Maximizing the encoded information via freezing the estimated parameters of a pulsed driven qubit

TL;DR

This paper investigates how applying a rectangular pulse to a driven qubit can freeze parameter estimation, revealing a trade-off between estimation accuracy and encoded information, with implications for quantum cryptography.

Contribution

It introduces a method to control the estimation of qubit parameters via pulse strength and detuning, impacting information encoding in quantum systems.

Findings

Estimation of parameters reduces encoded information.

Pulse strength and detuning differently affect estimation and encoding.

Encoded information depends on initial state when estimating θ, but not φ.

Abstract

We use a rectangular pulse to freeze the possibility of estimating the coherent parameters ($\theta,\phi$) of a single qubit and the encoded information. It is shown that, as the possibility of estimating the parameters increases, the amount of encoded information decreases. The pulse strength and the detuning between the qubit and the pulse have a different effect on the estimation degree and the encoded information. We show that if the weight parameter, $\theta$ is estimated, the encoded information depends on the initial state settings. Meanwhile, the encoded information doesn't depend on the estimated phase parameter,$\phi$. These results may be useful in the context of quantum cryptography, teleportation and secure communication.