  The phenomenon of quantum revivals resulting from the self-interference of
wave packets has been observed in several quantum systems and utilized widely
in spectroscopic applications. Here, we present a combined analytical and
numerical study on the generation of orientational quantum revivals (OQRs)
exclusively using a single-cycle THz pulse. As a proof of principle, we examine
the scheme in the linear polar molecule HCN with experimentally accessible
pulse parameters and obtain strong field-free OQR without requiring the
condition of the sudden-impact limit. To visualize the involved quantum
mechanism, we derive a three-state model using the Magnus expansion of the
time-evolution operator. Interestingly, the THz pulse interaction with the
electric-dipole moment can activate direct multiphoton processes, leading to
OQR enhancements beyond that induced by a rotational ladder-climbing mechanism
from the rotational ground state. This work provides an explicit and feasible
approach toward quantum control of molecular rotation, which is at the core of
current research endeavors with potential applications in atomic and molecular
physics, photochemistry, and quantum information science.

Quantum Physics