Quantum Computing Gates via Optimal Control

TL;DR

This paper uses optimal control techniques to design and experimentally implement complex quantum gates, such as PE and COMP, in a three-spin NMR system, advancing quantum gate engineering.

Contribution

The paper introduces novel entropy-manipulating quantum gates designed via optimal control, demonstrating their practical implementation in an NMR system.

Findings

Successfully designed and implemented PE and COMP gates using GRAPE.

Achieved efficient and robust RF pulses for a three-spin system.

Demonstrated potential for complex gate design in quantum computing.

Abstract

We demonstrate the use of optimal control to design two entropy-manipulating quantum gates which are more complex than the corresponding, commonly used, gates, such as CNOT and Toffoli (CCNOT): A 2-qubit gate called PE (polarization exchange) and a 3-qubit gate called COMP (polarization compression) were designed using GRAPE, an optimal control algorithm. Both gates were designed for a three-spin system. Our design provided efficient and robust NMR radio frequency (RF) pulses for 13C2-trichloroethylene (TCE), our chosen three-spin system. We then experimentally applied these two quantum gates onto TCE at the NMR lab. Such design of these gates and others could be relevant for near-future applications of quantum computing devices.