Recent content by QFT25

I have been looking into what is like being a Post Doc in theoretical physics, and the impression that I get is that it is like graduate school, except you are paid a bit more money and some how you have much more work to do. I want to become a professor in theoretical physics but at the same...

Bump. Come on read it. I promise it is good.

This is a draft of a my SoP that I plan to send out to all of the Ivy league schools for physics Ph.D. What do you think of it. Do you think it is superb, downright terrible or somewhere in between. All relevant information about me is contained in the Sop. Enjoy reading it and thank you very...

Homework Statement I'm doing research with a Professor and I'm constructing a likelihood function which has parameters the density parameters found in the Friedman equation found using Massive Gravity Action H Homework Equations H(z)^2=a + b (1 + z) + c (1 + z)^2 + d (1 + z)^3 + r (1 + z)^4...

Can an momentum eigenstate have a eigenvalue which is time dependent.

Thanks you all very much for the wonderful suggestions. I'll look into Carroll I heard a lot of good things about it,

Homework Statement Prove that if a particle starts in a momentum eigenstate it will remain forever in a eigenstate given the potential c*y where c is a constant and y is a spatial variable. Homework Equations (h/i)d/dx is the momentum operator and a momentum eigenstate when put in the...

I'm taking a general relativity class and the professor is really good. When I'm in class I understand everything he is saying. However when it is time to do problems sets from Wald I struggle a bit because I find Wald hard to read. I'm not saying Wald is bad but I feel like I can benefit if I...

Homework Statement Consider the case when the three Ising spins are replaced by quantum spins 1/2's with a Hamiltonian H=-J(s1.s2+s2.s3+s3.s1) calculate the quantum partition function Homework Equations Partition function is the sum of E^(-H*B) where B is 1/kt The Attempt at a Solution...

Homework Statement A generalized potential suitable for use in a covariant Lagrangian for a single particle. This is Goldstein problem 9 chapter 7. −Aλν(xμ)uλuν where Aλν stands for a symmetric world tensor of the second rank and u^v are the components of the world velocity. If the...

Can this be moved to the homework help section?

I'm also in the same situation and would like some points on where to proceed once I have Lagrange's equation's of motion. Can Minkowski force be just the mass times the four velocity? Also to find the force in a Lorenz frame, that refers to just the spatial component of the Minkowski force right?

No because Sin[1/z] at z=0 is not a isolated singularity so it isn't analytic in in a neighborhood of z or in this case x.

Yes Sin[1/x] as x goes to zero is undefined. However Sin[1/x] ranges between as -1,0 and 1. Also as x/(Sin[x+Pi]) as x goes to zero approaches negative -1. Hmm now that I think I think about it is un defined right because it will go between 0 and -1 right. So it is irregular point right?

The series looks like x/(1/x -1/x^3+1/x^5...) so as x goes to zero the numerator goes to zero and the denominator increases without bound because of all of the (1/x) terms. So in my head I was like zero over infinity is zero.