Hi everyone,
apologies if this question has been asked already. My search didn't give any results.
Can anyone tell me the definition of \sigma_8 in terms of the power spectrum? A reference where I could find it is perfect too!
Thanks a lot
Hello everyone,
I am not an expert in the topic so I apologize in advance if the question has an easy answer. I think it is well known that if we have a set of N vortices in a superfluid their mutual interaction is logarithmic. Meaning that if \vec x_n is the position of the n-th vortex, then...
Hello everyone,
I was wondering if anyone knows what the completeness relation for the fundamental representation of SO(N) is.
For example, in the SU(N) we know that, if T^a_{ij} are the generators of the fundamental representation then we have the following relation
$$...
Hello everyone,
I have been reading around that when performing the analytic continuation to Euclidean space (t\to-i\tau) one also has to continue the gauge field (A_t\to iA_4) in order to keep the gauge group compact.
I already knew that the gauge field had to be continued as well but I didn't...
Thanks for your reply. I indeed checked that for an action of the kind:
$$
S=-\int d^4x\left(-(\partial_t+i\mu)\Phi^*(\partial_t-i\mu)\Phi +\vec\nabla\Phi^*\cdot\vec\nabla\Phi+m^2|\Phi|^2\right)
$$
the 2-pt function in the Euculidean and Minkowskian case are related by an analytic continuation...
Thanks a lot for the quick answer! My question however, goes beyond lattice simulations. I don't have any lattice and everything is continuous. The questions is: is it still true that:
$$
\langle O_1O_2\rangle (\tilde\omega,\vec k)\longrightarrow\langle T(O_1O_2)\rangle(\omega,\vec k)
$$
when...
Hello everyone,
my question is about Euclidean correlators (say a 2-pt function to be specific) in presence of non-zero chemical potential.
The question in particular is: is it still true that the Minkowski time ordered 2-pt function can be simply obtained from the Euclidean one by analytic...
Hello everyone,
I would like to know if there is a known, rigorous way to regularize a Green's function in coordinate space. In particular, it is known that the Green's function for a circle of radius R and source located at \vec x_0 is given by:
$$
G(\vec x,\vec...
Hello everyone,
I know this is a very basic question but I was wondering, in the context of inflation, what does it mean to have gaussian or non-gaussian fluctuations.
First of all, are we talking about the fluctuations of the inflation?
Second of all, how is the nature of the fluctuations...