Stellar Tidal Disruption Events by Direct Collapse Black Holes
  We analyze the early growth stage of direct-collapse black holes (DCBHs) with
$\sim 10^{5} \ \rm M_\odot$, which are formed by collapse of supermassive stars
in atomic-cooling halos at $z \gtrsim 10$. A nuclear accretion disk around a
newborn DCBH is gravitationally unstable and fragments into clumps with a few
$10 \ \rm M_\odot$ at $\sim 0.01-0.1 \ \rm pc$ from the center. Such clumps
evolve into massive population III stars with a few $10-100 \ \rm M_\odot$ via
successive gas accretion and a nuclear star cluster is formed. Radiative and
mechanical feedback from an inner slim disk and the star cluster will
significantly reduce the gas accretion rate onto the DCBH within $\sim 10^6 \
\rm yr$. Some of the nuclear stars can be scattered onto the loss cone orbits
also within $\lesssim 10^6 \ \rm yr$ and tidally disrupted by the central DCBH.
The jet luminosity powered by such tidal disruption events can be $L_{\rm j}
\gtrsim 10^{50} \ \rm erg \ s^{-1}$. The prompt emission will be observed in
X-ray bands with a peak duration of $\delta t_{\rm obs} \sim 10^{5-6} \ (1+z) \
\rm s$ followed by a tail $\propto t_{\rm obs}^{-5/3}$, which can be detectable
by Swift BAT and eROSITA even from $z \sim 20$. Follow-up observations of the
radio afterglows with, e.g., eVLA and the host halos with JWST could probe the
earliest AGN feedback from DCBHs.
