  In this article, we study Coleman bounce in weakly nonlocal theories which
are motivated from string field theory. The kinetic term is extended via an
infinite series of high-order derivatives, which comes into play at an energy
scale $M$, without introducing any new states or ghosts in the mass spectrum.
We calculate the bubble nucleation in thin-wall approximation, treating the
system in semi-classical manner. We find that the effect of nonlocal scale $M$
in the theory is to suppress the vacuum tunneling rate from false to true
vacuum compared to the standard local bouncing scenario. Likewise, we show that
as we move further away from the bubble wall, the effects of nonlocality gets
reduced and this suppression is significant only around the wall of the
nucleated bubble. From our investigations, we conclude that the main effect is
due to the fact that the nonlocality smears the solution of the local bubble
profile. However, the energy of the bubble wall remains unaffected by the
microscopic nonlocal behavior of the theory in the thin-wall approximation. We
also discuss the cases for Lee-Wick theories and applications of our result to
cosmology.
