The tensors tag has no wiki summary.
7
votes
6answers
862 views
What is a tensor?
I have a pretty good knowledge of physics but couldn't understand what a tensor is. I just couldn't understand it, and the wiki page is very hard to understand as well. Can someone refer me to a good ...
6
votes
3answers
566 views
What is the difference between a spinor and a vector or a tensor?
Why do we call a 1/2 spin particle satisfying the Dirac equation a spinor, and not a vector or a tensor?
2
votes
0answers
109 views
Stiffness tensor
Let's have a stiffness tensor:
$$
a^{ijkl}: a^{ijkl} = a^{jikl} = a^{klij} = a^{ijlk}.
$$
It has a 21 independent components for an anisotropic body.
How does body symmetry (cubic, hexagonal ...
1
vote
0answers
74 views
Einstein +Maxwell 's tensor
Why is it true that we can deduce that Einstein's GR equations coupled with Maxwell's EM equations may be written in the form $$R_{ij}=C(F_{ik}F_j^{\,\,k}-{1\over 4}g_{ij}F_{mn}F^{mn})$$
without ...
1
vote
0answers
54 views
Equivalence of simple formulations of qubit entanglement
I'm reading some very elementary treatments of quantum computation and am unsure about the correspondence among "definitions" of qubit entanglement.
One definition states that (1) the bits of a ...
1
vote
1answer
281 views
Levi-Civita symbol in Euclidean space
Suppose a component of tensor field is described by $B^k=\varepsilon^{kij} \phi_{ij}$. If we define $B^k$ in an Euclidean space then does the rising or lowering of the indices of the Levi-Civita ...
2
votes
1answer
140 views
How quantum field transforms in case of some particular spin
Except when a particle is spin-0, field of all particles transforms when frame of reference is changed, and this defines what spin is. The question is, specifically how does the quantum field ...
1
vote
1answer
105 views
Calculating electromagnetic invariant in matrix form
I'm kind of confused. I want to calculate the electromagnetic invariant $I := F^{\mu\nu}F_{\mu\nu} $, but I'm not sure what is the easiest way to do so. So, I was trying to do it in matrix form, i.e. ...
1
vote
2answers
367 views
Tensor product notation [closed]
In the image there is a tensor product:
$$F_{\mu\nu}F^{\mu\nu}=2(B^2-\frac{E^2}{c^2})$$
It's about how this operation on the co- and contravariant field strength tensors can give one of the ...
0
votes
0answers
55 views
Cubic symmetry and a stiffness tensor [duplicate]
Possible Duplicate:
Stiffness tensor
Let's have a stiffness tensor:
$$
a^{ijkl}: a^{ijkl} = a^{jikl} = a^{klij} = a^{ijlk}.
$$
It has a 21 independent components for an anisotropic body. ...
