I just noticed that last week’s episode of The Universe on Time Travel, which I told you about here and here, is available online on their website. Click here to learn more about the ins and outs of it, and I show you how to make one too! Kind of.
It is a difficult subject to explain, and one that must be tempting to Continue reading ‘Time Travel a Click Away’
I just noticed, via this article at the Guardian, that not only has Edward Witten been awarded the Institute for Physics’ Isaac Newton medal, but his lecture at the ceremony has been posted online for all to see! See the link below. It is not often that you get an opportunity to see Witten, one of today’s giants in theoretical physics, on the public stage, to the extent that most people outside the field have not heard of him at all. The public view of who is driving forward and massively contributing to the field is rather skewed as a result of the number of appearances and grand pronouncements (often on subjects they’d be better shutting the hell up about!) from certain other renown theoretical physicists. So here’s an opportunity to hear from one of the true masters of the field.
When you speak to sensible people in the subject, whatever their own work is about and whether they like some of the things he works on or not (such as string theory), they will quite readily concur that he has done a huge amount for the field, driving forth many powerful ideas, sharpening the way we think about certain kinds of problems, conceiving of new ideas, and overall strongly influencing much of the basic manner in which practitioners think about the physics they are doing. Often, even if he is not the originator of a particular Continue reading ‘Witten at Your Fingertips’
In case you were wondering, things are moving steadily along in the search for the Higgs boson, and in the general ramping up to study entirely new frontiers of particle physics. I noticed a couple of interesting articles today that give you a nice sample. The first, by Dick Ahlstrom in the Irish Times, and is about the announced “rediscovery” of the W and Z bosons at the Large Hadron Collider, by a team working at the LHCb experiment. (I personally think that the term “rediscovery” is somewhat misleading since it makes it seem like the community forgot where they (the key signatures of the unity of the electromagnetic and weak nuclear forces at high energy) were since their discovery in the early 80s, but let me not quibble too much.) The point is that experimental teams are refining their searching techniques while sifting through all the new data being produced in the collisions at the LHC, and one thing you need to do before you begin to look for new things (like the Higgs) is to make sure you can find and recognize old things. Especially very important old things. Continue reading ‘Happy Higgs Hunting’
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 Continue reading ‘Emerging Gravity’
Well, 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.
Dynamical 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 Continue reading ‘Scenes from School’
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 are a few students here and there who have some familiarity with strings, huddling together at times for warmth in a sea of miscommunication, misinformation, and strange preconceptions. Let me be the first to point out that the string community also tends to pass on its prejudices about other Quantum Gravity approaches to its students. But my goodness it does seems extreme to me that an approach that has so many clear benchmarks of success (at achieving goals that at least used to be key objectives) in quantum gravity is treated as an irrelevant backwater by the community that thinks of itself as the main practitioners of quantum gravity. Odd. Anyway, my main message is to try to clearly show that the basics are quite easy to grasp if a student has a decent education in Continue reading ‘Minority Report’
(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 Continue reading ‘Arrival’
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):
Continue reading ‘Summer School Prep’
After my colloquium at UC Riverside some weeks back, I was asked an important question I’ve been asked before, and no doubt will be asked again. The same question may have occurred to you given things I’ve written here about the subject of my research concerning applications of string theory (particularly, ideas from quantum gravity) to understanding (relatively) recent experimentally measured phenomena. (The technique of “gauge/gravity dualities”: See also the special Physics Today May issue with articles on all of this. I wrote about that here. It tells you some of what we can and can’t do with the computational technology, and prospects for improvement, etc.)
So the question is “Is it real?”. This is particularly referring to the black hole in the discussion. Recall, one computes properties of new novel liquid phases of matter (that seem to be closely related to what shows up in the lab) by using a toolbox that involves the equations of gravity, in a higher dimensional spacetime, and much of the thermal nature of the system is controlled by a black hole solution of those equations. So people want to know if that black hole is real. A version of the conversation is like this: (Imagine I’ve already introduced the technique, the higher dimensional spacetime, and the black hole…)
Continue reading ‘But is it Real? (Part One)’
…is all very well, but to look for Heaven…is to live here in Hell*.
One of the things I worked a lot on in earlier months this year (and late ones of last year) was the lead article in a cluster of articles that has appeared in the last few days in May’s special edition of Physics Today. They are sort of departmental-colloquium-level articles, so for a general physics audience, more or less. It’s about some of the things I’ve told you about here in the past (see e.g. here and here), concerning exciting and interesting applications of string theory to various experiments in nuclear physics, as well as atomic and condensed matter physics (although we do not have an article on the latter in this cluster). I had a fun time working with Peter Steinberg on the article and remain grateful to him for getting us all together in the first place to talk about this topic way back in that AAAS symposium of 2009. It was there that Steven Blau of Physics Today got the excellent idea to approach us all to do an article, which resulted in this special issue.
My article with Peter Steinberg, “What black holes teach about strongly coupled particles”, is here, and the pdf is freely downloadable (update: alternative link here). It is mostly about the theoretical aspects of the whole business and the relevance of the string theory Continue reading ‘The Search For Perfection…’
…more to go. I’ve finished one of the papers I’ve been writing (this one co-authored with my student, Tameem) after delaying on it for months. I’m not sure how things got quite this backed up in terms of things I have to do, but they have. I meant to start on a new, long project last week, and all my efforts these days have been toward clearing away all those things I want to get done and dusted before focusing on that. It is taking time, but gradually the clearing is happening. Two more manuscripts to complete.
This paper reports on the continuation of the work we’ve been doing over the years in understanding the physics of various model systems in an applied magnetic field. This is in the context of holographic models of important strongly coupled phenomena that are of considerable interest in lots of fields of physics (particle physics, nuclear physics, condensed matter physics, atomic physics). (Since I don’t want to explain holography and so forth every time I talk about it, see a post I did about some of that here, and related posts in the list at the bottom of this one, if not sure what I’m talking about.) (Hmmmm, I see from my SPIRES listing that I’ve got seven papers mentioning magnetic field explicitly in the title in the last three years, and three or four more of the rest are occupied in large part with the issue too. No, really, I’m not obsessed.)
The issue here is the study of structures that suggest themselves as earmarks of Fermi surfaces in strongly coupled systems. It has been a goal for a long time in the context of gauge/gravity duals to understand what the signals of a Fermi surface would be. Would it be some geometrical object in the dual gravity theory, perhaps? Access to a computationally tractable description of such an object would be rather Continue reading ‘News From The Front, VIII: One Down…’
Ah yes. I’ll admit it: Except for the moustache and a few other details, the scene is eerily familiar… 
(The embed for the video is below.)
Does anyone know who originally started this brilliant series? For those who don’t know it is a 4 minute clip from the 2004 film Der Undergang that several people have periodically re-subtitled with words that have Hitler reacting to an event of some sort. (Warning: Many of them are full of language some might find a bit strong, so watch out!!)
Here it is*:
Continue reading ‘Peer Review Reactions’
Well, a very gentle sort of wham. Yesterday the Large Hadron Collider at CERN had its first collisions of protons! It is a warm start, making sure everything is working before ramping up the energies to regimes where we hope to see new physics, but it is a very exciting milestone nonetheless*. Recall that a few days back they hit the landmark of getting the machine to circulate beams again for the first time. (If you’ve forgotten what all of this is for, please search the blog for “LHC” and/or look in the related posts list at the bottom of this one.) Above right is a visual reconstruction of some of the collision data seen at the ALICE detector, and you can see more of this sort of data at CERN’s website (from where I got this graphic).
From the press release:
I’ve no idea why I do this to myself. I was just about managing things schedule-wise and aiming to make sure I have some fun on the weekend when the following thing happened. I went to Monday’s departmental colloquium and before it, ran into Moh, our organizer this year. I’d been trying to see if there was still room to schedule a speaker I’d thought of inviting, and he mentioned that the dates we’d earlier discussed had all been filled. Then he mentioned that he was desperately trying to find a speaker for next Monday, and was thinking that he’d have to simply cancel it that week.
This was at 4:05pm. Now watch how rapidly I move to ruin a perfectly good schedule Continue reading ‘There Goes the Weekend’
Mark your calendar for Sunday! The West Hollywood Book Fair is on from 10 am to 6:00 pm that day, and there’s so much to see and do with readings, panels, discussions, authors, special celebrity guests, food, exhibitions, writing workshops, discount book offers, signings, swag (no doubt), and so forth. I’ve not been before, but as you know from reading here I’m a big fan of cities going gaga over books for a while, being a regular visitor to the LA Times Book Festival when it comes in the Spring. The calendar of events and much more about the event can be found at the website here.
Here’s another thing. Despite the fact there was no mention of a spankingly splendid Continue reading ‘More Book Fun!’
Today I’m pleased to announce that we have a guest post from a very distinguished colleague of mine, Len Adleman. Len is best known as the “A” in RSA and the inventor of DNA-computing. He is a Turing Award laureate. However, he considers himself “a rank amateur” (his words!) as a physicist. 
He’s one of my colleagues on whom I can always rely for a fun and interesting conversation, even if it is just for a fleeting moment during a chance encounter in an elevator. The other day he told me he’d been thinking a lot about quantum mechanics, and it seemed like it would be fun to share his thoughts with others here on the blog. So join in using the comment form if you’ve some thoughts of your own in response.
Here’s Len.
-cvj
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For a long time, physicists have struggled with perplexing “meta-questions” (my phrase): Does God play dice with the universe? Does a theory of everything exist? Do parallel universes exist? As the physics community is acutely aware, these are extremely difficult questions and one may despair of ever finding meaningful answers. The mathematical community has had its own meta-questions that are no less daunting: What is “truth”? Do infinitesimals exist? Is there a single set of axioms from which all of mathematics can be derived? In what many consider to be on the short list of great intellectual achievements, Frege, Russell, Tarski, Turing, Godel, and other logicians were able to clear away the fog and sort these questions out. The framework they created, mathematical logic, has put a foundation under mathematics, provided great insights and profound results. After many years of consideration, I have come to believe that mathematical logic, suitably extended and modified (perhaps to include complexity theoretic ideas), has the potential to provide the same benefits to physics. In the following remarks, I will explore this possibility.
But, be warned: I am not a physicist and these ideas are embryonic. At best they indicate a possible direction; a fully functional theoretical framework, if possible at all, would be the work of lifetimes.
For most of my academic life, my primary topic of research (and affection) has been Continue reading ‘Len Adleman: Quantum Mechanics and Mathematical Logic’
Here’s an odd coincidence. Thursday, just for fun, I declared it Monopole Day in my facebook status. It was largely because I was prepping a class on Dirac’s ideas about magnetic monopoles (roughly: point sources of magnetic fields analogous to point sources of electric fields), why it seems (from looking at Maxwell’s equations - the defining equations of electricity and magnetism) that Nature might very much like the idea of them (using a symmetry argument - roughly: electric and magnetic fields can turn into each other so if there’s one kind of point source, isn’t it strange that there’s not the other?) but chose to hide them away…
It’s a favourite topic of mine (and many physicists - it is one of the first grown-up tastes of modern ways of thinking about physics that you get as an advanced undergraduate, actually), and so I was excited to lecture about it (as I am every year… I find en excuse to bring monopoles into every course I teach… almost). I even handed out one of my class worksheets, which was all about how to build a monopole (on paper - you take a semi-infinite solenoid (a “Dirac String”) and let the magnetic flux lines spill out Continue reading ‘Thursday was Monopole Day’
I make it a rule to never do that. It’s bad form. Best to be avoided.
Seriously, though, over on the Intersection, Sheril wants your kiss and tell photos. What she’s really looking for is…. well, here are her words:
Have you ever taken a picture of bears nuzzling in the field or kissing fish? How about a provocative pair of human subjects? (With their permission!) Are you interested in having an image credited to you in a science book debuting next Fall? If you’re a photographer with intriguing pictures of kissing and cuddling [no higher than PG-13 content please], email me before September 14 at srkirshenbaum@yahoo.com.
So go and send her some of your material if you have what she’s looking for! If not, consider making some new material. It’s for science.
-cvj
On Friday I was involved in an interesting conversation in an unusual format. It was a chat with cosmologist Anthony Aguirre at UCSC, and it was all about research in aspects of cosmology and of string theory, touching on issues such as the nature of quantum Continue reading ‘Talking Heads’
The College of Letters, Arts, and Sciences here at USC has built a new website, and gone quite far in including extra media, and links and portals on YouTube, Facebook and so on. One of the things they did was have a filmmaker make lots of videos. Lots. Things about faculty, research, teaching, learning, etc. All very exciting. Have a look, here, if interested. Mira Zimet, who makes the films, gave me a call and asked me if I’d like to contribute, and I agreed. I chatted on and on for about 45 minutes to an hour and she cut two short films out of it. The shorter one is on the site and has me saying some general things about research, teaching, science, and USC. Mira made the second because she thought it might be a nice extra video for the College’s YouTube portal. It has me talking a bit more about what string theory is and does, Continue reading ‘Scenes from Work’
Here’s an interview that I missed when it first came out back in April. It is with Edward Witten, the single most influential person in my area of theoretical physics for quite some time now. This is for no other reason than his off-scale abilities in every key area of theoretical physics. He was my mentor back in the early ’90s, and the Continue reading ‘Witten Interview’
One of the words I dislike most in my field - or more accurately, a common usage thereof - is “fundamental”. This is because it is usually used as a weapon, very often by people in my area of physics (largely concerned with particle physics, high energy physics, origins questions and so forth), to dismiss the work of others as somehow uninteresting or irrelevant. 
I don’t like this. Never have. Not only is it often allied to a great deal of arrogance and misplaced swagger, it is often just plain short-sighted, since you never know where good ideas and techniques will come from. A glance at the history of physics shows just how much cross-pollination there is between fields in terms of ideas and techniques. You never know for sure where valuable insights into certain kinds of problems may come from.
Fundamental physics is a term I used to hear used a lot to refer to particle physics (also called high energy physics a lot more these days). This was especially true some years back when I was an undergraduate in the UK, and it persisted in graduate school too, and is still in use today, although I think it is declining a bit in favour of less loaded terms. Somehow, a lot of particle physics is regarded as being all about the “what is everything made of at the very smallest scales” sort of question, first discussing atoms, and then atoms being made of electrons surrounding a nucleus, and the nucleus being made of protons and neutrons, and those in turn being made of quarks, and so on, in this was arriving at a list of “fundamental” particles. There’s the parallel discussion about the “fundamental” forces (e.g., electromagnetism and the nuclear forces) being described in terms of exchanges of particles like photons, gluons, and W and Z particles and so forth. There’s no real harm in the use of the term fundamental in this context, but this is about where the word gets elevated beyond its usefulness and starts becoming a hurdle to progress, and then a barrier. 
Somehow, “fundamental”, meaning “building block” gets turned, oddly, into “most important”. The issue of what the smallest building blocks are gets elevated to the most important quest, when it is in reality only a component of the story. It is rather like saying that the most important things about the Taj Mahal are the beautiful stones, tiles, and other components from which it is constructed.
Perspectives have evolved a bit since my salad days, with the rise of wider Continue reading ‘News From The Front, VII: What is Fundamental, Anyway?’
…At least in my field, as submitted to the ArXiv. Just saw “Remarks on the world-sheet saga” by Bert Schroer. The abstract (and the paper) is full of excellently derisive turns of phrase that are hilarious to read! Example from the abstract:
Attention is given to how such misleading metaphors originate and how their support is maintained by quantum mechanical analogies to models which for good reasons never existed before in particle physics physics and whose only purpose is to uphold the string metaphor. The correct localization is inconsistent with the idea of world-sheets and the string-theoretical interpretation of T-duality.
He’s not actually trying to make the reader laugh, I think, but is attempting to make some serious physics points in there, apparently suggesting alternative lines of Continue reading ‘Best Abstract of the Year So Far?’
I’ve no idea why I’m writing a blog post about this, since I can’t really explain any of the details in a way that won’t sound tediously technical. I’m just pleased since I had a sort of perfect workshop moment for a couple of hours after the weekly picnic at the Center today. I’d been talking a bit last week with Lincoln Carr, an excellent condensed matter theorist at the Colorado School of Mines, and had also been talking with Allan Adams, another excellent physicist, from MIT. Allan and I seem to be on the same page as theorists and so I really enjoy talking with him. We work on string theory, but are not fussy about where the physics that it can be applied to might come from. As long as it is good physics. We both seem to love the idea that there’s so much rich physics, that might be accessible with string theory, Continue reading ‘Just Great!’
Well, there are two Aspen cafes that are probably a bit sick of me. The last couple of days saw me frequenting one or other of them while I worked on a number of things, primarily finishing writing a paper. I’ve focused on little else but finishing it up so that I can get on with other things, such as my various other projects, and also to allow me to pay attention to the interesting talks coming up in the workshop Continue reading ‘Haunting while Working’
There were a couple of string theory stories in New Scientist last week. I forgot to mention them earlier. One is entitled “What string theory is really good for”, by Jessica Griggs. The other is entitled “Why cats fail to grasp string theory”, by Ewen Callaway.
Well, since cats are involved, of course I’m going to start with an extract from the second (even though it is obvious that the cats are deliberately skewing the results):
[...] Osthaus’s team attached fish or biscuit treats to one end of a string. A plastic screen with a small gap at the bottom separated cats from their reward, requiring the felines to tug on the string to get the treat.
With a single string attached to the food, most cats learned to paw at the string to get a snack. But when Osthaus’ team introduced a second piece of string, [...]
Well, that was to pique your interest. You’ll have to go off to the source article to get to grips of this second piece of stringy research. The first article? It’s a discussion of Continue reading ‘Uses For Strings?’
Well, it was an unusual day here in Aspen. It was a day with lots of talks. Six of them, I think. There were four workshop talks scheduled for the morning, each of half an hour I think. Also got into a discussion before the sessions began, helping to explain how gauge/gravity duals work to a condensed matter colleague. I checked a voicemail message (only a relatively limited set of people have my number and so I figured it was a call to which I’d want to respond) and, despite the fact that I’m in retreat mode and would normally ignore it, returned the call. It was an office at USC wanting to put me in touch with a journalist who needed help. From Esquire. No, it is not what you think. I suggested they can could call me at 13:05, and at 10:30 went to the talks.
Somehow, successive speakers kept running over time due to lots of (actually, pretty interesting) interruptions and discussions, so I did not mind that we got to 12:50, and my talk, which was scheduled for 12:00-12:30, had not happened yet. With Continue reading ‘An Odd Time’
Ah, time to relax a bit after a somewhat busy last couple of days glued to the notebook and computer. The results? (1) A hasty colloquium to an audience of mixed expertise to try to get across a sense of why some of us are excited about various applications of string theory a diverse range of physics including ongoing experiments in nuclear physics and condensed matter physics (the person who was going to do it was a bit ill apparently so I stepped in with some hastily prepared slides… a bit messy but hopefully some use)… (2) Two papers with my student Tameem on applications of string theory techniques to superconductivity (one will appear on the ArXiv in about 20 minutes if you are interested [update: it is here.])… (3) Notes for a talk I’ll give on Thursday about said new results… (4) Several discussions with and ideas sent to some documentary film makers about some new TV shows coming up - Season 4 of The Universe! Seems I’ll get involved in some of them (stay tuned)…
So this morning I went to sit and cool down a bit at a cafe I like to visit a lot when in Aspen. Ink Coffee. Ok, I see that I did not yet mention I was in Aspen. Have been for Continue reading ‘Ink Time…’
Jester at Resonaances reports on a talk by Jörg Wenninger about the progress at the Large Hadron Collider (LHC).
There’s information about the repairs, more thoughts about the accident last year, and somewhat frightening news about issues of quality control on some of the manufacturing of crucial parts that may haunt the entire project for some time to come.
Of all of the videos I’ve seen of people visiting the Large Hadron Collider (LHC), this one is the funniest by very far… yes… it’s John Oliver again:
Embed died, so link here.
The probability discussion is just priceless…
Continue reading ‘John Oliver at the LHC’
Gosh, time flies!
I almost did not get to announce this before it was upon us. Tomorrow and the day after combine into a notable event in the College Commons series here at USC. Some of us have been working on this for quite a while. On Tuesday we have Stephen Hawking giving a big public lecture entitled “Out of a Black Hole”. Here’s the announcement. Note that general tickets for seats in Bovard Auditorium all went within hours of us releasing the tickets several weeks ago, but there is room in the two spill rooms that we have set up where there will be screens relaying the talk. Make a bit of an event of it and go with friends! [Update: I forgot to mention that we had a competition in local high schools and also at USC where the prize was to ask Stephen Hawking a question. People submitted questions over the last few weeks and we selected some of the best. There will be three undergraduates and three high school students coming up from the audience (we've a lot of high school students visiting us for the talk) to ask him a question each at the end. Should be fun.]
The day after, there will be a related event. Some of us from the physics department Continue reading ‘Hawking Talking, and More’
I presume you’ve heard the news by now, concerning stem cell research in the USA. If not, listen to and read some of the NPR reporting on it here (by Julie Rovner Continue reading ‘The Great News Of The Day’
9:00pm - 10:00pm
…Must be here somewhere. Maybe inside the monolith? No. Seems it is not inside the jumbo suitcase, which I have not used since Aspen last year anyway, and I’m pretty sure that I did not use it on that trip. Where can it be? That box over there? No. (But I found that bag of plastic book covers that I’ve been using sparingly since I left Preston for London in 1986. Excellent. The things I don’t throw away…) Well, never mind, would be silly to make myself miss a flight over an inflatable pillow that I have not seen in over a year. If I play my cards right, I won’t need it anyway….
9:10pm Now to put all those things I set aside earlier into my trusty little day trip bag. Change of clothes, electric shaver, toothbrush and so forth. I suppose I will bring the laptop. And some bits of equipment that might be useful as backup for Peter’s plan. Or whatever. You never know. Yes, I throw in my copy of Accordion Crimes. Almost finished it, and if I do, would be good to get another Annie Proulx to continue enjoying her wonderful writing…
9:17pm Will someone tell me how I managed to be perfectly on time, and then fritter away some of it to make sure I’m slightly panicky late again? Sigh. I was more or less ready at 9:00, when I should have left. Despite all the events of the previous 24 hours ((Day One) - Valentine’s Day Diary - Available on DVD) I got everything together on time, and wouldn’t it be rich if I missed the flight?
9:23pm I leave finally, using the batcave, slowing to check that entrance closes, then vanish into the night toward the airport. Saturday night late in LA. Surely everyone is out having awkward dates? The roads will be clear this late on a Saturday night, right? I can make my 10:07 check-in cutoff, I’m sure.
9:33pm. 101 Freeway. Full of traffic. Don’t you people have dates you’re supposed to be on!!?? This is my road! My! Road!
Continue reading ‘24 - Physics Edition (Day Two)’
Well, the good news is that there’s a definite schedule in mind for the restart of the Large Hadron Collider (LHC). (See related posts below for more.) We can resume licking our chops in anticipation of exciting new physics of various sorts! I learned about this from US LHC Blogs with posts by Steve and Peter. Some key things (apparently from a widely circulated email that heralds an official press release to follow soon) are as follows. First, Steve’s synopsis of the schedule:
Continue reading ‘Once More, With Feeling?’
No, it’s not my solution to things (you know, when patient, tiring, endless, circular discussion and explaining that it is work in progress does nothing to stop the whining of those who’ve made up their mind in advance…) but it certainly makes me laugh out loud! Enjoy:
(Click to go to larger version.)
Taken from Abstruse Goose, which is hilarious!* This follows on nicely from Continue reading ‘Another Approach?’
The usual answer you’ll get from the person on the street (as it were) includes lots of nice words about wiggling strings that look like particles, and so forth, and that’s fine. However, the [informed] next level answer, when you’ve worked enough in the field, is that we don’t know. I’ve told you why (at least in part) in previous posts and so I’ll let you read them. We’re still working on it.
While we work, we’ve learned that it is a quite marvellous thing (from the bits of it we’ve come to grips with) that is teaching us a lot about all kinds of physics, and mathematics too. Some of this may be good for describing things about Nature, and we’re still working out lots of that (although see some of the exciting things I’ve been talking about in my previous post and the links therein).
So what do we put on the T-shirt? (You know, the analogue of Maxwell’s equations for electromagnetism - light, etc - that every physics undergrad likes to have on their T-shirt). Well, we don’t know yet.
But that’s all my opinion. Every now and again it is good to hear from one of the masters about what they think of string theory*, and what it is and so forth. Happily, Joe Polchinski has been known to agree to stand up and give an exposition on this Continue reading ‘So What Is String Theory, Anyway?’
Yes, I’ve been a bit quiet of late, I know. I’ve so many things on, both professional and personal that it sometimes keeps me occupied from when I wake up just before sunrise right through to falling asleep a bit after midnight. And yes I know that means I’ve been not getting the traditional full nights of sleep, but if my body insists on getting up at 5:30am, who am I to resist? I thought it was due to jetlag from the trip a couple of weeks ago, but it seems to have taken. I don’t mind too much since watching the light change as the sun rises is a marvellous way to start the day.
Among the things I’m up to (yesterday and today so far) is a strip-down-and-redesign of a short talk for an exciting symposium that is coming up in a few weeks in Chicago. The American Association for the Advancement of Science is having their big annual shindig there (apparently the biggest science conference in the world) and there will be a number of addresses, plenary talks, and keynote speakers and the like (including Al Gore, by the way), and also several sessions of symposia and other presentations on various topics.
While slightly annoyed at the fact that one major day of the conference is on Valentine’s day (which means I’ll have to be out of town on just the day that maybe, just maybe, on the off-chance, you know - if the universe sneezes or something, somebody might want me to be their Valentine…*), I was looking at that day’s schedule and it caught my eye that there’ll be a session (with several presenters) entitled “The Science of Kissing”, and three hours long, no less:
Continue reading ‘Preparation’
For some reason I don’t understand, I occasionally get a copy of some random (as far as I can tell) issue the International Journal of Modern Physics A in the post. It just arrives. The people at World Scientific are presumably hoping I’ll get hooked by it and take out a personal subscription or something. Not sure. Well, it has not happened yet (just as it did not with the unsolicited regular arrivals of Angeleno a while back). But you never know.
Anyway, before putting the one that arrived recently on to my shelf (I can’t easily throw things like that away… it’s a problem, I know) I glanced through the contents to see if there were clues as to why this one was sent to me. I found no obvious ones, but the very first article caught my eye. It was a rather good essay by Steven Weinberg (1979 Nobel Prize in Physics) on BCS (J Bardeen, L N Cooper and J R Schrieffer - No, nothing to do with College Football’s BCS.) theory of superconductivity and the importance of the idea of spontaneously broken symmetry in condensed matter physics and then in particle physics (see last year’s Physics Nobel, by the way). I thought I’d point it out to you, since it is rather nicely written and very instructive (whether or not you’re already familiar with the phenomenon/idea).
He begins with some overstatement, however. He expounds upon the difference between particle physicists and condensed matter physicists and although it is amusingly written in parts (I assume intentionally) he really over-eggs the pudding, in my opinion. Look at this:
Continue reading ‘Weinberg on BCS’
I noticed that Robert Helling shared some thoughts about thermodynamics and gravity today on his blog. He is understandably confused about several aspects of the issue, especially when applied to cosmological issues. (What is the entropy of our universe? Does the Second Law really apply? Does equilibrium thermodynamics even apply here?)
I’ve nothing remarkable to add to the discussion at this time except to note that a blanket statement that thermodynamics and gravity don’t seem to go together (which I don’t think he’s strongly saying) is not one I’d make, since we have a major class of working counterexamples.
The context is the gauge/gravity duals I’ve talked about here a lot, starting with AdS/CFT and beyond. There we know that the gravitational systems are essentially able to display the more garden variety thermodynamics by being immersed in the (regulating-box-like) anti-De Sitter type backgrounds. Then we see that black holes Continue reading ‘Thermodynamics and Gravity’
Takuya Okuda talking about Wilson Loops at the SCSS, UCLA, Dec. 2007. Click to enlarge.
The next regional string meeting is a two-day one at USC, this Monday and Tuesday. It’s going to be full of interesting talks and conversations, as usual. Please encourage your graduate students to come, especially, since special effort is made to make sure that each talk begins with a pedagogical portion to help non-experts in that subfield navigate and see the motivation.
The speakers are:
Continue reading ‘Southern California Strings Seminar’
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