(c) Dr Paul Kinsler. [Acknowledgements & Feedback]

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Auckland 1987-1989

I had already done a BSc at University of Auckland logo University of Auckland, but since there was no undergraduate honours course available in the Physics Department, I had to either do the two year Masters degree that was the next step in physics at the University of Auckland, do something else, or go somewhere else. I thought that since I quite enjoyed physics, I'd do the MSc, which consisted of one year of course work, followed by a one year research project.

The first course was a General Relativity paper taught at a rather challenging pace by Prof Houton -- the pace was due largely to the fact that we'd had no real relativity coursework since first year, so we had to hear some second and third year level lectures before we were able to follow the graduate course we we enrolled to do. Hard work, but it turned out all right in the end.

Second was a Quantum Mechanics paper taught by Prof. Stamp, who helped teach a casual disregard for where any factors of two and hbar might be -- after all, you can always sort them out after you get some something that looks like a result. This course was in two parts, and the second part was quantum field theory. Assuming there'd be some QFT in the exam, I studied this part quite hard, and got a good handle on it -- so naturally there was no QFT in the exam at all. Subsequently I've never needed it for anything -- beyond it providing a context in which to use the other bits of physics more useful to me on a day to day level.

Then there was Solid State physics... which I remember little non-subject detail about, but the course material at least stayed in my mind long enough to be helpful when I moved into the semiconductor field some years later (see Sheffield). I also sat in on the lectures for the Particle Physics paper. Briefly I helped set up the JANZOS cosmic ray detector, built to detect those originating from supernova 1987A. All I did, though, was spend a week helping to arrange some moderately heavy objects on top of a rather cold hill; I didn't stick with the project long enough to do anything complicated, let alone any of the research component.

Finally, there was the Quantum Optics course given by Peter Drummond, whose standout feature I recall was the requirement to derive the master equation, one of those calculations which seems to have influenced the way I approach many problems, in it's step-by-step reduction of a problem into a manageable form by well specified approximations. To me, "well specified" means a combination of the mathematical simplification as well as its physical motivation. It is not always necessary to fully understand an approximation to use it, but if you can avoid conflating several approximations into one combined step, you can always go back and reonsider each step as necessary. And then, if you decide you need to remove an approximation or jest weaken it, you know exactly where to start and do not lose the value of the preceeding steps.

One thing I remember in particular was seeing a seminar on Chaos theory presented (I recall) by an ex-graduate student of Auckland. This was before Chaos was a big thing, so it was new stuff to most of the audience. So this guy gave a very enthusiastic talk, telling us how chaos theory would revolutionise physics and all that. "Oh yes", I thought, "but let's not get too carried away". Oops. Now, of course, chaos has arrived properly and become an impressive area of research in it's own right, but naturally there are still area of physics where chaos is't really that relevant.

I have a habit of going to see seminars on almost any topic at all. Once I went to one given by some atmospheric physicist, something to do with melting of microscopic ice crystals due to pollution. At one point I put my hand up and asked something along the lines of "You have used a concentration gradient of (some pollutant) on the surface of your crystals, but you also said the layer is only nanometers thick. If the layer consist on only a few molecules, how can you talk about a concentration gradient?" -- fully expecting to hear some convincing sounding reason. But, no, there wasn't one; although I'm pretty sure you could attempt a justification on some statistical basis. Still, this sort of thing is not uncommon -- a few years later I got caught out in a rather similar way.

After the course work there was the research component, a one year thesis project. I'd got a taste for quantum optics from the course, but didn't really know what would be best to do, allthough Peter Drummond had quite a long list of things. There was one which looked interesting, related to something Stephen Carter was working on already with Peter, but to me at the time it looked too hard. But I was going to see Peter about topics, and thought it would sound better if I'd picked a topic already. So I chose one from the list almost at random -- on noise induced switching in an optical cavity containing a nonlinear kerr medium. As is the way of such things, this one rather arbitary choice had a rather profound effect on what I researched for the next five or so years -- until the end of my PhD.

The topic was generated by Peter after seeing an apparently suspicious looking result published in a journal paper, so the project was basically to check the papers methods while also trying a different derivation of the same kind of result. It turned out that there was a problem with the published work -- they had transformed into a randomly moving reference frame in a bid to make the effects of noise more tractable, but such a reference frame can lead to the appearance of switching even though it was just the frame that had shifted. I developed a more general approach using van Kampen's cumulant expansion method, which allowed coloured noise as well (rather than just the idealised spiky white noise), and this made what had been done rather clearer.

I then moved onto something more quantum mechanical, studying the swiching between the two stable states of a degenerate parametric oscillator due to quantum noise. This is again a nonlinear crystal inside an optical cavity, but a second order rather than a third order process, and a two mode rather than a single mode system.

As is pretty typical of theoretical topics, there was a component which needed computer simulation of stochastic differential equations. For this I had to teach myself the basics of stochastic calculus, and then learn FORTRAN to code the simulations. I'd been familiar with BASIC for years, and had done some Pascal in CompSci, and had also done some assember coding. FORTRAN, however, seemed a nightmare -- until I discovered the IMPLICIT NONE command which stopped the compiler accepting all my typos as extra varaiables it needed to declare. I still program in FORTRAN, and one benefit of this early experiance was an inclination to follow syntax specifications exactly, and get compilers and suchlike to check syntax exacly, as in the long run it saves an enormous amount of time. Coding, whether it is HTML, FORTRAN, C, or whatever, is tricky enough, and there will inevitably be mistakes that need to be located and fixed. Allowing a computer program to guess your intent using some predefined rules only allows new types of bugs and other mistakes. Computer code, whilst extraordinarily flexible and powerful in applications, are also astonishingly rigid in its expression. You do yourself no favours by pretending that this isn't so.

By most of the way through my research year, I was getting some good results when Peter Drummond unexpectedly moved to the University of Queensland in Brisbane to take up a new job. This left me without a supervisor, so I was reassigned to Prof Dan Walls. Dan had some different ideas about what he wanted me to do, but although did I look at them; I managed instead to derive an analytical solution to the parametric oscillator switching problem I'd being doing under Peter's supervision -- where upon I never really looked at Dan's suggestions again. With the new solution I wrote up my Masters thesis, and submitted it.

But what to do next? I'd developed a taste for reseach, so looked around for suitable universities. I did the GRE general and physics tests which I needed if I was to go to the USA. As I recall, I got accepted to study at one of the University of California campuses, maybe USCD, to work with Carl Caves who was then in the Electrical Engineering department. However, they were unlikely to accept my graduate coursework and thesis as credit towards my PhD, which was a drawback. In the end I decided to work with Peter Drummond again and do my PhD at the University of Queensland, partly because it would seem less far from home, and partly because apart from the occaisional unexpected departure, working with Peter was rewarding and I could continue to persue the things I'd worked on at Auckland.

I was awarded a first class honours grade for my MSc, but by then I was already at the University of Queensland in Brisbane, Australia.

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Date=20080916 0320 16 20020106 20000223 19990121 Author=P.Kinsler Created=1999