Centre updates

Tuning into quantum: scientists unlock signal frequency control of precision atom qubits

CQC2T scientists, led by Prof Michelle Simmons, have achieved a new milestone in their approach to creating a quantum computer chip in silicon, demonstrating the ability to tune the control frequency of a qubit by engineering its atomic configuration.

The team from UNSW Sydney successfully implemented an atomic engineering strategy for individually addressing closely spaced spin qubits in silicon. The scientists created engineered phosphorus molecules with different separations between the atoms within the molecule allowing for families of qubits with different control frequencies. Each molecule could then be operated individually by selecting the frequency that controlled its electron spin.

“The ability to engineer the number of atoms within the qubits provides a way of selectively addressing one qubit from another, resulting in lower error rates even though they are so closely spaced,” says Professor Simmons. “These results highlight the ongoing advantages of atomic qubits in silicon.”

Tuning in and individually controlling qubits within a 2 qubit system is a precursor to demonstrating the entangled states that are necessary for a quantum computer to function and carry out complex calculations.

“We can tune into this or that molecule – a bit like tuning in to different radio stations,” says Sam Hile, lead co-author of the paper and Research Fellow at UNSW. “It creates a built-in address which will provide significant benefits for building a silicon quantum computer.”

Read paper here
Read article here

Dr Jacq Romero named L'Oréal Australia women in science fellow

Dr Jacq Romero, a researcher in CQC2T's photonic quantum computation program at the University of Queensland, has been named one of five L'Oréal Australia women in science fellows. Romero was recognised for her work creating quantum “alphabets” using the orbital angular momentum of light.

CQC2T congratulates Dr Romero and the four other fellows.

See the full list of fellows in Cosmos Magazine

Learn more about Dr Romero's work

Large-scale quantum circuitry challenges can be overcome for electron spin qubits in quantum dots or donors

Prof Andrew Dzurak and Prof Andrea Morello have contributed to a review of approaches to quantum circuitry for semiconductor spin qubits showing that electron spin qubits in quantum dots or donors offer several opportunities to overcome the challenge of wiring up large qubit arrays.

Sparse qubit array with local electronics

The review was published in npj Quantum Information and concludes that continuous development of semiconductor technology is paving the way for the construction of a large-scale universal quantum computer.

Read the full article in npj Quantum Information