Quantum coherence control of solid-state charge qubit by means of a suboptimal feedback algorithm

TL;DR

This paper presents a suboptimal feedback algorithm for controlling quantum coherence in a solid-state charge qubit, enabling effective protection of arbitrary states, including those on the Bloch sphere's equator.

Contribution

It introduces a simple bang-bang control protocol within a Bayesian feedback scheme for quantum coherence management in solid-state qubits.

Findings

Effective coherence protection for arbitrary states.

Simple bang-bang control protocol for Rabi oscillations.

Enhanced control over states on the Bloch sphere's equator.

Abstract

The quantum coherence control of a solid-state charge qubit is studied by using a suboptimal continuous feedback algorithm within the Bayesian feedback scheme. For the coherent Rabi oscillation, the present algorithm suggests a simple bang-bang control protocol, in which the control parameter is modulated between two values. For the coherence protection of idle state, the present approach is applicable to arbitrary states, including those lying on the equator of the Bloch sphere which are out of control in the previous Markovian feedback scheme.