Efficient C-Phase gate for single-spin qubits in quantum dots

TL;DR

This paper proposes a robust, efficient controlled phase (C-Phase) gate for single-spin qubits in quantum dots, analyzing its performance under realistic noise conditions and showing potential for fault-tolerant quantum computing.

Contribution

It introduces a one-step C-Phase gate using magnetic field or g-factor gradients, with detailed analysis of its duration and fidelity under realistic noise effects.

Findings

Gate error probabilities below 10^-4

Potential for fault-tolerant quantum computation

Analysis under charge and nuclear field fluctuations

Abstract

Two-qubit interactions are at the heart of quantum information processing. For single-spin qubits in semiconductor quantum dots, the exchange gate has always been considered the natural two-qubit gate. The recent integration of magnetic field or g-factor gradients in coupled quantum dot systems allows for a one-step, robust realization of the controlled phase (C-Phase) gate instead. We analyze the C-Phase gate durations and fidelities that can be obtained under realistic conditions, including the effects of charge and nuclear field fluctuations, and find gate error probabilities of below 10-4, possibly allowing fault-tolerant quantum computation.