Recent content by blue2script

I guess this is what you search for: http://reference.wolfram.com/mathematica/tutorial/ConstrainedOptimizationLinearProgramming.html Take a look at the paragraph Application Examples of Linear Programming Cheers blue2script

Simultaneous "eigenspace" of non-commuting matrices Hello! I have been working on the following "brain teaser" the whole day long without any success. I am not even sure there is a "clean" solution. I would love to hear your opinion. Before presenting the whole problem, here is an easy...

I have a problem concerning a one-dimensional random walk in potentials. Assume a one-dimensional space [0,1] and a probability distribution p(x). At every point x we have a probability p(x) to go left and 1-p(x) to go right. Assume some smooth distribution of p(x) with boundaries p(0) = 0 and...

Hey sufive, ufff... this is more than two years away and I am not working in this stuff any more. I don't think I got the answer at the time I wrote all this. Now, after two more years of studying, I think its just a matter of complex integration. What you do is you shift m slightly in the...

Hmm.. right. But then, what is the physical interpretation of the product above? And what is the probability density of a fermion field?

Hey all! Just a very short question: May I interpret the Lorenz invariant quantity \bar\psi\psi as being the probability density of a fermion field? Thanks! Blue2script

Hi all! I only have a short question concerning nuclear magnetic resonance: the basic principle is that we apply an external magnetic field, the protons (the core of H^1) is split into two energy levels (depending on the alignment of its spin) and we can apply an external high-frequency pulse...

Maybe I can render the question more precisely: Given a proton in an outer magnetic field I get two energy levels depending on the direction of spin. I can plug the outer field into the Lagrangian. After determing the feynman rules I should be prepared to calculate the decay rate of a proton in...

Hey all, I am just wondering if one can directly calculate the Einstein coefficient in spontaneous emission of, say, two-level atoms through feynman diagrams? I searched for sources in google but could not find anything. Thanks a lot for an answer! Wit best regards, blue2script

Ok, but that depends on if you count the fermion number of antiparticles with a plus or a minus? Anyway, what about the velocity-dependence? Thank you! Blue2script

Hi all! Just a short question I am wondering about. Take a bound state with some valence and sea level. The momentum distribution of the valence quarks and antiquarks has a very direct interpretation. But what about the fermion density? Say the fermion number of the valence quarks is 4 and for...

Hi humanino, thanks for these data sets, they are a good point to start with! The problem is: I want to compare the sea and valence quark distributions of the proton with theoretical calculations in the 1+1 dimensional Gross-Neveu model. In this model I can calculate these two distributions for...

Dear all, I want to calculate the following integral \int_{-\infty}^0 dk \frac{k\left(\frac{k^2-m^2}{k}\cos\frac{2(x M - k)c_0}{m y} + m\sin\frac{2(x M - k)c_0}{m y} + \frac{k^2+m^2}{2k}\right)}{\sinh^2\frac{(x M - k)\pi}{2my}((k^2 - m^2)^2 + 4 k^2 m^2 y^2)} in the limit y\to 1 to...

Dear all! I am currently searching for experimental data on the sea and valence quark distribution of the proton together with the gluon distribution. You find plenty of F^p_2(x) structure functions but no consideration on how it splits in terms of sea and valence quarks. A big thanks for...

Ok, forget it again, think I got it. It is just the momentum density divided by the fermion density. Anyway, thanks for reading!