We study constraints on a number of patch inflationary models in
noncommutative spacetime using a compilation of recent high-precision
observational data. In particular, the four-dimensional General Relativistic
(GR) case, the Randall-Sundrum (RS) and Gauss-Bonnet (GB) braneworld scenarios
are investigated by extending previous commutative analyses to the infrared
limit of a maximally symmetric realization of the stringy uncertainty
principle. The effect of spacetime noncommutativity modifies the standard
consistency relation between the tensor spectral index and the tensor-to-scalar
ratio. We perform likelihood analyses in terms of inflationary observables
using new consistency relations and confront them with large-field inflationary
models with potential V \propto \vp^p in two classes of noncommutative
scenarios. We find a number of interesting results: (i) the quartic potential
(p=4) is rescued from marginal rejection in the class 2 GR case, and (ii) steep
inflation driven by an exponential potential (p \to \infty) is allowed in the
class 1 RS case. Spacetime noncommutativity can lead to blue-tilted scalar and
tensor spectra even for monomial potentials, thus opening up a possibility to
explain the loss of power observed in the cosmic microwave background
anisotropies. We also explore patch inflation with a Dirac-Born-Infeld tachyon
field and explicitly show that the associated likelihood analysis is equivalent
to the one in the ordinary scalar field case by using horizon-flow parameters.
It turns out that tachyon inflation is compatible with observations in all
patch cosmologies even for large p.Comment: 16 pages, 11 figures; v2: updated references, minor corrections to
match the Phys. Rev. D versio