Polarization tensor
= Polarization tensor
{title2=$\epsilon_{\mu\nu}$}
A closed-string polarization tensor specifies the target-spacetime tensor state multiplying $\partial X^\mu\bar\partial X^\nu e^{ik\cdot X}$. Its decomposition into symmetric trace-free, antisymmetric and trace parts separates the graviton, <Kalb–Ramond field> and <dilaton> polarizations.