Here I am, getting ready to pull an all-nighter studying for my grad quantum mechanics and mathematical methods in physics finals. By anyone’s standards, I shouldn’t be here. In fact, I shouldn’t be studying physics at all. Up until a year and a half ago, I had never studied physics. Ever. In addition, I had […]

In my earlier posts, I mentioned several times that axions don’t interact very much with the particles in the standard model, with the exception of photons. Awesomely enough, not only can axions decay to photons, but photons can decay to axions as well! This is called the Primakoff Effect (and Inverse Primakoff Effect): when axions […]

In cosmology, the roles that axions play are pretty complicated, but I’m going to try to do my best to explain them. 80% of the matter in the universe is made up of “dark matter”, and we don’t really have any idea what it is. A lot of cosmologists think that, along with dark energy, […]

In 1977, two physicists named Roberto Peccei and Helen Quinn came along and proposed something radical: let’s add an additional U(1) symmetry to the standard model. This wouldn’t just be any symmetry, they said – it’ll be a global symmetry that we will force to be spontaneously broken, resulting in a new gauge boson that […]

Today, the Nobel Lectures were streamed live: Englert: The BEH mechanism and its scalar boson Higgs: Evading the Goldstone theorem You can find the video here:

Clearly, this U(1)a problem that Weinberg discovered needed to be solved, and so Gerard ‘t Hooft, a brilliant Dutch physicist, looked into it, and found the solution. There was no U(1)a problem, he said, because the vacuum of QCD is so complicated that there is no true U(1) a symmetry, even though the QCD Lagrangian […]

Now we are back in 1975. Steven Weinberg, one of the greatest physicists of all time, realizes there is a big problem in the standard model, and he calls this problem “The U(1) Problem”. When you look at the equation that describes the way quantum chromodynamics acts – its Lagrangian – you find this global […]