Classical limit of higher-spin string amplitudes

Abstract

It has been shown that a special set of three-point amplitudes between two massive spinning states and a graviton reproduces the linearised stress-energy tensor for a Kerr black hole in the classical limit. In this work we revisit this result and compare it to the analysis of the amplitudes describing the interaction of leading Regge states of the open and closed superstring. We find an all-spin result for the classical limit of two massive spinning states interacting with a photon or graviton. This result differs from Kerr and instead matches the current four-vector and the stress-energy tensor generated by a classical string coupled to electromagnetism and gravity respectively. For the superstring amplitudes, contrary to the black-hole case, we find that the spin to infinity limit is necessary to reproduce the classical spin multipoles.

Angular Momentum Loss due to Tidal Effects in the Post-Minkowskian Expansion

“…are listed in Table II. The expression for the result (35) is also provided in electronic format in the ancillary file.…”

“…Of course the complete Poincaré covariant result (35) provides the resummation of the PN expansions ( 43), (44) to all orders in the velocity to leading order in the coupling, O(G 3 ). Conversely, as we shall discuss in Section V, independent PN calculations of the leading-order components ( 43), (44) will provide useful cross checks of the results obtained so far.…”