SciForums.com > Science > Physics & Math > Need help with metric tensor PDA View Full Version : Need help with metric tensor Post ReplyCreate New Thread nameless12312-13-05, 07:25 PMG(,ab)= metric tensor in relativity G(,ab)= Lambda(c ,a)lamdba(d,b)G(,cd) It is given in my lecture notes that Gbar(,ab)=G(,ab) I'm not too sure what to make of the Gbar, where normally a bared variable denotes a variable as observed in a different intertial frame. It seems abit odd to me as barring G( a matrix quantity) seems to me like barring numerals like bar1 or bar2. Anybody can help? Physics Monkey12-13-05, 09:15 PMTensor notation can sometimes be non-standard and confusing, but in this case I assume that your professor simply meant that the numerical value of the components of the metric are the same in both frames. In other words, the metric components always look like -1, 1, 1, 1 (or the opposite depending on your preference) in all frames connected by Lorentz transformations. Dinosaur12-13-05, 09:41 PMI cannot help much with tensor analysis, but I know it would help a moreknowledgable person if you used superscripts & subscripts. Gab = LcaLdbGcdI think the above is the expression you intended. Perhaps I have the sub's & sup's reversed, and you meant the following. Gab = LcaLdbGcdNote that there is a pattern to a correct tensor equation, making it obvious when a mistake has been made. nameless12312-14-05, 03:59 AMThanks for the replies, I've slept on the problem and woke up realizing that the definition of G was inertial frame dependent. Ie the Matrix G is the matrix that returns a value G when product with L(the Standard Lorenzt in an inertial frame) as below: LGL(transpose)=G As L is the same in all frames, G will be the same in all frames. Dino, I tried copying and paste the notation with subscript, but that didnt work. Did not realize that there was a function to quote equations. Thanks for showing it to me though. Rosnet12-14-05, 08:02 AMIf you're into tensors, check out this somewhat old thread: Tensors Dinosaur12-14-05, 10:13 AMNameless123: Try X(sub)2(/sub) & X(sup)3(/sup) using less than and greater than characters instead of left & right parentheses. You will get X2 & X3 Post ReplyCreate New Thread