Recent content by jeppetrost

"Which we can then deduce that n is divisible by 4 since 2n=4*r=2(4*r)" I'm not sure where you're going here, or if you miss typed. You want to deduce something about n^2, right?

I knew because I did it. I want you to be in on this with me. We want to show that if n^2 is even, then it is a multiple of 4. I'm just looking for possibilities, basically. So we look to see, if we can say anything about n if n^2 is even. Turns out we can. There are two possibilities, right...

Exactly. You want to show that n^2 is even iff (if and only if) n is even. With that done, you're almost there.

"can I assume that if n is not divisible by 4 then it must be odd?" no. take 2 for example. You need to think just a step more. If n^2 is even, then what is n - even, odd or both? -- Does that help you? (hint: it does)

I'm curious if this is an exercise in proofs by contradiction or if you're simply making matters much harder for yourself.

Wait, wick rotations and legendre transform are two entirely different things. And the hamiltonian is actually the lagrangian of the field (for appropriate metrics and some stuff). I'm not sure I get your point.

I think you've miss typed somewhere. Your sum only has a q, not a p.

What is first and last isn't really the point, I think. In fact, in most calculations, time is taken as the zeroth dimension. But this is purely by convention and not at all important. I guess my point is, you shouldn't understand it as "first time, then one spatial dimension, then another...

Well, a simple pendulum only undergoes (approximate) SHO under certain condition, do you know which? And by non-harmonic, I think you're simply supposed to show a pendulum -not- under SHO. Ie, you have to break the conditions you just thought of.

You can only have photoelectric effect if the electron is already in some potential. Say your electron is in some metal and you shine light on it to make it jump off - this is photoelectric effect. Compton scattering is scattering photons off free electrons.

Comparing this with classical terminology can be a bit confusing. Elastic scattering is when the initial and final states are identical. This means the kinetic energy is conserved. (Photons have kinetic energy. In fact, they have only kinetic energy. Take this question to the SR/GR forum if...

This is hard to answer. Mainly because no one really has any clue at all. In the cozy confines of the standard model of particle physics, nothing is 'smaller' than the elementary particles. They aren't made of anything. In exactly the same way, light (being treated as a particle, as you may or...

I don't think so, Halls. I think he just mis-wrote the first integral. It's supposed to be erf(t) not erf(6). Just look at his later calculations. Anyway, what Halls said is basically what I meant. 'Closed form' means that you can write the integral in terms of elementary functions.

Okay, so the point is you can't put that integral into closed form. Just leave it as it is. What you _can_ do is differentiate is. So what you want to do is simply differentiate your possible solution and put that back into the original differential equation.

.. What is this.. Aaah, that's a physicist's answer!