The double copy of the multipole expansion

Understand

We consider the classical double copy, that relates solutions of biadjoint scalar, gauge and gravity theories.

• Using a recently developed twistor expression of this idea, we use well-established techniques to show that the multipole moments of arbitrary vacuum type D gravity fields are straightforwardly mapped to their counterparts in gauge and biadjoint scalar theory by the single and zeroth copies.
• We cross-check our results using previously obtained results for the Kerr metric.
• Our results provide further physical intuition of how the double copy operates.