Many-body quantum state control in the presence of environmental noise

TL;DR

This paper demonstrates a method for controlling many-body quantum states, including Schr"odinger cat states, with high fidelity despite environmental noise, using gradient-based optimal control techniques.

Contribution

It introduces a robust control approach for many-body quantum systems under environmental noise, specifically applying Krotov's method to achieve high-fidelity state transfer and rotation.

Findings

High-fidelity quantum state control achieved

Control robustness against environmental noise demonstrated

Application to Schr"odinger cat states in harmonic chains

Abstract

We consider the quantum state control of a multi-state system which evolves an initial state into a target state. We explicitly demonstrate the control method in an interesting case involving the transfer and rotation of a Schr\"{o}dinger cat state through a coupled harmonic oscillator chain at a predetermined time $T$. We use the gradient-based Krotov's method to design the time-dependent parameters of the coupled chain to find an optimal control shape that will evolve the system into a target state. We show that the prescribed quantum state control can be achieved with high fidelity, and the robustness of the control against generic environment noises is explored. Our findings will be of interest for the optimal control of a many-body open quantum system in the presence of environmental noise.