Recent content by xyver

Homework Statement I do not understand equal signs 2 and 3 the following Angular momentum operator identity: Homework Equations \hat{J}^2 = \hat{J}_1^2+\hat{J}_2^2 +\hat{J}_3^2 = \left(\hat{J}_1 +i\hat{J}_2 \right)\left(\hat{J}_1 -i\hat{J}_2 \right) +\hat{J}_3^2 + i...

Where is my mistake?

Homework Statement I want to show that tr\left(\hat{\rho}_{mixed}\right)=1 tr\left(\hat{\rho}_{mixed}^{2}\right)<1 when \hat{\rho}_{mixed}=\frac{1}{2\pi}\int_{0}^{2\pi}d \alpha \hat{\rho}(\psi) Homework Equations tr\left(\psi\right)= \sum_{n}\langle n|\psi|n\rangle...

Ok, so this is restricted to gold members. Yes, google is a workaround, but that does not search explicitly in the title.

Hello, I am looking (searching :) ) for a possibility to use the AND operator, for example find all of the following words in the title of a subject in this forum: integral density operator integral AND density AND operator +integral +density +operator. There is already a thread...

I found the solution here: http://books.google.de/books?id=0Yx5VzaMYm8C&pg=PA110&redir_esc=y#v=twopage&q&f=true . That's Heinz-Peter Breuer, Petruccione, "The Theory of Open Quantum Systems", pp. 110-111. Nearly every step ist explained.

The definition should be \hat{\rho}=\sum_{i}p_{n}|\psi(t)\rangle\langle\psi(t)| I can do with that: \partial_{t}\hat{\rho}=\partial_{t}\sum_{i}p_{n}| \psi(t)\rangle\langle\psi(t)|+ \sum_{i} p_{n}|\psi(t) \rangle\partial_{t}\langle\psi(t)| \Leftrightarrow...

Homework Statement \hat{\rho}(t)=? |\psi(t)\rangle=U(t,t_{0})|\psi(t_{0})\rangle \imath\hbar\partial_{t}\hat{p}=[\hat{H},\hat{\rho}] Homework Equations \imath\hbar\partial_{t}\hat{p}=[\hat{H},\hat{\rho}]...