0
$\begingroup$

This question already has an answer here:

Are M2 and M5 membranes in M-Theory excited states of some underlying field, or are they fundamental? In what sense are membranes solitonic?

In the reference question, someone made a comment that had no reply and I am just as curious

"My question is, what is the M brane itself? Is there an underlying M brane field where the branes are excitations of the field? Or is the M brane simply a fundamental object made out of no fields?"

I am confused what an M Brane really is. M2 membranes are strings when you compatify a membrane on a circle, if I am not wrong, so this means all strings and branes are really just solitons?

$\endgroup$

marked as duplicate by ACuriousMind Apr 13 at 15:57

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ 1. The "just soliton" confusion is already addressed in the duplicate. 2. We do not have a universally accepted version of full M-theory, so there is no framework in which one could ask the question what an M-brane "really is". However, I suggest that this question is effectively equivalent to asking what strings are made of and just as meaningful. $\endgroup$ – ACuriousMind Apr 13 at 16:32
0
$\begingroup$

M2-brane is a classical solution to the equations of motion of 11 dimensional supergravity. It couples electrically to the three-form field (a.k.a. C-field) of 11D SUGRA, while there is also an object that couples to the C-field magnetically -- M5-brane. Thus M2 and M5 are magnetic duals of each other. They can be considered fundamental similarly to strings and D-branes in string theories, but its not clear what they become in full M-theory.

$\endgroup$
  • $\begingroup$ Strings and branes in string theory are the membranes in M-Theory correct? This means all strings and branes are just solitons? $\endgroup$ – S. Beck Apr 13 at 16:28
  • $\begingroup$ @S.Beck No, it's not that simple. There are dualities between certain types of D-branes and M-branes. But we can only study M-branes as supergravity objects, full picture is not available without full M-theory $\endgroup$ – Kosm Apr 13 at 17:41

Not the answer you're looking for? Browse other questions tagged or ask your own question.