The Halo Spin Transition as a Probe of Dark Energy
  We present a numerical evidence supporting the claim that the mass-dependent
transitions of the halo spin orientations from the intermediate to the minor
principal directions of the local tidal fields can in principle be a useful
discriminator of dark energy models. We first define a spin transition zone as
the mass range of the halos, $\Delta m_{t}$, for which the intrinsic spin
alignments with the minor tidal principal directions become as strong as that
with the intermediate principal directions. Then, utilizing the halo samples
from the DEUS simulations performed separately for the WMAP7 $\Lambda$CDM,
phantom DE and quintessence models, we investigate if and how the three
different dark energy models differ in $\Delta m_{t}$. It is shown that the
differences in $\Delta m_{t}$ among the three dark energy models are
significant enough to discriminate the models from one another and robust
against the variations of the smoothing scale of the tidal field and redshift.
Noting that a narrower spin transition zone is more powerful as a probe of dark
energy, we also show that the spin transition zones become narrower at higher
redshifts, in the filamentary environments and for the case that the tidal
fields are smoothed on the smaller scales. Our result is consistent with the
scenario that $\Delta m_{t}$ is mainly determined by how fast the nonlinear
evolution of the tidal field proceeds, which in turn sensitively depends on the
background cosmology.
