Recent content by ehj

But isn't it possible to tune the repetition rate to an external signal? This is the greatest concern at the moment. In the storage ring the particles are bunched up, and the bunches pass a point at a certain rate (40 Mhz in our case). The laser pulse must hit these bunches and even if they...

Thank you for the response. I havn't checked some of those websites yet. The wavelength does not matter that much , anywhere between IR and UV would work. I must however be able to focus it to the diffraction limit (or close). Is this difficult with fs pulses? You say that the wavelength is...

I am in dire need of some information on pulsed lasers. I'm not quite sure if this is the correct forum for this kind of question but here goes. I would like to know if you can buy a commercial pulsed laser system that can deliver a repetition rate of 40Mhz and 20 fs pulse duration while being...

I have read several places that for a simple Higgs triplet model we can have either Y=0, +/- 2 This part I understand, because we have the relation Q=T3+Y/2 and any other Y values would therefore not allow for an electrically neutral Higgs. But what I don't understand is the claim that Y=+/- 2...

I havn't had much classes on numerical methods in quantum mechanics and I'm wondering how one would solve a general problem involving 2d motion. With general, I mean a problem that cannot be separated. Consider for instance the hamiltonian \hat{H} =...

I figured it out. Posting solution in case sombody might run into the same problem in the future :P I assume 2^(1/3) + 2^(1/2) = a , where a is rational => 2=(a-2^(1/2))^3 <=> 2 = (a^3 + 6a) + sqrt(2)(-3a^2 -2) Which is a contradiction since sqrt(2)(-3a^2 -2) is an irrational multiplied by a...

Thats not a proof? And besides, doesn't 1 - sqrt(2) and 1 + sqrt(2) both have infinately many decimals, nevertheless their sum is rational, 2.

How do you show that the cubic root of two + the square root of two is irrational? I can easily show that each of these numbers is irrational, but not the sum :/.

I thought this was obvious from context :) but when I say experience I mean in a spacetime-sort of way, I just don't know what word to use. When I say experience an event, I mean coordinatesystem-experience or let's say that a specific (one) plane of simultaneity represents the present, when I...

This question arose when I read the Rietdijk-Putnam argument or "Andromeda paradox". Let's arrange two inertial frames of referance like usually, S being considered stationary (could be you sitting in a chair) and one that moves with a relative velocity v with respect to S, S' (a guy walking...

Maybe you can even say v^2=b and v>=0 <=> v=sqrt(b) where >= means bigger than or equal to ?

So you say that saying "v is positive" is like adding a condition like v^2=b and v>0 => v=sqrt(b)

"I did not and would not say "v2= b <=> v= sqrt(b)"." I know, I didn't say you did. I completely agree with your latest post, but I don't see it's relevance? I never mentioned "and" in any of the math? The only problem I have now is that you said that v^2=b => v=sqrt(b) It gives rise to a...

But you said earlier: "(B=-sqrt(A) or B=sqrt(A)) <=> A=B^2" is correct." The statement "sqrt(A)=B => (B=-sqrt(A) or B=sqrt(A))" is also a correct statement" Which gives you that sqrt(A)=B => A=B^2 If that is rearranged and B replaced with v and A with b you get: v=sqrt(b) => v^2=b which is...

So if I have an expression, for instance a speed squared equals something, but I'm only interested in writing the positive solution, it would only be mathematically correct to write: v^2 = b <= v=sqrt(b) Right?