Optimizing for an arbitrary perfect entangler. II. Application

TL;DR

This paper demonstrates how to optimize quantum control protocols to efficiently generate perfect two-qubit entanglers across different quantum platforms, achieving higher fidelity and speed than traditional gate implementations.

Contribution

It introduces a general optimization functional for creating arbitrary perfect entanglers, applicable to various quantum systems, and compares two optimization methods to highlight the importance of the target functional.

Findings

Faster entangler creation with higher fidelity than standard gates.

Applicable to nitrogen vacancy centers and superconducting qubits.

Optimization approach significantly impacts the quality of entanglement.

Abstract

The difficulty of an optimization task in quantum information science depends on the proper mathematical expression of the physical target. Here we demonstrate the power of optimization functionals targeting an arbitrary perfect two-qubit entangler, creating a maximally-entangled state out of some initial product state. For two quantum information platforms of current interest, nitrogen vacancy centers in diamond and superconducting Josephson junctions, we show that an arbitrary perfect entangler can be reached faster and with higher fidelity than specific two-qubit gates or local equivalence classes of two-qubit gates. Our results are obtained with two independent optimization approaches, underlining the crucial role of the optimization target.