Recent content by QuantumRose

This clears my mind, thank you

Thank you!

That's the thing that bothers me a lot. What is the physical reality that corresponds to no solution? does that mean no current anywhere or what?

Well, I think there are two cases, one is for the upper bound I solved(corresponds to the top drum flying up); the other case is for the lower bound(it corresponds to the situation when the top drum is falling down, i.e. N_1 and N_2 are not enough to support the top drum.)

I just fixed that, now it should be fine.

Problem: https://drive.google.com/open?id=19PDuyshgP6u4U9mXU3BfrF031J8wL12B Attempt: I tried to solve the range by listing out the Newton's 2nd laws of each drum https://drive.google.com/open?id=1Eslg2Wy3orG41eywwm_O6qN4OQ3QN-bA and from the equations of the drum 2, I get...

Opps, such a silly mistake... thank you!

The question: Show that the Lorentz condition ∂µAµ =0 is expressed as d∗ A =0. Where A is the four-potential and * is the Hodge star, d is the exterior differentiation. In four-dimensional space, we know that the Hodge star of one-forms are the followings. 3. My attempt Since the four...

That helps me a lot! Thanks! Indeed, my calculations are wrong after (3). And I also forgot that ##\nabla'## only acts on x' !

Here is the question: By using the equality (for boson) ---------------------------------------- (1) Prove that Background: Currently I'm learning things about second quantization in the book "Advanced Quantum Mechanics"(Franz Schwabl). Given the creation and annihilation operators(), define...