I seem to be having a bit of friction with Nature right now. Need to sort this out. Monday, waking up in the desert (family visit – staying in a house not a tent), I put my hand on my pants to put them on and go out into the world. There was a strikingly sharp and hard jab, as though I’d grabbed a needle with my finger. I thought it odd, not having had a needle or other pointed object in my clothing. I decided to have a look… There, partly visible in one of the pockets was a scorpion! I thought about this for a few seconds and tried to recall whether there was some kind of venomous variety in this area, and whether this was one of them. Pausing for a while, I felt slightly dizzy for a tiny moment and then decided that was my imagination, and then I carried the pants out to the kitchen to discuss the matter with one of my hosts. After some research (and his rapid dispatching of the unfortunate beast), I decided that it was the wrong sort, and moreover, at only a few inches in length, probably too juvenile. Also, my finger showed no signs of distress, and so I got on with the day.
Last night, back home in Los Angeles, I discovered an unwelcome visitor in my crawl […] Click to continue reading this post
I hope you’re having a really great and peaceful holiday time, whatever tradition you use to celebrate the season. I’ve been rather taken up with a number of things, including a bit of family travel, and family visits, which meant that I lost some blogging days. Sorry about the quiet.
Is anyone else hoping that (when they release it in the future on DVD/Blueray) the director’s cut of Peter Jackson’s “The Hobbit” will actually be 40 minutes shorter than what’s out in cinemas now?
-cvj Click to continue reading this post
…of Mexico. It was an excellent evening again this year (November 30th, actually). This was the second one (the first was in 2010) and I think the idea is to try to make it an annual event. It is in that great space downtown, Vibiana, the former Cathedral of St. Vibiana (now de-frocked, I suppose).
Anyway, the fellow (photograph right) making something (whatever it was) using liquid nitrogen caught my scientist’s eye (I usually carry a couple with me when I go out). It reminded me of the ice-cream people used to make at various departmental parties in physics departments in my past. (Always seemed like a good idea for novelty, but I never ate any of the ice-cream. I think I’m a fan of making things like that the slow way, letting the flavours settle in…) I wondered what he was making, but did not wait to find out since I was not on my own and a crowd immediately formed around him.
What happened a short time later was a bit unexpected. I enjoyed listening […] Click to continue reading this post
What? The final exam I set on Friday. I spent a lot of time trying to get this final exam right. The problem is that I tend to decide at some point that I want to set an “interesting” exam, and then this usually ends up being more work for me than for the students, since you not only have to think of the questions and make them the right level of difficulty (made harder by being open book and, in this case, a take home -well, take to where ever for 4 hours), but then endlessly debug to see that it has no mistakes (since I won’t be present to answer questions). This time, I spent a lot of time on units, since I wanted to set an exam that kept all the factors of c and mu and epsilon present in all the relativistic notation and right down to the final unpacked Maxwell equations and all the quantities they computed in various examples. I decided to have them explore a little non-linear electrodynamics, since everything they’d seen was mostly linear. You start with the familiar (Maxwell) form of the equations:
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Well, Thursday’s meeting was a blast! I had decided not to try to get people to RSVP for the meeting this time, and so when it came down to the day before, I had no idea how many were going to show up. This meant that I had to make some guesses about how much coffee and tea and cookies to organize, which was a little bit of a challenge. But just before 9:00am people began to show up, and kept showing up, and by time I was ready to start off the day’s meeting, there was a really good crowd!
In the end it was a great day, with five really good talks and lots of excellent discussion. […] Click to continue reading this post
You might remember that during the Spring and early Summer I was deeply embroiled in making a film. (See several earlier posts, e.g. here, here, here, and here).) It was a short film to celebrate the 50 year anniversary of the Aspen Center for Physics, and I was keen (in my role as filmmaker) to give it a treatment that benefits from my being a theoretical physicist, and one who is familiar enough with the Center, all in order to get the right tone of the film. (Jump to the end of the post if you want to see it without more background thoughts.) There’s a spirit of the Center that is quiet, reflective, and inspiring of thoughts that need time to be explored, so I definitely did not want the usual loud, buzzing, overly busy type of film that you often see about science activity. It did not seem appropriate. Working with Dave Gaw (who was an awesome principal cinematographer and editor for the project) and with Bob Melisso (who shared some of the production and direction work with me), I think the result strikes the right note overall. A fun side note: I got to design a number of unique (and definitely handcrafted) elements for the look that I think you’ll like and recognize from other visual work of mine you’ve seen on this blog, and just as with my earlier film projects from 2009 (see here and here) it was a real buzz to help figure out how to make them fly, and then see the elements come together in their final form up on screen.
People really seemed to like the film a lot, from what I’ve heard. (It was shown extensively at many of the Summer events celebrating the 50th at the Center.) So while it did take a lot of my time, it seems like it was time well worth spending since […] Click to continue reading this post
The next Southern California Strings Seminar is on Thursday 13th December! I’ve now made the website for this one and it is here. Come back to it from time to time to see the updates of talk titles as speakers let me know what they are. It is a one-day event filled with five talks and plenty of time for discussion. I’ve snagged a lovely room in the Doheny library again. (Photo left has a shot of the room we used last time it was at USC in May 2011. The most recent one was over at UCLA.)
You are welcome to come and do physics with us! Also, if you’re part of a group in […] Click to continue reading this post
Sort of stuck this morning. I was up at 6:30am (more or less my usual time these days) with good intentions to get back to do a nice stretch of work on The Project for the first time in a while. But it is almost 10:30am and I’ve done nothing (not counting procrastinating, making fruit compote for pancake breakfast, sending a bunch of emails, and so forth).
It is difficult sometimes to reboot back onto task on a project when one is suddenly done with one of the major things pulling you away from it. Classes are over, you see, and so I am transitioning into a different mode, and not super-efficiently.
I think maybe before I have to leave to run errands out in the world (after lunch), I must get something done toward […] Click to continue reading this post
“I know! Clamp a clamp to it, and then clamp to the clamp with two other clamps…!”
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Penultimate lecture today in the graduate electromagnetism class. These last four lectures are a lightning tour through some important concepts – showing how many of the things we’ve been doing all semester fit with Special Relativity. (For example, amusingly, showing that the Lorenz gauge condition is in fact Lorentz invariant…) It is fun to show a powerful example of how an important guiding principle (such as writing equations in a Lorentz-covariant way) can end up making several features of the theory seem much more natural, while also leading to new physics. This is fun to do, although it does mean that I end up writing whole new notes for this since I am not a fan of the way some of these electromagnetism books (Jackson included) decide to treat time in an odd way, such as treating it as imaginary (which must be so confusing to some students) just so as to write Lorentz transformations like a rotation, or using mostly negative signatures for spacetime, and so forth. And, inexplicably, using different units of measurement from the choices made in the rest of the book… Anyway, so the last two lecture-writing sessions have mostly been one of fiddling with minus signs and factors of c, 4 Pi, minus one, and so forth. Joy. Well, the group seems excited since they’re beginning to see things that they’d seen in other classes and it is all making some sort of sense now (Klein-Gordon equation, duality, etc., etc…) I think the last class will show how many of these things flow from variational principles. Maybe I’ll find a little time to do the Born-Infeld model? I’m excited too, although I’ll be sad to end the class and stop working with this fun group of students.
Today I managed to grab a few sketches on the train. This afternoon coming home on the Expo line these two snoozing gentlemen were kind enough to sit still for a few minutes each for me to get down a few impressions of their features. This was all helped a bit by the train sitting still for a while as we waited for a truck to get off the line. Apparently it was parked or stuck there.
Perhaps not helpful was this young guy who watched me drawing and then decided […] Click to continue reading this post