The greens-functions tag has no wiki summary.
8
votes
1answer
145 views
Correlated three-particle Green Function
I know the relationship between normal and correlated two-particle Green Functions for fermions:
$$G_c(1,2,3,4)=\Gamma(1,2,3,4)=G(1,2,3,4)+G(1,3)G(2,4)-G(1,4)G(2,3)$$
Also known as irreducible ...
2
votes
0answers
57 views
spectral functions
Please, I would like to understand why you call the function $A(k,\omega)$ (here :The Spectral Function in Many-Body Physics and its Relation to Quasiparticles ) a spectral function? For me, as a ...
2
votes
2answers
276 views
Greens function in EM with boundary conditions confusion
So I thought I was understanding Green's functions, but now I am unsure. I'll start by explaining (briefly) what I think I know then ask the question.
Background
Greens are a way of solving ...
3
votes
1answer
220 views
Deriving the reduced Green's functions in Polchinski's volume 1
In equation 6.2.7, Polchinski defines his reduced Green's functions $G'$ on the 2-manifold to satisfy the equation,
$$ \frac{-1}{2\pi \alpha '}\nabla ^2 G'(\sigma_1, \sigma_2) = ...
4
votes
1answer
189 views
Boundary conditions of relativistic wave solutions?
If you take Einstein's field equations,
\begin{equation}
R_{\mu\nu}-\tfrac{1}{2}g_{\mu\nu}R = -\kappa T_{\mu\nu},
\end{equation}
and you insert the metric
\begin{equation}
g_{\mu\nu} = \eta_{\mu\nu} ...
1
vote
1answer
38 views
Trouble following the Saclay method (spectral representation of thermal Green functions)
Note: I just answered my own mathematical question by writing it up, but I thought I'd share it anyway in case someone else has a similar difficulty. :) I'm still left with my real physical question: ...
5
votes
1answer
248 views
Analytic continuation of imaginary time Greens function in the time domain
Consider the imaginary time Greens function of a fermion field $\Psi(x,τ)$ at zero temperature
$$ G^τ = -\langle \theta(τ)\Psi(x,τ)\Psi^\dagger(0,0) - \theta(-τ)\Psi^\dagger(0,0)\Psi(x,τ) \rangle $$
...
6
votes
2answers
536 views
Sources to learn about Greens functions
For a physics major, what are the best books/references on Greens functions for self-studying?
My mathematical background is on the level of Mathematical Methods in the physical sciences by Mary ...
9
votes
1answer
274 views
Boundary conditions / uniqueness of the propagators / Green's functions
My question(s) concern the interpretation and uniqueness of the propagators / Green's functions for both classical and quantum fields.
It is well known that the Green's function for the Laplace ...
2
votes
2answers
250 views
Correlation functions in thermal field theory etc
Suppose I am studying a field theory at finite temperature or some black hole formation scenario from boundary theory perspective in the sense of AdS/CFT. How is it possible to gain information about ...
