Adiabatic quantum dynamics under decoherence in a controllable trapped-ion setup. (arXiv:1903.05748v1 [quant-ph])

Suppressing undesired non-unitary effects in a quantum system is a major
challenge in quantum computation and quantum control. In this scenario, the
investigation of the adiabatic dynamics under decoherence allows for optimal
strategies in adiabatic protocols in the presence of a surrounding environment.
In this work, we address this point by theoretically and experimentally
analyzing the robustness of the adiabatic theorem in open quantum systems. More
specifically, we derive a favorable decohering scenario to exploit the validity
conditions of the adiabatic approximation as well as its sensitiveness to the
resonance situation, which typically harm adiabaticity in closed systems. As
illustrations, we implement both an oscillating Landau-Zener Hamiltonian and
the adiabatic quantum algorithm for the Deutsch problem. Strategies to optimize
fidelity and a preferred time window for these quantum evolutions are then
analyzed. We experimentally realize these systems through a single trapped
Ytterbium ion $^{171}$Yb$^+$, where the ion hyperfine energy levels are used
as degrees of freedom of a two-level system, with both driven field and
decohering strength efficiently controllable.