Recent content by physlad

Thanks for responding, chrispb! So are you familiar with the leshouches input/output? If yes, I was trying to let softsusy make some approximate calculations for me, but it refuses to do that because it's too accurate! (I get all sorts of problems, tachyons, non-convergence, etc.). Basically...

Any experts in using SOFTSUSY (the tool) here?

Thank you very much, JJacquelin! now I see it :D

Hi, I was reading a review and I saw this equation, A^2 = \frac{|B^2 - C^2|}{\sqrt{(1-sin^2(2x))}} - C^2 - B^2 - 2D^2 Then at some point he writes: "expanding for large tan(x), this expression becomes, A^2 = -2(C^2 + D^2) + \frac{2}{tan^2(x)}(B^2 - C^2) + O(1/tan^4(x)) Could anybody explain...

I was reading about AdS/CFT and its possible description of superconductors. It is said that superconductors may exhibit a strong coupling behavior. In general, AdS/CFT is thought to be a good tool to study strong coupling dynamics. Now, my question is what are the properties that define a...

when a space (or spacetime) is said to be maximally symmetric, does this mean that it is homogeneous?

As far as I know, string theory does not introduce a new "time" dimension, only extra spatial dimensions. Also, the predictions of string theory cannot be tested by nowadays experiments. Its predictions take place at the Planck scale (~ 10^19 GeV). So, the theory cannot be proved nor falsified...

when we apply Higgs mechanism to the lagrangian of a complex scalar field... we get terms for a Glodstone boson, a massive scalar and a massive vector field in the new lagrangian.. we also get other terms.. one of them takes following form A_\mu \partial^\mu \xi this term is said to...

Gravity: An Introduction to Einstein's General Relativity by James B. Hartle This book focuses on the physics rather than the mathematical construction of GR (but it doesn't ignore it, I think!) There is also Sean Carroll's book: Spacetime and Geometry: An Introduction to General Relativity...

I was reading about the momentum-energy tensor (or stress-energy tensor), at one point the author says, " \theta^{\mu\nu} = (\partial^\mu\phi)(\partial^\nu\phi) - g^{\mu\nu}L This is clearly symmetric in \mu and \nu." \theta^{\mu\nu}: is the stress-energy tensor \phi is a scalar field...

Yes, I got it. Thanks

I was reading about the principle of least action and how to derive Newton's second out of it. at a certain point I didn't follow the calculations, so the author defines a variation in the path, x(t) \longrightarrow x'(t) = x(t) + a(t), a \ll x a(t_1) = a(t_2) = 0 Now, S...

CompuChip, thanks for the clear explanations. however, you said earlier that time may look (partially) as space to a certain observer. can I ask what do you mean by (partially) and could you give me an example of such case? (has this got to do with the so-called Lorentz Boosts?)

hey folks, i'm just curious. are there any biologists who don't accept the theory of evolution? if yes, how do they scientifically explain the diversity of species (other than believing in Intelligent Designing stuff)? cheers

If we lived in a 2D space, we wouldn't recognize a curvature that takes place in a 3rd dimension. likewise, in our 3D space, the curvature that is caused by mass/energy takes place in a 4th dimension, which is spacetime (ct). Is this correct??