Demonstration of a small programmable quantum computer with atomic qubits

TL;DR

This paper demonstrates a programmable five-qubit trapped-ion quantum computer capable of executing various quantum algorithms with high fidelity, showcasing its flexibility and potential scalability for larger quantum systems.

Contribution

The authors present a fully programmable five-qubit trapped-ion quantum computer that can implement arbitrary algorithms using native gate sets, with high fidelity and reconfigurability.

Findings

Achieved 98% mean fidelity for native gate operations

Successfully implemented Deutsch-Jozsa and Bernstein-Vazirani algorithms with over 90% success rates

Performed quantum Fourier transform with fidelities up to 84%

Abstract

Quantum computers can solve certain problems more efficiently than any possible conventional computer. Small quantum algorithms have been demonstrated on multiple quantum computing platforms, many specifically tailored in hardware to implement a particular algorithm or execute a limited number of computational paths. Here, we demonstrate a five-qubit trapped-ion quantum computer that can be programmed in software to implement arbitrary quantum algorithms by executing any sequence of universal quantum logic gates. We compile algorithms into a fully-connected set of gate operations that are native to the hardware and have a mean fidelity of 98 %. Reconfiguring these gate sequences provides the flexibility to implement a variety of algorithms without altering the hardware. As examples, we implement the Deutsch-Jozsa (DJ) and Bernstein-Vazirani (BV) algorithms with average success rates of 95 % and 90 %, respectively. We also perform a coherent quantum Fourier transform (QFT) on five trappedion qubits for phase estimation and period finding with average fidelities of 62 % and 84 %, respectively. This small quantum computer can be scaled to larger numbers of qubits within a single register, and can be further expanded by connecting several such modules through ion shuttling or photonic quantum channels.