  State preparation protocols ideally require as minimal operations as
possible, in order to be implemented in near-term, potentially noisy quantum
devices. Motivated by long range interactions (LRIs) intrinsic to many
present-day experimental platforms (trapped ions, Rydberg atom arrays, etc.),
we investigate the efficacy of variationally simulating non-trivial quantum
states using the Variational Quantum-Classical Simulation (VQCS) protocol
explored recently in [SciPost Phys. 6, 029 (2019)], in the presence of LRIs. We
show that this approach leads to extremely efficient state preparation: for
example, Greene-Horne-Zeilinger (GHZ) states can be prepared with O(1)
iterations of the protocol, and a quantum critical point of the long range
transverse field Ising model (TFIM) can be prepared with > 99% fidelity on a
100 qubit system with only one iteration. Furthermore, we show that VQCS with
LRIs is a promising route for exploring generic points in the phase diagram of
the long-range TFIM. Our approach thus provides concrete, ultrafast protocols
for quantum simulators equipped with long range interactions.
