Construction of practical quantum computers radically simplified

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NQIT researchers at the University of Sussex have proposed an exciting new architecture for scalable ion trap quantum computing that could radically simplify the engineering challenge of building a large-scale quantum computer.

Quantum computers could solve certain problems - that would take the fastest supercomputer millions of years to calculate - in just a few milliseconds. They have the potential to create new materials and medicines, as well as solve long-standing scientific and financial problems. Universal quantum computers can be built in principle - but the technology challenges are tremendous, perhaps more difficult than manned space travel to Mars.

In a new paper published in Physical Review Letters, Dr Seb Weidt and Professor Winfried Hensinger and colleagues from the Ion Quantum Technology Group, present a fundamentally different approach for trapped-ion quantum computing that uses voltages and microwave fields to control the ions, rather than lasers. This new design is based on individually-controlled voltages applied to each logic gate location, analogous to a traditional transistor architecture within a classical computer processor. When implemented, it would allow a substantial reduction in the number of laser beams required and a simplification of the design of the “chip” used to hold the trapped-ion qubits.

As a first step towards this concept, they have demonstrated a versatile quantum gate based on a far-field microwave ion trap, with an impressively high fidelity of 98.5%. This is more than an order of magnitude improvement compared with the previous demonstration using this method and very close to the 99% required for fault-tolerant quantum computing.

This new proposed architecture, along with the far-field microwave ion trap result, puts the construction of large-scale quantum computers within reach of current technology.

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Professor Winfried Hensinger and Dr Seb Weidt
diagram of a trapped-ion quantum computer