Understanding Tangent Vectors in GR Notation

In summary, the conversation is about using Carroll's textbook to learn about GR. The problem discussed involves finding the components of tangent vectors at a given point in Euclidean 3-space, using the notation of \{\partial_x, \partial_y, \partial_z\}. The concept of using directional derivatives to define vectors in GR is also mentioned.
  • #1
Irid
207
1
I'm trying to learn some GR from Carrol's textbook, but I'm a little lost there. For example, this simple problem:

In Euclidean 3-space, let p be the point with coordinates (x,y,z) = (1,0,-1). Consider the curve passing through p:

[tex]x^i(\lambda) = (\lambda, (\lambda-1)^2, -\lambda)[/tex]

Calculate the components of tangent vectors to these curves at p in the coordinate basis [tex]\{\partial_x, \partial_y, \partial_z\}[/tex].

The attempt at a solution

The components of tangent vectors are given by

[tex]V^i = \frac{dx^i}{d\lambda}[/tex]

It is of course in the basis of x,y,z. But I don't understand what does the basis [tex]\{\partial_x, \partial_y, \partial_z\}[/tex] mean. The notation is new to me, but I think that

[tex]\partial_x \equiv \frac{\partial}{\partial x}[/tex]

so how can this be used as a basis? If you just take these derivatives at each component of the curve, you always get (1,1,1), right?
 
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  • #2
In GR, and differential geometry in general, you often define a vector as a directional derivative. So the vector ai+bj+ck (where i,j,k are the usual unit vectors) is written as a*d/dx+b*d/dy+c*d/dz. Since the derivative along the direction i is d/dx etc.
 
  • #3
Alright, so this is a trivial problem then, right?
 
  • #4
Irid said:
Alright, so this is a trivial problem then, right?

Sure. Just like what you did in Calc I but written in GR type notation.
 

FAQ: Understanding Tangent Vectors in GR Notation

What is "GR notation"?

"GR notation" refers to the notation used in the field of General Relativity to represent mathematical equations and concepts. It is a shorthand method of writing complex equations and is essential for understanding and communicating ideas in this field.

Why is "GR notation" important?

"GR notation" is important because it allows scientists to condense complicated equations and concepts into a more manageable form. This makes it easier to study and understand the principles of General Relativity, which is crucial in advancing our knowledge of the universe.

How is "GR notation" different from other notations?

"GR notation" is different from other notations, such as standard mathematical notation, because it is specifically designed for use in the field of General Relativity. It includes symbols and conventions that are unique to this field and may not be found in other branches of mathematics.

Do I need to be familiar with "GR notation" to understand General Relativity?

While having a basic understanding of "GR notation" can be helpful in understanding General Relativity, it is not a requirement. Many concepts can be explained using more common mathematical notation, and resources are available to help bridge the gap between the two notations for those who are new to the field.

Where can I learn more about "GR notation"?

There are many resources available for learning "GR notation", including textbooks, online tutorials, and courses. It is also helpful to study the work of renowned scientists in the field of General Relativity who have extensively used and contributed to the development of "GR notation".

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