Adiabatic passage and ensemble control of quantum systems

TL;DR

This paper demonstrates how adiabatic passage techniques can be used for robust ensemble control of quantum systems, enabling permutation of eigenstates with high fidelity even with uncertain coupling parameters.

Contribution

It provides a mathematical proof of robustness for chirped pulse control and introduces new adiabatic protocols for arbitrary eigenstate permutations in quantum ensembles.

Findings

Proven robustness of chirped pulse control protocols.

Designed new adiabatic control schemes for eigenstate permutations.

Simulations successfully achieved all permutations in a 4-level quantum ladder.

Abstract

This paper considers population transfer between eigenstates of a finite quantum ladder controlled by a classical electric field. Using an appropriate change of variables, we show that this setting can be set in the framework of adiabatic passage, which is known to facilitate ensemble control of quantum systems. Building on this insight, we present a mathematical proof of robustness for a control protocol -- chirped pulse -- practiced by experimentalists to drive an ensemble of quantum systems from the ground state to the most excited state. We then propose new adiabatic control protocols using a single chirped and amplitude shaped pulse, to robustly perform any permutation of eigenstate populations, on an ensemble of systems with badly known coupling strengths. Such adiabatic control protocols are illustrated by simulations achieving all 24 permutations for a 4-level ladder.