Practical trapped-ion protocols for universal qudit-based quantum computing

Abstract

The notion of universal quantum computation can be generalized to multilevel qudits, which offer advantages in resource usage and algorithmic efficiencies. Trapped ions, which are pristine and well-controlled quantum systems, offer an ideal platform to develop qudit-based quantum information processing. Previous work has not fully explored the practicality of implementing trapped-ion qudits accounting for known experimental error sources. Here, we describe a universal set of protocols for state preparation, single-qudit gates, a generalization of the Mølmer-Sørensen gate for two-qudit gates, and a measurement scheme which utilizes shelving to a metastable state. We numerically simulate known sources of error from previous trapped-ion experiments, and show that there are no fundamental limitations to achieving fidelities above 99% for three-level qudits encoded in 137 Ba + ions. Our methods are extensible to higher-dimensional qudits, and our measurement and single-qudit gate protocols can achieve 99% fidelities for five-level qudits. We identify avenues to further decrease errors in future work. Our results suggest that three-level trapped-ion qudits will be a useful technology for quantum information processing.

Trailhead for quantum simulation of SU(3) Yang-Mills lattice gauge theory in the local multiplet basis

“…Complementarily, recent advances in forming highfidelity qudits within the hyperfine structure of trappedion systems (for example Ref. [135]) indicate that exploratory calculations using the qutrit encodings presented above for the f1; 3;3g truncation may be implementable on such systems in the near future. In addition to their appealing connectivity, these systems of trapped ions are intriguingly capable of naturally generating interaction Hamiltonians that swap populations between qudit levels with a coupling constant determined by level-dependent CG sums.…”

Quantum tomography for quantum systems optimization

“…5,6 The latter is of particular interest, as trapped ions, in principle, make it possible to obtain high coherence times and high accuracy of one-and two-qubit gates. [7][8][9] In practice, however, experimental limitations still not allow achieving sufficiently high fidelity values of quantum transformations for chains of several ions. Debugging of quantum transformations is often performed by optimization of control parameters with respect to randomized benchmarking curves.…”

Experimental Demonstration of Swift Analytical Universal Control over Nearby Transitions

“…Therefore, such a technique can go beyond addressing a certain transition, and can be tailored to simultaneously drive nearby transitions. The combination of individual and simultaneous control would lead to the capability of arbitrary manipulations in the nearby transitions, and may assist in quantum logic operations on multi-level systems [7,[19][20][21][22][23][24][25]. Remarkably, as this technique removes the weak drive limitation, it might be also useful for spectroscopy, where a faster probe to obtain more information might be possible.…”