Purely Kinetic Coupled Gravity
  Cosmic acceleration can be achieved not only with a sufficiently flat scalar
field potential but through kinetic terms coupled to gravity. These derivative
couplings impose a shift symmetry on the scalar field, aiding naturalness. We
write the most general purely kinetic action not exceeding mass dimension six
and obeying second order field equations. The result reduces to a simple form
involving a coupling of the Einstein tensor with the kinetic term and can be
interpreted as adding a new term to Galileon gravity in curved spacetime. We
examine the cosmological implications of the effective dark energy and classify
the dynamical attractor solutions, finding a quasistable loitering phase
mimicking late time acceleration by a cosmological constant.
