Australian researchers have found a breakthrough in manufacture of quantum computing. As the basic building blocks, this new type of qubit is able to facilitate large scale production of a quantum computer.
However, the research is not one of its kind as far as manufacture of quantum computers is concerned. There are several ways to make one of these high-tech computers. Some may take up a few square feet, but to manufacture on a large-scale may requires thousands of square feet.
To capture a qubit, scientists use optical tweezers and ion traps. They also use superconducting materials to locate their quantum superpositions. These methods and techniques are relatively easy – most equipment are affordable and easy to assemble.
To link a small number of qubits might not demand much space, but scaling up will probably bring complications.
Thanks to the newly discovered technology in coding information, the qubit can be operated using electric signals. Since the previous technology involved magnetic signals, manufacture can now be done across a larger distance. That makes it easier and cheaper to build into a scalable computer.
“Entanglement’ is such an important process that if the quantim bits are either too close or too far apart, the process does not occur,” says Guilherme Tosi, the University of New South Wales researcher, who developed the new qubit.
The ‘flip-flop qubit’ balances between these two extremes creating a perfect sweet spot for entanglement within a few hundreds of nanometers.
This might just be the final piece of puzzle in the realm of silicon-based quantum computers.
“Although we only have its blueprint, the development of this device is as crucial as the 1998 seminal paper by Bruce Kane on silicon quantum computing ” stated Andrea Morello, the research team leader.
“Similar to Kane’s paper, our project is a proposal and the qubit is yet to be built.” Morello explains. “Our experimental data suggests that the project is possible and hopefully we shall demonstrate this later. But I think this research is as visionary as Kane’s original paper.”
The flip flop qubit’s main function is to code information on both the nucleus and electron of a phosphorus atom. The atom, which is implanted in a silicon chip, is chilled to absolute zero temperatures and the whole unit is saturated with magnetic fields.
Through multiple processes that involve binary properties(spin), qubit’s value can be calculated. If the spin is ‘down’ for a nucleus while ‘up’ for an electron the overall qubit’s value is 1. When reversed, qubits value becomes 0. The spin states are therefore crucial in quantum operations.
In flip-flop, researchers use electric fields instead of magnetic ones to control the qubit. This gives two main advantages – easy integration with electronic circuits and better communication of the qubits over lager distances. “To effectively control this qubit, you need to move the electron away from the nucleus using electrodes at the top. As a result, electric dipoles emerge,” says Tosi.
“This is the important point,” explains Morello. “The electric dipoles interact over large distances of up to 1,000 nanometres.”
“It(the distance) allows us to place key classical components between the single-atom qubits while retaining the exact nature of the quantum bit. So, there is plenty of space of interconnects, readout devices or contor elecrodes,” adds Morello.
“In a nutshell, the new flip-flop qubit could make future quantum computers small and affordable. It is an ingenious design that no one had ever thought of before,” says Morello.
The research has been published in Nature Communications.