The IMF and multiplicity of stars from gravity, turbulence, magnetic
  fields, radiation and outflow feedback
  We perform a series of three-dimensional, magnetohydrodynamical (MHD)
simulations of star cluster formation including gravity, turbulence, magnetic
fields, stellar radiative heating and outflow feedback. We observe that the
inclusion of protostellar outflows (1) reduces the star formation rate by a
factor of $\sim2$, (2) increases fragmentation, and (3) shifts the initial mass
function (IMF) to lower masses by a factor of $2.0\pm0.2$, without
significantly affecting the overall shape of the IMF. The form of the sink
particle (protostellar objects) mass distribution obtained from our simulations
matches the observational IMFs reasonably well. We also show that
turbulence-based theoretical models of the IMF agree well with our simulation
IMF in the high-mass and low-mass regime, but do not predict any brown dwarfs,
whereas our simulations produce a considerable number of sub-stellar objects,
which are produced by dynamical interactions (ejections). We find that these
dynamical interactions also play a key role for the binary separation
distribution and stellar kinematics in general. Our numerical model of star
cluster formation also reproduces the observed mass dependence of multiplicity.
Our multiplicity fraction estimates generally concur with the observational
estimates for different spectral types. We further calculate the specific
angular momentum of all the sink particles and find that the average value of
$1.5 \times 10^{19}\, \mathrm{cm^2\, s^{-1}}$ is consistent with observational
data. The specific angular momentum of our sink particles lies in the range
typical of protostellar envelopes and binaries. We conclude that the IMF is
controlled by a combination of gravity, turbulence, magnetic fields, radiation
and outflow feedback.
