Silicon quantum chips have exceeded 99% accuracy

Three separate research groups have demonstrated high fidelity rates in silicon-based quantum processors, demonstrating independently the feasibility of using silicon chips to conduct computations at the quantum level. The research results were published in the journal “Nature“. The three teams achieved fidelity levels above 99 percent in their experiments. Silicon chips can be used to build large-scale, error-correcting quantum computers.

Silicon-based quantum devices with tro atoms

More accurate results

Specifically, the team from the University of New South Wales (UNSW) in Australia demonstrated fidelity levels of up to 99.95 per cent for operations on a single qubit and 99.37 per cent on two qubits. The team at the Delft University of Technology in the Netherlands achieved 99.87% with one qubit and 99.65% with two qubits. The team at the RIKEN Institute in Japan achieved 99.84% fidelity in a one-qubit system and 99.51% with two qubits. In silicon-based quantum chips, dedication has always been relatively low. The results obtained in these new studies, however, are significant because, as Professor Andrea Morello, leading the Australian team, said:

“When errors are so rare, it becomes possible to detect them and correct them when they occur. this shows that it is possible to build quantum computers that have sufficient scale and computational power to handle significant computations.”

Andrea Morello

UNSW’s system is based on a three-qubit chip, consisting of two phosphor atoms and an electron implanted in a silicon substrate. The two atoms can communicate via an electron, to which they are both connected. In this way, logical operations can be performed between the two nuclei, exploiting their nuclear spin to create a qubit.

“If you have two nuclei connected to the same electron, you can have them perform a quantum operation. Even if you don’t run the electron, those nuclei securely store their quantum information. But now we have the ability to make them communicate with each other via the electron, to make universal quantum operations that can be adapted to any computational problem”


said physicist Mateusz Mądzik of UNSW.

A visualization of UNSW’s three-qubit system for Sidi blog Universe

An excellent study divided by team

The other two teams created silicon and silicon-germanium alloy quantum dots and installed a two-electron qubit gate, a circuit of multiple qubits. They then modified the voltage applied to their respective systems, using a protocol called “gate set tomography” to characterize their installations, and both achieved a margin of error of less than 99 per cent.

“The presented result makes spin qubits, for the first time, competitive with superconducting circuits in terms of universal quantum control performance. This study demonstrates that silicon quantum computers are promising candidates, along with superconductivity, for research and development towards large-scale quantum computers”.

Netherlands Seigo Tarucha

Commented the team leader from the Netherlands Seigo Tarucha.

The silicon nanoelectronic device for Sidi blog Universe

A few previous articles on Universe to find out more about the topic:

  1. The benefits of learning about Quantum Computing today
  2. Five reasons why you should study Quantum Computing
  3. A new turn towards the “quantum brain”

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