(IEEE.Spectrum) Tony Uttley, President of Honewell Quantum Solutions announced in March, “We expect within next three months we will be releasing world’s most powerful quantum computer”.  On cue, last week the company claimed it had reached that mark.
The benchmark measurement, called quantum volume, is essentially a combined measure of the number of physical qubits, how connected they are, and how error prone they are. For Honeywell’s system, which has 6-qubits, that number is now 64, beating a 53-qubit IBM system that had a quantum volume of 32.
The quantum volume measure isn’t a universally accepted benchmark and has an unclear relationship to the goal Google claimed in 2019, which compares a quantum computer to the theoretical peak performance of classical computers.  But Uttley says it’s the best measure so far. “It takes into account more than just how many physical qubits you have,” he says. Just going by the number of qubits doesn’t work because, “you don’t necessarily get all or even any of the benefits of physical qubits” in real computations.
Honeywell’s computer uses ytterbium ions trapped by an electromagnetic field within a narrow groove built in a chip. The qubit is represented by the spin state of the ion’s outermost electron and that of its nucleus. The qubits are manipulated using lasers and can be moved around the trap to carry out algorithms. Much of the quantum volume advantage of this system comes from the length of time the qubits can hold their state before noise corrupts them and crashes the computation.
Uttley predicts 10-fold boosts in quantum volume per year going forward. His confidence comes from the nature of the ion trap system his team has developed. “It’s like we built a stadium, but right now we’re only occupying a handful of seats.”

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