The quantum information science and technology could be transformed by a new qubit platform.

This article is viewed on a digital device. The bit is either 0 (or 1), which is the basic unit of information. Researchers around the globe are working hard to create a new type computer that uses quantum bits or qubits.

A team from the U.S. Department of Energy (DOE), Argonne National Laborator, has published a paper in the journal Nature describing the creation of a new qubit-platform. This was achieved by freezing neon gas at low temperatures and spraying electrons from a lightbulb’s filament onto the solid. The solid then traps one electron. This system could be used to build future quantum computers.

The quality requirements for qubits in order to realize a useful quantum computing device are very strict. There are many qubits available today, but none is the best.

What makes an ideal qubit? According to Dafei Jin (Argonne scientist, principal investigator on the project), it has at least three of these sterling qualities.

It can be in both a 0 and 1 state simultaneously (remember the cat!) It can remain in a simultaneous 0 and 1 state for a long time. This is what scientists call “long coherence.” It’s a time period that can be perceived on a clock in our everyday life.

Second, the qubit is able to be switched from one state of existence to another within a very short time. Ideally, this time would be approximately one billionth of a second (nanosecond), which is the same time step as a classical computer clock.

Third, qubits can be linked to other qubits in order to work together. This linking is known as entanglement by scientists.

Although the qubits of today aren’t ideal, companies such as Honeywell, Intel, Google and Honeywell have chosen their favourite. They are actively pursuing technological advancement and commercialization.

Jin stated that Jin’s ambitious goal was not to compete with these companies but to create and discover a fundamentally different qubit system that could lead him to an ideal platform.

There are many types of qubits, but the team selected the simplest — one electron. A simple filament of light that you might find in a toy for children can quickly produce an unlimited supply of electrons by heating it up.

The qubit is sensitive to any disturbances from its environment. This is a challenge for all qubits, even the electron. The team decided to trap the electron on a pure, solid neon surface in vacuum.

One of the few inert elements that doesn’t react with other elements is neon. Jin stated that solid neon is inert and can be used in vacuums to protect qubits from being damaged.

The team’s qubit platform includes a chip-scale microwave resonance made from a superconductor. The microwave resonator is also used in the larger home microwave oven. Superconductors, metals that have no electrical resistance, allow electrons and photons interact at close to absolute zero without any loss of energy or information.

“The microwave resonator is crucially able to read out the qubit’s state,” stated Kater Murch (a Washington University in St. Louis physics professor and senior co-author of this paper). It concentrates the interaction of the qubit with the microwave signal. This allows us to measure how well the qubit functions.

“With this platform we achieved, for first time ever strong coupling between a one electron in a near vacuum environment and a single microwavephoton in the resonator,” stated Xianjing Zhang, a postdoctoral appointment at Argonne, and the paper’s first author. Zhou said, “This opens up microwave photons to control every electron qubit and link many in a quantum process.”

The team tested the platform using a scientific instrument called a “dilution fridge”, which can reach temperatures as low at 10 millidegrees above absolute 0. This instrument is part of the many quantum capabilities at Argonne’s Center for Nanoscale Materials (a DOE Office of Science user facility).

The team tested an electron qubit in real time and determined its quantum properties. The solid neon provided a stable environment for the electron, with low electric noise that can disturb it. The most important thing was that the qubit achieved coherence times within the quantum state comparable to state-of the-art qubits.

“Our qubits actually work as well as those that people have been working on for 20 years,” stated David Schuster, a University of Chicago physics professor and senior co-author of this paper. This is just our first series. The qubit platform is far from optimal. We will keep improving coherence times. This qubit platform operates at a very fast speed, just a few nanoseconds. It is therefore possible to scale it up to more entangled qubits.

This remarkable qubit platform has another advantage. Jin stated that the platform’s relative simplicity should allow it to be easy to manufacture at low costs. It would seem that an ideal qubit is on the horizon.