Non-gaussianity consistency relation for multifield inflation.

While detection of the "local form" bispectrum of primordial perturbations would rule out all single-field inflation models, multifield models would still be allowed. We show that multifield models described by the δN formalism obey an inequality between fNL and one of the local-form trispectrum amplitudes, τNL, such that τNL >1/2(6/5fN)(2) with a possible logarithmic scale dependence, provided that 2-loop terms are small. Detection of a violation of this inequality would rule out most of multifield models, challenging inflation as a mechanism for generating the primoridal perturbations.

The Post-Newtonian Approximation for Relativistic Compact Binaries.

We discuss various aspects of the post-Newtonian approximation in general relativity. After presenting the foundation based on the Newtonian limit, we show a method to derive post-Newtonian equations of motion for relativistic compact binaries based on a surface integral approach and the strong field point particle limit. As an application we derive third post-Newtonian equations of motion for relativistic compact binaries which respect the Lorentz invariance in the post-Newtonian perturbative sense, admit a conserved energy, and are free from any ambiguity.