Entanglement dynamics of two Ising-coupled qubits with nonperpendicular local driving fields

TL;DR

This paper provides an approximate analytical solution for the entanglement dynamics of two Ising-coupled qubits with nonperpendicular local driving fields, relevant for solid-state quantum experiments, and identifies parameters for entangling gate generation.

Contribution

It introduces a novel analytical approach to model two coupled qubits with nonperpendicular control fields, aiding the design of entangling gates in solid-state systems.

Findings

Derived analytical expressions for local invariants and rotations.

Identified parameters for generating any entangling gate.

Applied results to recent experimental data on singlet-triplet qubits.

Abstract

We present an approximate analytical solution to the dynamic equation of two Ising-coupled qubits with oscillating classical control fields that are nonperpendicular to the static drift fields. This is a situation that has recently arisen in some solid-state experiments. With our solution we derive the analytical expressions for the local invariants as well as the local rotations needed to isolate a purely nonlocal gate. This determines the set of parameters that are required to generate any entangling gate. Moreover, we use our results to describe a recent experimental work on capacitively coupled singlet-triplet qubits in GaAs and discuss possible differences for a similar device in silicon.