Question Statement
Polyacetylene can be modeled naively as a one dimensional chain of carbon atoms each separated by a lattice constant 'a'. Taking the electrons in such a system to be nearly free and applying a weak periodic perturbation we can derive a dispersion relation giving a curve...
I've been doing some Cosmology, but I'm having a really hard time understanding the results for the age of the Universe intuitively. For example I can work out from the FRW equation that in the case of no Cosmological constant and no radiation in a flat matter dominated universe the age is...
Question statement: We are given that Ca and CaF2 are both Ca face-centred cubic lattices, and that in the case of CaF2 there is a basis of F ions at +/-(1/4, 1/4, 1/4). Then explain qualitatively how the ratio of the (2 0 0) and (4 0 0) Bragg peak intensities in the X-ray diffraction patterns...
I'm looking at charmonium and its decays. Given a list of data on the charmonium states I'm asked to say why ψ'' has a leptonic branching ratio a thousand times small than ψ' and J/ψ.
From my understanding this is due to OZI suppression. But I'm having a hard time understanding it...
Problem statement:
The Bragg angles of a certain reflection from copper is 47.75◦ at 20◦C but is 46.60◦ at 1000◦C.
What is the coefficient of linear expansion of copper? (Note: the Bragg angle θ is half of the
measured diffraction (deflection) angle 2θ).
Attempt at solution:
Using...
Hi,
I've found geodesic equations for the metric:
\begin{equation}
ds^{2} = -c^{2} \alpha dt^{2} + \frac{1}{ \alpha } dr^{2} + d \omega ^{2}
\end{equation}
where
\begin{equation}
\alpha = 1 - \frac{r^{2}}{r_{s}^{2}}
\end{equation}
I have found that for a light ray:
\begin{equation}...
I'm trying to derive Saha's equation, and I've come up against this definite integral, which I can't seem to find anywhere and may not even be doable; I'm not sure.
\begin{equation}
\int\limits_0^\infty \frac{x^{2}}{e^{x}+1}dx
\end{equation}
Can anyone help? Thanks!
I'm learning about 2D inviscid irrotational flows of constant density. In the example of flow past a cylinder there is the sentence "since the flow is irrotational as r tends to infinity, it is irrotational everywhere" and I can't get my hear around that.
Why is this the case?
Irrotational...
Homework Statement
The Hamiltonian for a rigid rotator which is confined to rotatei n the xy plane is
\begin{equation}
H=-\frac{\hbar}{2I}\frac{\delta^{2}}{\delta\phi^{2}}
\end{equation}
where the angle $\phi$ specifies the orientation of the body and $I$ is the moment of inertia...