Recent content by kuecken

I was wondering about the following Λ=I+iT T are the generators and Λ a continuous LT transformation, thus it is real. Therefore T needs to be imaginary. And we can find two sets one being the generators for SO(3) J_i and the other for boosts K_i, which are both imaginary. Now I am wondering...

sorry i meant U(2) from the title!

Hi, For SU(2) I can have that all Noether charges commute with one of the charges as one of the generators of the Lie algebra is the identity. Can somebody explain me how this is related to the properties of SU(2)? Charges can be considered to be generators of the transformation. So if this...

Hi, I am looking for an introduction to heat capacity measurements at low temperature (10K). (For example for producing the linear dependence of the electronic heat capacity on T). I fail to find a simple introduction. Can anyone mention keypoints or a good source? Thank you!

Why are exited states of an Isotope metastable? Is it because they have a large spin and therefore the final states they decay to have to be excited as well? And therefore they have less energy gain? I am thinking about 116 In (the 1+ and 5+ state) both can undergo a β- decay. Thank you!

I was not thinking about a specific one. The link actually helps a lot thanks.

Hello, I need some help understanding the possible decays of buttomonium b\bar{b}. If I consider weak and electromagnetic interaction I could get final quark-anti-quark pairs, by simply annihilating b\bar{b}, or lepton-anti-lepton pairs (the neutral ones only with Zo resonance). So why are...

Hi, I have problems with the following: Number of modes for a 2d crystal with one atom per primittive unit cell. 1. Number of discrete vibrational modes? Should there be 2N of them? That is what I come up with if I think of one transverse and one longitudinal mode for each k. But I am...

Hi, I was just trying to draw a Feynman diagram for ψ' to χ_{c} states. So we have a electromagnetic transition. I feel tempted to just have c and \bar{c} coming in and letting a γ leave from one of the legs. But that looks like an incomplete Feynman diagram to me. Maybe I have to get two...

This is the expression I arrived at. However, can I argue that the g_{\gamma\beta} in front of ∇ is arbitrary? Or how do I do that last step

∇_{\mu}g_{\alpha\beta}=0 is the metricity equation (∇ the covariant derivative). However, I wondered whether also ∇_{\mu}g^{\alpha\beta}=0 holds? When I checked it, it did not. But I really want it to hold, so I was wondering whether I made a mistake. Thank you.

Why does the quantum defect depend only weakly on the principal quantum number n? The dependence on l is strong. Because this will change the probability distribution of the electron to be closer to the nucleus and thus the shielding of the other electrons a lot. A change in n, however...

Hi, assuming I have the potential for a diatomic molecule in the groundstate i=o and excited state i=1 V_i( r ) = D( 1 − exp[ −β ( r − r_i)] )^2+ C_i Using collisional excitation with fast electrons. What is the vibrational quantum number of the state the molecule will most likely be...

Magnetization-polarization tensor I found it now

oh really? I was looking for sth like this. that's good thank you!