Recent content by QuantumDuality

According to this this the Darboux transformation preserves the discrete spectrum of the Haniltonian in quantum mechanics. Is there a proof for this? My best guess is that it has to do with the fact that $$Q^{\pm}$$ are ladder operators but I'm not sure.

If it is the asymptotic behavior of the Airy's function what it's used instead of the function itself: Does it mean that the wkb method is only valid for potentials where the regions where ##E<V## and ##E>V## are "wide"?

Homework Statement A disc of radius R rolls without slipping along the parabola y= ax2. Obtain the constrain equation Homework Equations Because there's no slipping, then: ##R d \theta = ds (1)## Where ##\theta ## is the angle between the line from the center of the disc to a fixed point...

I understand that in a system composed of two articles, the total angular momentum is: J = J1 + J2 From the operators: J^2, Jz, J1z, J2z，J^21z，J^22z, I get two possible sets of operators that commute: {J^2, Jz, J^21z, J^22z} and {J^21z, J^22z, J1z, J2z} What I don't understand is why the...

Homework Statement In a configuration having axial symmetry about the z axis, a line current I flows in the −z direction along the z axis. This current is returned at the radii a and b, where there are uniform surface current densities Kza and Kzb , respectively. The current density is zero in...

In the lecture notes http://top.electricalandcomputerengineering.dal.ca/PDFs/Web%20Page%20PDFs/ECED6400%20Lecture%20Notes.pdf at page 15 eq. (2.46) it says that the dielectric tensor in an isotropic media can be represented by: δi j A(k,ω) + ki kj B(k,ω) I understood that in the case of I. M...

I got it!. I always forget to use the product rule, Thanks

I know there's a similar post, but i didn't understand it. Why the derivative respect to t in terms of the complex conjugate of ψ is: instead of being the original S.E in terms of ψ* or the equation in terms of ψ with the signs swapped

but if we have for example: f(x) = x³ y = x² then f(y) = (x²)³ = x⁶ dy/dx = 2x dy = 2x dx using the equation you suggest: ∫f(x)dx=∫f(y)dy ∫x³ dx=∫2x⁷ dx i'm missing something?

the first step of the Plancherel's Theorem proof found in: http://mathworld.wolfram.com/PlancherelsTheorem.html, says: let be a function that is sufficiently smooth and that decays sufficiently quickly near infinity so that its integrals exist. Further, let and be FT pairs so that...

I'm a Telematics engineer (yes, an umpa lumpa of science) from Mexico. I signed up in this forum because i want to take a masters related to quantum computing, so I'm actually studying quantum physics.