Hello here,
I am currently working on the topic of inflation.
It seems that at the stage of inflation, the universe can be described as a de Sitter space. In such a space, all spacetime diffeomorphisms are preserved. (That is something I don't really understand but I keep reading that so I...
Hello everyone,
I am a student in particle physics and cosmology in some Belgian university. I'll finish my master degree in June of this year.
I am searching for PhD studentships in Europa or US, but it is very difficult to get a place somewhere. I applied to some universities, I'm still...
Hello everyone :)
The CMB is polarized. I read in Dodelson's book "Modern Cosmology" that we can expect a signal of polarization weaker than the signal of temperature.
Is it only because the Stokes parameters obey $$I^2 = Q^2 + U^2 $$ (I drop V because Thomson scatering can't create V...
Hello everybody, (sorry for the eventual Engrish)
I can't find any convincing answer for the following question :
Why do we always (or often) plot the CMB power spectrum in this way :
jb.man.ac.uk/research/cosmos/vsa/images/CMB_power_spectrum.gif
I mean the y-axis is $$C_\ell \ell...
Thanks very much for your answer.
In fact, the matrix that I give is unitary as you said.
But this is not EXACTLY the matrix as in the paper of Kobayashi and Maskawa ;
The V_3,3 term have been corrected. In the paper they write a sin(θ3) term in place of a cos(θ3) term.
Thank you ! :smile:
Hello everyone,
I'm studying some lectures on electroweak interactions and I was reading the paper from Kobayashi and Maskawa, particulary the matrix :
But these matrix have to be unitary... And my professor said that it was not the case. When I compute the product of this matrix and...
Hello everyone,
When we speak about the SU(2)L group (in electroweak interactions for example), about what group do we talk ? What is the difference with the SU(2) group ? And with the SU(2)R ? Why is the label so important ?
I ask this because I see that a Lagrangien can be invariant...
Hello QuArK,
Thanks for your answer. The pdf link is interesting.
But I'm searching a more physical and intuitive answer... Why a higher opacity implies a lower effective temperature ?
Edit : I think I have got it !
http://www2.astro.psu.edu/users/rbc/a534/lec18.pdf
On the third page.
Thanks...
Hey everyone,
This is my first post on this forum. Please tell me if I do some mistake. :)
So, there is my question ; I have search a long time on the web but I don't find any answer...
Why the metallicity influences the effective temperature and the luminosity of a star ?
I read...