Author Archives: Clifford

A Hop Over To Canada

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Well, as I said in the previous post, I’m leaving my hideaway/retreat mode and popping over to Vancouver for a short spell to help out at a Summer School. It’s the PIMS (Pacific Institute for Mathematical Sciences) Summer School on Particles, Fields, and Strings. I’m giving four lectures on some of the techniques in string theory that it helps to know in order to do some of the fun things we do to get at interesting physics (such as the topic of the post before). My title is something like “Perturbative and non-perturbative string theory”, and I’ve no clue what the level of the students really is, so goodness knows how far I will get in four one hour lectures. But it does not hurt to try. I’ll be laying the groundwork for several of the lecturers who will be talking about the more advanced stuff closer to their research work, and so I hope to at least help the students gain confidence with ideas and language that will show up all over the place in the two weeks following my presentations.

So what will I cover? Well, I’m going to tailor things to the responses of the students as […] Click to continue reading this post →

Atoms and Strings in the Laboratory?

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depiction of lithium trap from the Kastler Brossel lab in france

A depiction of a lithium trap from the Kastler Brossel laboratory, in France. Details here.

[Despite appearances, I did not choose the music in what is to follow. I just put on iTunes set to random, and started typing, reporting on what was playing as I went along. Nevertheless, there were some nice resonances.]

Now playing: Mr Day, John Coltrane.

So. I must put the Aspen time on hold for a short while, as I promised to give four lectures in Vancouver starting tomorrow. While I sit here in a lounge in Denver at 8:00am, wondering why I booked a 7:00am flight out of Aspen, and also wondering exactly what is in this muffin that I picked up to have with the (rather good) tea they have here this morning, I thought I’d tell you about a little bit of really nice physics that’s going on in the neighbourhoood of my world. Since I’m too cheap and too disinterested to pay for a connection to the web, this’ll only get uploaded quite a bit later when I get a free hookup. (This is a bit more technical in places than usual. Please don’t give up too easily. Oh, and you might have to read some things I point to from earlier to get everything I’m saying – I’m not one for endless repeating myself I’m afraid.)

You can think of this as another story in the line of development I’ve been pushing (and telling people about here and elsewhere) for many years now. Applications of string theory to a broader range of physics areas than the popular discussions of the topic seem to touch upon. I told you last year about the exciting work going on in understanding properties of new phases of nuclear matter being unlocked at the Brookhaven experiment RHIC (colliding heavy nuclei together to create a sort of hot quark-gluon soup). That work continues. This new work pertains to experiments as well, and this time, these are closer to the human scale bench top experiments we all get misty-eyed over (ok, I do, maybe no-one else). It is super-cute stuff. I should […] Click to continue reading this post →

Recovery Time

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Today’s going to be a slow day, with a bit of pottering about town (groceries, new novel), sitting at home (laundry, reading, writing), and working on some physics things here and there. It’ll be good to slow down. I went on another long hike yesterday, back in my more usual solitary mode. Last week’s to Willow (see a couple of earlier posts) was with my friend and colleague Albion Lawrence who I’d not seen for a long time, and so we spent a very pleasant time catching up on things (mostly sharing about books and film, as we do) as we walked.

on_west_maroon_trailYesterday’s hike, following (initially) the West Maroon trail, was taken up with conversations with myself, both internal and external, and that’s something I enjoy a great deal. I thought I’d spend a lot of time thinking over various issues in physics that I’ve been puzzling over in my work, or that I’d learned about from various conversations and seminars while here at the Center. But I did not, surprisingly. Or not much. It was a very physics-free day, even though I was out there struggling along in the West Maroon area for over five hours (out and back to the bus).

Part of this might be because due to the large amount of snow on the ground in places, I lost the trail, and so spent a lot of time following the river trying to pick it up […] Click to continue reading this post →

Chiropteral Mirror Symmetry?

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Spurred by the previous post showing M-theory’s possible relation to matters Chiropteral , Joe Polchinski (who I think, in 1995 or 1996, first drew the diagram that I messed with in that post) emailed me* to say that there is a quite striking appearance of batman-ology in the string theory literature. It’s from one of the classic Mirror Symmetry papers of 1990 by Candelas, De La Ossa, Green, and Parkes, “An Exactly soluble superconformal theory from a mirror pair of Calabi-Yau manifolds.” (you can find it via here). Here it is:

batman ish mirror symmetry diagram

What is this? It has to do with spaces in string theory called “Calabi-Yau manifolds”, which are important (in some approaches) as starting points for constructing models […] Click to continue reading this post →

Black Hole Battles

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lenny susskind, kc coleSomehow, I only learned about this today, and it is already standby tickets only, but you never know. If you’re in LA and interested in a different kind of conversation, consider taking in the event (part of the Aloud series) at the downtown Los Angeles Central Library tomorrow night at 7:00pm. It’s between two friends and colleagues of mine, the science writer K C Cole and the scientist Lenny Susskind! The event is entitled, “The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics”, and presumably will be about Lenny’s reflections on some of the exciting squabbles over various important issues in black hole physics that took place (and still take place) in our field of physics. The above turns out to be (I just learned from a Google search) the title of a book he’s written, so you might be interested in it for your Summer (or other) reading.

Some of you may recall her really great conversation with Alan Alda that took place at USC earlier this year. I reported on it here. K C tends to run these sorts of […] Click to continue reading this post →

On Good Ideas

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A commenter, slim potato, implicitly asked a really good question earlier. It was a comment on a post I did yesterday about my struggles with a computation I was working in a notebook working on. I gave an answer, but since I know that a lot of readers don’t read the comments, and because one of the missions of this blog is to give a window on what scientists such as myself do and (importantly) how we do it, I thought I’d elevate the comment and my response into a post. Feel free to add your own thoughts to it in the comments, either as a non-scientist, a scientist, a specialist from another field, or other.

slim wrote:

I would have assumed that most of your time when working on a paper was involved on catching good ideas, not getting muddled with conventions and calculations.

cvj wrote:

Hi,

Thanks. That’s a common misunderstanding of what we do. What makes a field of physical science like physics work is computations – all of that business with calculations (including checking that your computations conventions are internally consistent) is vital to the field.

Frankly, “Good Ideas” are a dime a dozen. Anyone in my field ought to be able to think of at least six of them before breakfast. What makes a good idea go […] Click to continue reading this post →

Once More Unto The Breach…

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Ugh. A night of computing (while making and eating dinner and recuperating from a strange day-long headache – dehydration? side effects from the big hike the day before?) and muttering to myself at various points left me in a state of confusion last night. I went to bed tired and confused after getting into a muddle and realizing that I’d been probably mixing conventions in parts of my computations over the last few days, leaving me with a flipping minus sign in a result. No, I really mean “flipping”, since sometimes a 1/16 was -1/16, and sometimes that represents a physical truth and other times it represents a computational mistake – and I got confused as to which was which. Ugh.

All of this was coupled with occasionally wandering outside into the late night air filled with hungry insects in order to seek the fragment of wireless signal (I accidentally discovered it nearby on the weekend) in order to download the odd reference to check an idea or a fact. I’d have a few minutes before the bugs would find me and start to chew (I suffer from being particularly tasty to insect life – always the first person to be multiply bitten at any outdoor evening gathering), at which point I’d have snagged the download of the paper and can then run back in to the safety of indoors, flapping my arms around my head like a madman. It is an amusing dance, since I can find the […] Click to continue reading this post →

UK Physics Education and the Olympiad

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You might be interested in this for all sorts of reasons, whether you’ve interest in science education in the UK or not. It relates to similar issues elsewhere, such as the USA. It’s a rather good (if a bit depressing) report on physics education in the UK, and how the UK does in the international Physics Olympiad compared to other countries. There’s a visit to the “training camp” for the Olympiad, and interviews with students and teachers. Have a listen – it is only nine minutes long.

The UK does not do very well, to cut to the chase. Not very well at all. China is the powerhouse, with the US and Iran also being very good. Notably, all three countries invest heavily in serious training and educational programs for the Olympiad, and it is also notable that Iran has very strong female representation.

More worrying, perhaps, is the decline of students’ knowledge of physics overall, since […] Click to continue reading this post →

Some Saturday Shopping

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Well, of course I made it to the Aspen farmer’s market. Why would I pass up the opportunity to pay $3.50 a pound for assorted squashes? (And that was some of the more reasonably priced stuff…) I like to support these things, and mingle with the people, so I go anyway. Also some of it is very good, even though there are very few actual fresh produce vendors compared to the farmer’s markets I’m used to in Los Angeles. (This latter fact is not entirely traceable, I think, to having a smaller target population, or being at high elevation.) (Of course there’s a lot of selling of knick-knacks of various sorts of the tourists…. you know: hand carved dual dog bowls with Western outdoor themes and so forth…)

Here’s the (half-folded) bike with some of my findings:

saturday pickings from the market in Aspen

You can get a closeup on the basket by clicking the image on the right. Some apricots, […] Click to continue reading this post →

Altered Saturday Plans

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river in aspenWell, I was supposed to go for an early morning hike to start off the day, but it has not happened. It was just meant to be a short one, since I’m staying in a little cabin out of town not too far from the start of a lovely trail. Then I was to go to the farmer’s market (more on that later) and then after lunch go to pick up my ticket for the chamber music concert I’m to go to this afternoon. (I say “pick up” and not “buy” since I was the lucky winner (well, one of them) of a little ticket lottery at the Aspen Center for Physics for tickets to concerts in the neighbouring Aspen Music Festival. Hurrah!)

Well, the hike did not happen. Why? Well, at about 6:30pm yesterday while scribbling fragments of equations and furrowing my brow while sitting in a cafe in town (a change of venue after a day at the Center(re) sitting in the office, you see), I began to realize that a computation I was stuck on might actually be becoming unstuck! Various parts […] Click to continue reading this post →

Although No News is Good News…

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…(as the saying goes) it’s nice to get the real thing from time to time.

I’m almost fully in retreat mode now, being back at Aspen and settled in to my office at the Center and so forth. It’s good to see some familiar faces and catch up a little on physics news, and gossip (still waiting for some good juicy stuff there). I’ve settled into my accommodation (which on the plus side has no wireless or other web connection, but on the minus has HBO, which I shall have to studiously avoid), and have done a quick cycle around town (brought the Brompton again of course) to check that everything is in order. So by mid-afternoon on day one, yesterday, I was settling into my project(s). All good.

The good news of the title? Well, usually when someone contacts me about my book, D-Branes […] Click to continue reading this post →