Author Archives: Clifford

I’m Melting, I’m Melting!

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Ah. Now I feel the Summer. We’ve been having a streak (starting Monday, or that’s when I noticed anyway) of quite hot days here in LA and, as usually happens above a certain temperature, sleepy_me_sketch_smallI’ve begun to be in danger of shutting down. I tend to get perpetually sleepy in such conditions, and wake up quite early in the morning (which is good for avoiding the heat with an early start), and so get to sleep relatively early. During the day I’m going at half speed if I don’t manage my temperature properly. I’m not a big fan of just switching on and blasting the air conditioning the whole day, so you can say it is entirely my choice to have these issues. Instead, I try to manage good airflow at times of day when it is possible, and shield interiors from heating up under the influence of the sun. It works pretty well, but there’s a point in the middle to late afternoon where things […] Click to continue reading this post →

Emerging Gravity

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In the New York Times this week there’s an article* by Dennis Overbye on Erik Verlinde and his paper on the idea that gravity is not a force at all, but a consequence of thermodynamics. You can think of it as an extreme take on one of the directions a lot of the research (that I’ve mentioned a number of times has been going on in string theory) has been pointing, although I think it is safe to say that there’s a lot to be done on making the statement a concrete one that you can do physics with. I think it contains the germs of the right thing we’re all reaching for, but does not quite get there yet. We’re now quite routinely formulating some of the key physics of gravity entirely as physics of a completely non-gravitational dual theory – this is the content of what we call holography – and in particular the quantum physics of black holes in those settings get holographically mapped to the thermodynamics of the non-gravitational physics. This is the basis of the tools that we’ve been applying to studying aspects of phenomena showing up in various experimental systems in nuclear physics and cold atomic physics (and studies of phenomena relevant to various condensed matter systems are also being done). I’ve told you about a lot of this in various posts. (Some of them are listed below.) Running this the other way, the model non-gravitational systems (certain gauge theories at strong coupling and with large rank gauge groups) can be thought of as examples of how gravity (and space-time itself) is really an emergent phenomenon, appearing simply as […] Click to continue reading this post →

Tales From The Industry XXXII: A Matter of Time

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patzcuaro_clocksHere are some clocks I saw at the House of Eleven Courtyards (Casa de los Once Patios) in the historic town called Pátzcuaro (at the aforementioned lake of the same name). It was a convent, and is now a place to go and see lots of arts and crafts in action, as well as buy some. The clocks, housed in copper, mark the entrance to an entire room of copper workmanship in various forms.

The clocks have reminded me to give you an update on something else. Through some of May and June, I did a lot of work for the show The Universe, which airs on the History Channel (as you probably already know from reading here over the years. See here.). There will be, as usual, several topics covered over the upcoming season, and it will be interesting to see how the various filmmakers put together their episodes. It is worth noting that the History Channel have done something remarkable here. This is now the longest run that any cable channel has had for a science show. They built an audience with a solid show, and kept producing good episodes and gathering more (and it is worth saying, an admirably diverse set of) viewers over the years.

In fact, the show has been so successful that they are going to, I predict, pay an […] Click to continue reading this post →

Tzintzuntzan

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yacata_1(Top prize for the best name on last month’s trip.) This is the name of an existing town as well as the nearby archeological site, the subject of this post. On the Sunday I referred to in a previous post, several of the School went off on a bus to do some sightseeing West of Morelia. This is one of the places to which we went. I learned a bit about the pre-Columbian mesoamerican civilization, the P’urhépecha (or Purépecha), whose capital was Tzintzuntzan (place of the hummingbirds). The structures in my photos (click for larger view) are called Yácatas, which are on a plateau overlooking the lake Pátzcuaro. […] Click to continue reading this post →

Morelia Cathedral

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Morelia is a beautiful city. One of the things that strikes you is the high concentration of architectural features that are either churches or related to churches (convents, chapels, etc) in the core of the city. The queen of these is the cathedral, which was across the street from my hotel (and gave it its name). Here it is during the day. The photograph was taken quite early in the morning to take advantage of the pleasant light (click for larger view):

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It has fountains and gardens on both sides of it, and so acts as an all important […] Click to continue reading this post →

Street Invasion!

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cyclovia_morelia_3On Sunday in Morelia, Mexico, I was walking along the main street near my hotel and it seemed that something unusual was going on. The street was empty of cars, and some sort of event was going on. I saw a few cyclists here and there in the distance, but not the sort that look all hardcore and determined to go fast and determinedly on their way, but instead the more leisurely stop-and-smell-the-flowers sort. I wondered almost immediately if I had run into a local ciclovía, and a few minutes later, a sign confirmed this. Wonderful!

I’ve been waiting for such a thing to come to LA for a while now, since I heard of it last year when I part (and presented) in a public discussion downtown at the Artwalk about bike issues in the city, and had heard that it was becoming more widespread (it started in South America – Colombia) but it was an unexpected treat to find one right outside my hotel room! Here are three more picture. Click for larger view.

cyclovia_morelia_1 cyclovia_morelia_2 cyclovia_morelia_4

It was great to see lots of people out and about just using the streets with no cars […] Click to continue reading this post →

Produce

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tomato_crop Well, here’s the first batch of the season (not counting the onesies and twosies I’ve nibbled over the last few weeks as I go by), representing four different varieties… By the way, my compost played a role in all this, so it is quite satisfying.

If the War goes well, I ought to get more of these soon. Several plants are producing tomatoes.

News from the Front? Fluffy has started the above ground […] Click to continue reading this post →

Scenes from School

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unam_astro_math_mexico_2Well, my work at the Quantum Gravity school over (see previous posts here, here and here), I hopped on a plane yesterday, in order to return to Los Angeles. It was an excellent time. I enjoyed being in Mexico again, and seeing a new part of it (see posts to come), and the school was well organized and very enjoyable. The students were very receptive overall, and I spent a huge amount of time chatting with them about physics between sessions, over lunch, and on the bus back and forth between the campus and the city (and on the excursion on Sunday for a while). A number of students seemed very interested in some of the quantum gravity phenomena that are possible to describe using string theory – surprised in most cases (since the background independence issue that keeps being waved about by some as a naive (in my view) and bluntly used principle seems to have served as a block to many) – and it was a pleasure to be able to open them up to new physical ideas. It worked pretty well because I gave them three lectures on the basics of string theory, and so could build on that material in the one to one discussions to explain more detail.

lunch_waiting_unam_mexicoDynamical changes of spacetime dimension is one thing that captured a lot of interest, as well as string theory’s various ways of showing in model examples how spacetime is an emergent, classical approximation to an underlying quantum description that does not have manifest spacetime geometry. The latter is something that all approaches to quantum gravity hope to realize in one way or another (since those sorts of ideas and fantasies about what quantum gravity should be appeared in the mid 20th Century), and exactly how it emerges in string theory is a beautiful story. Who knows, perhaps they will take these hints from string theory about how quantum gravity can work and develop them […] Click to continue reading this post →

Victory!(?)

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In other news…

It’s a long story. You should refer to last year’s start of The Troubles, starting with the Great Tomato Atrocity. This year it began with the lovely tomato on the right…tomato_gift (click for a larger view).

At first I thought it was an early attack by Fluffy (in the 3.x series, presumably – I did battle with series 1 and 2 last Summer – especially since I’d deployed the first level of countermeasures already this season, the shields around the main tomato area of the garden. Had Fluffy found a way past those? Would I have to fortify them? I was very annoyed since I wanted to make a gift of that tomato and had been admiring it every day since it began to ripen, waiting for the moment to pick it. Evidently mine were not the only admiring eyes. And my paws were not the first to get to it. So I decided to launch more level one of the offensive countermeasures, to test the possibility that something other than Fluffy was a work here. Perhaps one of Fluffy’s allies. The Fluffy series with less good PR: Slinky. I might need to be fighting a war on two fronts. […] Click to continue reading this post →

Minority Report

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This is a quick update on the school. I’ve been trying to give the students some of the core concepts they need to help them understand what string theory is, how it works, and what you can do with it. Here’s the really odd thing about all this (and an explanation of the post title): While this is a school on Quantum Gravity, after talking with the students for a while one learns that in most cases the little they’ve heard about string theory is often essentially over 20 years out of date and almost always totally skewed to the negative, to the extent that many of them are under the impression that string theory has nothing to do with quantum gravity at all! It is totally bizarre, and I suspect it is largely a result of things that are said and passed around within their research community.. So there […] Click to continue reading this post →

Arrival

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(Anyone remember Mike Oldfield? I recall a lovely piece of music of his with the same title as this post and it has now been playing distantly in my head as I type…very pleasant.)

Well, I’m sitting at an outside table across from the main square with the cathedral and having a simple lunch. It is hot, and so I have a glass of cold pale beer in front of me, and everyone around me is speaking Spanish. This feels like it could be that I am back in Madrid, but in fact I am in Morelia, Mexico. (I can tell because, among other things, I’ve never been offered a shoe shine quite so many times in the space of 15 minutes…) It is quite a lovely place, as far as I’ve seen so far (I’ve not explored much yet). I’m resting after a very early morning travel schedule which saw a slight panic (er…long story) at LAX to catch my flight which left just before 1:00am. The seats were fixed to the bolt upright position the whole flight and so the two and a half hours I’d planned to snooze were not so […] Click to continue reading this post →

Summer School Prep

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So, it is that time of year.

I’ve got to give three introductory lectures on string theory in a Summer school somewhere in Mexico next week. So I must break away from intense work on The Project (which is going well, so maybe you will hear about it sometime soonish(ish)….) and focus on how to cram all the cream into three comprehensible and useful lectures. I hate overdoing the “it can be shown” line that ends up making the whole thing seem like magic (as is so often done), so this is always a challenge. Here’s how my preparation usually goes (and indeed it went this way this week): […] Click to continue reading this post →

A Treasure Trove!

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As I’ve mentioned before, I listen online to Radio 4, one of the BBC radio stations I love for its variety, breadth and depth of programming. Between it and NPR affiliate KPCC, my day is usually rather full of (spoken-word) radio of a wide variety. I’ve noticed that Radio 4 has been doing a programme called “A History of the World in 100 Objects”. The Director of the British Museum does a 15 minute programme on each of 100 objects and talks about aspects of its historical significance. (If you think you don’t like history (maybe bad experiences in school or something like that) this might be a great way back into the subject for you. Not liking a subject is usually, I find, an issue with how it was presented to you and not with the subject itself.) It’s a lovely way of quickly plugging into aspects of world culture in interesting ways, and rather reminds me of the short series that we here at USC in the College Commons called The Cultural Life of Objects, organized by my colleagues Anne Porter and Ann Marie Yasin. (See also the Collections event, and my post about it.)

The BBC series is about half way now, and it has been quite wonderful. I strongly recommend it to you. Here’s the marvellous thing: The entire series can be podcast […] Click to continue reading this post →