  AH Her is a Z Cam-type dwarf nova with an orbital period of ~ 0.258 d. Dwarf
nova oscillations and long-period dwarf nova oscillations have been detected,
but no quasi-periodic oscillations (QPOs) and negative superhumps (NSHs) have
been found. We investigated the association between NSHs, QPOs, and outbursts
of AH Her based on \textit{TESS} photometry. We find for the first time the
NSHs with a period of 0.24497(1) d in AH Her, and trace the variation of the
amplitude and period of NSHs with the outburst. The amplitude of the NSHs is
most significant at quiescence, weakening as the outburst rises, becoming
undetectable at the top, rebounding and weakening at the plateau, and
strengthening again as the outburst declines. The variation of the accretion
disk radius can explain the NSHs amplitude variation except for the plateau, so
we suggest that the relationship between NSHs amplitude and outburst can be
used as a window to study the accretion disk instability and the origin of
NSHs. In addition, we find the periodic variations in the amplitude, maxima,
and shape of the NSHs ranging from 2.33(2) d to 2.68(5) d, which may be related
to the precession of the tilted disk. Finally, we find QPOs at the top of AH
Her's long outburst with ~ 2800 s similar to HS 2325+8205, suggesting that the
presence of QPOs at the top of Z Cam's long outburst may be a general
phenomenon
