Tensor calculus for general relativity question.

In summary, the conversation is about using the metic proposed by Einstein in the first cosmological model based on general relativity. The stress energy tensor is shown to be that of a static, spatially uniform perfect fluid and ρ and p are determined in terms of G and K. The question then asks for the ratio of ρv / ρm in a universe with only cold matter and vacuum energy. The person is asking for help with computing the curvature tensor, as they always end up with errors.
  • #1
iampeterr
2
0
Use the metic that Einstein proposed in the first cosmological model based on general relativity.

ds2 = -dt2 + (dr2) / (1 - Kr2) + r2(dθ2 + sin2θd[itex]\phi[/itex]2) where K > 0

Show that the stress energy tensor is that of a static, spatially uniform perfect fluid and determine ρ and p in terms of G and K. If the universe contains only cold matter (denoted by subscript m, with pm << ρm) and vacuum energy (denoted by subscript v, with pv = -ρv), what is the ratio of ρv / ρm?

could someone help me out? its something I've been working on for a while now and end up in some weird mess.
 
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  • #2
iampeterr said:
Use the metic that Einstein proposed in the first cosmological model based on general relativity.

ds2 = -dt2 + (dr2) / (1 - Kr2) + r2(dθ2 + sin2θd[itex]\phi[/itex]2) where K > 0

Show that the stress energy tensor is that of a static, spatially uniform perfect fluid and determine ρ and p in terms of G and K. If the universe contains only cold matter (denoted by subscript m, with pm << ρm) and vacuum energy (denoted by subscript v, with pv = -ρv), what is the ratio of ρv / ρm?

could someone help me out? its something I've been working on for a while now and end up in some weird mess.

Every time I try to compute the curvature tensor, I end up with pages of mathematics that always has an error.
 
  • #3
which part do you get up to ?
 

FAQ: Tensor calculus for general relativity question.

What is tensor calculus?

Tensor calculus is a branch of mathematics that deals with the study of tensors, which are mathematical objects that describe linear relations between different sets of vectors and scalars. It is an important tool in understanding the mathematical framework of general relativity.

How is tensor calculus used in general relativity?

Tensor calculus is used in general relativity to describe the curvature of spacetime, which is a fundamental concept in the theory. Tensors are used to represent the geometric properties of spacetime, such as the curvature and the gravitational field.

What are the main differences between tensor calculus and traditional calculus?

Traditional calculus deals with functions of a single variable, while tensor calculus deals with functions of multiple variables. In traditional calculus, the derivative represents the rate of change of a function, while in tensor calculus, the derivative represents the rate of change of a tensor along a specified direction.

Are there any practical applications of tensor calculus in general relativity?

Yes, tensor calculus is used in various practical applications in general relativity, such as in the study of gravitational waves, black holes, and the dynamics of galaxies. It is also used in the development of mathematical models for the behavior of matter and energy in the universe.

Is it necessary to have a strong background in mathematics to understand tensor calculus for general relativity?

While a strong background in mathematics is helpful, it is not necessary to understand tensor calculus for general relativity. Many concepts in tensor calculus can be understood intuitively, and there are various resources available for beginners to learn the basics of tensor calculus in the context of general relativity.

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