Response to D.T. Son's comment on ``Is there a `most perfect fluid' consistent with quantum field theory?''

TL;DR

This paper responds to a comment on the authors' previous work, clarifying that their conclusion about the existence of exceptions to a viscosity bound remains valid despite the raised subtle point.

Contribution

It clarifies that the original conclusion about exceptions to the viscosity bound is unaffected by the comment's subtle point.

Findings

The original viscosity bound conclusion remains valid.

The comment's subtle point does not invalidate the initial results.

The response affirms the robustness of the original theoretical bounds.

Abstract

This is a response to the comment, arXiv:0709.4651. It is noted that while the comment raises an extremely interesting and subtle point, the original conclusion that theoretically consistent exceptions exist for the proposed general bound for the ratio of shear viscosity to entropy density, appears to remain unaffected by the issue raised.