String Theory: Two Types of Branes Are One At energy levels
where predictions from string theory and general relativity
match up, D-branes and p-branes are equivalent. Though
Polchinski was aware of Strominger’s work on p-branes — they
discussed their projects over lunch regularly — both scientists
thought that the two types of branes were distinct. Part of
Polchinski’s 1995 work on branes included the realization that
they were actually one and the same object. It might seem odd
that this hadn’t occurred to either of the men before 1995, but
there was no reason to expect that the two types of branes would
be related to each other. To a layman, they sound basically the
same — multidimensional surfaces existing in a 10-dimensional
space-time. Why wouldn’t you at least consider that they’re the
same things? Well, part of the reason may be based on the
specific nature of scientific research. When you’re working in a
scientific field, you are quite specific about the questions
you’re asking and the ways in which