What is the parity inversion of antisymmetric tensor

genxium
Messages
137
Reaction score
2
First by antisymmetric tensor I mean the "totally antisymmetric tensor" like this:

##\epsilon^{\alpha\beta\gamma\delta} = \left\{ \begin{array}{clcl} +1 \;\; \text{when superscripts form an even permutation of 1,2,3,4} \\ -1 \;\; \text{when superscripts form an odd permutation of 1,2,3,4} \\ 0 \;\; otherwise \end{array} \right.##

You may refer to this link for more information about pseudo tensors: http://farside.ph.utexas.edu/teaching/em/lectures/node120.html

I'm ok with that 3-vectors, 4-vectors are invariant under parity inversion. However I'm confused by WHAT IS THE PARITY INVERSION of antisymmetric tensor? There's NO COORDINATE in it.

Any help is appreciated :)
 
Mathematics news on Phys.org
The answer is basically already in the link you posted. It relates the components in the new system to the determinant of the coordinate transformation. What happens with the determinant if you make a parity flip?
 
Hi @Orodruin, do you mean that to verify whether parity inversion changes the antisymmetric tensor I can perform sth like:

##\left\{ \begin{array}{cl} \frac{\partial x'}{\partial x}=-1 \\ \frac{\partial y'}{\partial y}=-1 \\ \frac{\partial z'}{\partial z}=-1 \end{array} \right.## and ##J(parity \; inversion) = \left[ \begin{array}{clclcl} \frac{\partial x'}{\partial x} & \frac{\partial x'}{\partial y} & \frac{\partial x'}{\partial z} \\ \frac{\partial y'}{\partial x} & \frac{\partial y'}{\partial y} & \frac{\partial y'}{\partial z} \\ \frac{\partial z'}{\partial x} & \frac{\partial z'}{\partial y} & \frac{\partial z'}{\partial z} \end{array} \right]##

Thus ##det(J) = -1## implies that antisymmetric tensor is inverted after the parity inversion?
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.

Similar threads

Replies
1
Views
4K
Replies
5
Views
2K
Replies
1
Views
2K
Replies
2
Views
3K
Replies
6
Views
2K
Replies
1
Views
2K
Back
Top