Optimal state transfer of a single dissipative two-level system

TL;DR

This paper develops an optimal control approach for transferring quantum states in a dissipative two-level system coupled to an environment, demonstrating effective transfer profiles and robustness against temperature changes.

Contribution

It introduces a method combining optimal control theory and the Bloch-Redfield formalism to optimize state transfer in dissipative quantum systems.

Findings

Achieved ideal state transfer within a dimer system in the FMO model.

Identified control profiles robust to temperature variations.

Demonstrated the effectiveness of automatic differentiation in quantum control optimization.

Abstract

Optimal state transfer of a single two-level system (TLS) coupled to an Ohmic boson bath via off-diagonal TLS-bath coupling is studied by using optimal control theory. In the weak system-bath coupling regime where the time-dependent Bloch-Redfield formalism is applicable, we obtain the Bloch equation to probe the evolution of the dissipative TLS in the presence of a time-dependent external control field. By using the automatic differentiation technique to compute the gradient for the cost functional, we calculate the optimal transfer integral profile that can achieve an ideal transfer within a dimer system in the FennaMatthews-Olson (FMO) model. The robustness of the control profile against temperature variation is also analyzed.