Recent content by M. Kohlhaas

thanks @all Aha. That's great. Thank you very much. I'm happy now.

i am reading a book written by malcolm ludvigsen and i have difficulty in understanding the following: he introduces the maxwell tensor via m\ddot{x} = eF(v) where v is the four-velocity and \ddot{x} the four-acceleration of a charged partice. he then states that F(a,b) = aF(b) is "clearly"...

My level of preparation is something like a desaster i would say. I haven't heard any lectures on general relativity. I just read some chapters in Malcolm Ludvigsen's general relativity and Carroll's spacetime and geometry, mainly the introductory parts on geometry and einstein's equation. They...

So here I'm begging for your suggestions. Thanks.

Thanks. :smile:

I'm just reading the schroeder/peskin introduction to quantum field theory. On Page 21 there is the equation \phi(x)=\int\frac{d^3 p}{(2\pi)^3}\frac{1}{ \sqrt{2\omega_{\vec{p}}} } (a_{\vec{p}} e^{i \vec{p} \cdot \vec{x}} +a^{+}_{\vec{p}} e^{-i \vec{p} \cdot \vec{x}} ) and in the...

In this case the convention is to first apply C_2 and then \sigma^(1). The book's name is "symmetry - an introduction to group theory" written by Roy McWeeny. Hier is an excerpt; the certain special thing which i asked for is marked in red...

Hello, in my Book is a formula, namely sigma^(1) C_2 = sigma^(12) where sigma^(1) is a reflection about the x-z-plane, C_2 is a pi-rotation about the z-axis and sigma^(12) is a reflection about the midway plane between x-z- and y-z-plane. When i in my Imagination make the steps on the...