Recycling pulsars to millisecond periods in general relativity

We use models of rapidly rotating neutron stars in general relativity to construct evolutionary tracks for the recycling of pulsars to millisecond periods. We give an exact treatment for a simple recycling scenario where accretion occurs from the inner edge of a Keplerian disk onto a bare neutron star. For this scenario we tabulate the shortest achievable period and corresponding accreted rest mass for 13 nuclear equations of state. For each equation of state, we determine whether a nonrotating 1.4 M_⊙ star can be spun up to millisecond periods without exceeding the maximum mass or rotation limits. We find that spin-up is possible for all of the equations of state, even those with a static maximum mass close to 1.4 M_⊙.