Squeezed bispectrum from multi-field inflation with curved field space
  metric
  We investigate influences of the curved field-space metric of multi-field
inflationary models on the squeezed bispectrum. The reduced bispectrum in
squeezed limit is computed using the {\delta}N formalism. The calculation is
performed under the slow-roll approximation and assumption that field
derivative of the field-space metric is sufficiently small such that the
contributions from Riemann tensor of the field-space can be approximately
ignored. Based on these approximations, We compute the analytic expressions for
the reduced bispectrum in squeezed limit, and find that, for such a nearly flat
field-space metric, the field dependence of the metric can significantly alter
both amplitude and shape of the reduced bispectrum. The reduced bispectrum from
this nearly flat field-space metric can lead to spectral index of the halo bias
which amplitude is 2 -- 4 times larger than that from the flat field-space
model. This modification of the spectral index of the halo bias due to the
curved field-space metric could leave observable imprints in future galaxy
surveys.
