Recent content by Kazza_765

I'm not using a Bayesian formulation (at least I don't think I am). The least-squares fitting is using the Levenberg-Marquardt method. I should have said the covariance matrix rather than the Hessian (although, if I recall correctly, one is the inverse of the other divided by two?). I...

Hi all, I have a question regarding least-squares, and I'm certain I can't be the first one to encounter it, but I've had no luck searching the literature for a solution. Here it is: Say we have a non-linear least-squares optimisation problem. We have data points y_i and a model y(x_i;{\bf...

Terrific, thankyou very much. Off to the library now. (I reckon it's always better to have someone recommend a good book than just typing "statistical physics" in the catalogue.)

Basically I have an (infinite) population of isolated atoms with a bunch of discrete energy levels available to them. I want to work out what the expected population of each of the states is at a given temperature. They're complex atoms (transition metals) and spin-orbit coupling combined...

Hi all, I've just taken my first postgraduate "Managerial Economics" class (aimed at people who haven't studied economics before), and my lecturer has thrown me a curve ball with the concept of opportunity cost. Either my memory's not as good as it used to be, or his isn't. Anyway, he gave an...

You may also find helpful the chapters written by Grant in the book, Methods in Computational Chemistry, Volume 2, Relativistic Effects in Atoms and Molecules.

Yeah, I think I misunderstood what you were saying, but I'll still defer to someone with a better knowledge of GR to say whether or not this would work.

I have to defer to someone with a better understanding of GR to refute that, but since it would essentially be a free energy device I'm quite certain it wouldn't work that simply.

I'm not sure I understand you properly, do you mean like a donkey chasing a carrot? http://www.christian-education.org/images/donkey.gif Remember Newton's 3rd law. There will be an equal and opposite force on the source of the mass, tending to push it towards your spaceship. If you wish to...

For the sake of completeness, in case anyone needs a reference in the future, I found that the following book is an absolutely must have for any relativistic atomic structure calculations, and also provides the most thorough coverage of Dirac-Hartree-Fock theory. Relativistic Quantum Theory of...

Could you though? I would think you would only be able to calculate the moment of inertia, not the actual mass. You could attach it to a spring with a known spring constant and use simple harmonic motion.

This has been bugging me for a while, but feel to tell me if it's a nonsensical or silly question.. Suppose there were 4 spatial dimensions instead of 3. How would we go about constructing the Pauli matrices? Assuming each matrix still only has 2 eigenvectors, we require 4, 2x2 mutually...

I'll be using the Grasp2K relativistic atomic structure package this year, and I'm trying to find some good sources of information on the Hartree-Fock method. I'm having trouble getting my head around some of the finer points, so I figure the best thing to do is get my hands on as many sources...

I know three people that had them and then had to get new ones (they were popular here when they first came out), except most of their problems were due to the phones being too fragile. One friend had it in her purse one day, came home, took it out and it was in two pieces. Another had it in his...

Lol. Its funnier the way I first heard it. What has two legs and bleeds?