Semiconducting double-dot exchange-only qubit dynamics in presence of magnetic and charge noises

TL;DR

This paper theoretically investigates how magnetic and charge noises affect the dynamics and coherence times of a double-dot exchange-only qubit, highlighting its potential for quantum computation despite environmental disturbances.

Contribution

It introduces a detailed noise model for the DEOQ and extracts coherence times using an envelope-fitting method based on experimentally relevant parameters.

Findings

Magnetic and charge noises significantly influence qubit dynamics.

Coherence times are estimated for realistic device parameters.

Return probability behavior reveals noise impact on qubit stability.

Abstract

The effects of magnetic and charge noises on the dynamical evolution of the double-dot exchange-only qubit (DEOQ) is theoretically investigated. The DEOQ consisting of three electrons arranged in an electrostatically defined double quantum dot deserves special interest in quantum computation applications due to its advantages in terms of fabrication, control and manipulation in view of implementation of fast single and two qubit operations through only electrical tuning. The presence of the environmental noise due to nuclear spins and charge traps, in addition to fluctuations in the applied magnetic field and charge fluctuations on the electrostatic gates adopted to confine the electrons, is taken into account including random magnetic field and random coupling terms in the Hamiltonian. The behavior of the return probability as a function of time for initial conditions of interest is presented. Moreover, through an envelope-fitting procedure on the return probabilities, coherence times are extracted when model parameters take values achievable experimentally in semiconducting devices.