and there's constant lightning forking across the city - I love thunderstorms and this is a goodie! There may be a slightly soggy Japanese student wishing he'd taken my advice. More on that shortly.

Perhaps the one in Beijing isn't quite so spectacular in terms of contrast but to put picture to theme, here's an utterly spectacular photo of a supercell.

Of late I've been keeping to my promise and have been going in pain-staking detail through the notes from the summer school which preceded Strings. I've also made a commitment in an attempt to kill two birds with one stone (or it may be a klein bottle). The ITP is not a teaching university so there are no undergraduates. This means that I'm not getting any teaching experience (apart from English corner which though very enjoyable is more a free discussion session chaired by me with the occasional quiz that I throw in). However, there are occasionally courses run by the professors on various topics, many of which I would love to attend if they were not almost all in Chinese. So, I've decided to take the matter into my own hands and offered to teach a group of students a course on geometry, topology and physics (following Nakahara) which will not only force me to get some teaching experience but it will also force me to get a deeper knowledge of the subject (I feel pretty happy with most of the book already but it'll be good to be forced not only to understand it myself but also to have to explain it to others - usually the best test as to whether you really do understand something).

So, come September I hope to teach a very understanding class a topic with which I only have a passing knowledge. The subject of the book I mentioned is something which is used as the first language of string theory but for the work I've done in the past, most of it is unnecessary. Should be fun!

Anyway, so that's a few months off yet. For now I have office company. When I was in Japan a few months ago I spoke with a PhD student about some of my ideas. We kept in contact and I arranged a visit for him to come to the ITP for a couple of weeks so we could talk more extensively and try and start up a collaboration. Through various crossed wires I was expecting to get some funding for this though that has fallen through and so we're funding this trip ourselves (or at least out of my travel grant). Not the best situation but if we can get some good work done then it will be well worth it. Tatsuya arrived this afternoon from the Yukawa institute via Osaka, and we quickly got down to discussing what work we would be doing together. After some dinner he asked if rain was imminent to which I replied, looking wisely at the clouds, that it was unlikely for a couple of hours. I asked if he wanted me to walk him back to the hotel but he insisted that he knew the way and would be absolutely fine. The difference between a ten and fifteen minute walk in this case is rather important as somewhere between those time frames the heavens decided that I didn't know my cumulonimbus from my streptococcus and set a deluge on the city. There's a moral to this tale though I wouldn't trust me on what it is.

OK, the thunderstorm has turned into one of the most dramatic I've ever seen. I'm heading outside.

Monday, June 26, 2006

Strings 06 powerpoint and pdf

Most of the slide files from Strings 06 are now online and can be found at this location.

Saturday, June 24, 2006

Wrapped Strings

Three weeks of string school and strings conference has now come to an end and I'm feeling a little weathered by it all. I'm attempting not to lose the momentum I've built up by actually going through the notes from the school, a task which I always promise to do but something else always seems to come up. In less than a week a friend from Japan will come over and we have some project ideas that we will be working on for a couple of weeks so it's now or never in terms of consolidation.

Anyway, there are too many other things to do right now to write reviews for the other talks but the least I can do is to summarise the summary presented by Robert Dijkgraaf at the end of Strings '06.

He started by illustrating the various football tactics of the countries in the world cup (if you haven't seen this then e-mail me and I'll send it to you), England's one man strategy, Germany's direct efficiency etc. This also included China which has nobody on the pitch at all (though this was altered by completely filling the pitch with white dots). He then explained that a similar picture could be drawn for string theory where the players on the pitch are the many areas of the subject which have been discussed over the last week, culminating with a possible goal from LHC. Added to this was the possibility of success for loop quantum gravity, though this tactic ended with an own goal, and rapturous applause.

Robert spoke about the landscape of ideas which is filling the stringy world at the moment and in particular the great intellectual diversity which is allowing technical progress in many long standing problems.

Again, the hope was echoed that LHC, astroparticle physics and the next generation of microwave observers may give us real signs of string theory in the coming years (see Sarah Shandera's talk for details).

The first subject which he said had been at the forefront of many talks in the meeting were the new developments in dynamical supersymmetry breaking and the control we have over this now using things like the Seiberg duality relations. The main point seems to be that we no longer have to come up with some convoluted mechanism for this phenomenon but rather dynamical SUSY breaking is generic in both QFT and string theory.

Next was the work on non-SUSY black holes and the attractor mechanism for these solutions. The question now seems to be what is the microscopic description of such objects.

Also on the topic of black holes was the subject of quantum black hole entropy and the important steps we have taken towards understanding N=2 black holes. Strominger's intuitive derivation of the OSV conjecture in terms of a gas of branes and antibranes was cited.

Again, black holes, but this time in terms of a probe of quantum gravity physics in terms of the recent work on bubbles of meta-stable vacua and bubbles of nothing in Kaluza-Klein black holes.

Another important topic was that of the real possibility of solving perturbative N=4 SYM in the large N-limit using the spin-chain formalism. Though I haven't written about it yet, there were talks about the all loop Bethe ansatz and integrable scattering of magnons and strings in AdS_5xS^5. In terms of quantum gauge theories, the emergent geometry from matrix models, thermal instantons and open strings was discussed as important new insights.

Closer to home, the Standard model was spoken about in terms of the model building on del Pezzo surfaces, D-brane realisation of the MSSM and coisotropic branes on toric orientifolds (I'm simply quoting the last statement without a true understanding of it). The fact that we should certainly have data from the LHC within three years is exciting for all the obvious reasons.

Next was the topic of landscape gardening both from inside and out. Vafa's work was cited as 'The Geometric Swamplands Program' and this, along with more studies on the distribution of vacua (plus Douglas et al's recent work showing the finiteness of the number of vacuum solutions) go some way towards understanding what we can and can't have in a theory of quantum gravity.

Seemingly the most likely candidate for really seeing stringy effects are in the realms of cosmology and in particular the CMB where stringy signatures in non-gaussianity and tensor-scalar ratios will perhaps be detectable when Planck comes online. Also Jonathan Feng's work on superWIMPS was mentioned as a possible detectable form of dark matter at the LHC.

Next was the work on topological string theory and how there is currently such a huge richness of mathematics coming from the subject. This work includes the result of a closed formula for an all genus amplitude on a compact Calabi Yau being imminent.

More on the mathematical side of things were the topics of the geometric Langlands program, more generalised stringy geometries and Sergei Gukov's work on categorification (again I'm just quoting there, I don't claim to have a good handle on that talk even though sergei is an excellent speaker).

On more isolated points were the fact the Martin Schnabl has proved two of Sen's three conjectures using open string field theory, the work of Nekrasov on topological quantum field theory and the fact that we are now going beyond the study of half BPS states and Jerome Gauntlett's work on a new, infinite family of supergravity backgrounds.

The point was made that with both the Poincare conjecture and Fermat's last theorem being solved in the last decade, this really seems to be a golden age of mathematics. Can it also become a golden age of physics?

Reading through all of that again I'm not surprised that my brain is feeling a little bruised. It seems that there have been many exciting steps towards understanding a great number of areas of string theory, quantum gauge theories, black hole physics and mathematics and we are very close to understanding some deep long-standing problems. The prospect of particle and cosmological searches for stringy signatures is an extremely exciting one.

Finally Robert spoke about some of the problems of the conferenece. These were all things which were lacking, including front page headlines in the New York Times, no voting, not enough jokes in the afternoon sessions and little in the way of 'metaphysical multiverse babbling'. One particularly important point was that being behind the great firewall, people could read Peter Woit's blog but not Lubos Motl's!
Finally it was noted that David Gross gave a talk which didn't go far overtime and Yau gave a talk which was extremely comprehensible.

Robert was not given an easy task to sum up everything from the last week (which itself was a summary of the last year) into just half an hour but the above points which he made seemed to set the tone of the last six days pretty well.

Now everyone is heading back to their various corners of the world, many I presume with new projects, insights and collaborators.

This has been my first strings conference and I have to admit to feeling quite far out of my depth most of the time though by chatting with people about the talks I've had many long-standing questions answered for me. I presume that each time I go to a conference and talk more with physicists in diverse areas that my understanding will grow. This has also given me some more impetus to learn some of the areas which I've neglected while concentrating on my own particular pet topics. It's been great as well to see friends from conferences I've attended over the last few years and I look forward to catching up with them again soon.

Though hopefully I will add some final reviews over the coming days, the physics content of this blog may lighten up a bit for a while. Right now I have to head outside where the Beijing weather is throwing another wobbly as detritus is zipping past my window at dizzying speeds and dust devils are swallowing the workmen building the skyscrapers surrounding my apartment. Baksun.

Friday, June 23, 2006

Strings 2006 Day 3 and 4

Paul Cook, a grad student from Caltech, and I have reviewed the first three days' talks here. There may be mistakes because many of these areas are not directly linked to our research so if we've made errors then please tell us. Also, if people have questions about what certain words or concepts mean then please ask. It's excellent for me to find out such things and formulating a response should help me to understand these ideas in greater depth.

As noted in the comments in the previous post it's a real shame that the talks have not been filmed as a large proportion of the string community is not here to see what's been going on. As this is my first strings conference I have many impressions which I will talk about when the lectures are all out of the way and things have calmed down a little here. I've now been going to stringy talks for the last three weeks with only two days break so I'm feeling slightly jaded. I'll also talk about, though hopefully not wallow in, these sentiments at some point.


On Tuesday morning Jonathan Feng was reviewing dark matter candidates and in particular the possibility of detecting warm dark matter in the form of gravitinos or axinos. The reason that these particles must be warm is to prevent the clumping of matter which is seen in cold dark matter simulations and the lack of structure in hot dark matter scenarios. Most interestingly from this talk was the possibility of detecting dark matter in collider experiments (LHC or ILC) even if the lightest superpartner is only gravitionally coupled. This is because charged supersymmetric particles which are stable for a matter of seconds or months can be trapped before they decay into gravitinos. In his paper there are links to possible experimental scenarios for this detection.

Tohru Eguchi described how the distribution of Calabi Yau monifolds is peaked around singular points in the Calabi-Yau moduli space, but also that the number of distinct Calabi-Yau manifolds near each singularity in the moduli space is finite. The "discrete" nature of the distribution of physical manifolds follows from considerations of flux quantisation.

Robert Dijkgraaf spoke about constructing gauge theories on a compact Calabi Yau. He spoke about a factorisation method for the moduli space of Calabi Yaus whereby the two-cycles and three-cycles are split into separate sections of the space. Somehow the moduli space of two-cycles was embedded in that of three-cycles (such that two cycles are constructed by contraction of a single direction in the latter).

Eva Silverstein spoke on "Black Holes as Catalytic Vacuum Converters". She first outlined a simple scenario where the space is in a metastable ground state where supersymmetry is dynamically broken. Consider a black hole in this space. As it Hawking radiates (but not necessarily to an extremal state), the horizon will increasingly "push" the moduli toward the black hole's preffered attractor point. This could quite generically cause the moduli to cross into a basin of attraction of a lower energy vacuum. If this happens in a sufficiently large area of space near the black hole, this could catalyze a change of vacuum of the whole universe, in a time far less than it might take to tunnel. She then outlined a specific scenario, where heavy mass particles are Hawking radiated from an evaporating black hole (note that begin radiated means that this scenario is NOT dependent on what initially formed the black hole). If a sufficient density of these particles is reached, this would cause a vacuum transition into a vacuum where these particles are light. Phenomenologically, this puts constraints on the sorts of black holes and/or vacuum structure in our universe, as any evaporating black hole could perform this catalysation.

Ashok Sen
spoke about the calculation of entropy of four dimensional black holes in higher derivative corrected gravity. This is a further application of his technique of calculating the entropy and moduli solely as a Legendre transform of the integral of the Lagrangian over the S^(D-2) of the horizon. These black hole solutions are not necessarily supersymmetric.

Herman Verlinde spoke about his bottom-up approach to string phenomenology. In this approach he separates the high energy closed string dynamics from the gauge theory described by open strings by studying the theory of a D-brane in a throat of a Calabi Yau. The structure of the throat determines the quiver diagram describing the gauge theory and in particular the cone over a del Pezzo-8 singularity gives the minimal supersymmetric standard model with several extra U(1) factors and extra generations of Higgs. It appears that the resolution of these extra U(1)s may be understood (My memory on this point is not great I'm afraid).

Things get a little more hazy now and so we shan't be able to review all of the talks in as much detail. Again it would be great if anyone who has taken notes from the talks would like to provide a review.

David Tong
spoke in his usual enthusiastic style, giving a review of his work on quantum vortex strings. He started by giving an overview of the possible solitonic objects that one can find in an N=2 supersymmetric gauge theory when more and more degrees of freedom are added and allowed to develop vevs. This simple gauge structure allows a huge number of interesting configurations of domain walls connected by vortex strings with monopoles threaded on the strings etc. The fascinating point about these theories is that when you study the quantum dynamics of the vortex string, given by a two dimensional sigma model, you find that the BPS spectrum of states exactly models that from the four dimensional theory. David was in danger of being savaged by Witten during the questions but escaped with what sounded like convincing rebuttals.


Few details from Brain Greene's talk which was presented by Koenraad Schalm. The punchline was that stringy effects in the CMB spectrum would add oscillatory behaviour which should be detectable in the next generation of microwave telescopes.

Mina Aganagic reviewed how the holomorphic anomaly of the topological string partition function can be understood from the point of view of symplectic transformations of the cycles in the Calabi Yau. In the "complex polarisation", the topological string partition function is modular under monodromies (a subgroup of the symplectic group) generated by moving around loci in the moduli space where a cycle in the Calabi Yau shrinks; however it suffers from the holomorphic anomaly. On the other hand, in "real polarisation", the partition function has no holomorphic anomoly, but suffers from a failure of modular invariance. The holomorphic ambiguity in complex polarisation can be identified with the failure of modular invariance in real polarisation. She then showed how (as has previously been demonstrated using complex polarisation) one can find the topological string partition function recursively in a worldsheet genus expansion, using the failure of modular invariance to pick up terms from lower-genus boundaries of the moduli space, at any given genus.

Sarah Shandera (standing in last-minute for Henry Tye) spoke about specific string-theory motivated observables in cosmology. In particular, she outlined how in the context of D3 - anti-D3 brane annihilation (a useful scenario as it provides both inflation and then a simple mechanism for reheating at the end of inflation), one can get sufficient inflation even when the inflaton does not seem to obey the slow-roll condition. In her model, the DBI action necessarily implies a "speed limit" on the D3 brane as it falls down a Calabi Yau throat toward an anti-D3 brane, despite a steeper potential. This model implies an effective field theory with a particularly unusual kinetic term (from a field theory perspective). As a result it makes very definite predictions, which furthermore will potential be observable within the next few years. The work included some great actual numbers for cosmologists to work with -- something which hopefully the rest of the string theory community will be able to emulate soon!

Andy Strominger and Shiraz Minwalla's Thursday talks were reported on in the previous post.

We're going to leave it at that for now but hope to be able to talk further about the other lectures in the next couple of days.

Thursday, June 22, 2006

Strings 2006 day 4, parts b and c

Since visitors to this blog have increased 15-fold over the last week I feel particularly bad about not keeping up with the overview of the lectures. I've been taking the fantastic opportunity of this week to talk and build up my collaborations with other physicists. This is something I get to do very little when in the department in Beijing though I'm hoping that that will change soon. The work outside lectures has so far been taking up an enjoyable large part of my time. Together with a PhD student from Munich I'm investigating a couple of new projects which could be really exciting if they don't turn into dead ends. It's also a great chance for me to meet some more of the Chinese string theorists.

Together with the fact that after three weeks of lectures I'm feeling pretty tired, especially in the sizzling temperatures, I haven't been posting as I'd hoped. I have however hopefully roped a couple of other people into reviewing some of the talks which I missed either physically or mentally and hopefully I'll be able to post those over the next couple of days.

For now, after another gruelling day and a conference banquet with perhaps 10 speakers all singing their praises of the organisation of the committee I have enough energy to talk about a couple of the talks in brief. The speakers during the dinner were in large part talking about the rise of physics in Asia and though a large part of this was related to India, Japan, China and Korea, it was noted that those who are sharply on the rise ought to be helping all those countries who are currently not getting a look-in on the world science-scene. Wise words indeed. It was also posited that by 2010 Strings should perhaps return to an Asian country and Korea was briefly whispered. The next three years the conference will be in Madrid, Geneva and Rome, all of which are fine venues but certainly 2010 away from Europe seems wise.

Today Andy Strominger gave an interesting talk about the proof of the OSV conjecture which links the partition functions of black hole states in IIA string theory with the partition function for a the square modulus of the partition function for a topological string theory. This was a seven step proof which I shan't be able to reproduce here but is shown in full in this paper. Essentially this comes from studying the sum over near horizon bound states of D4-D2-D0 branes and then lifting to M-theory. The partition function has two contributions, one from wrapped M2 branes and one from wrapped anti M2-branes and it's these two contributions which give Z_top and Z(bar)_top to give the surprising relationship between the partition functions. Apparently in progress is a direct derivation of the OSV conjecture using GS formalism on the worldsheet.

Yesterday morning was a good talk from Juan Maldacena on Giant Magnons. In very brief summary this is related to the spinning string - spin chain link of Tseytlin et al and what has been found is a particular solitonic mode on the spin chain called the giant magnon. In fact in looking around for more information I came across a nice review of the subject by Lubos Motl here.
I don't think I could do any better than simply link to his site though if I can rope someone into writing more then I shall do so.

Shiraz Minwalla gave a talk today in his usual frenetic style about calculating the full SUSY partition function for N=4 SYM compactified on a 3-sphere. It appears that they have calculated this for everything up to the 1/8th BPS states and the 1/16th states are currently in progress. The calculation of these states is related to the giant graviton modes. Looks like some great work but unfortunately though his speed of delivery is exciting, it's just too fast for me to keep up.

Other talks to review are an impressive stand-in for Henry Tye by his student Sarah Shandera, Martin Schnabl on the analytic results in string field theory, Hawking on why string theory is completely unnecessary for cosmology (some, in particular Raphael Bousso, may disagree with some of the points of this talk ;-). Also a couple of interesting talks about emergent geometry to review.

OK, lots more talks to write up but another early start tomorrow with many interesting seminars so I'll leave it at that brief summary for now.

Monday, June 19, 2006

Strings 2006 Day 1

If you're here to read a clear-cut summary of the talks at Strings 2006 you've probably come to the wrong place. These posts will contain some of the thoughts of a young researcher for whom most of the lectures are way out of his area of expertise. I hope that other people can comment and contribute more elucidating accounts of what was discussed.


Day one of Strings got underway in the usual understated Chinese manner with a public opening ceremony in the Great Hall of the People. I'd been warned that no cameras would be allowed in and so left mine behind. As we walked in film crews were shooting and digital cameras were going off left, right and centre. Consequently I have no pictures of the impressive hall or the interesting lectures which took place in front of the crowd of around 3000. I'll attempt to get some pictures from the other participants ASAP.

After some introductions and a few short speeches about the new KITPC and the 10th anniversary of the Morningside centre for mathematical sciences (where one of the mathematician's who recently claimed to have solved the Poincare conjecture may well be coming to take up residence in the near future) came the main three speakers.

First David Gross gave a general introduction to string theory. I was somewhat worried when a slide came up with the title 'superspace' and he began talking about anticommuting numbers but in fact he managed to keep it at a level that would have given the non-physicists in the audience a reasonable gist of the idea. There wasn't anything terribly controversial in what he said and in contrast to Hawking's lecture in Hong Kong where he spoke about the need for the human race to jump ship from the Earth ASAP none of the lectures were particularly edgy, though they were all well done for the audience concerned. Sitting behind Witten and Vafa I didn't think that they'd learned anything new but they seemed entertained by parts of the talks. He did mention a little about emergent spacetime and quoted Witten's prophecy that 'Spacetime may be doomed' and Nathan Seiberg that he believes that 'space and time are illusions'.

Andy Strominger spoke next and pleased the crowd with his opening remarks in Chinese. Having stayed here for some time his Chinese is rather impressive. His talk was on the topic of black holes in string theory which is a huge area of interest for many reasons, including understanding the black hole information paradox. With illustrative cartoons, Andy's was the most lighthearted talk (though the content is clearly not simple) and his friendly style seemed to sit well with the audience.

The main event was a talk given by Stephen Hawking. Before he came on, a wave of people rushed to the front, cameras and telephoto lenses at the ready. As he entered the hall, a frenzy of cameras dazzled the stage as everyone wanted to get a photo of such a physics superstar. The chairman asked for calm and told people that Hawking had specifically requested no flash photography but everyone ignored him completely. It was all pretty embarrassing, even when the chairman said that last time Hawking said that the journalists acted like barbarians towards him, this didn't budge them and they kept snapping away. In fact, even when ordered in Chinese it still took a good few minutes to clear them and all through the talk there were still flashes around the room. The request had been made because apparently the system that he uses to control the speech and the slides will not work with flashes going off.

Anyway, nothing particularly (newly) controversial but his talk was about the beginning of the universe. He spoke about his work with Roger Penrose showing that the beginning of the universe had to have a singularity and he mentioned the Hartle-Hawking wave functional of the universe where questions about the beginning of time become non-sensical, just like asking where is South of the South Pole.

Having caught the bus at 6.40 in the morning everyone was feeling pretty shattered after three hours of talks so we were quickly rushed back to the main conference venue where we dived into the buffet. Tasty enough (with good spicy tripe) but nothing in particular to write home about. Unfortunately they're toning down the Chinese aspect for the sensitive stomachs so I'm hoping to take a few participants out to get some real local food.

So, now comes the part where I'm on far more shaky ground. As I've mentioned before, my path in string theory is a very narrow one and there are many mainstream areas in which my ignorance is gaping. I will write short reviews of some of the talks that interested me but if other people would like to comment and fill in the gaps with comments then I will be happy to post the comments in full in a separate posting once I've collated them.

The first talk was by Witten on 'gauge theory and the geometric Langlands program'. This is an interesting link between a proposal which appears at first sight to live purely in the language of number theory but it was shown in concrete terms by Witten and Kapustin that in fact the dualities involved on the number theory side actually translate into interesting dualities in field theory.

I attempted to write a summary of the talk but it ended up being more complicated and convoluted than just linking to this slightly older talk which was presented before his paper which came out earlier this year. If anyone wants to write a short review of the talk then I would be most grateful. Unfortunately though my maths is just about up to understanding the terminology and probably most of the individual paragraphs, it's not good enough to feel I have an overview of the whole thing.

Essentially the first steps you need to understand are how to form a topological field theory by forming a twisted basis of generators between the poincare and supersymmetry generators. This four dimensional supersymmetric theory is then compactified on a Riemann surface and because of the twisting the supersymmetry remains in the lower dimensional theory. In the two dimensional theory you study branes as well as 't Hooft and Wilson lines and this is where my stream of reasoning gets onto very shaky ground. Help is asked for here...

Lecture two was by Vafa on 'The Swampland' which I've been unaware of until very recently. String theory gives an immensely large number of solutions and we have no way at the moment to pick uniquely which one gives the physics we see around us. Doing this would be perhaps the greatest triumph that we could hope for from string theory (give or take some cosmological answers). Anyway, there's a huge debate about the interpretation of the landscape which I'm pleased hasn't dominated too much at the conference so far. The swampland hypothesis takes a different view. It says: Let's figure out what properties a field theory has to have in order to be inconsistent with string theory. That is to say, which classes of field theories can't possibly be in the landscape? Which are in the swampland? It has been hypothesised that there are several criteria of a theory which will preclude it from having a consistent UV completion with gravity.

These conjectures are:

  • The moduli in the string landscape are always parametrised by the vevs of scalar fields.
  • These moduli cannot have finite non-zero directions.
  • At the infinite points in moduli space you will always find an infinite tower of massless states.
  • Near these points the moduli space has negative curvature.
  • There are no non-trivial one cycles in the moduli space.

This all sounds reasonable but it could be a powerful new direction away from the current concentration on the range of possible string vacua. It seems that what is important is to tighten these constraints and find more so that we can define all those theories which can live in the landscape by finding out exactly which can't.

Third was a double talk by David Shih and Ken Intriligator about dynamical supersymmetry breaking and metastable non-susy vacua. This sounds like some impressive work in which they've used Seiberg duality in certain regions of (Nf,Nc) space to understand the small field behaviour of the potential of scalars in an N=1 SUSY theory. They've shown that for a certain class of N=1 SUSY theories that a metastable vacuum solution can exist and that the decay time for tunneling to the zero potential in the susy solution is large. It was pointed out that at finite temperature this stability will clearly be removed so in a cosmological context this would complicate matters.

Next were lectures by Hiroshi Ooguri and by Xi Yin on counting states in a D4-D2-D0 system. Again I'm at a loss to summarise these talks in any way whatsoever so ask for anyone who wants to volunteer an explanation. Hiroshi was talking about a particular quiver gauge theory in which dynamical susy breaking a la Intriligator and Shih is seen.

After dinner was a one hour discussion session chaired by Andy Strominger. An impressive panel of string theorists (see top of post for photo) was asked questions between its members and from the audience on any physics topic they could think of beyond questions of tenure and funding.

Unlike the reports of last year, there were no great arguments and indeed almost no mention of the landscape at all. There was talk about the fact that we haven't been able to study very high energy scattering using string theory. There was a brief discussion of the LHC Olympics and the fact that string theorists should attempt to integrate themselves with the experimental/phenomenological work as much as possible. There was also a bit of chat about the ideas of emergent dimensions and the AdS/CFT correspondence and what directions we may be able to push the concept to understand it more. Interesting though it was I don't think that a great deal was learnt from it. This is probably because everyone was shattered at the end of a very long day and were perhaps wary about last years antics.

OK, so I appear to have stumbled my way through all of that with little in the way of useful comment so I ask anyone who can expand in a more useful manner to either e-mail me or add a comment.

Sunday, June 18, 2006

Direction, Destruction, Creation, Reproduction and on

Today is perhaps one of the most important days in the history of physics in China. Today the formal agreement was signed for the beginning of the KITPC. The Kavli Institute for Theoretical Physics in China. This institute (much like the KITP in Santa Barbara), funded with a large grant from the Kavli foundation will be a centre of excellence where workshops will be held and perhaps most importantly world experts in many different fields will congregate for many weeks or months at a time stimulating cutting edge research with the community already here.

Fred Kavli during a dedication at Stanford University (photo linked from here)

The KITPC will be part of the Institute for Theoretical Physics which is where I'm based now and so is of direct relevance to my own future...I have to make the most of this!

This will be an incredible opportunity for the students especially, who up until now have been rather isolated from the rest of the world community and with the help of the KITPC will really be able to integrate and show their potential.

News cameras and suits abounded as the document was signed though I felt rather sheepish in my T-Shirt and jeans having not been warned about the event before hand. I therefore didn't get any photos of the event but I'm sure I'll find some to link to at some point. David Gross (Nobel Laureate 2004, director of the KITP in Santa Barbara and general smart chap all round) was there to sign the deal. All being well there will be a workshop next year for three months on a subject which I'd really like to get involved with, it would be an awesome opportunity for me if I can get myself up to speed by then.

Within an hour of the signing we headed over to the venue for the Strings 2006 and with temperatures around 36 today we sat outside with the great and the good and caught up with old friends over a very toned down Chinese buffet. It's really good to see other string theorists I haven't seen for a couple of years in some cases and catch up, both as friends and as scientists. I really hope to be able to take this opportunity to start up some great new projects and meet more interesting folks from around the world.

Tomorrow is the opening ceremony where Hawking, Gross and Strominger will be speaking in the Great Hall of the People to a huge crowd. Due to traffic constraints this means getting up at 6 tomorrow morning so I'm going to make a hasty exit for now but plan on posting after my expected 16 hour day of listening/working/chatting tomorrow.

Friday, June 16, 2006

The Middle of the Beginning

I continue unapologetically to take photos of sunsets over the mountains through the skyscrapers from my flat in Beijing. This evening has been particularly sensorally stimulating as I sat on the balcony listening to radio 4 feeling nostalgic, munching on dumplings, calculating solutions to killing spinor equations and looking up from my work occasionally at the stunning view.

With just a day to go (written yesterday) this has been by far the most useful summer school I've yet attended. I realise now how difficult it is to find a series of lectures which is at just the right level to push you without losing you. It's easy to find a school which at first sight is great until you realise that the reason you think it's so marvelous is because you understand it all having covered it before. Clearly not particularly useful.

I spent a wonderful month at TASI last year meeting great people, listening to some great physics and eating superb pizza at silly o'clock in the morning. Unfortunately I have to give a warning about the TASI website and hope that they do something about it for next time (at least the next string TASI). On the website the level of the physics prerequisite is indicated by the comments:

'The audience will be composed primarily of advanced theoretical graduate students. Experimentalists with a strong background in theory are also encouraged to apply. Some post-doctoral fellows will be admitted, but preference will be given to applicants who will not have received their Ph.D. before 2006. The minimum background needed to get full benefit of TASI is a knowledge of quantum field theory (including RGEs) and familiarity with the Standard Model. Some familiarity with SUSY would be helpful'

I warn anybody who reads this to make sure it is true for the year you are going. It was not certainly not true in 2005 and consequently the level was frankly set way higher than I was prepared for. It was perfect for some people but many had sat through a year's worth of string theory grad lectures. Knowing how to quantise a bosonic string and having just about got the hang of homotopy was not enough to jump straight into tachyon condensation, flux compactification and duality cascades. I should reiterate at this point that it's a fantastic school. The month spent meeting people and chatting was worth it but I could have increased my understanding a lot further had I not been sitting in lectures which were way over my head. One year on and now I feel that I could benefit fully from that level of lectures.

It seems strange then that I call myself a string theorist yet I'm currently attending a fairly basic school in the subject and am learning so much (OK, perhaps the new material is only a quarter of the total but the rest is instilling fully in my mind those things which I've vaguely known about for some time). The reason for the gaps in my knowledge are, I believe, because I specialised so early, as most people have to in the UK if they want to finish their PhD in the allotted three years. It's also because I didn't work as hard as some people who miraculously finish in three years and also read all the relevant texts on the subject but I haven't met one of them myself yet.

Anyway, so I've learnt many useful things over the last two weeks. In large part this has been in terms of example calculations which I've never found fully derived in text books. One of these which I've just been running through now is the calculation used to discover how many preserved supersymmetries are in a given supergravity background. The equation itself is simple enough and now having seen some examples illustrated in detail I feel ready to tackle some more complicated examples on my own.

Today we've finished off with a great set of talks on the AdS/CFT correspondence. I'm pleased to say that only a fraction of the examples were new to me but it has got me thinking in some new directions for possible projects.


I thought that perhaps I would be able to have a single lie-in to catch up on sleep before Strings starts for real. An early phone call this morning eliminated any possibility of that. Tomorrow we have a discussion with David Gross in the morning followed by a banquet lunch and then a reception for the beginning of the Strings meeting. I expect to be running on adrenalin only for the next week. I'll attempt to keep as up to date as possible with the various talks at Strings which I feel I can be in the least bit illuminating on.

Thursday, June 15, 2006

Stringy Plans

The String school is winding down now and it's certainly been the most beneficial school I've attended yet. I'll explain why in a post at some time when I'm not running around chasing my own tail. A few photos on Li Miao's blog of the lecturers and students.

Visitor numbers have shot up since Peter Woit at Not Even Wrong linked to the article I wrote below. No questions yet but I hope that it may be useful for some people.

The lecture timetable for Strings '06 is now online and it looks like a great list of speakers and subjects to my semi-trained eye.

Off-physics there's a short but interesting article about the hoped return to China's former cyclecentric nature. There are currently a million or so drivers in Beijing which is only around 20% of the possible volume. Looking at the current situation on the roads this is a pretty scary thought.

Right, tails to chase kappa symmetries to understand...

Wednesday, June 14, 2006

Survival Guide for Beijing during Strings 2006

From the 19th of June around 500 physicists will descend on Beijing for the Strings 2006 conference. This will be my first 'Strings' and so I can't offer any insight into the goings on on that front yet. I have however been in Beijing for around eight months now and though I'm no China expert there are a few things I've picked up along the way which may be of some use. However, if anyone follows these guidelines and ends up in a dark hutong at three in the morning without two kuai to rub together I can't be held responsible ;-)

Please ask more questions if there's more you want to know, I'll see if I can help.

Monday is set to be 41 degrees though whether that's horribly dry or drippingly humid depends on the direction of the wind. That said, last Monday we had similar predictions and it didn't get much above 30. The hotel for the conference should have air con which will most likely be set very high so it's also worth bringing something to stop you getting frostbite. Several people from the pre-Strings school are now moping about with summer colds so be warned.

While I'm on the subject of weather, it's raining about once or twice a week at the moment (occasionally with impressive thunder to boot). This may seem like the perfect opportunity to get outside and cool off in some lovely summer rain but be warned, again depending on the direction of the wind the rain is likely to contain muddy sand or be highly polluted from the factories.

OK, I'm probably not selling Beijing well yet so I should interject to mention that Beijing is an awesome city once you've worked your way around some of the simple obstacles. I'm generally having a superb time out here and if you do have the chance to explore it's well worth it.

The food of course is excellent and you can get just about everything under the sun in Beijing. There's a reasonable quantity of spicy food so be warned that what look like bell peppers may pack a punch. The Szechuan peppers also take some getting used to as they numb your mouth on contact which can be a little disconcerting when first encountered.

Muslim food from the North and West tends to be reasonably mild with superb kebabs, flat-breads and lamb in all forms. Further South the food is often slightly sweeter with things like dim sum coming from Hong Kong and around that region. Of course Beijing duck should be sampled though the real delicacies are the miscellaneous duck organs and limbs which give such a range of flavours and textures. The pancakes are fine but they don't taste that much better than anywhere else.

People eat early here on the whole. Lunch is often over and restaurants closed by 12.30 or 1 and people regularly eat by 5.30 in the evening. If you're wandering out to find a restaurant at 8 in the evening you will have to be heading somewhere specific as most places will be closed by that time. Street food is however on offer most of the day and night and the pancakes with egg and spices is not a bad snack.

Most restaurant menus are in Chinese only, it may be worth coming with a few translations of the basic food items to find them and point on the menu, though when you spot the character for chicken, don't be surprised if you find a dish of feet or tongues sitting in front of you.

When it comes to paying for the meal there's usually a great play for who is going to foot the bill. This can go on for some time and often gets rather animated. I made the mistake recently when going to a restaurant with an English friend of letting him pay without putting up a fight (I'd paid the last bill and we'd agreed previously). As I was clearly the host and had ordered the food, the waitress who up to that point had been all smiles shot me a look of death as she realised what scum I was for letting my guest pay. Just be aware that you may be thought of badly if you don't put up a fight.

You don't need to tip in restaurants. Until recently tipping was illegal though it appears to be welcomed in fancy hotels. The fact that it's not expected can make it a little awkward and I still can't work out what is a mean amount and what is too much.

For those who want to sample some of the finer delicacies, head to Wangfujing where you can get all manner of insects, arachnids and crustacea on a stick. The grubs are probably the strongest tasting of them all and the scorpions don't appear to sting you when eaten. It's all a bit touristy though so clearly you shouldn't feel that just because it's strange it's normal for the locals. They probably spend their time laughing at the strange Waigouren who eat all the detritus.

Don't drink the tap water unless it's been boiled. You'll be given some water in the hotel and you can ask for a continuous supply of thermosflasks of boiled water to be taken to your room.

I've become somewhat immune to what I'm told by the Trieste connoisseurs is very poor coffee. There was virtually no coffee consumed in Beijing just a few years ago and now with cafes popping up all over the place quality has become less important than quantity. I imagine that they'll serve it in the hotel though I can't promise that it won't be vile.


Taxis are pretty cheap with a journey right across the city costing just 5 or 6 dollars in the middle of the day. After midnight prices are ramped up though often there's no choice as the metro stops after about 10.30. Taxi drivers drive fast and swerve in and out of traffic. They seem to know what they're doing but accidents do happen.

ALWAYS CARRY A CARD WITH THE NAME OF YOUR HOTEL IN CHINESE ON IT. The English name of the hotel will probably not be known and in eight months I've only met three taxi drivers who admitted to speaking any English. They can rarely read a map and even fewer can read Pinyin (the Latinised transliteration of Chinese). I've only been ripped off in a taxi a couple of times but just always make sure that they start the meter which will read 10 or 11 kuai (also called yuan and renminbi) when you set off.

Cheaper and often quicker than a taxi is the metro. 5 kuai for anywhere you want to go in the city, the trains are well air conditioned though rammed at rush hour. The signs are in English though often the maps are in Chinese so make sure you know which stops you've got to change at before you head out. It's infuriating but people will go straight into the train as soon as it's stopped before letting anyone else off. Just make sure you're reasonably near the exit when getting close to your station (there are announcements in English). Trains run every five or ten minutes most of the day. There are no ticket machines so you have to ask for a three or five kuai ticket at one of the windows. Just indicate the price with your fingers as they rarely speak English. It's three kuai on the outside line and five to go on the inner lines too.


There are several main shopping areas, Wanfujing being one of the largest with lots of modern clothes stores. The silk market sells everything from silk to sculptures to mp3 players and haggling is compulsory. They'll often quote ten times the price you should be paying so you have to haggle really hard. They love it! Most of the things you can buy in the silk market can also be purchased in the Friendship store which used to be the only shop that non-Chinese were allowed to buy things in. All prices are marked and you can get some great deals there.

Rip-off DVDs are everywhere. They come in different ranges of quality depending on the price and often a five kuai (60 cent) DVD will not work about half the time. The ten kuai ones tend to come in nice boxes and work more often. Films that have come out that week at the cinema are likely to be filmed in a cinema. Be aware that what you are buying is clearly illegal and is clearly detrimental to the industry. Also be aware that (as far as I know) to take them back into the States is illegal and you can get a hefty fine if caught. As a lover of Asian cinema I find it impossible to turn down a Kim Ki Duk or Kitano film which would cost me 20 quid back home. You can also buy box sets of TV series and complete collector's editions of every film by Kurasawa, Hitchcock, Almodovar etc. for very little money.

For those who want to know, I can tell you where you can buy Chinese editions of a huge range of mathematics and physics books for just four or five dollars each. I still don't know the legality of this though I believe that there is an agreement with the publishers (Springer in particular). If you want to stock up on differential geometry or random matrix theory texts, now may be the time. Again, I don't know the legality about taking them out of the country but the opportunity may be too hard to resist.

China is still almost entirely a cash culture. While in the big hotels and restaurants you will be able to pay with a credit card, expect to be using cash the rest of the time. Perhaps a third of all machines will accept major international debit and credit cards and will give denominations of 100 kuai only.

There is of course a huge list of things to see and do in Beijing depending on your tastes. There are enough temples to fill several months if that's your thing. Museums aplenty including an area called 798 gallery in Dashanzi which is filled with contemporary artist's studios. There's Beijing opera for those with strong eardrums and extremely impressive Chinese acrobatics which you can either see a whole show of or have a sample in certain restaurants. There are huge numbers of places to get foot massages to rest your weary soles having trekked about the city and plenty of bars and clubs (in Sanlitun, Houhai, Chouyang etc.) to relax in afterwards.

To head further afield by train you generally have to book a few days in advance but while you're here there are many places to see which are definitely worthwhile visiting.

Anyway, those are a few pointers which may or may not help/set your mind at rest just before heading out here. It should be an excellent conference I hope and there may even be some physics involved. If people want to ask more questions on anything they're worried/concerned about then please do.

Sunday, June 11, 2006

Superposition of States

The campus hotel in which the string school participants are staying comes with an impressive list of possible garments that one may need cleaning during a stay at the CAS.

Apologies for the blurred photo.

String school reaches its half-way point and with it I'm feeling that this has been the most beneficial school I've attended yet. The school is nominally aimed at those who've never seen string theory before though, as I'm coming to realise, however good a physics school is it's virtually impossible to give a good grounding in any major topic from scratch in such a few lessons. For this reason, because I've been reading through string papers and books for the last couple of years and giving myself a reasonable basis in geometry and topology, this course is consolidating things that I know and filling in some of the gaping holes in my knowledge at the same time.

Unfortunately though the lecturers are all extremely good I think that those who really don't know any of these areas and are not exceptionally fast (which some of the students here really are) will be pretty lost when listening to lectures on tachyon scattering amplitudes and Dolbeault cohomolgy. Still, even if you're not following the subtleties of the lectures, each time you hear an important phrase repeated it slowly embeds itself in your subconscious to build up the web of understanding which is an important step in getting to grips with these strange worlds we inhabit. They're also giving us a decent number of exercises which really is the best way to learn the subject.

The end of the lectures on SUGRA were enjoyable but the pace picked up vastly as, in four lectures we went from a premise of no knowledge of supersymmetry to a homework assignment of calculating the D3 brane solution in IIB SUGRA including working out the number of killing spinors. A fine problem to tackle but far from trivial for someone who hasn't played around with spinors in higher dimensions late into the night.


After my ping-pong-antics in the depths of winter I figured that I'd be a little less likely to be laughed off the court if I took to the basketball arena. With clunky shoes and a shiny new ball in hand I strode on to gasps of amazement from the comparatively diminutive locals who were on the court at the time. I was quickly snapped up by a team, happy to have the tallest player by almost a foot. We sat back and watched as highly skilled players darted and drove, fakied and generally showed off their impressive techniques. My heart sank just a little. For the first three games I was the star of the show as I simply stood by the basket, gave a little bounce and placed the ball in the hoop. At this point I realised that I'm comparatively tall but about as fit as a barn hog. It took them only a little longer to realise their long-term mistake. By this point the speedy Chinese had also noticed that it didn't take a great deal to stop my one-man assault on all other teams and quickly my reign was over. I shall be back again though the colour I turned after five games means that I should probably take things a little easier next time. I should also perhaps slow down on the kung pao ji ding.


I'm reliably informed that the football going on at the moment is somehow more important than that which fills the screens at all other times. All outdoor drinking venues and most indoor establishments seem to have been decked out in the newest, largest and loudest entertainment systems to keep the beer and football hungry crowds satisfied. I feel like a real grump as I sit there being far more amused watching the crowd than watching the football but I just don't get carried away by it all as everyone stands up and cheers, hugs and high-fives as a goal is scored. My Chinese friends are most perturbed by this English man who clearly has half of his life missing.

The England game came along and we watched the first half surrounded by wonderful food which drew my attention far more than the match. Mini-spicy lobsters go from the tank to the tray in a matter of moments and all manner of gastropods ooze along before being prepared in whichever style you prefer your molluscs.

Half way through the game we all retired to a friends house where I could keep half an eye on the game while being initiated into the interesting and sometimes cruel world of Mahhjong. It appears to be one of many games which at first sight doesn't appear to need a great deal of skill but I'm sure there's much more to it than that. Unfortunately my unclouded blank mahhjong slate meant that I wasn't thinking too much about it and I took the first six of eight games. Soon I began to see the intricacies of the game in more detail, it all became a little more complicated and with that flash of insight my winning streak was quickly annihilated. Anyway, despite the fact that I'm never likely to win again I'll be returning to the table to wile away a summer night at some point soon.

Mid-mahhjong rounds we popped to a local club to sweat-off some of the duck calories on the dance floor and were faced with an MC of impressive pedigree. Having come here from LA he claimed to take all the bling out of hip-hop and take it back to its roots. Unfortunately along with the bling he took the rythm and bounce leaving a crowd of rather unimpressed Koreans wondering what we were all supposed to be chanting.

I mentioned in the previous post about some of the delicacies that are regularly consumed at the local drinking venues. This stand, two minutes walk from my flat, has not only an impressive array of anatomical delicacies but a vendor with impressive eyebrow action.


Today I returned to one of my favourite pass-times. Sitting in a cafe, drinking a fine mug of slightly low-grade coffee and working through some maths problems. This time Andrew came along too and we spent a good few hours making sure our understanding of the mathematical background needed for compactifications was up to scratch. We covered a good deal of ground and feel ready to tackle tomorrows lectures on compactifications, heterotic string theory and p-brane solutions. Along with a two hour English class that I'll be teaching tomorrow evening it looks like being a busy day.

Tuesday, June 06, 2006

Outside In

With Monday threatening temperatures above 100 I'm enjoying the pleasant 90 or so we're having before it's too late.

This is what I was looking forward to and am now enjoying so much:

Interaction with a group of people who are keen to discuss, learn and explain is, as I mentioned in my last post, to me one of the highlights of life as a scientist.
This snap, taken in my office, is not of us coming up with an exciting new theory but just some of the more experienced of us explaining the basics of string theory to those who are new to the subject.


All of a sudden the tables have turned once more and I'm a local, with insider knowledge and an insight into what it's all about in Beijing. Strange indeed!

Saturday morning I picked up my friend, Andrew, along with two of the professors with family in tow to take them to their hotel before the string summer school, of which day two has just finished. Jet-lagged and presumably a little dazed, the others were taken to the Great Wall at some frightful hour the next morning while I caught up with some reading, and Andrew slept in the campus guest house.

Given my travel-weary friend's state we headed for a gentle stroll around one of the temples and Houhai lake surrounded by the smell of stinky toffee and the constant ankle threats from the rickshaw drivers. My Chinese has been improving recently and heading to the local beer garden where I'm less inhibited to make mistakes seems to be the key. I had a decent conversation with one of the rickshaw drivers while resting on a bridge over the lake and when asked the meaning of a swear word which one of the passers by had said I offered him my phrase book with its list of useful slang. Him and his friends had clearly never seen anything like this and were roaring with laughter and showing it to as many others as they could find. It's nice to feel I'm adding something to the local culture.

Often during an evening in a British pub the beer may be accompanied by such sumptuous feasts as pork-crackling and the like, in Beijing we sit around with our fine glasses of draught munching on chicken's feet, pig's trotters and spicy duck's neck. These have become reasonably regular snacks and are all a lot more pleasant than crackling ever was.

So, the school has started and, as I predicted in my previous post it's a wonderfully refreshing change for me to be listening to physics and chatting physics. In fact, what's even more refreshing is to feel that i can really answer other people's questions with some confidence. The make up of the course is almost entirely Chinese with perhaps five percent from India and Pakistan, two Brits and a Columbian. Most are in the middle of their PhDs though there are a couple of keen undergrads and myself, possibly the only postdoc in the room.

Mild looks of anxiety echoed around the room as the first announcement was made that there would be an exam at the end of the course, the top three scorers being sent to the Trieste Spring school on string theory next year. I appear to be exempt from this offer as I come from a developed country and the idea is to be able to fund a student from a developing nation who otherwise wouldn't be able to go. Seems like a pretty good cause for an exam so I quite understand the situation.

Apart from two or three good but cursory lectures on string theory in my first year in Southampton, I've never really had a full course on it from the ground up. Though I've been studying a simple limit of string theory for the last couple of years and have read a reasonable fraction of the various books on the subject, these lectures are so far a great refresher for me. Professor Randjbar-Daemi is giving some great lectures on 11-dimensional supergravity and has a lecture style which suits me extremely well. His comfort with the topic makes the whole thing sound like a story and I've been enlightened on many points already. Professor Li from the ITP is giving a series of lectures on the basics of the bosonic string, the first topic in string theory which is vital before getting into the full and gory machinary of the subject. It's a tough job to try and teach the whole thing, 2d conformal field theory, modular spaces and all in just five hours. The pace is just right for me though as it's refreshing my memory in things that I have known and long forgotten, though I'm going to have to spend a little while over the next few days rederiving the results, something that I've done on too many occasions now to remember.

Outside of lectures I'm also beginning to chat through some problems with Andrew which he's working on at the moment and it looks like there could be some really interesting results to come out of this particular question.

As I mentioned before, I'm now seen as an approachable local by those from outside Beijing. The lecturers also seem keen to pick my brains about where the good watering holes are. They're a friendly bunch and this is a great opportunity for me to chat more in a relaxed environment with some of the important people in my field. Even for some of the Chinese from outside Beijing I've got important information about where the good restaurants are so it looks like being a gastronomically exciting couple of weeks too.

Anyway, after three (this post was suspended overnight) 13 hour days of work/chatting physics I'm going to get some shut-eye before tomorrow's lectures on compactification begin. Should be fun!

Friday, June 02, 2006

Sparks of Enthusiasm

I'm hoping that the next six weeks or so will add a new dimension to my research life here, which has been distinctly lacking of late. As I mentioned a while ago, my life in Beijing is pretty stress and commitment free with any commitments I do have being self-imposed ones which I'm very happy to take on.

As the only non-Chinese speaker in the department, everyone is very friendly to me but I'm essentially left to do my own thing when it comes to research. This is great in some ways but something is clearly lacking. One of the aspects I enjoyed most about my PhD time in Southampton was the time spent chatting with the other students about our research, new papers which interested/bewildered us and problems that we'd come across. The grad student office probably wasn't the best environment most of the time to get your head down and read through a paper as, when people weren't gossiping about non-physics topics, they were at the whiteboard, chewing through some problem (often something trivial which had us stumped).

This interaction is one of the highlights, in my mind, of a healthy research career. I'm not someone who can sit alone, shut myself away in an office and come up with a ground-breaking paper (my second to last paper was written in such a manner but I would only count the results as interesting and not ground-breaking).

Anyway, here in Beijing the language barrier does present a ficticious but seemingly present wall to cultivating a healthy physics repartee with most in the department. The blame for this lies entirely with me but simply accepting this doesn't change the situation. Of late I've been collaring PhD students and getting them to chat with me about their work which has been thoroughly enjoyable and a good change.

I had a good chat with one of the students a couple of days ago about their paper which is along very similar lines to the Sakai-Sugimoto D4-D8-D8(bar) brane setup which has suddenly been the focus of renewed interest. In the paper of Gao et al, they use instead a D2 brane background and find various interesting results which are dual to a non-linear realisation of the two-dimensional Gross-Neveu model. A couple of hours chatting over this paper was extremely refreshing.

Not only do I miss the one-on-one contact to talk and learn about new physics from those with more and less experience around me but the number of seminars I get to attend on interesting topics which are in English is exceedingly limited. I do go to the seminars but generally the only medium of information exchange is via the slides which isn't a great way to become well-informed.

Anyway, hopefully all this is about to change, at least for a few weeks. Tomorrow a friend, and current student of my former supervisor, will be arriving in Beijing for a two week summer school on string theory which I will also be attending and will hopefully comment on as the lectures progress. I hope that this will be an excellent opportunity to talk physics again (strange to say it but this idea is really getting me enthused just thinking about it - I feel my brain has been muffled for rather too long!).

Following the summer school is the main event, Strings 2006, which I hope will be a good chance to meet a lot of the people working in my field for real and chat about the recent developments in my small subsection of the subject.

After what will probably be a pretty heavy schedule of lectures, if all works out, I will have a student from Japan over to visit the department. As there is no specific funding to get PhD students to Beijing for visits, this is proving a little difficult, but we've both agreed that if the worst comes to the worst and there is not funding available that we will fund it out of our own pockets. The chance of building a good collaboration with an enthusiastic and talented PhD student is not to be missed.

This all gives me a hectic schedule for the next six weeks or so but I can't wait to see what the outcome of it all is. Before all this starts for real I'll have a couple of days to drag my jet-lagged friend around Beijing and hopefully get some good snaps on the way.

In the mean time I sit in my office sifting through papers and books somewhat half-heartedly attempting to spark a new project. I have a list of ideas and will talk about them when I've either killed them or they've blossomed to a healthy extent.


All being well I'm now on Mixedstates, a collection of physics blogs with a page which regularly updates new feeds. Link also to the right.