Absorption by Extremal D3-branes

TL;DR

This paper investigates the absorption probabilities of various massless and massive scalar fields in the extremal D3-brane background, revealing universal behaviors and implications for dual field theory supermultiplets.

Contribution

It demonstrates the equivalence of absorption probabilities across different fields and provides a detailed analysis of the effective potentials and numerical results for all energies.

Findings

Absorption probabilities tend to zero at low energies and one at high energies.

Different fields exhibit identical absorption probabilities, indicating supermultiplet relations.

Oscillatory patterns in absorption cross-sections as a function of energy.

Abstract

The absorption in the extremal D3-brane background is studied for a class of massless fields whose linear perturbations leave the ten-dimensional background metric unperturbed, as well as the minimally-coupled massive scalar. We find that various fields have the same absorption probability as that of the dilaton-axion system, which is given exactly via the Mathieu equation. We analyze the features of the absorption cross-sections in terms of effective Schr\"odinger potentials, conjecture a general form of the dual effective potentials, and provide explicit numerical results for the whole energy range. As expected, all partial-wave absorption probabilities tend to zero (one) at low (large) energies, and exhibit an oscillatory pattern as a function of energy. The equivalence of absorption probabilities for various modes has implications for the correlation functions on the field, including subleading contributions on the field-theory side. In particular, certain half-integer and integer spin fields have identical absorption probabilities, thus providing evidence that the corresponding operator pairs on the field theory side belong to the same supermultiplets.