I am a theoretical physicist from the University of Oslo.
It was during high school at Møglestu Videregående Skole in Lillesand that I decided to become a physicist. This is something I have never regretted. In the end it was an easy decision to make. I didn't consider factors such as how much money I would earn and whether it would be hard to find a job after I had graduated. I only knew that I wanted to study and work with something that was interesting to me, and to make a long story short, there's nothing more interesting than physics.
In principle there were a lot of other options. I think I'm quite lucky because I have always enjoyed the challenge of learning about new things, whatever they may be. Therefore, I could probably have gone into a variety of other subjects and been perfectly happy with my choice.
However, physics is a very special subject. Although there are different kinds of physics, its general purpose is to discover the fundamental laws describing how everything in the universe behaves. "Finding the rules of the game" is something that very much appeals to my natural curiosity, and physics deals with the most fundamental game of them all -- nature.
So, after high scool I knew what to study, but not quite where to do it. In reality there were only two real contenders. Either I would go up to Trondheim and study at what was former known as NTH (Norwegian Institute of Technology), or I would get my education at the University of Oslo.
In the end I opted for Oslo, mainly because I did not really fancy moving all the way to Trondheim, but also because in Oslo I would have more freedom in selecting which classes to take.
An added bonus was that the first year I could go to the local college (formerly known as ADH - now HiA) in Kristiansand and take all the maths classes that I needed, while at the same time taking the compulsory philosophy introduction (Examen Philosophicum) which is required of all the students.
Then in the autumn of 1991 I was off to study physics in Oslo. I enjoyed my time there tremendously. It was wonderful to spend my time studying all sorts of interesting and fascinating stuff. When you're interested in the things you're working on, it is usually much easier to learn it properly, so my studies proceeded quite smoothly.
By the end of 1992 I had finished my Cand. Mag (Bachelor) degree and started working on a thesis for my Cand. Scient (Masters) degree. My supervisor was Jon Magne Leinaas and he had suggested that I do some work related to vacuum!
To the non-physicists this might not sound terribly interesting, but it's not as crazy as it sounds. It's a common misconception that vacuum by definition means a place which is totally empty. After the laws of quantum mechanics (or rather quantum field theory) were discovered, it became clear to the physicists that such a definition didn't make any sense, because empty space could, in fact, not exist! Such a thing was not allowed by the fundamental laws of nature!
It is important to be aware that this has absolutely nothing to do with the practical problems involved in creating a vacuum. Let's say you have some kind of box and then you start trying to remove every particle from it. It turns out that this is an impossible task, as you will never succeed in emptying the box totally! This is because all the time socalled virtual particles will appear from nowhere inside the box, stay around for a very short period of time before disappearing again! No matter what you do to the box, you won't be able to stop this from happening!
This may sound like some New age nonsense, but it isn't! It's the way nature works, and it has been confirmed by an almost unlimited number of experiments! Despite this, the phenomenon is not really common knowledge, although it is obviously extremely important for our understanding of the physical world. I guess that part of the reason is that you don't really learn about it in school (at least in Norway), unless you choose physics in the last year of high school.
Most people will have learned about something called Newton's laws in school. These are apparently very important, but the way they are first introduced in Norwegian school, most people do not find them very interesting. In the first part of the 20th century, it was however discovered that these laws were incorrect. They seemed to work very well for ordinary stuff (like balls and springs etc.), but for small particles they seemed to predict crazy things, like all the ordinary stuff in the world being unstable and bound to desintegrate within less than a millisecond. This didn't seem to happen, so something was obviously wrong.
The laws of Newton were eventually replaced by the laws quantum mechanics (or quantum field theory) and relativity. The great thing about these new laws were that they seem to agree with every experiment that has been made. On the other hand, it turned out that the particles behaved in a very weird manner, including this ability for particles to just appear out of nothing.
Do you still think that these things sound crazy? You're not alone - everybody thinks it sounds completely crazy, but in physics we don't mind that our theories are crazy as long as they are correct, i.e. they agree with experiments! If that's the way nature works, then that's what we have to deal with! Nobody understands why it works that way, though! It's one of the things that makes physics so exciting and fascinating!
Anyway, let's get back to these mystical virtual particles. Where do they come from, how can they just appear and disappear, and where do they end up after disappearing? These questions appear to have no meaning, at least they are not answered by our current theories.
So, in modern physics, vacuum is no longer defined as empty, but as the lowest possible state of energy that a system can have. If you remove all particles from the box I mentioned above, there is vacuum inside, even though these virtual particles appear and disappear all the time. This is because this is the lowest possible state of energy for the box.
Now, in my thesis I looked at a slightly different situation. I examined the box above with the exception that we added a magnetic field concentrated to a very small area. The idea was to investigate whether this would influence the virtual particles.
The answer turned out to be yes. Even though the virtual particles never were inside the magnetic field, they were influenced in such a way that in total there was an electric current of virtual particles going around the magnetic field. This current was called a vacuum current.
I spent a lot of time calculating the various properties of this current, as well as the energy distribution etc. around the magnetic field. Ind the end my thesis was called " Magnetic Flux Strings and Vacuum Polarization". (Flux strings because the magnetic field I studied was a very thin string.)
I handed in my thesis in June 1994 and had my final exam in September that year.
This wasn't my last exam ever, though. After I started working at FFI I have taken classes at the university on my spare time, usually one class in the autumn semester and two classes in the spring. I don't have any particular reason for taking these classes, I just take the classes I find to be most enjoyable. I've taken classes in Physics, Mathematics and Mechanics, including all sorts of wonderful stuff like Group Theory, Statistical Mechanics, Differential Geometry, Topology, Numerical Methods, Continuum mechanics, Fluid Mechanics, Fracture Mechanics, Chaos Theory and Game Theory. This semester (spring 2001) I'm taking a class called FYS206 (Electromagnetic Waves and Applications).
Since I'm at work all day, I haven't got the opportunity to go lectures (usually), so I just work on the stuff on my spare time, maybe one or two days a week. I will continue indefinitely taking new classes at the university. When I eventually run out of interesting mathematics and physics classes, I will just move on other subjects.