potential1dg.f90

Ground state of the time-independent Gross-Pitaevskii equation

real(kind(1.d0)) function potentialV(z)
  !
  ! User supplied potential
  !
  ! This function takes on input the coordinate z and returns the value
  ! of the potential at this point 
  !
  ! all values in atomic units
  !
  use system1Dg
  implicit none
  integer, parameter :: dp=kind(1.d0)
  
  real(dp), intent(in) :: z

  real(dp), parameter :: wz = 1.d-13

  ! harmonic potential
  potentialV = 0.5d0*mass*(wz**2*z**2)

  ! extra quartic component
  potentialV = potentialV + 2.d0*mass**2*wz**3*z**4

  return
end function potentialV