Lyapunov Control on Quantum Open System in Decoherence-free Subspaces

TL;DR

This paper proposes a Lyapunov control scheme to steer open quantum systems into decoherence-free subspaces and manipulate their states, demonstrated through numerical simulations on a four-level system.

Contribution

It introduces a novel Lyapunov control method for quantum open systems in DFS, enabling targeted state manipulation within decoherence-free subspaces.

Findings

The scheme successfully drives the system into DFS.

Numerical simulations confirm effective state control.

The method is applicable to multi-level quantum systems.

Abstract

A scheme to drive and manipulate a finite-dimensional quantum system in the decoherence-free subspaces(DFS) by Lyapunov control is proposed. Control fields are established by Lyapunov function. This proposal can drive the open quantum system into the DFS and manipulate it to any desired eigenstate of the free Hamiltonian. An example which consists of a four-level system with three long-lived states driven by two lasers is presented to exemplify the scheme. We have performed numerical simulations for the dynamics of the four-level system, which show that the scheme works good.