Covariant derivate same as normal derivative?

In summary, the covariant derivative of a composition of functions can be deduced from the Leibniz rule. However, in some cases, there may be a graded Leibniz rule, particularly when working with supersymmetry. In these cases, one must be more careful with the covariant derivative.
  • #1
vitaniarain
11
0
hey, I'm getting really confused with something. If i have the covariant derivative of say, constant * exp(2f), is this equivalent to 2*constant*exp(2f) * cov.deriv. of f ?
 
Physics news on Phys.org
  • #2
As a rule covariant derivatives are defined so as to satisfy the Leibniz rule. The formula for a covariant derivative of a composition of functions can be deduced from this rule.

What is your f? What kind of a covariant derivative? Sometimes, however, it can be a graded Leibniz rule (when you are playing with supersymmetry, for instance). Then one has to be more careful.
 
  • #3
thanks for the reply. f is a scalar field. what do u mean what kind of covariant derivative i didn't know there were many. this is in the framework of general relativity..
 
  • #4
vitaniarain said:
thanks for the reply. f is a scalar field. what do u mean what kind of covariant derivative i didn't know there were many. this is in the framework of general relativity..

Covariant derivatives occur in the context of general relativity or in the context of gauge theories.
 
  • #5


No, the covariant derivative is not the same as the normal derivative. The covariant derivative takes into account the curvature of the space in which the function is defined, while the normal derivative does not. In the example you provided, the covariant derivative of a constant times the exponential of 2f would be equal to the constant times the covariant derivative of 2f, plus the exponential of 2f times the covariant derivative of the constant. This is because the covariant derivative of a product is not equal to the product of the covariant derivatives of each term. It is important to carefully consider the context and definitions of these derivatives in order to properly apply them in your calculations.
 

1. What is a covariant derivative?

A covariant derivative is a mathematical operation that generalizes the concept of a derivative to curved spaces, such as Riemannian manifolds. It takes into account the curvature of the space in order to define a unique directional derivative at each point.

2. How is a covariant derivative different from a normal derivative?

A normal derivative is defined in Euclidean spaces and does not take into account the curvature of the space. A covariant derivative, on the other hand, is defined in curved spaces and takes into account the curvature when computing the directional derivative.

3. Can a covariant derivative be used in place of a normal derivative?

No, a covariant derivative cannot be used interchangeably with a normal derivative. They have different definitions and properties, and are used in different contexts. A covariant derivative is only applicable in curved spaces, while a normal derivative is applicable in Euclidean spaces.

4. Why is a covariant derivative important in physics?

In physics, many phenomena occur in curved spaces, such as in general relativity. In these cases, a normal derivative cannot be used to describe the behavior of objects, and a covariant derivative is needed to take into account the curvature of the space. It is also important for formulating equations and laws that are valid in curved spaces.

5. How is a covariant derivative calculated?

The specific formula for calculating a covariant derivative depends on the specific metric and connection used in the space. In general, it involves calculating the directional derivative along a given vector using the Christoffel symbols, which represent the curvature of the space. This can be done using tensor calculus and can be quite complex for more complicated spaces.

Similar threads

  • Differential Geometry
Replies
8
Views
3K
  • Differential Geometry
Replies
6
Views
2K
  • Differential Geometry
Replies
5
Views
2K
  • Differential Geometry
Replies
3
Views
2K
  • Differential Geometry
Replies
2
Views
3K
  • Differential Geometry
Replies
15
Views
4K
  • Differential Geometry
Replies
14
Views
3K
  • Quantum Physics
Replies
14
Views
2K
Replies
37
Views
8K
  • Advanced Physics Homework Help
Replies
5
Views
2K
Back
Top