P-branes ---Brane theory?
There are higher dimensional objects in string theory with dimensions
from zero (points) to nine, called p-branes.
In terms of branes, what we usually call a membrane would be a two-brane,
a string is called a one-brane and a point is called a zero-brane.
As we have seen the equations require boundary
A special class of branes is found when the
Dirichlet boundary conditions are used so the endpoint is fixed
to move only on some
D-branes are the result of this
D-branes are actually dynamical objects which have fluctuations and can
move around. For example they interact with gravity. In the diagram below
we see one way in which an closed string (graviton) can interact with a
D2-brane. Notice how the closed string becomes an open string with endpoints
on the D-brane at the intermediate point in the interaction.