A team of researchers from UNSW have demonstrated the operation of a new type of quantum bit, called a ‘flip-flop’ qubit.
It’s not a pair of thongs, rather a major breakthrough in the world of quantum computing.
A flip-flop quantum bit (qubit) combines the “exquisite quantum properties of single atoms, with easy controllability using electric signals”, just like those used in ordinary computer chips.
Qubits are essentially units of information that are used to make quantum computing calculations.
According to team lead, Professor Andrea Morello, new qubits, or new modes of operations, are sometimes discovered by lucky accident.
“But this one was completely by design,” he said. “Our group has had excellent qubits for a decade, but we wanted something that could be controlled electrically, for maximum ease of operation. So we had to invent something completely new.”
The team out of UNSW was the first in the world to demonstrate that using the spin of an electron as well as the nuclear spin of a single phosphorus atom in silicon could be used as qubits.
While both qubits perform exceptionally well on their own, they require oscillating magnetic fields for their operation, Morello explained. He also explained that magnetic fields are difficult to localise at the nanometre scale, which is the typical size of the individual quantum computer components.
We already noted this flip-flop qubit discovery wasn’t an accident, but it’s worth highlighting that the team has been working on this for a while. A few years ago, they realised that by defining the qubit as the combined up-down/down-up orientation of the electron and the nucleus of the atom would permit controlling such qubit using the electric fields alone. Today’s result is the experimental demonstration of that idea.
“This new qubit is called ‘flip-flop’ because it’s made out of two spins belonging to the same atom – the electron and the nuclear spin – with the condition that they always point in opposite directions,” added Dr Rostyslav Savytskyy.
“For example, if the ‘0’ state is ‘electron-down / nucleus -up’ and the ‘1’ state is ‘electron-up / nucleus-down’, changing from ‘0’ to ‘1’ means that the electron ‘flips’ up and the nucleus ‘flops’ down. Hence the name!”
It’s a lot to wrap your head around if you aren’t immersed in the world of quantum computing, but it’s great to see UNSW continue its work of smashing barriers in the quantum space.
You can read more about the flip-flop qubit breakthrough via the UNSW newsroom and in the paper published in Science Advances.