Recent content by pstq

Hi, Could someone enlighten me in this matter? . how the calibration of cosmic distance scale affects the determination of the age of globular star clusters? thanks a lot :)

thanks a lot :):):)

this is not coursework questions nor homework per se, so I hope this is the right place to post this. In case I am wrong , my sincerest apologies

Hi, I am trying to figure out how to draw all the three level Feynman diagrams corresponding to this lagrangian density L = \frac{1}{2} \partial _{\mu} \phi \partial^{\mu} \phi - \frac{\mu^2}{2}\phi^2- \frac{\eta}{3!}\phi^3-\frac{\lambda}{4!} \phi^4+i \bar{\psi} \gamma _{\mu} \partial^{\mu}...

Hi there. 1. The problem statement I am asked to write the equations which give us the mass of a black hole as function the proper time. Homework Equations The Schwarzschild metrics is given by $$ ds^2=-(1- \frac{2GM}{r})dt^2+(1-\frac{2GM}{r})^{-1}dr^2+ r^2(d\theta^2+ \sin^2(\theta)...

Hi all , I need some help with this problem, Homework Statement A hydrogen atom, which is in its ground state |1 0 0 > , is put into a weak time-dependent external electric field, which points into the z direction: \boldsymbol{E}(t,\boldsymbol{r}) =...

Hi all ! I need some help Homework Statement The nucleus of an hydrogen-like atom is usually treated as a point charge Ze. Using the first order perturbation theory, estimate the error due to this approximation assuming that the nucleus is a sphere of radius R with a uniform charge...

Hi all! Homework Statement If we consider the hydrogen atom as a spinless particle. Let this system in the state \Psi ( \vec{r} )= \frac{1}{6} [4 \Psi_{100} ( \vec{r} )+ 3 \Psi_{211}- \Psi_{210} ( \vec{r} ) + \sqrt{10}\Psi_{21-1} ( \vec{r} )] Calculate: 1) Expectation value of...

Thanks!

Hi all! Homework Statement I have to show: \sqrt{(j \pm m ) (j \mp m+1} <j_1 j_2 m_1 m_2 | j_1 j_2 j m\mp 1 > = \sqrt{(j_1 \mp m_1 ) (j_1 \pm m_1+1} <j_1 j_2 m_1 \pm1, m_2 | j_1 j_2 j m > +\sqrt{(j_2 \mp m_2 ) (j_2 \pm m_2+1} <j_1 j_2 m_1 , m_2 \pm1 | j_1 j_2 j m > Homework...