Recent content by Worldline

Hi we know the relation between wavelength, frequency and energy : The greater the energy, the larger the frequency and the shorter (smaller) the wavelength -> E=h\upsilon On the other side, SAR is common property that measures absorbed energy. Now if we calculating SAR for human brain...

You are right, But i found the explicit relation with use of the Koszul formula in a orthonormal frame. Thank u, it was helpful Really Thank u, Nice suggestion, I got the book !

So what about spinors ? we need spin connections, whenever we want to compare them.

Exactly i study Teleparallel gravity, that is a gauge theory for translation group,and i know how to derive spin connection in terms of vielbeins, but i want its definition in GR.

what is the formula of spin connection in GR ? can we show it in term of structure coefficients ?

Thank you for ur comments

What is the best software for GR calculations ? GRTensor ?

Very helpfull. Thank you

Thanks for ur answers, But in Teleparallel Gravity we can easy define an energy-momentum tensor for gravity. So it seems that the impossibility of defining an energy-momentum tensor isn't a characteristic of gravity, but a property of geometrical picture of GR

but other fundamental fields have well defined tensorial expression. I think it is because in GR , we consider gravitational effects as inertial effects, and inertial effects can't be expressed with tensors...

why general relativity can't define any tensorial expression for Gravitational energy momentum density ?

Thank u dude

what is the meaning of superpotential tensor in teleparallel gravity ? it defined as :

Ok. but i don't understand the relation between invariance of Lagrangian under action of transformation with an element of U(1) and conservation of current. in my point of view the U(1) elements are just phase angle.

It is said that : electrodynamics is a gauge theory for U(1) gauge group . what is its physical concept? Mathematically it mean that the field is invariant under transformation under components of U(1) group, that we can show them with e^{i\theta} and we can consider them as a phase angle . so...