Understanding Pointlike & Local Energy Density

[bernhard.rothenstein]

How do you name a physical quantity that can be defined at a given point in space: pointlike? local? Say energy density.

 

[selfAdjoint]

How do you name a physical quantity that can be defined at a given point in space: pointlike? local? Say energy density.

Well it's a field. But what kind depends on the type of quantity. Spinor, scalar, tensor, density of weight d, etc.

 

[robphy]

Do you actually mean something that can be defined "only at one point"?
Or something "distributional" (like a Dirac delta function)?

Do you have a specific detailed example?

 

[pmb_phy]

Well it's a field. But what kind depends on the type of quantity. Spinor, scalar, tensor, density of weight d, etc.

It seems to be way you use the term "write" It seems okay. Folks you might use the term "word."

Adios

Pete

 

[bernhard.rothenstein]

point like? punctual?

Do you actually mean something that can be defined "only at one point"?
Or something "distributional" (like a Dirac delta function)?

Do you have a specific detailed example?

I mean density of energy which can be defined in the case of an uniform distribution as ro=m/V but as ro=dm/dV in the case of a nonuniform distribution having well defined magnitudes at different points in space. Do you say that it is a pointlike or punctual physical quantity.
Thanks to al who have answered my question.

 

[jtbell]

When we have a time-varying quantity and we want to refer specifically to its value at a certain point in time, we often use the word "instantaneous". Are you looking for a similar word to refer to the value of a spatially-varying quantity, at a particular point in space?

In that case, I think the best word would probably be "local", e.g. "local energy density," as opposed to the "average energy density" over a region of space.