Different kind of four-dimensional brane for string theory

We present a generalization of the string's Polyakov action that describes a conformally invariant four-dimensional brane. The new extended object is very different from the traditional D-branes of string theory, but, nevertheless, shares some structural similarities with the string, especially when it comes to the lowenergy limit of small tension. We introduce a rather rich structure of tensors that can play a role at low energies. In analogy with the bosonic string, we initiate the quantization of the new brane discussing the extent in which it produces a critical dimension of spacetime and Einstein's equations coupled to a scalar dilaton under some approximations.

Automated summary

We present a generalization of the Polyakov action for strings that describes a conformally invariant four-dimensional brane. This new extended object is different from traditional D-branes in string theory, but shows some similarities with strings in the low-energy limit. We introduce a rich structure of tensors that can have a role at low energies and discuss the quantization of this new brane and its implications on the dimensionality of spacetime and Einstein's equations.