Recent content by koroljov

Thank you all for your replies. I'll look further into it.

Homework Statement I understand, mathematically, that the translation operator (both for infinitesimal and finite translations) can be written as a function of the momentum operator. It is said then that momentum "generates" translation. Similiary, the rotation operator can be written as a...

Hmmm. The solution, which is well-known by now, so it doesn't matter anymore anyway, is to demand that the vector potential becomes zero at r=infinity. (hence it becomes zero at r=b). There are other possibilites that will yield the correct solution too.

I found the answer. Thanks anyway.

Homework Statement I have to find the magnetic vector potential in a round coaxial cable. The internal conductor has a finite (known) conductivity. The external conductor is a perfect electrical conductor. Both the radius of the internal and the external conductors are known. I have to assume...

This question is likely a stupid question, or based on some trivial misconception, but I can't find where the error is. Imagine a hydrogen atom. An electron is sitting nicely in its orbital. I measure its quantum numbers to know in which orbital it is. It will remain there for now, since the...

Yes, I see, you are correct. How dumb of me to not see that. Purely out of curiosity: Is it even possible to do this in spherical coordinates directly? I mean, using the correct derivatives when "squaring" the components will give me another vector operator, but the end result (L^2) is an...

Substitute u = ln(n), then substitute 1+u = v^3, and you simply have the integral of 3 dv

Thanks for your response. I can't say I completely understand it though. In Quantum mechanics, as it is being taught to me, we never used classical Hamiltonian mechanics (except for the hamiltonian in the Schrödinger equation). Rather, we converted from classical mechanics to quantum mechanice...

Well L = - i * h * (r x nabla) = - i * h * ( u_phi * d/theta - u_theta/sin(theta) * d/dphi ) where h=hbar, nabla=grad operator, u_phi and u_theta=phi and theta unit vectors, x = vector product. Substituting cartesian values u_theta = (cos(theta)*cos(phi), cos(theta)*sin(phi)...

Hi I am trying to calculate L^2 in spherical coordinates. L^2 is the square of L, the angular momentum operator. I know L in spherical coordinates. This L in spherical coordinates has only 2 components : one in the direction of the theta unit vector and one in the direction of the phi unit...

You're right, but the change of momentum is known if the electrical field used to accelerate it is known. I know. Hmmm. That must be it. I should have thought of that. Thank you for this information.

Consider the double-slit experiment with electrons. It is so, that observing trough which split the electron goes will destroy the interference pattern. This can be seen in a thought experiment in which one adds a light source near the splits. One can calculate that as soon as the...

I have managed to solve the problem. More calculations convinced me that the sum is, in fact, zero.

I was trying to solve an exercise. We are given an AC circuit (see attachment). We had to find the current trough the resistor, the inductor and the capacitor. This can be solved using the impedance: The voltage by the source is sinusoidal: V=V0*sin(w*t)=(complex) V0*exp(j*w*t) The total...