Quantum dot qubits with quadrupolar geometry

Robust implementations of semiconducting quantum dot qubits must overcome the effects of charge noise that currently limit coherence during gate operations. Here, I describe a scheme for protecting solid-state qubits from uniform electric field fluctuations with a specific physical implementation: a quadrupole qubit in a triple quantum dot. The unique design of the quadrupole qubit enables particularly simple pulse sequences for suppressing the effects of noise during gate operations. Finally, I will discuss an advanced implementation of the quadrupole qubit where the spin and the charge degrees of freedom are hybridized in order to generate a very wide sweet spot that can provide even stronger protection against charge noise.