Sydney a natural choice for a $10 million grant to suppress quantum errors

Quantum Promise

The quantum revolution promises to revolutionize technology by developing machines that can calculate in entirely new ways.

By exploiting the strange nature of matter on the smallest scales, quantum machines offer opportunities to develop new materials and design new pharmaceuticals and chemistry. The limits of his promise are unknown.

However, the unusual physical properties – entanglement, superposition, teleportation – that offer the potential for quantum computation are notoriously fragile and easily subject to interference. This is known as decoherence.

“We’re trying to exploit the properties of matter at the atomic scale, with all the weirdness that comes with it,” says Professor Bartlett.

“By encoding information into the electronic current within superconductors, we create bits of quantum information, commonly called qubits.

“Unlike digital bits in classical computers, which are switches that are turned on or off, qubits encode information using the superposition, or uncertainty, of quantum states.

“This means that we can develop completely new computer programs to solve different problems. But it also means that the information is very vulnerable.”

Error versus logic

This vulnerability means that quantum computers produce errors about as quickly as they produce useful information.

“Our goal is to protect our quantum information so that the useful information outlasts the error rate. This means that a large part of the work of the qubits we make is to suppress errors,” says Professor Bartlett.

This is at the heart of “quantum error correction,” which essentially involves writing code that allows physical qubits to suppress errors so that a few of the qubits can perform meaningful computations.

This creates the difference between ‘physical qubits’ and ‘logical qubits’.

Dr. Harper said: “Even after we have produced a logical qubit, resulting from the error-suppressing work of dozens or even hundreds of physical qubits, the trick we must perform next is to entangle two or more logical qubits so that they can work together. .”

Ultimately, the goal of a universal, fault-tolerant quantum computer will likely require millions of entangled logic qubits. That means scientists must develop ingenious code to reduce the number of qubits that perform error correction.

The qubits of tomorrow

Professor Bartlett said: “It is an emerging truth that tomorrow’s large-scale, functional quantum computers will not be built with today’s noisy qubits.

“However, it is by benchmarking existing error correction on noisy qubits that we can anticipate the development of robust quantum error correction that will maximize the performance of the next generation of qubits as they emerge.”

Professor Bartlett said the quantum technology industry is a global business.

“We are fortunate here in Sydney to be connected to global supply chains with leading technology companies, such as IBM and Microsoft.

“This means that we are not only at the forefront of research, but also in the pole position for training quantum engineers to develop a domestic industry.”