Realizing two-qubit gates through mode engineering on a trapped-ion quantum computer

TL;DR

This paper introduces a mode engineering approach in trapped-ion quantum computers to simplify two-qubit gate implementation, reducing control complexity and aiding scalability by manipulating the ion chain's normal modes.

Contribution

The authors develop and experimentally demonstrate a method to engineer ion chain modes, reducing the need for complex pulse modulation in two-qubit gate operations.

Findings

Successfully demonstrated mode engineering in a three-ion chain

Reduced pulse modulation complexity in two-qubit gates

Potential for scalable ion trap quantum computing

Abstract

Two-qubit gates are a fundamental constituent of a quantum computer and typically its most challenging operation. In a trapped-ion quantum computer, this is typically implemented with laser beams which are modulated in amplitude, frequency, phase, or a combination of these. The required modulation becomes increasingly more complex as the quantum computer becomes larger, complicating the control hardware design. Here, we develop a simple method to essentially remove the pulse-modulation complexity by engineering the normal modes of the ion chain. We experimentally demonstrate the required mode engineering in a three ion chain. This opens up the possibility to trade off complexity between the design of the trapping fields and the optical control system, which will help scale the ion trap quantum computing platform.