D7-brane dynamics and thermalization in the Kuperstein–Sonnenschein model

Abstract

We study the temperature of rotating probe D7-branes, dual to the temperature of flavored quarks, in the Kuperstein–Sonnenschein holographic model including the effects of spontaneous breakdown of the conformal and chiral flavor symmetry. The model embeds probe D7-branes into the Klebanov–Witten gravity dual of conformal gauge theory, with the embedding parameter, given by the minimal radial extension of the probe, setting the IR scale of conformal and chiral flavor symmetry breakdown. We show that when the minimal extension is positive definite and additional spin is turned on, the induced world volume metrics on the probe admit thermal horizons and Hawking temperatures despite the absence of black holes in the bulk. We find the scale and behavior of the temperature in flavored quarks are controlled dramatically by the IR scale of symmetry breaking, and by the strength and sort of external fields. We also derive the energy-stress tensor of the rotating probe and study its backreaction and energy dissipation. We show that at the IR scale the backreaction is nonnegligible and find the energy can flow from the probe to the bulk, dual to the energy dissipation from the flavor sector into the gauge theory.