  In holography, quasinormal spectra of black branes coincide with the poles of
retarded finite-temperature correlation functions of a dual quantum field
theory in the limit of infinite number of relevant degrees of freedom such as
colours. For asymptotically anti-de Sitter backgrounds, the spectra form a
characteristic pattern in the complex frequency plane, colloquially known as
the "Christmas tree". At infinite coupling, the tree has only one pair of
branches. At large but finite coupling, the branches become more dense and lift
up towards the real axis, consistent with the expectation of forming a branch
cut in the limit of zero coupling. However, it is known that at zero coupling,
the corresponding correlators generically have not one but multiple branch cuts
separated by intervals proportional to the Matsubara frequency. This suggests
the existence of multiple branches of the "Christmas tree" spectrum in dual
gravity. In this note, we show numerically how these additional branches of the
spectrum can emerge from the dual gravitational action with higher-derivative
terms. This phenomenon appears to be robust, yet, reproducing the expected weak
coupling behaviour of the correlators quantitatively implies the existence of
certain constraints on the coefficients of the higher-derivative terms of the
dual gravity theory.
