  A new type of atom-light hybrid quantum gyroscope (ALHQG) is proposed due to
its high rotation sensitivity. It consists of an optical Sagnac loop to couple
rotation rate and an atomic ensemble as quantum beam splitter/recombiner
(QBS/C) based on atomic Raman amplification process to realize the splitting
and recombination of the optical wave and the atomic spin wave. The rotation
sensitivity can be enhanced by the quantum correlation between Sagnac loop and
QBS/C. The optimal working condition is investigated to achieve the best
sensitivity. The numerical results show that the rotation sensitivity can beat
the standard quantum limit (SQL) in ideal condition. Even in the presence of
the attenuation under practical condition, the best sensitivity of the ALHQG
can still beat the SQL and is better than that of a fiber optic gyroscope
(FOG). Such an ALHQG could be practically applied for modern inertial
navigation system.
