Semiclassical Tunneling in 1+1 Dimensional String Theory
Abstract
We describe time-dependent tunneling of massless particles in 1+1 dimensional string field theory. Polchinski's description of the classical solutions in terms of the Fermi sea is used to identify the leading instanton contribution connecting the two half-lines. The field theory lagrangian is proportional to
1/
g
2
, where
g
is the string coupling constant, but the
S
-matrix for tunneling from one half-line to the other behaves as
exp(−C/g)
. We note the constant~
C
involves curious boundary contributions and observe that a prescription connecting the two half-lines unifies treatments of the Fermi level above and below the barrier. We also note the relation to recent work of Brustein and Ovrut.