How are gravitational waves polarized?

1 Answer
Sep 21, 2017


It is a result of the symmetry in the perturbation equation that describes their origination.


The linear-polarization state of the CMB in a direction #nhat# can be described by a symmetric trace-free 2 × 2 tensor.

Looking at the geodesic deviation by setting first #A_"xx" = 0# then setting #A_"xy" = 0# will show that there are two distinct physical states for the wave — these are the gravitational wave polarization states. The effect of a wave in either state is to compress the geodesics in one direction while simultaneously stretching the geodesic separation in the orthogonal direction during the first half-cycle of a wave. During the second half-cycle, it switches the compression and stretching effects between the axes.

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