With seconds to spare

A few random links...

• First to a site which I mentioned, perhaps a year ago, but is always worthy of a plug. There's big news in the Beijing music scene this month as Sonic Youth are due out here. The tickets are very expensive but I would love to go and see them, so will attempt to pick some up tomorrow. Pandora is one of the best resources I've found to discover great new music. By selecting a band or song to begin with, this online radio player choses songs based on the style of music from your original choice. By telling the station whether you like a particular track or not it will evolve to give you more and more of the type of music you really like. Listening to a station today seeded with Sonic Youth I've found a host of new bands I'd never previously heard of.

• Discovery sites (Digg, Pandora, Stumbleupon, del.ici.ous Plime, and presumably many more) are becoming big business and allow the user to find web content based on what other people with similar tastes have liked in the past, rather than based on a specific web search. It's a powerful tool but also an easy way to fritter away time jumping from one interesting site to another, not taking anything of any real content in. It's definitely one of the many new branches of web technology which will be interesting to keep an eye on.

• On a side note I wonder if anyone has tried to develop a community del.ici.ous site where papers from the ArXiv can be tagged for searching more appropriately than the current search functions available online. At the very least I would like my pdf files to be tagged with the basic information about each paper and not have to type it all into an unweildy title name.

• While we're on the topic of the ArXiv I'll point to both the papers by Jacob Bourjaily (here and here )and the subsequent positive analysis by Lubos Motl. The papers are geometric engineering of F-theory (a 12 dimensional theory where the complex dilaton-axion of IIB string theory take on a geometric interpretation as the complex structure of a two-torus). The geometry of the compactified dimensions determines the symmetries and matter content of the low energy theory and so in these papers the standard model gauge groups and matter content are constructed via this process of geometric engineering, 'unfolding' from larger gauge groups.
• Jacob shows that not only is a three flavour standard model a generic feature of a particular (and perhaps natural, from the string theory perspective) orbifold singularity but that smaller gauge groups are more natural from this construction than grand unified theories with large gauge groups. He points out however that the fact that the standard model symmetries aren't completely 'unfolded' is not obvious from this model.
• Lubos gives a more thorough explanation although the general idea of the papers isn't too difficult to understand, even without knowing the background in great detail.

• There was lots of news a couple of weeks ago about a huge calculation of the structure of an immense but important symmetry group. I'll just leave this as a series of links, if you want to read the maths there's some fascinating discussion at John Baez's site and if you just want to look at the pictures, well, they're pretty too. The American Institute of Mathematics has some details here, too.

• The subsequent edition of This Week's Finds also contains a wealth of interesting material on solar flares plus more information about groupoids.

Apart from that I've been rather too busy calculating to read any new science over the last week or so.

• From the BBC comes the news that the new wing of the Tate Modern has been given the go ahead. Without a doubt it's an exciting piece of art but it has a lot of critics who are not impressed. I like the look from the artist's impressions and the claim that London is becoming riddled with different styles of architecture is a century or so too late. The architects, Herzog and de Meuron, are also the designers behind the Beijing Olympic stadium - The Bird's Nest. I go past this whenever I go to the airport and would love to get there some time to take some photographs myself.

• My parents recently came back from a trip to Paris where they took this rather fun picture:

This is an original image.

• From Kevin at the Weifang Radish came some useful hints for internet use in China, definitely good if you want to keep up with blogs and news but don't want the lag of proxies.
  

Right, the weekend beckons and I have another few hours to work before I start running around the city again. Happy Easter to all...

The best of a good lot

The Couchsurfing website was down for a good part of today and I haven't managed to get a place for tonight. It now being tonight means that I'm in the office again after a day which has not bought many surprises having had less than two hours sleep last night. I expect similar tonight but tomorrow evening I'll be flying back to Beijing where, unless my last guest has booby-trapped the flat (something which I'm not ruling out) I should have a good night's sleep waiting for me. 4 hours in 3 days isn't ideal but I can catch up soon.

Anyway, because I'm not going to write anything remotely original in this state I'll try and catch up with some links from the last week or so.

• One of the problems with the debate between string proponents and opponents is that there is usually little in the way of actual scientific debate. On the internet such debates usually end up in a comment section of name-calling and little physics is actually discussed. It looked like Joe Polchinski had really got the ball rolling when he wrote a reply to Lee Smolin's book, answering many of the accusations which had been leveled against the subject and the community. This was the perfect opportunity to have a level-headed debate but, as far as I'm aware, Lee Smolin never replied. In a comment on Asymptotia Lee states that he doesn't feel it necessary to respond to Joe's points because they are already answered in the book. Having read the book and Joe's article thoroughly disagree with this statement.
  
• However, there has now been a public debate on the subject (which can be downloaded from here) (now another debate at Oxford as well) with contributions from Lee Smolin, Michael Duff and from Nancy Cartwright. Clifford's thoughts on the debate can be found on his blog, together with a very long comments thread involving all relevant parties and achieving nothing, yet, as far as I can tell. (NB. I haven't listened to the debate yet but plan to as soon as I'm awake enough to concentrate on it).
  

• The last couple of posts from Backreaction have involved the interface between science and art. Justin Mullins is a British artist, also interested in science and has some pictures of some of the most important equations in physics and mathematics. I've been in contact with him since finding his site, about a couple of points of explanation. He seems like a friendly chap and I'd be interested to see the work and chat with him when I'm back in the UK.

• A nice article from the BBC about how technology can promise so much, but occasionally take much longer than expected to deliver, deals with high temperature superconductors and what they may/will be able to do for us in the near future.

• I was also interested in this article from the BBC about the robot which is teaching itself to walk. The linked sites from the article are worth looking through for more information, too.

• Another great photo from Bad Astronomy Blog shows over 1000 black holes lighting up the sky. This may seem a little counterintuitive but of course black holes are not even slightly black if they are busy eating.

and a few videos:

• From Pharyngula comes the History of Creationist Thought, by Robin Ince, which has some lovely observations and superb timing.

• Toomanytribbles has a good range of interesting short movies on a range of both inspiring and depressing subjects, but I particularly enjoyed the short animation Das Rad.

• I had planned to post two videos a while ago but Retrospectacle beat me to both of them. The first is a demonstration of one of my favourite hands-on physics demonstrations from school - the phenomenon of non-Newtonian fluid dynamics. This can be found displayed within the scientific context here (though not very enthusiastically discussed), and the not so scientific context here, both are fun, but if you haven't tried it before I suggest getting a few tablespoons of cornstarch (cornflower) and mixing it with just enough water to form a liquid paste. Then try and pick it up and see what happens.

• The second video was from a documentary I saw on octopuses several years ago and is remarkable footage of what happens if you put a giant octopus up against a shark!

• Flip Tomato has an interesting discussion and impressive presentation on Split Supersymmetry. Sadly he doesn't get onto Supersplit Supersymmetry, which is a joy to read :-)
  

• From Laowai Chinese comes a table of all 409 Chinese words you can possibly say - with the odd variation allowed ;-)

OK, I've run out of steam. It's getting late and I have a desk to lay my head on so I'll see if I can get some shuteye.

Update: Just remembered this news today that caves which may have necessary conditions to harbour life on Mars have been spotted. This is all highly speculative, but exciting nonetheless.

String theory and M-theory a Modern Introduction - reviewed

String Theory and M-Theory by Becker, Becker and Schwarz seeks to update the three or four main texts on string theory which are currently on the market. It was clear that the time was right for a new book on the subject, and this seems to hit the mark very well. I've read sections of it in detail and browsed the rest. From my point of view this is the most approachable book on the subject which doesn't shy away from getting stuck into the technicalities.

For someone learning this subject from scratch the structure of the book leads you in very nicely with a good number of well-chosen worked examples and many unworked problems at the end of each chapter which will get you familiar with the material. I think the idea of these worked examples is a good way to make sure you're really following, while not every step is spoon-fed like this.

I may sound a bit overenthusiastic, but in the few hours I've had to read through this so far I've been genuinely impressed. It doesn't go into as much detail on certain topics as you would find in Green, Schwarz and Witten, Polchinski or, unsurprisingly, Di Francesco et al (CFT), but to get you up to speed and reading cutting edge papers, I think this will do very well.

The main extensions to the previous texts are not much of a surprise: Flux compactifications, black holes in string theory and the gauge/gravity duality. There are major modern subjects which are not discussed in detail or indeed at all, for instance D-brane model building isn't covered and as far as I can tell tachyon condensation is given only a cursory mention. I'm sure there are many other important areas which are not covered extensively but once you've read the main chapters, you should be ready to learn from the more complex reviews on the topics which have been deliberately left out.

The index seems to be a little sparse, for instance you have to look for 'Anthropic Principle' to find the entire section on The Landscape. I've found another couple of similar omissions.

It is suggested that the book be used for a one year course and this seems very doable, including going through all the questions. It's not going to render the current top books dispensable but I think that for many topics the style and approach here will be much better for the first timer who finds Zwiebach too basic and Polchinski daunting on a first reading.

The Newtonian Legacy reviewed

I wasn't expecting to write about Nick's book just yet but starting it on Saturday evening I couldn't bring myself to shut down the computer. Not willing to go to sleep with so many unanswered questions I stayed up until late Saturday night reading through it, thoroughly engaged and amused.

So, it's a murder mystery set in and around historic Winchester in Southern England at the PHI Institute. This is perhaps the English, fictional equivalent of the Perimeter Institute or the IAS (have a look here for a very good read about the IAS). A post doc is murdered and the affairs that he was engaged in and the circumstances of his death become more and more intriguing throughout the story. A fellow postdoc who finds the body gets involved. Not only does he assist the police in uncovering what was going on but along the way he and his colleagues explain to the police officer involved (who happens to have an undergraduate degree in physics) what the people at the PHI Institute actually do and why they do it. It goes without saying that he also gets caught up in several steamy affairs, the local narcotics scene and arms traders - it comes with the job, you know!

As we follow the exploits of the wide array of characters (drug dealers, bohemian artists, hit men as well as the physicists and police), we discover about the Higgs mechanism (from the basic ideas through to composite Higgs models), possible alternative scenarios at the LHC, the interesting and highly strung politics of just about any physics institute, the basics of string theory, some cryptography and the history of alchemy. Along with this are the philosophical musings of the postdocs at the institute, all pretty accurately portrayed.

The idea of mixing in science with an engaging storyline for the general public has a long history and I thoroughly enjoyed the stories of Mr Tompkins from George Gamow when I started learning about quantum physics and special relativity.

The weighting of science to storyline is different in The Newtonian Legacy, but for an interested reader I think it gets the balance right. As long as they have a basic grounding in school physics and a keen mind they will come away, not fluent in the language of technicolour, but they should have a good idea of why we are all getting so excited about the LHC and understand more of what being a theoretical physicist is about. This book is a very enjoyable read, and it's free, so go take a look.

Anyway, I'm sure this took a lot of time and energy and I hope Nick won't be under too much more pressure if I suggest this would make a great series, I hope to see more from the PHI institute in the future.