Nonperturbative dynamical decoupling control: A spin-chain model

This paper considers a spin-chain model by numerically solving the exact model to explore the nonperturbative dynamical decoupling regime, where an important issue recently arose. Our study has revealed a few universal features of nonperturbative dynamical control irrespective of the types of environments and system-environment couplings. We have shown that, for the spin-chain model, there is a threshold and a large pulse parameter region where the effective dynamical control can be implemented, in contrast to the perturbative decoupling schemes where the permissible parameters are represented by a point or converge to a very small subset in the large parameter region admitted by our nonperturbative approach. An important implication of the nonperturbative approach is its flexibility in implementing the dynamical control scheme in an experimental setup. Our findings have exhibited several interesting features of the nonperturbative regimes such as the chain-size independence, pulse strength upper bound, noncontinuous valid parameter regions, etc. Furthermore, we find that our nonperturbative scheme is robust against randomness in model fabrication and time-dependent random noise.