2006-07-23 18:01:50 UTC
"Does it make sense to speak about the number of
strings found in a volume of space?"
Could anbody comment on this? I would be
interested if one has to imagine string theory
as filling all of space with strings Or branes),
or whether this is the wrong visualization.
[Moderator's note: one can construct the "number of strings" operator in a
perturbative treatment of string theory - much like you can talk about
the number of particles and/or the level of the harmonic oscillator.
However, both in quantum field theory and string theory, this quantum
number is a bit problematic. It is certainly not conserved. In QFT, it
depends on the energy scale at which you understand the system - because
with a high enough scale, you find very many gluons inside the proton,
to say an example. The "number of particles" behaves strangely when
you include interactions. The latter statement is also true in string
theory. The real physical objects at nonzero coupling are not just the
"bare 1 string" that you know from g=0. LM]