Recent content by itler

Hi, that's also an interesting aspect, yes. But wouldn't it - at least theoretically - also be possible to really increase the number of electrons in total? Maybe by putting the semiconducting sphere close to a strong corona discharge "blowing" electrons onto it? These additional electrons...

Conductivity of a semiconductor charged with "externally added" electrons Hi, how does it influence the conductivity of a semiconducting sphere (I take a sphere as it should make some considerations easier than for a cylindrical wire) if I add external charges to it? Don't know how this...

Yes, your interpretation - assuming k-space picture at small cells - is what I expected. But I think it is not easy to put this into a consistent mathematical form? I tried to interpred it along the same way as you do in accoustics when going from Fourier transform to "windowed Fourier...

Hi, can anybody rigurously explain the relationship between the band diagram in k-space (I think I understand this one) and the diagram in real space (as is often used to explain the p-n-junction).

Of course, sorry, I forgot... Hm, but the domain of f is not simply R^n, but the set of functions on R^n? So this is an infinitely dimensional vector space with all its complications like - What´s meant by "eukidean norm" here (probably ||g|| = sqrt(integral(g^2))) - Norms on infinite...

Hi, I have a general question about variational calculus (VC). I know the standard derivation of Euler-Lagrange equations and I´m able to use them. Nevertheless I think what I generally read cannot be the whole truth. Generally if f:M->R (M: arbitrary topological space, R: real numbers)...

I found an article, <http://www.phy.bme.hu/~van/Publ/VanNyi99a.pdf>, which states: "...A strict mathematical theorem tells us the condition of the existence of a variational principle for a given differential (or almost any kind of) equation (see for example in [?, ?])..."...

Why isn´t it as simple as taking for the general PDE F(x,y,z,f_x,f_y,f_z,f_xy,...) = 0 the functional G(F) := Integral(F^2(f)) This is =0 for the solution f of the PDE, >=0 for all other functions (not solving the PDE) and if there were some notion of continuity this could be...