  We report the results of a first study that uses numerical simulations to
estimate the accuracy with which one can use gravitational wave observations of
double neutron star inspiral to measure parameters of the neutron-star equation
of state. The simulations use the evolution and initial-data codes of Shibata
and Uryu to compute the last several orbits and the merger of neutron stars,
with matter described by a parametrized equation of state. Previous work
suggested the use of an effective cutoff frequency to place constraints on the
equation of state. We find, however, that greater accuracy is obtained by
measuring departures from the point-particle limit of the gravitational
waveform produced during the late inspiral.
  As the stars approach their final plunge and merger, the gravitational wave
phase accumulates more rapidly for smaller values of the neutron star
compactness (the ratio of the mass of the neutron star to its radius). We
estimate that realistic equations of state will lead to gravitational waveforms
that are distinguishable from point particle inspirals at an effective distance
(the distance to an optimally oriented and located system that would produce an
equivalent waveform amplitude) of 100 Mpc or less. As Lattimer and Prakash
observed, neutron-star radius is closely tied to the pressure at density not
far above nuclear. Our results suggest that broadband gravitational wave
observations at frequencies between 500 and 1000 Hz will constrain this
pressure, and we estimate the accuracy with which it can be measured. Related
first estimates of radius measurability show that the radius can be determined
to an accuracy of ~1 km at 100 Mpc.
