Probing Electrostatic Disorder via g-Tensor Geometry

TL;DR

This paper investigates how electrostatic disorder affects hole spin qubits through g-tensor anisotropy, proposing a readout protocol and analyzing sensitivity to disorder for improved qubit stability.

Contribution

It introduces a method to probe electrostatic disorder effects on g-tensor components using Berry phase-based readout and identifies optimal conditions for qubit sensitivity.

Findings

Proposed a readout protocol with high signal-to-noise ratio within tens of microseconds.

Analyzed the dependence of qubit response on geometry and disorder-induced dipolar perturbations.

Identified magnetic field directions and regimes where the qubit is most sensitive to disorder.

Abstract

Low-frequency charge noise induced by fluctuating electrostatic disorder is a major limitation for semiconductor hole spin qubits. Here, we analyze the quasistatic response of a hole spin qubit to individual two-level fluctuators (TLFs). We show that, due to the anisotropy of the g-tensor, the qubit response depends on the geometry of the fluctuator-induced dipolar perturbation. We then propose a readout protocol that isolates selected g-tensor components through an accumulated Berry phase and estimate, within our readout model, an order-unity signal-to-noise ratio with a total protocol time in the tens of microseconds. Finally, using microscopic simulations, we compute the quantum Fisher information (QFI) to identify magnetic field directions and confinement regimes in which the qubit is most sensitive to disorder-induced variations of selected g-tensor components.