High-fidelity ion-trap quantum computing with hyperfine clock states

TL;DR

This paper introduces a geometric-phase gate for ion-trap quantum computing using hyperfine clock states, aiming to achieve high fidelity and fault tolerance by minimizing spontaneous emission.

Contribution

It presents a novel gate implementation leveraging magnetic-field-insensitive qubits and Raman beams, reducing spontaneous emission and improving gate fidelity.

Findings

Reduced spontaneous photon emission to below 10^-8 per gate

Elimination of main infidelity source in previous implementations

Potential to reach fault-tolerant quantum computing thresholds

Abstract

We propose the implementation of a geometric-phase gate on magnetic-field-insensitive qubits with $\hat{\sigma}^z$-dependent forces for trapped ion quantum computing. The force is exerted by two laser beams in a Raman configuration. Qubit-state dependency is achieved by a small frequency detuning from the virtually-excited state. Ion species with excited states of long radiative lifetimes are used to reduce the chance of a spontaneous photon emission to less than 10$^{-8}$ per gate-run. This eliminates the main source of gate infidelity of previous implementations. With this scheme it seems possible to reach the fault tolerant threshold.