Small cosmological constant from a peculiar inflaton potential
  We propose a novel scenario to explain the small cosmological constant (CC)
by a finely tuned inflaton potential. The tuned shape is stable under radiative
corrections, and our setup is technically natural. The peculiar po- tential
approximately satisfies the following conditions: the inflation is eternal if
CC is positive, and not eternal if CC is negative. By introducing a slowly
varying CC from a positive value to a negative value, the dominant volume of
the Universe after the inflation turns out to have a vanishingly small CC. The
scenario does not require eternal inflation but the e-folding number is
exponentially large and the inflation scale should be low enough. The scenario
can have a consistent thermal history, but the present equation of state of the
Universe is predicted to differ from the prediction of the {\Lambda}CDM model.
A concrete model with a light scalar field is studied.
