Hybrid quantum computation gate with trapped ion system

TL;DR

This paper demonstrates a hybrid quantum gate using trapped ions that combines discrete and continuous variables, enabling advanced quantum operations like state overlap measurement and NOON state generation.

Contribution

The authors realize a nonlinear hybrid quantum gate with trapped ions, integrating discrete internal states and motional modes for universal quantum computing.

Findings

Successfully implemented a conditional beam splitter Hamiltonian gate

Demonstrated quantum state overlap and parity measurements

Generated NOON states using the hybrid gate

Abstract

The hybrid approach to quantum computation simultaneously utilizes both discrete and continuous variables which offers the advantage of higher density encoding and processing powers for the same physical resources. Trapped ions, with discrete internal states and motional modes which can be described by continuous variables in an infinite dimensional Hilbert space, offer a natural platform for this approach. A nonlinear gate for universal quantum computing can be implemented with the conditional beam splitter Hamiltonian $|e\rangle \langle e| ( a^{\dagger} b + a b^{\dagger})$ that swaps the quantum states of two motional modes, depending on the ion's internal state. We realize such a gate and demonstrate its applications for quantum state overlap measurements, single-shot parity measurement, and generation of NOON states.