Conditional operation of a spin qubit

TL;DR

This paper demonstrates the coherent conditional operation of a spin qubit using a double quantum dot system, highlighting its potential for fast multi-qubit control in quantum computing.

Contribution

It introduces a novel geometry enabling fast conditional gates through capacitive coupling between a singlet-triplet qubit and adjacent quantum dots.

Findings

Capacitive coupling strength quantified

Fast conditional gate operation achieved

Potential for multi-qubit quantum algorithms

Abstract

We report coherent operation of a singlet-triplet qubit controlled by the arrangement of two electrons in an adjacent double quantum dot. The system we investigate consists of two pairs of capacitively coupled double quantum dots fabricated by electrostatic gates on the surface of a GaAs heterostructure. We extract the strength of the capacitive coupling between qubit and double quantum dot and show that the present geometry allows fast conditional gate operation, opening pathways to multi-qubit control and implementation of quantum algorithms with spin qubits.