Observational Upper Bound on the Cosmic Abundances of Negative-mass
  Compact Objects and Ellis Wormholes from the Sloan Digital Sky Survey Quasar
  Lens Search
  The latest result in the Sloan Digital Sky Survey Quasar Lens Search (SQLS)
has set the first cosmological constraints on negative-mass compact objects and
Ellis wormholes. There are no multiple images lensed by the above two exotic
objects for $\sim 50000$ distant quasars in the SQLS data. Therefore, an upper
bound is put on the cosmic abundances of these lenses. The number density of
negative mass compact objects is $n<10^{-8} (10^{-4}) h^3 {\rm Mpc}^{-3}$ at
the mass scale $|M| > 10^{15} (10^{12}) M_\odot$, which corresponds to the
cosmological density parameter $|\Omega| < 10^{-4}$ at the galaxy-scale mass
range $|M|=10^{12-15}M_\odot$. The number density of the Ellis wormhole is
$n<10^{-4} h^3 {\rm Mpc}^{-3}$ for a range of the throat radius $a =
10^{1-4}$pc, which is much smaller than the Einstein ring radius.
