Phonon-induced decoherence of a charge quadrupole qubit

TL;DR

This paper investigates how phonons cause decoherence in a charge quadrupole qubit within triple quantum dots, demonstrating that high-fidelity quantum gates are achievable despite phonon interactions.

Contribution

It provides an analysis of phonon effects on charge quadrupole qubits and identifies operating conditions for high-fidelity gate implementation.

Findings

High-fidelity (>99.99%) gates are possible despite phonon-induced decoherence.

Symmetric charge distribution in the qubit suppresses charge noise effects.

Optimal pulse sequences can mitigate phonon effects in quantum dot qubits.

Abstract

Many quantum dot qubits operate in regimes where the energy splittings between qubit states are large and phonons can be the dominant source of decoherence. The recently proposed charge quadrupole qubit, based on one electron in a triple quantum dot, employs a highly symmetric charge distribution to suppress the influence of charge noise. To study the effects of phonons on the charge quadrupole qubit, we consider Larmor and Ramsey pulse sequences to identify favorable operating parameters. We show that it is possible to implement typical gates with $>99.99\%$ fidelity in the presence of phonons and charge noise.