Dynamical second-order noise sweetspots in resonantly driven spin qubits

TL;DR

This paper investigates how ac driving in resonantly driven spin qubits can create dynamical second-order noise sweetspots, significantly enhancing dephasing times by reducing charge noise sensitivity.

Contribution

It introduces a method to induce second-order noise sweetspots in resonantly driven spin qubits using ac gates, improving qubit coherence.

Findings

Identification of dynamical second-order sweetspots with increased dephasing times

Demonstration of control over exchange interaction and noise coupling via ac driving

Potential for improved quantum gate fidelity in quantum dot spin qubits

Abstract

Quantum dot-based quantum computation employs extensively the exchange interaction between nearby electronic spins in order to manipulate and couple different qubits. The exchange interaction, however, couples the qubit states to charge noise, which reduces the fidelity of the quantum gates that employ it. The effect of charge noise can be mitigated by working at noise sweetspots in which the sensitivity to charge variations is reduced. In this work we study the response to charge noise of a double quantum dot based qubit in the presence of ac gates, with arbitrary driving amplitudes, applied either to the dot levels or to the tunneling barrier. Tuning with an ac driving allows to manipulate the sign and strength of the exchange interaction as well as its coupling to environmental electric noise. Moreover, we show the possibility of inducing a second-order sweetspot in the resonant spin-triplet qubit in which the dephasing time is significantly increased.