String theory as a Lilliputian world

Understand

Lattice regularizations of the bosonic string allow no tachyons.

• This has often been viewed as the reason why these theories have never managed to make any contact to standard continuum string theories when the dimension of spacetime is larger than two.
• We study the continuum string theory in large spacetime dimensions where simple mean field theory is reliable.
• By keeping carefully the cutoff we show that precisely the existence of a tachyon makes it possible to take a scaling limit which reproduces the lattice-string results.