Recent content by Azelketh

The knowledge of which neutron spin is in a particular state reduces the transition rate by 1/2 according to Dickes argument, but he claims that it increases the transition rate with respect to that of a single lone neutron. This can only be valid if the transition rate for a single neutron is...

Thank you for your reply. This is starting to make much more sense now. So for the first neutron in an excited state, with the second in the ground state, you have the state as you suggested: $$| \uparrow \downarrow \rangle = \frac{1}{\sqrt{2}} ( | \uparrow \downarrow \rangle - | \downarrow...

I'm not sure but I suppose it means that the N dipoles are all interacting with the field while in phase with each other. I don't know about the Dicke model, as I'm struggling to understand Dickes papers, but for a system interacting with field : E=A cos(kx-ωt) Assume that the wavelength of E...

Hi, I am trying to understand what keeps getting referred to as "super radiance". So this has led me to R. H. Dickes 1954 paper "Coherence in spontaneous radiation processes". http://dx.doi.org/10.1103/PhysRev.93.99 . On the first page Dicke presents a "simple example", that is not simple at...

This difference between being a student and a researcher does seem to be key. I would go so far as to say that I never deeply understood any of the material I studied as an undergrad. Thanks for your replies. It seems that I'm not alone in my confusion.

hmm I might have to do that. It is just incredibly frustrating though, when after so much time reading a paper if asked to explain what it is about I can pretty much only say "they measured some stuff *shrug*" end of my understanding.

Well the biggest contributor to the time per paper is trying to understand the papers. I can 'read' a paper in 10 minutes no problem, I'll just have absolutely no idea what any of it meant. I think that mostly its my lack of familiarity with the physics. I am looking at papers to do with...

Hi I thought that physics forums could be the place to ask you guys (others who are currently in or have already completed PhD programs) some questions. I've recently started a PhD program in physics in the UK, and my general state of being is complete and utter confusion. In my attempt...

ahh finally solved it, using \int \partial^3 x e^{i(p+r).x} = (2\pi)^3 \delta^3(p+r) and working through. Thanks for the assitance TSny!

ah, I think its \psi and \psi^* that have the incorrect signs. Will edit through all above to correct this. Bloody sign errors, when will they end!

Ok, I see how you can change the order of the integration, and changing one of the P's to r to make it clearer to me, to get : Q=\frac{-1}{(2\pi)^6} \int \partial ^3 x [ \int \partial^3 P \frac{1}{\sqrt{2 ω_p}}( a_p e^{ip.x } + b_p^* e^{-ip.x}) \int \partial^3 r \sqrt{ \frac{ω_r}{2}}(...

Homework Statement Hi I a attempting to derive the expression for the conserved Noether charge for a free complex scalar field. The question I have to complete is: " show, by using the mode expansions for the free complex scalar field, that the conserved Noether charge (corresponding to complex...

I see how I've gone wrong on the last few lines. Thanks for your help vanadium 50 , jfy4 and dextercioby!

My apologies for a less than comprehensive post at first; Well, usually in the vector form of E and B or the 4 vector A, where; A= ( \phi, \vec{A} ) where \vec{A} is the magnetic vector \phi is the scalar electric potential. E = -∇\phi - \frac{\partial\vec{A}}{\partial t} And, B= ∇ X...

Hi, I've been trying to solve problem 2.1 a in Peskin and schroeder, an introduction to QFT. The problem is to derive Maxwells equations for free space, which I have almost managed to do, using the Euler- lagrange euqation And the definition of the field tensor as F_{μv} = d_μ A_v - d_v A_μ...