Recent content by salparadise

Hi mfb, I'm only considering finite cylinders for the ferromagnetic cores. My intuitive guess was also that the red ferromagnetic cores would change the field distribution on the blue core, but I can't see how this can come out from Maxwell equations... So, from the equation I can only agree...

Thanks for the answers. I think that now I understand better the situation. My problem was not so much the total energy, but the fact that ferromagnetic materials also "concentrate" magnetic flux density lines, what is e.g. used for magnetic shielding. And I was imaging a hollow sphere of a...

Hello, Imagine I have an infinite wire with a DC current. Around it there two rings of ferro-magnetic material, not far from each other. Does changing the mu_r of one of the first ring, changes the magnetic field in the second ring? - If I consider just Ampére law (macroscopic...

I understand. So, the threshold energy for having hadron production in a process that has only leptons as input particles is the pion mass. This is minimum energy required for producing a new pair of quarks. mathman: I believe you're confusing strong interaction with weak interaction. It is...

Hello, I was looking at the quark masses and had this doubt regarding the muon decay: Why can't the muon decay into up and down quarks (plus neutrino). I know the explanation is because muon doesn't exhibit hadronic decays because its mass isn't big enough m_\mu=107MEV. But I just saw that...

Hope this is comprehensible, I'm posting only the relevant part of the code. This code is intended to change parameters value in a file with following structure: -------------------------------------------------------------------------------- ... Block Minpar # comment: # parameter_id...

Hello, I would like to know if in sequential access mode to a file, it is possible to overwrite a given record in the middle of the file, while keeping all the subsequent records. When I write a record in the middle of an existing file, it makes the file to terminate imediatly after the...

Hi, I'm having the same doubt here. I think that both models share in common that only two spin states are allowed for each position in the lattice. But while in the Ising model only nearest neighbours interactions are allowed, in the Heisenberg model this restriction does not apply...

Hi, My question is. Can in principle, a Lagrangian density for some theory be a pseudo-scalar. Normally people say that the Lagrangian needs to be a scalar, but it case it is a pseudo-scalar it would also be a eigaen function of the parity operator. This topic could well be on the...

I was wondering why in 3D Euclidean space, the transformation of axis inversion, which is a length preservation one, doesn't show up in the Killing vector field. Where only translations and rotations are present. My guess is that this is because, axis inversion is a discrete symmetry, and...

Hello, Anybody could please help? Thanks

Hello, I'm reposting this in the current section as I'm looking not only for help with homework assignment, but because I'm also looking for good reference textbook. I'm taking a course on group theory in physics, but the teacher is really bad at making the bridge between the maths and the...

Hi, I noticed there's an error on my post. on the 1' irrep as direct product of the 2D irreps there should be minus sign. Anybody can help with this question? Thanks

Group Theory: Most general scalar potential out of 2 doublet irreps of S3. I'm taking a course on group theory in physics, but the teacher is really bad at making the bridge between the maths and the physics. As homework I have to do the exercise below. I think I know how to do it but I'm...

Hello Mute, thanks for the help. I've managed to do it, after Taylor expansion of \sqrt{1-x}, where in my limit: x=\frac{4m^2}{s}\rightarrow 0. As I'm under some time pressure to finish this, very bigg, home exam I'm already not thinking so clearly.. Thanks again