Yes, it is that time of year when the city goes purple. Or lavender.
The jacaranda trees go crazy for a while. There are stretches of several blocks long, Continue reading ‘Jacaranda Time!’
Archive for the 'work' Category
It has been rather a tiring last several days. I’ve been focusing on writing a big report on various internal matters that my committee was charged to study for the whole academic year. The issues are rather large, and the solutions I was trying to present require not just cosmetic tinkering but major changes in the way things are done. So the key thing to get right in writing it is a tone that is critical of what there currently is in place while at the same time painting a picture of what could be in its stead, while also beginning to show how to get there. If you don’t balance all three just right, there’s no chance that anything will change, since either lots of people will just be pissed off that you trashed their system, or threatened the status quo, or they’ll agree but say there’s nothing that can be done, or they’ll say you have not really thought it through. I think I’ve managed to get the balance right.
It was due on Monday. On Sunday night, I had something down, but I did not really like Continue reading ‘Tired’
That’s it. The class is over… I have to admit that I’m pretty sad to see the end of it, although I’m very very tired. It was such a great group. (I’ll be toasting the end of it all with some of the splendid stuff to the right.)
Recall that we stepped away from black holes. After a look at cosmology for some lectures, where we understood the role of four crucial components in determining a universe’s properties (curvature, matter, radiation, and vacuum energy) we dove back into formalism for a short while (one lecture) to develop a little more the tools we needed to properly under stand how to formulate Einstein’s field equations.
It did not take long… You need only the idea that it makes sense to formulate everything in terms of objects that allow you to express the full sense of an equation in any coordinate system you care to write. Once that is done (the objects are called tensors, and the idea and how they work is pretty simple to get to grips with) the key to formulating the field equations of gravity is to have a look at the structure of other familiar systems. The field equations of electromagnetism (Maxwell’s equations) and the field equations for Newton’s formulation of gravity give the required clues. A rummage around the geometry to find the appropriate object to express the physics in terms of uncovers the Riemann tensor and its cousins (”contractions” to get Ricci and so forth), and you’re almost there. A step back to learn how to package energy Continue reading ‘Sad Ending’
Wow, doesn’t time fly when you’re having a busy semester! I meant to tell you about this early March shoot a while back, but got swamped and it fell off the desk. I recalled that I’ve been neglectful because I learned that the show in which some of this will be used will air on Tuesday night (9:00pm I think - “The Universe” on the History Channel). The episode discusses the end of the universe, as far as I know. The point is to discuss the various speculations that have been made about how the universe might end, and what current knowledge (such as the famous 1998 supernova observations showing that the universe’s expansion is accelerating) seems to suggest about which of those scenarios might be more likely. Of course, for the discussions to make sense, you need someone to talk about some of the basics, such as what it means for the universe (indeed, the whole of spacetime) to expand and collapse. Who you gonna call? 
Ok. I’m one of many you can call. It was a new (to me) producer/writer, Savas Georgalis, who called this time, and we worked together on plans about how we might Continue reading ‘Tales From The Industry XX - Sporting Locations’
Morning cup of tea, and short reflection - coming up for air before diving back in…
It’s a bit of a mess here, time-wise. Just not enough hours in the day. Everything totally fragmented. Yesterday was grueling… here’s some of it:
Up at 5:30am, finding that I’m immediately thinking about a physics project for a bit (I fell asleep doing so, having been the whole evening in the Casbah drinking coffee and doing the same) before having to break off to get ready, get to office early to start an insanely busy day. Answer a ton of email, and deal with other online stuff, planning to ignore it for the whole rest of morning. Note that flimmaker/journalist friend B has sent me an email with a list of comments and suggested changes to my script for the Video. Got to discuss it with A, my collaborator in Chemistry on this. Whenever are we going to meet in the next few days? Sigh. (Must remember to do blog post about this new project, and how I ended up involved with the Chemistry department!)
After some dithering, decided to drive in, since the plan was to stay super-late and probably involve driving someone home.
Cold as I walk to the office from where I parked on the street. Mostly in my mind, and Continue reading ‘Up for Air’
Yesterday here at USC was my last lecture in the class about black holes (see also here). We’ve got to move on to other topics (Cosmology, Einstein’s equations, etc) and so cannot do any more. It was a fun last lecture though. I pulled together a few scraps of things I did not finish in the previous lecture (such as the extraordinarily high percentage of binding energy per unit rest mass you can extract with rotating black hole orbits - just what you need to power things like quasars) and then finished with:
- A taste of Hawking radiation, the Bekenstein-Hawking entropy and the wonderful and beautiful subject of black hole thermodynamics that opens up when you combine gravity with quantum mechanics*, followed by…
- A quick discussion of the Penrose process for extracting energy from rotating black holes. (I’m sure that all (past, present or future) super-advanced civilizations must be using them as the ultimate emissions-free means of generating energy for heating their homes and so forth. No, really.)
*Of course, all undergraduates commonly hate it when you dare bring in stuff from other classes, so to Continue reading ‘A Farewell to Black Holes’
There’s really nothing like a sweet potato roasted in the heart of a wood fire. A wood fire lit out under a clear big sky with a full moon. After a long day of hiking. A day of hiking in the desert on a super hot day of vivid blue, brown, and gold. Delicious flavours, textures and colours.
I spent most of last week on retreat in Death Valley. It was Spring break, and I was Continue reading ‘Potato, Moon’
I got an email from one of the group’s graduate students today*, pointing to an archive of videos of lectures by the great Sidney Coleman. He’s doing quantum field theory. This makes this a marvelous resource, in principle, and so I thought I’d share them with you. They are here.
I wonder: are these the lectures that Jacques Distler has mentioned attending a few times in the past on his blog? This was the 1975-1976 year, a graduate course. I wonder if anyone (else) I know was in that class room…
[Update: I learned from the discussion over on Jonathan Shock’s site that there are some partial lecture notes from the course here, by Bryan Gin-ge Chen, based on notes by Brian Hill. He’s looking for help on completing the project, so get in touch if you want to help out.]
I’ve never seen Coleman in action before, and so I was immediately rather curious, Continue reading ‘Lighting Up Field Theory’
The next Categorically Not! is on Sunday March 9th (upcoming). The Categorically Not! series of events that are held at the Santa Monica Art Studios, (with occasional exceptions). It’s a series - started and run by science writer K. C. Cole - of fun and informative conversations deliberately ignoring the traditional boundaries between art, science, humanities, and other subjects. I strongly encourage you to come to them if you’re in the area. Here is the website that describes past ones, and upcoming ones. See also the links at the end of the post for some announcements and descriptions (and even video) of previous events.
The theme this month is Puzzles! Here’s the description from K C Cole:
What isn’t a puzzle? The universe, life and everything are essentially puzzles that, to borrow from Einstein, “beckon like a liberation.” Designing buildings, choreographing dances, cooking meals and getting along with other people all involve solving puzzles (as, of course, does figuring out what’s right in front of your eyes—not to mention putting together a program such as Categorically Not!) A love of puzzles and the challenge of solving them is deeply embedded in human nature.
Gwen Roberts, Scott Kim, Gavin Scott. Our March 9th Categorically Not! features puzzlemaster Scott Kim, who’s Continue reading ‘Categorically Not! - Puzzles!’
Not long ago David Morrison (UCSB) came to the mathematics department here at USC to give a colloquium.
This was a treat for me for many reasons. Here are three:
- It’s always good to see Dave. He’s one of the people I’ve known in the field was since my very first postdoc when I was learning to survive in the big bad world on my own after graduate school. I mostly could not understand a word he or anyone there else said in those days (IAS Princeton, right in the belly of the Continue reading ‘Beyond Einstein: Fixing Singularities in Spacetime’
A commenter asked how the aforementioned movie viewing and panel discussion went on Friday (movie: Jumper), and so I thought expand a bit on the answer I gave:
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It went very well. We were at the School of Cinematic Arts, at USC. We had a full house in the Norris Theatre, which was great to see. Most of the audience was students from the SCA, I think, with some of the faculty present, and people from the film’s parent studio, and several others. For the panel, present were two of the film’s producers, the visual effects supervisor, costume supervisor, production designer… basically, the perfect people to have a discussion with about the physics! I won’t try to list all names since I did not catch all of them and don’t want to mis-credit people for being there who weren’t.
Teleportation physics aside for a moment, I’m very impressed with how they realized Continue reading ‘Tales From the Industry XVII: Jump Thoughts’
Well, only four weeks and change behind us in this course, and… the class (see here and here) is ready to understand this wonderful equation:
and all that it implies. What is it? It encodes the shape of spacetime around a spherical blob of mass of total mass M. No, don’t worry too much about the details, since this is not a lecture about General Relativity….. it is just nice (I hope) every now and again to get a look at the sorts of things we use in our day to day work. This “warped” spacetime encodes what we interpret as the gravitational field (in the old Newtonian language) due to a spherical (or, to a good approximation, almost spherical) mass. Like the sun, or the earth, or that tennis ball in the corner there*. It is an exact solution Continue reading ‘Mass Matters’
It was one of those Friday nights when I was in the mood to get out of the house, but not entirely sure what to get out to. “Out” was more important than “where”, you see. Wanted to do a bit of thinking and to relax and let the heavy week of too many meetings fall away from my shoulders.
In the end, I did a combination of things. After my mood, followed by my 
trajectory, turned away from Pasadena (where I was planning to see Persepolis, as was my original plan - I’ll do it later… really want to see that film) at about 10:30pm I arrived in the Valley and hung out at Charlie O’s which is one of the more happening of the neighbourhoody jazz clubs in LA. (Sadly, in this context, “happening” by LA late night standards means that there’s more than about nine people present.)
There’s always something on each night and you can just walk in and sit at the bar to Continue reading ‘Friday Night Wanderings’
Well, Tuesday was a big day in class. We reached a landmark - the introduction of one of my very favourite thoughts of the 20th Century: the Equivalence Principle. This is the realization of Einstein’s that there’s something profoundly odd about Newtonian mechanics and Newtonian gravity that hints at something deeper.
Quick reminder from high school (just two formulae, please bear with me): You know Continue reading ‘Equivalence’
While the wonderful downpour carries on outside (the whole of Southern California is in the grips of a powerful storm), I’ll continue with the discussion of the re-invigoration of the study that I started a short while ago…
(One of my all-time favourite wood-working tools. The good old-fashioned plane. Planing a bit of wood is jolly good therapy too.)
One of the main things I envisioned, and put into my sketches, was lots of space for books. Lots. I wanted big bookcases that fit the room, and so I planned a simple but robust design that stretched them eight feet from the floor to the ceiling. Of course, I wanted to make them myself - Building them myself would be more fun and much Continue reading ‘Bookcases’
Brief note before running off to a long meeting…
Can’t work out whether today’s second long class on the structure of Special Relativity was scary or not. Last lecture we did the classic thought (and real) experiments that lead to the deduction of the Lorentz transformations, and the realization that the words “space” and “time” really should be combined into “spacetime”, and that they need to be thinking in those terms. At the end of the lecture and for most of today, I spent a lot of time emphasizing why Special Relativity is really not weird at all, and developed everything from there on as a very simple analogy to rotations in Euclidean space. The only thing that’s different is this minus sign in front of the “t” part, which is either annoying or beautiful. I urged them to pick the latter since without it there’d be just boring Euclidean four-space, with no yesterdays or tomorrows…
Of course, a bit of time must be spent (forgive the unintended pun) developing some Continue reading ‘Did I Scare Them?’
By the way, do you remember that I had to do that presentation entitled “What Matters to Me and Why”*, last semester? (Blog post here, with follow-up post with transcript and audio here.) Well, it turns out that science writer and journalist KC Cole (of USC’s Continue reading ‘What Matters to KC Cole’
So it is that time. A new semester is upon me, and a totally new course to deliver. Today was my first day back on campus after the break (at least during a regular working day).
Sunday saw me sitting down (in the newly completed study) thinking about how I was going to structure the course. This usually has me sitting with the textbook, a pen, a hand drawn calendar on a big sheet of paper, and a frown on my face trying to figure out roughly what topics I will cover, how many lectures I will devote to each, how many class worksheets (see earlier post) I might have, when the midterms will be, and so forth.
What I am teaching? Why, only one of my most favourite topics to teach in the entire Continue reading ‘Lecture One’
… but pass it on a retake!
While quickly building an ad hoc washing line pulley assembly from a bag of hooks, eyes, and pulleys, and a 2×4, I put this together at first (blotted out some background for privacy of myself and neighbours - click for larger view):
Huh. Does not want to hang level. Why? A tenth of a second after the thought, I burst out laughing loudly at my error. Ironic since I love teaching about pulleys in basic physics, and for some reason students are scared of pulleys. (Not as scared as they are of torque (why?), but scared nonetheless. I try to help them overcome those fears.) I made an obvious mistake. (Do you see it?)
As I get older and busier, I seem to increasingly value quiet spaces. I always loved them, but now they seem more vital to me than ever. So I seek them out constantly. It’s important to note that it is, as they say, all relative. My whole house is a quiet space in a quiet part of a neighbourhood, which is itself in a relatively quiet part of the city. Nevertheless, I’ve been monitoring my working patterns of late and noticed quite a bit of fragmentation, which bothers me a lot. Sure, a lot of it is self-inflicted (email, blogging, and so forth can always be managed better - that’s another issue to discuss), but some of it has to do with finding good spaces to work, depending upon the type of mood and type of work to hand.
I’ve lots of favourites, and many of them are cafes and bars around the city, some places on campus (my office is not high on that list though), the odd bench in a park here and there, and so forth. But those are mostly for working in my “public space” mode. Sometimes I want to work in a different mode, or sometimes I want to just stay Continue reading ‘A Retreat’
My always-ignored advice to anyone studying for exams is that the best thing you can do the night before is get a good night’s sleep. Long study periods long before the previous night should have been used to build up your skills and knowledge. Late-night cramming at the expense of being fresh and having your wits about you in the morning is not really going to help much, if at all. (Heh… long study periods….call me old-fashioned.)
On this very matter, Yvette (one of our regular commenters here) has outdone herself once again with her literary skills! Here is part of her seasonal (as in finals season) poem:
The Night Before Finals
By Yvette Cendes
T’was the night before finals
And all through the dorm
Crazed cramming and panic
Was quite the norm.The students were restless
And none touched their beds
While theorems and formulas
Danced in their heads.With textbook in hand Continue reading ‘’Twas the Night Before Finals…’
Well, it’s been a crazy week here in my corner of the universe. I’m still trying to find the time to break off from several things in order to update you on things from last week and the week before. Meanwhile, new things have this way of happening anyway, and sometimes I’d like to mention them too. So it is with teaching matters. Two Fridays ago was the last lecture of my electricity and magnetism class. We’d done magnetization, they’d waded through another couple of class worksheets I prepared for them on the topic, we’d remarked upon similarities and differences with respect to polarization in the electric case, and with a few hints about what phenomena were to come when they do electrodynamics (the second part of the course - we’d strictly been dealing with statics) a feeling of some sadness came over me as I said the last words of the class. I’d liked this group. They got it. I was going to take them out of their comfort zone and get them to work a bit harder and stretch themselves a bit harder, and the benefits (I hope) became apparent to them when they could see further, run faster, and jump higher (with respect to their abilities as physicists, I mean). (See some earlier thoughts on that here, as I prepared to start teaching the class.) They responded well by not whining about the extra effort required, but instead rolling up their sleeves and having a go, with good humour, a good sense of camaraderie, and remaining reasonably engaged and interactive right down to the very last lecture. They got it. I love it when that happens.
Monday of this week was really the end - they had their final exam (see photo above - Continue reading ‘Finally’
Yep. All done. Sitting in great cafe with a cup of camomile, listening to one of my favourite Mingus albums on the cafe’s overhead speakers, feeling that it all went well. (The latter - Mingus in a great cafe late at night? - is not really the Kentucky I remember.) I seem to have gone three for three. Class, seminar, colloquium. No disasters, besides skimping on the sleep a bit here and there and writing some of the material at the last minute. Good.
So I gave the seminar at noon*, talking about much the same material I did in my Santa Barbara talk I mentioned before here. We then went to lunch at a Korean place nearby that was rather good. I ordered the bi bim bap (as I often do at Korean places) and to my disappointment, it did not come in the super high temperature Continue reading ‘My Work Here is Done’
I’m in Lexington, Kentucky, for a couple of days to give three presentations at the University of Kentucky (or “UK” as everyone refers to it here - I hope that explains the previous post). I should be preparing two of them instead of blogging, but… you know how it is. Here’s how I got here:
On Wednesday afternoon, after a class on magnetostatics, and an attendance of a lunchtime event where four of our faculty (Biology, Geology, Cosmology (our very own Elena Pierpaoli!), Biology) presented their research, I dashed for a plane. Some hours later, at 10:45pm local time, I touched down in Chicago, and 15 minutes later was on the highway in the company (and car) of Nick Halmagyi.
Our mission? To hang out for a few hours in an excellent bar or two of his acquaintance and catch up on what’s been going on with each other, workwise and otherwise. The Charleston was indeed excellent, and (after chortling a bit about the memory of my annoyance at being charged $29 for a serving of a single malt scotch in a bar in Aspen during the Summer) proceeded to order the same here (he the Macallan, me the Talisker). At about 1:00am, the music stops and a guy with a face full of character sits down at the upright piano, is introduced to a scattering of applause, and proceeds to play some Chopin. Everybody shuts up and turns to listen. Appropriately, the piano sounds like all upright pianos in all bars all around the world sound (the tuning is just a bit wobbly), and the guy is good - really good. He stops playing the piece, and there’s some more scattered applause; someone (jokingly?) offers his a dollar as he walks away which he waves away enthusiastically; the music comes back up, and everybody turns back to their conversations. Nick and I continue to chat about various aspects of life, and order a couple more whiskeys.
At 1:25am or so we wander over to another bar. Nick seems a bit surprised by my suggestion to do this (’cos I’m supposed to be going to sleep), but I’m just enjoying walking for a bit in the cold, wearing a cozy hat and coat that normally get no use these days, and there’s something nice about a proper bar hop in a neighbourhood with good bars and in the company of someone who appreciates it. This bar has an Continue reading ‘A Return’
I’ve been distracted by several things recently, and so (even more than is usually the case) there’s far more to report than there is time to report it. Among the highlights are, as already mentioned in the comments, a Saturday visit to MOCA (Geffen Contemporary) to see the Takashi Murakami exhibition. (Coinciding nicely with me about to embark upon reading “The Wind-Up Bird Chronicle” by the other very well known Murakami: Haruki Murakami.)
His simplest motif - which he reuses again and again in many pieces - is the smiling flowers in various colours. The 2D version of the 3D flower box is one of my favourites, and here it is in a room that is wallpapered with the motif. There’s a more solemn one with a range of expressions on the flowers’ faces in an entire field of them (”Kawaii - Vacances”) (including one shedding a tear), but I could not find a good web reproduction of it. The below is a rather small version:
It’s only the second weekend since it opened here in LA and it is hugely popular, with tons of people in the exhibit spaces walking around excitedly and pointing at things. (This being LA, this included a lot of activity in the special Louis Vuitton room, which Continue reading ‘All in a Weekend’s Work and Play’
Well, it’s almost the end of the morning, I’ve just finished one set of tasks and about to move on to another and I thought I’d sit down and chat with a cup of coffee. This morning has largely been about three different outreach-type tasks. I hope to spend the entire afternoon on Physics research. I’m an optimist.
Here’s the shape of this morning:
At 7:00am I checked my email and found that an editor at a magazine was looking for something different from what I initially wrote in response to a question of hers about art and science. I’d spent some of the evening before writing something and sent it along, adding a couple of sentences at the end as a sort of final thought. Of course, she liked the last two sentences and not the rest so much (it was not getting directly at what she wanted me to speak to). So, a bit crestfallen, I tried again. In fact, I had indeed spoken to the issue, but had sort of buried it a bit. So I spent some time scraping away the unnecessary and bending and reshaping the text. Amazing how long that takes when you’ve got a word limit. I sent it along eventually. I’m not sure it is actually as good as what I wrote last night in terms of literature, but it is more to the point of what their feature is about, and so in that sense it is better. From the response I got back, it seems to be more like what they’re looking for now. I’ll tell you more about it when it appears… it’s all about a personal take on the interaction between art and science as far as inspiration goes, with a single piece to illustrate it. It’s the picking of a single piece that was the true difficulty. Took me days to decide. In the end, I had to make some hard choices indeed. I actually enjoyed thinking about the issue though. Sort of re-invigorating. I’d be happy to hear your thoughts about the matter in the comments. I’ll come back to this once the piece appears - if it does.
At 10:00am I called a television production company to talk about a new TV show for Continue reading ‘Coffee Thoughts’
Below I’ve reproduced the text of the approximately 20 minutes of that which I presented at the What Matters to Me and Why event on Wednesday. I mentioned my preparations for it in a previous post. The event was well attended, in an excellent setting (a hidden campus cafe I’d somehow not known about before, Ground Zero). There were students, faculty, staff, alumni, and several others. I chose to give a structured address to start so as to make sure that I did not go on for too long, as I might in a more off-the-cuff delivery. I very much wanted to leave plenty of time to interact with the audience through their observations and questions. I delivered it partly from memory and partly from reading, and wanted it to have a bit of a feel of being read a story, rather than a formal speech. I don’t know how successful that was, but it was fun for me. I think I might try that approach again some time.
[Update: - Audio of the event here.]
Overall, I think the event worked well, and I had a great time. A number of people (kindly) said at the end that they had a good time, and I hope everyone else did too!
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Hello Everyone.
First let me say that it is an honour to be here. I’d like to thank everyone concerned for inviting me to speak in this series. I imagine that everyone starts their piece by saying that they struggled to find a way of saying What Matters to them and Why in a short time. So I won’t dwell on that, except to say that it’s especially hard when, the day before preparing, you realize that it’s not going to be that hour long presentation you were expecting to squeeze your essence into, but 20 minutes!
Some time ago, when people started mentioning that they’d seen that I was a guest in this event, and that they were looking forward to hearing what I will say (!), I’d respond that I too was curious about what I was going to say, and would also try to show up and find out. This was actually true. The other thing that I (half-)joked was Continue reading ‘Some of What Matters’
Yesterday we saw the official “installation” of Howard Gillman the new Dean of the College of Letters, Arts and Sciences. I find this term amusing in this context, as it sounds a bit like putting in a new lightbulb, or perhaps a new operating system (the latter is, I guess is closer to the truth). I sort of had to go since it represents the outcome of a lot of work I did last year on the search committee* that advised the Provost and President on their choices, and of course I have an interest in it as an ordinary faculty member of the College and of USC in general - The LAS is truly the core of USC, and we need the new Dean to do a good job of steering it forward in this (happily) continuing period USC’s steady and rapid progress on all fronts. So a good opening speech is seen as a good sign. It was good - much more than good actually - and everybody seemed to have genuinely good things to say afterwards (as we munched on the always excellent food served at these events - the other reason we go to them).
Right: Not the most representative photo (click to enlarge), but you can see him mid-speech, with President Sample seated listening. Assembled is a lot of the faculty, mostly seated. All the other Deans from all the other units were present, as well as various vice-Presidents and so forth. They all precessed into the room, and members of USC Thornton School of Music’s choir sang the USC song, which was… quite a bit more pomp and circumstance than I was expecting. What you can’t see is that the room is about twice as big as the part you can see, there’s lots of faculty standing around in that part, with several tables of very tasty food and wine for all.
For the record, the fact that I thought that it was a good speech has nothing to do with Continue reading ‘New Installation’
Ok. So I want to make this post timely, but it means that it will begin to let a cat out of the bag. We’ll see how much I can save for a later post as I write1.
So, as I walked to the subway this morning (yes, they have one in LA), I went through my little checklist of things I take on self-assigned assignments of this sort.
Notebook for scribbling: Check
Pen for scribbling: Check
Camera: Check
Phone (now with decent back-up camera): Check
Spare battery for camera: Check
Decent excuse/reason for being spectacularly late: Check
Water: Check
Good footwear for endless walking back and forth: Check
By now you get it. I’m either doing one of my parade reports, or perhaps a street fair/party, museum exhibit, or some random science fair, object or installation or other. Yes, but which? Well, apparently I was going to the future:
The scene: The Los Angeles Convention Center. The event: The NextFest, brought to Continue reading ‘I’ve Got Next’
Yes, it has been that sort of time. The last several days have been full of far too many things - several of which it would be fun to blog about - but none of which have left me any time for doing the actual blogging part. What sort of things? Well, everything from social gatherings like a couple of parties and salon-type events on the one hand, the usual work-type events on the other (like yesterday’s reception to welcome new USC College faculty - I find those especially important to show up to as a means of re-engaging with a cross section of one’s colleagues, old and new, at the beginning of the year*), and on a third hand (sorry) there’s been a big crunch on the research side of things. The big crunch saw me in my office until about 3:00am after a long night of finishing up two companion papers with three of my students (this included breaking for a walk across campus at about 8:30pm to get some tasty mulitas at the excellent La Taquiza) and submitting them to the arXiv. Sensibly, the students went home by 1:30 or so, leaving me the silly one to tinker some more until the end. It was a really fun couple of projects uncovering some rather rich physics, and I’ll try to tell you about them some time soon.
So anyway, my plan today was to write you a 9/11 post, but not quite about what you Continue reading ‘That Sort of Time’
Back in LA, and down at the USC campus. Good to be back! Click below for larger view.
Well, it is the first day of the new academic year’s teaching cycle. I’m here in my office at 7:30am (the power of jet-lag) and somehow have to switch my mind back firmly onto teaching and other matters. It’s always tough to do this, since there are always lots of intensely interesting research issues that continue on my mind from the Summer, and I know that some of those will gradually begin to fade (if I am not careful) as my other duties take up so much of my day to day. My first class (part one of the upper level electromagnetism course) is at 10:00am, and I want to plan out the structure for the whole semester, and write a syllabus to hand out and discuss. As well as the first lecture, of course. I’ve not taught this part of the cycle before, and so I’ll have to be writing new lecture notes.
I want to try some new things this year. In particular, I’ve become increasingly Continue reading ‘Switching’
Ok, I can’t resist. From an earlier post:
…and of course video footage of me effortlessly squashing a star much larger than our own sun down into a tiny space should help out enormously later on with classroom control, and so forth…
Since my cover is now blown, here are some stills** (click for larger) from Tuesday’s (unexpected) episode of the History Channel’s “The Universe”*:
Continue reading ‘My Superpowers Revealed’
… for this year, anyway. The evening out ended with a trip to my primary hideout* of this year’s visit, the nature of which you can deduce from the photo. The barkeep at The Little Nell, Michelle, really knows how to make a decent gin gimlet. I asked for it Continue reading ‘Last Night in Aspen’
I stopped the previous post rather abruptly (I had to do another task and then run some errands) without getting to tell you a little twist at the end of the story. Here it is.
Having chipped away at the thoughts that Strominger’s talk stirred in my head for several days last week, scribbling equations to check that all I was thinking was on the right track (and chatting a couple of times with Nick Halmagyi down the hall), I decided that it was all fitting together so nicely that the framework and my extensions of it just had to be true. There was that feeling that it was too nice to be wrong, and it passed all the obvious checks I could think of. There were two independent consistency checks everything had to pass (using my way of formulating things) and they gave exactly the right results as required by the general setup, with no room for maneuver.
When that happens so nicely, usually at that point in thinking about a physics problem, a thought occurs to me. If I’m playing with a good idea and everything is working so well, then there’s at least 200 other people in the field who probably are also playing with it, and 199 of them have way more time than I do to think it through and write it up before I can. One should not really worry about these things in an ideal world, but I’d be lying to you if I said it did not come up as a concern from time to time. I’ve a history of having my thunder stolen out from under me several times in the field (and not always accidentally), so I’m a bit gun shy.
Anyway, I started writing a draft of the paper on Thursday the way I usually do: I write Continue reading ‘News From The Front, VI: Simultaneity’
I’ve been spending the day so far as an administrator, and not a researcher, since I have to present the results of two committees’ deliberations at one of the big annual organizational meetings tomorrow here at the Aspen Center for Physics. So I’ve been gathering and arranging data in a presentable form. Enough. I will take a break and blog a tiny bit before turning to a truly riveting task - reviewing an introductory physics textbook for a publisher… (Sigh…it is not so easy to escape these things, even out of semester time.)
I had big plans to do a hike each day on the weekend, but physics intervened. I should explain a bit more. Earlier last week I eventually got around to following Nick’s suggestion from an earlier post to take a look at Andy Strominger’s Strings 2007 talk entitled “Search for the Holographic Dual of N Heterotic Strings”. It was the usual nice Strominger talk, where he motivates the physics very well, and presents interesting and clear 
thoughts on the problem in hand. I shall try to say a bit more about what it is about later on, but the general gist of it is that it is to do with understanding certain types of four dimensional black hole in string theory. As you may know, one of the extraordinarily successful results in string theory in the last decade (and slightly more) has been that we can understand one of the most central results of semi-classical quantum gravity -that they have an entropy and behave like thermodynamical objects (the work of Bekenstein and of Hawking from the early 70s)- in precise terms in the full theory of quantum gravity that string theory appears to present us with. This started with the work of Strominger and Vafa in 1996, that showed how to describe a large class of black holes as essentially made of extended objects called D-branes (about which I’ve spoken at length earlier1).
Just to fill in the gaps roughly: Hawking’s result that black holes can radiate as thermodynamical objects comes from taking Einstein’s theory of General Relativity and combining it with Quantum Mechanics in a partial way. He could not really do much better since there was no proper quantum theory of gravity at the time, but even in Continue reading ‘News From The Front, V: Microscopic Weekend Diversions’
Some of the results of last Saturday’s wanderings. The wildflowers are in evidence nearly everywhere you look. Hiking through entire fields of them stretching off into the distance is such a pleasure:
The view toward Snowmass lake (you can just see it) that you can get from being on Continue reading ‘Clearing Out’