New article: Trapped ions and superconductors face off in quantum benchmark read more at here http://www.spinonews.com/index.php/science/item/3310-trapped-ions-and-superconductors-face-off-in-quantum-benchmark

Researchers at the JQI have performed a first-of-its-kind benchmark test of two small quantum computers built from different technologies.

Researchers sized up their own small-scale quantum computer against a device built by IBM. Both machines use five qubits the fundamental units of information in a quantum computer and both machines have similar error rates. While, the JQI device relies on chains of trapped atomic ions, IBM Q uses coupled regions of superconducting material.

To make their comparison, the JQI team ran several quantum programs on the devices, each of which solved a simple problem using a series of logic gates to manipulate one or two qubits at a time. Researchers accessed the IBM device using an online interface, which allows anyone to try their hand at programming IBM Q.

Both computers have strengths and weaknesses. For example, the superconducting platform has quicker gates and may be easier to mass produce, but its man-made qubits are all slightly different and have shorter lifetimes.

When put to the test, researchers found that the trapped-ion module was more accurate for programs that involved many pairs of qubits.

 

 

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Researchers attribute this to the simple fact that every qubit in their device is connected to every other meaning that a logic gate can connect any pair of qubits. IBM Q has fewer than half the connections of its JQI counterpart, and in order to run some programs it had to shuffle information between qubits, a step that introduced errors into the calculation.

When this shuffling wasn't necessary, the two computers had similar performance. "As we build larger systems, connectivity between qubits will become even more important," Monroe says.

The new study provides an important benchmark for researchers studying quantum computing. And such head-to-head comparisons will become increasingly important in the future. 

More information: [PNAS]