The basic units of quantum computers are being paved for by research conducted by the physicists at the University. This research promises to accelerate the use of Silicon technology as a viable alternative to other quantum computing technologies.
In research published in the journal Science Advances, physicists used a two qubit Silicon quantum device to achieve an unprecedented level of fidelity. This is the highest fidelity thus far achieved for a two-qubit gate in a Semiconductor and is on par with the best results achieved by competing technologies. The quest to develop practical and efficient quantum computing relies on Fidelity, which is a measure of a qubit's ability to perform error-free operations.
Researchers around the world are trying to figure out which technologies can be used as the basic units of quantum computing. Researchers are looking at which technologies have the ability to scale up most efficiently.
Adam Mills, a graduate student in the Department of Physics at Princeton University and the lead author of the recently published study, said that Silicon spin qubits are gaining traction.
By using a double quantum dot, the researchers were able to capture two electrons and force them to interact. The spin state of each electron can be used as a qubit. The research team, led by the Eugene Higgins Professor of Physics at Princeton, was able to perform this operation at a fidelity level greater than 99%.
A qubit is a quantum version of a computer bit, which is the smallest unit of data in a computer. The qubit has the same information that can be either one or zero. The qubit is able to do things that classical bits can't.
You can have superpositions of zeros and ones in a qubit. Each qubit can be a zero and a one at the same time. A fundamental quality of quantum mechanics is called superposition and it allows qubits to do operations that seem amazing. It allows the quantum computer to have a greater advantage over conventional computers, for example, using very large numbers or isolating the most optimal solution to a problem.
The spin in qubits is the electron's spin. It is a quantum property that can be used to create a magnetic field. A classical compass needle has north and south poles and rotates to align with the Earth's magnetic field. The spin of the electron can be aligned with the magnetic field generated in the lab, anti-parallel to the field, or in a quantum superposition of spin-up and spin-down. Conventional computers work by manipulating an electron's negative charge, while quantum devices harness the electron's spin.
Mills said that Silicon spin qubits have advantages over other qubit types. There could be a problem with these systems. There is only so much space you can use.
Silicon spin qubits are very small and made from single electrons.
If you want to make many on a chip using a superconducting approach, it is going to be difficult because our devices are just 100 nanometers across.
If you want to make a million or ten million qubits that are going to be required to do something practical, that is the advantage of Silicon spin qubits.
It has been a challenge for researchers to operate spin qubits with a high fidelity.
The two-qubit gate fidelity for spin qubits has not been as high as it could have been.
It was a challenge that Petta and Mills believed could be accomplished.
To perform the experiment, the researchers had to capture a single electron.
Petta said that they were trapping a single electron, a very small particle, and needed to get it into a specific region of space.
To do this, Mills, Petta and their colleagues needed a wafer-thin Semiconductor made primarily out of Silicon. At the top of the structure, the team patterned little electrodes that create the potential to corral the electron. Two cages were separated by a barrier and constituted the double quantum dot.
Petta said that they have two spins sitting next to each other. This is a two-qubit gate.
The interaction causes each spin qubit to evolve according to the state of its neighboring spin qubits, which leads to entanglement in quantum systems. The researchers were able to perform a two-qubit interaction. This is the highest fidelity for a two-qubit gate that has been achieved so far.
Petta said that the results of this experiment place this technology on an equal footing with the best results achieved by the other major competing technologies.
This device does it all, and it is an important aspect of the paper. This is the first demonstration of a spin qubit system where the state preparation, read out, single qubit control, and two-qubit control are integrated with performance metrics that exceed the threshold you need.
The work included the efforts of Mills and Petta, as well as graduate students from Princeton and the University of Pennsylvania. The Center for Quantum Information and Computer Science at NIST/University of Maryland, as well as Michael Gullans, Department of Physics, Princeton University, contributed to the paper.
More information: Adam R. Mills et al, Two-qubit silicon quantum processor with operation fidelity exceeding 99%, Science Advances (2022). DOI: 10.1126/sciadv.abn5130 Journal information: Science Advances Citation: In race to build quantum computing hardware, silicon begins to shine (2022, April 6) retrieved 6 April 2022 from https://phys.org/news/2022-04-quantum-hardware-silicon.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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