We already have some sort of quantum computer, but right now they’re not practical or reliable or big enough to fully exploit the technology’s huge potential.
To get closer to that ultimate goal, scientists are working on what they think could be the ideal building block for a quantum computer.
These building blocks are called qubits. Unlike classic computer bits, which store either 1 or 0 at any point in time, these qubits can exist in a simultaneous 0 and 1 state, similar to the famous Schrödinger thought experiment, where a cat can be both alive and dead.
This quantum capability promises an exponential leap forward in computing power.
There are several ways to build a qubit, and the vision outlined in the new research may be the closest thing to an ideal qubit, but there are still some ways to go before it becomes a reality.
It consists of a single electron trapped on frozen neon gas. The electron can then be manipulated with a superconducting quantum circuit.
“The relative simplicity of the electron-on-neon platform should lend itself to easy and inexpensive fabrication,” says quantum physicist Dafei Jin of Argonne National Laboratory in Illinois.
“It seems like an ideal qubit is on the horizon.”
The new qubit meets three main criteria set by the scientists. First, the need for it to remain stable over a long period of time, known as quantum coherence. In quantum computing, a long time is about a second.
The ultra-pure solid neon surface is very immune to interference. Trapping the electron in a vacuum allows the electron to remain stable long enough for the qubit to be manipulated for whatever task is at hand.
Qubits must also be able to change from one state to another very quickly (roughly a billionth of a second, or a nanosecond). Finally, they must be capable of entanglement – that is, they must be easily linked to other qubits.
It is these parallel, multi-qubit operations that will unlock the power and potential of full quantum computing.
Another important part of the new qubit is the superconductor-based microwave resonator underneath the qubit – it’s crucial for reading the qubit’s state and measuring how well it’s working.
“With this platform, for the first time ever, we have achieved strong coupling between a single electron in a near-vacuum environment and a single microwave photon in the resonator,” says Xianjing Zhou from Argonne National Laboratory.
“This opens up the possibility of controlling each electron qubit with microwave photons and combining many of them in a quantum processor.”
But that’s the rub — those extreme temperature requirements mean the tests were conducted in a scientific instrument called a dilution refrigerator, which reduces temperatures to just 10 millidegrees above absolute zero (that’s -273.15 degrees Celsius or -459.67 degrees Fahrenheit) can lower.
With that in mind, we’re clearly not ready to pack such qubits into laptops just yet. But even at this early stage, the qubit is already performing at the same level in terms of coherence as alternatives that have been in development for decades.
Companies like Google, Microsoft and IBM are pushing their own qubit designs, but the researchers behind the new technology believe the solution they’ve developed could be their most promising yet.
“Our ambitious goal is not to compete with these companies, but to discover and construct a fundamentally new qubit system that could lead to an ideal platform,” says Jin.
The research was published in Nature.
https://www.sciencealert.com/we-may-finally-have-the-ideal-building-block-for-quantum-computers Perhaps we will soon finally have the ideal building block for quantum computers