Recent content by sgd37

I'd be careful here because the RHS gives \frac{\partial}{\partial x^{\mu}}\delta^4(x-y) whilst the LHS gives you \frac{\partial}{\partial y^{\mu}}\delta^4(y-x) if you set t=x-y and use the identity you gave above you can see that \frac{\partial}{\partial...

Forgive me what I should have said is you don't have to transfer the space-time derivative. You are free to do so

Use the defining equations for the center of mass R and relative position r

You don't use integration by parts to transfer the spacetime derivative onto PsiBar since \; \dfrac{\delta \psi_i(x)}{\delta \psi_j(y)} = \delta_{ij} \, \delta^{(4)}(x-y) = \dfrac{\delta \bar\psi_i(x)}{\delta \bar\psi_j(y)} you have the choice over which delta function you integrate first...

Do you mean the Hopf map http://mathworld.wolfram.com/HopfMap.html

Have you checked if (\star(e\wedge e)+\frac{1}{\gamma}e\wedge e)|_{\Sigma} obeys the so(1,3) algebra commutation relations

I think there is a sign error somewhere because all you're showing is that \partial (\psi^*\partial\psi)+\frac{ie}{\hbar c}\partial\psi A \psi is real i.e. z-z^*=2Im(z) which is not a trivial statement for complex fields

So I'm working my way through Nakahara Geometry Topology and Physics. In exercise 11.4 of section 11.5.2 I'm tasked to show...

Homework Statement Hi I need to regularize \sum_{r \in Z+1/2} r In my opinion there are two ways of going about it either re-express it as \sum_{r \in Z+1/2} r = \sum_{r =1} r - \frac{1}{2} \sum_{r =1} = \zeta (-1) - \zeta (0) = \frac{1}{6} or \sum_{r \in Z+1/2} r =...

Ok by intend I mean I am applying for PhD's sorry for the ambiguity. All of them require a Research Proposal and without a concrete project to apply for I am at a loss as to what to put in the proposal. If anyone who has successfully obtained a Mathematical physics (string theory super sym...

Hi I intend to apply for a PhD in Mathematical physics My question is how does one write a research proposal without an in-depth understanding of the subject or its research possibilities. Can I ask the potential supervisor for assistance in writing it thank you

Unfortunately my BSc project was the only bad mark I had and I chose not to do one at Part III (mistake in retrospect) so I have only my grades. I have considered the 4 year PhD's and had applied to some with no success (Durham). The main attraction of an european master's is the dissertation at...

I've had more hard looks at myself since I left uni than I care to mention. I've even tried to abandon it all and do something completely unrelated. It seems that physics is the only thing I'm remotely good at. The only thing I may be trying to prove is that the Part III grades don't represent...

thanks for the reply and perspective Although I agree that a bad partIII + MSc (a good one I hope) will not trump the part III distinctions, they still are a limited number of those each year joining the pool. My hope is that a good MSc from a good European institution with an interesting...

Hi I would be grateful for some advice I graduated two years ago from Cambridge with a Pass (nowhere near high marks) in PartIII and I finished my Bsc with first class honours. I've tried getting a PhD placement at several universities in the UK with no success. I am thinking about trying...