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quantum computer

Researchers develop way to ‘tune’ superconducting ‘qubits,’ the basic computation units of a superconducting quantum processor.

By Pesach Benson, TPS

Researchers in Israel and the United Arab Emirates are advancing quantum computing by improving the performance of superconducting “qubits,” the basic computation units of a superconducting quantum processor.

The quantum features developed by Bar-Ilan University in collaboration with TII – the Quantum Research Center in Abu Dhabi, would allow the computer to be much faster and more powerful than a normal computer.

Quantum computers are expected to revolutionize both the speed and volume of computer processing, making quantum technology critical for advancements in physics, chemistry, artificial intelligence, cyber security, medicine, and more.

For the speed potential to be realized, the quantum computer needs to operate several hundred of “qubits” or quantum bits simultaneously. Traditional computing relies on “binary bits” using ones and zeroes, but qubits operate as ones and zeroes simultaneously. The challenge is to keep the qubits from unintentionally interfering with each other.

The Israeli-Emirati team developed what they called the “tunable superconducting flux qubit,” a micron-sized superconducting loop where electrical current can flow clockwise or counterclockwise, or in a quantum superposition of both directions.

For comparison, the average human hair is 50-70 microns wide.

Their findings were recently published in the peer-reviewed journal, Physical Review Applied.

Dr. Michael Stern, of Bar-Ilan University’s Department of Physics and Quantum Entanglement Science and Technology Center, compared flux qubits to playing a piano.

“Imagine wanting to play a certain note on a piano, but actually playing a number of keys together simultaneously and inadvertently, since the distance between the various keys isn’t large enough,” Dr. Stern said.

“One of the main advantages of flux qubits is that- the ‘pianist’ can always produce the sound he wants to produce due to the ample separation between ‘keys.’”

He added, “But of course, you need to tune the keys of your piano before playing.”

In keeping with the piano analogy, the technological complication encountered by flux qubits until recently was a difficulty in controlling and changing their “tone”. It was almost impossible to change the frequency of a flux qubit without destroying its coherence.

In the recent paper the researchers showed that they could not only control the production of the qubits, but also actively change their frequency without compromising their performance.

“The flux qubit allows keys to be disconnected from one another,” says Stern. “Just like in a symphony, it isn’t enough just to have keys that function, but also the ability to tune and control the keys independently of each other in order to work in unison.”