Stochastic learning control of adiabatic speedup in a non-Markovian open qutrit system

TL;DR

This paper demonstrates that stochastic search methods can effectively design control pulses to enhance adiabatic speedup and fidelity in open non-Markovian qutrit systems, outperforming ideal pulses especially under strong environmental influences.

Contribution

It introduces a stochastic search approach to optimize control pulses for open quantum systems, addressing environmental noise and improving adiabatic speedup and fidelity.

Findings

Optimal control pulses yield higher fidelities than ideal pulses.

Fidelity improvement is significant under strong system-bath coupling.

Maximal fidelity gain occurs at a critical environment memory time.

Abstract

Precise and efficient control of quantum systems is essential to perform quantum information processing tasks. In terms of adiabatic speedup via leakage elimination operator approach, for a closed system, the ideal pulse control conditions have been theoretically derived by P-Q partitioning technique. However, it is a challenge to design the corresponding control pulses for an open system, which requires to tackle noisy environments. In this paper, we apply the stochastic search procedures to an open qutrit system and successfully obtain the optimal control pulses for significant adiabatic speedup. The calculation results show that these optimal pulses allow us to acquire higher fidelities than the ideal pulses. The improvement of fidelity is large for relatively strong system-bath coupling strength and high bath temperature. For certain coupling strength and bath temperature, the maximal improvement can be achieved for a critical characteristic frequency which represents the memory time of the environment. Our investigation indicates that the stochastic search procedures are powerful tools to design control pulses for combating the detrimental effects of the environment.