# Search results

1. ### I How can we define a space?

I have a very simple reference about space. I noticed that most bodies in quantum mechanics, microscopic, star, galaxy, and the entire universe is spherical to begin with. Therefore space is spherical in nature. By induction, mathematical coordinates should be spherical regardless the object...
2. ### A Normalization of 4x4 matrix

Yes, you are correct. The paper normalizes the trace and your answer is correct for that part. I admit that I asked to many question on this one, because when I mentioned normalizing condition $G^2=1$ that is a different story....That is probably normalizing the whole matrix which can be...
3. ### A Normalization of 4x4 matrix

I am trying to normalize 4x4 matrix (g and f are functions): \begin{equation} G=\begin{matrix} (1-g^2) &0& 0& 0&\\ 0& (1+f^2)& (-g^2-f^2)& 0 \\ 0 &(-g^2-f^2)& (1+f^2)& 0 &\\ 0& 0& 0& (1-g^2) \end{matrix} \end{equation} It's a matrix that's in a research paper (which I dont have) which gives...
4. ### A How spin projector got included in inverse of Matrix?

The following matrix A is, \begin{equation} A= \begin{bmatrix} a+b-\sigma\cdot p & -x_1 \\ x_2 & a-b-\sigma\cdot p \end{bmatrix} \end{equation} The inversion of matrix A is, \begin{equation} A^{-1}= \frac{\begin{bmatrix} a-b-\sigma\cdot p & x_1 \\ -x_2 & a+b-\sigma\cdot p...
5. ### Mathematica Is the integral for current correct?

Hi, I am using Mathematica to calculate density of states and current of the Green's function times self energy in most simple form. I am not sure if I am getting current integral over energy implemented correctly. Shouldnt first current plot be a line with a slope? Below is my code...
6. ### Looking for resistivity vs. temperature lab charts

I am looking for low temperature resistivity of elements charts/data set such as mercury etc.
7. ### Looking for resistivity vs. temperature lab charts

Hi everyone, I am looking for basic elements resistivity vs. temperature laboratory measurements charts. Anyone has ideas where to look for? Regards
8. ### Berry's Curvature Equation cross product calculation

Hi, The following textbook Heisenberg's Quantum Mechanics shows an example of calculating Berry's curvature (top page on pg 518). It led to a following equation Vm= (- 1/B2 ) * i *∑ ( <m,B|S|n,B> ∧ <n,B|S|m,B> ) / A2 ................ the textbook claims that we add the term m = n since...
9. ### Rotations of spins and of wavefunctions

This is a question regarding the intrinsic angular momentum S of a particle of spin 1. Assuming S = s(s+1)I = 2I and I is the identity operator. In our case s = 1. Let |z> be a ket of norm 1 such that Sz |z> = 0, and let |x> and |y> be the ket vectors obtained from it by rotations of + 1/2 Pi...
10. ### Nanowatt switch?

Greetings, I am looking for equivalent of relay or optocoupler but in nanowatts range if there is any. I looked into a MOSFET however gate switch cannot be isolated and there is Id drop when conducting. Relay is cool because there is no current drop or voltage drop when switch is on. Timing...
11. ### Scientific Journal Publishing

I don't think its correct. I think he got PhD from University of Berlin by correspondence first. Then he got his papers published. If there was no need to have PhD to publish, he would not pursue PhD because it would not be a worthy and relevant task for him. He pursue things that were...
12. ### Scientific Journal Publishing

thanks for replies. I found them very useful.
13. ### Scientific Journal Publishing

Greetings Everyone, This is a question for those who have PhD's or anyone who published their work in some Scientific Journal. Do you need some academic background or what is the minimum academic requirement (bachelor, MSc, PhD , diploma or none) to publish your work in any scientific...
14. ### UNISA - opinions?

Is that the reason you did not finish it? I noticed that you have master's in theoretical physics. How did you finish it? I am looking for online master's in physics. The reason is that I do not want to quit my job. J
15. ### UNISA - opinions?

thanks for reply. You mentioned that they are very good. Very good in what? What is your experience with them?