Category Archives: research

We reached certain key landmarks in the quantum field theory class last week. Not only did we uncover how the Dirac equation predicts that the electron’s spin couples to a background magnetic field, but that it is (to a first approximation) twice the coupling that its angular momentum couples with. This is a remarkable output (once again) from that wonderful equation, the result of putting together Quantum Mechanics and Special Relativity. (I’ve discussed other properties of it before, here.) Makes you wonder, doesn’t it? If finding an equation that puts together QM and SR results in so many marvellous things about Nature just falling out so nicely (recall that spin, and also antimatter are also inevitable predictions of the Dirac equation), doesn’t it make you just thirst to know what we’ll learn (predict, explain, discover) when we find how Quantum Mechanics and General Relativity fit together? This is one of the great motivations for the work my research community does, in case you sometimes find yourself wondering – the quest for finding how Nature combines the two things together to make what we call Quantum Gravity. We’ve found one way, on the page, that you can put together QM and GR for sure (you’ve heard of it, it is called string theory) but it’s not yet clear if this form of quantum gravity is the one Nature chooses to work with, and in any case we need to work on it a lot more to understand what we’ve got, as it surely isn’t complete yet. There are huge pieces of the puzzle missing.

Anyway, the next thing we did was the classic computation of the first quantum correction to the “twice” I mentioned above. This is the computation of the famous […] Click to continue reading this post →

As far as particle physics and big questions about how the universe works, we are living in very interesting times, I’m happy to say. We’ve all been waiting for the Large Hadron Collider (LHC) for over two decades, and now it turns out (I’ve been hearing from a number of people in various conversations here at the center) that the machine is running really well – impressively so. That alone is great, but an interesting thing is that we are almost certainly going to know something significant before the end of the current scientific run next year, maybe even by the end of 2011!

Recall (see posts like this one) that the primary goal is to understand the physics responsible for the Higgs mechanism – the physics that gave mass to those elementary particles that have mass. The particle that does this is called the Higgs particle, and exactly how Nature implements the Higgs mechanism is what we hope to learn. There’s sort of a vanilla version of the story, that fits into the Standard Model of particle physics without any further adornment than just doing the basic job. Then there are more complicated versions of the story, where, in some cases, the Higgs comes as part of a bigger physics story that leads the way to what’s generally called Beyond the Standard Model Physics. As the machine searches toward higher and higher energy that probes higher and higher mass, the simplest possibilities will begin to fall by the wayside pretty soon if nothing is seen. An exciting thing is that it seems that whether or not we have the Standard Model Higgs might be known soon.

Now that’s exciting enough, but there’s more. Actually, a lot of people, for various […] Click to continue reading this post →

It was a quiet and good day today on the work front, here in Aspen. I started at the Center relatively early (having risen at about 7:00am today – a bit later than I have been) and the plan was definitely a vastly-mostly-physics day, digging into some of the things I’ve been puzzling over, and having some conversations with one or two people about their projects. The first order of the day, once arriving, was to turn off my phone and go dark on IM, and turn off my email… The plan for such days is to only check messages and so forth at lunchtime, and then much later in the afternoon, which is rather helpful, I find. (In fact, I ignore the phone for the entire day until the evening…)

I won’t give you a tedious blow by blow of my day, since it was mostly a mixture of sitting and reading or staring into space (along with some scribbling here and there), and so forth. I also went for some walks, down by the Aspen Institute (where there’s currently the interesting “Brainstorm Tech” conference sponsored by Fortune magazine going on) and of course over to the Music tent, where there were lots of people in the morning, since the Music Festival orchestra (and a lot of very young pianists – maybe from the piano competition? – taking turns) were rehearsing for tonight’s concert. I sent an email or two, I’ll admit, but they were specifically concerning a project I’m working on with a colleague back in LA, and so they count as ok.

I went for a walk to think and eventually returned to the tent after one or two […] Click to continue reading this post →