The Problem of Qubits

A new study published today has solved the biggest problem that had quantum computing proponents stumped. While the premise behind quantum computers is theoretically sound, its execution has been problematic since it was first imagined 30 years ago. That is, until now.

Researchers from the University of Tokyo’s School of Engineering have come up with a way to manage the problem of qubits — the unit of quantum computing, whose quantum effects tend to fall apart too quickly before any workable computing could be achieved.

A bit of a background: silicon-chip based, integrated circuit computing — what we use today — use zeros and ones to process information. These are called binary bits. Quantum computers, on the other hand, use quantum mechanics to encode 0s and 1s into two distinguishable quantum states, called quantum bits or qubits, to process information.

As quantum states, the phenomena of “superposition” and “entanglement” can be applied to qubits. It was this entanglement that the Japanese researchers were able to manage allowing for more stable quantum computing.

Controlling Entanglement

“There is a problem of the lifetime of qubits for quantum information processing. We have solved the problem, and we can continue to do quantum information processing for any time period we want. The most difficult aspect of this achievement was continuous phase locking between squeezed light beams, but we have solved the problem,” explained Professor Akira Furusawa, from the School of Engineering’s Department of Applied Physics.

The researchers used laser light to come up with a precise, continuous control technology that sustained the life of qubits and it was 60 times more successful than previous attempts. It was achieved by prolonging the entangled state of more than one million different systems — setting a record that could have been higher, had it not been limited by data storage.

Quantum computers are considered to be the next stage of computing. And rightly so. The potential of using quantum behavior to process information or data opens powerful possibilities for computing. Quantum behavior, like superposition and entanglement, allows for computers with processing power unparalleled to anything we have today.

Furusawa acknowledges that the next step is to make quantum computing practical. He and his team will work on creating 2-D and 3-D lattices of the entangled state to “enable us to make topological quantum computing, which is very robust quantum computing.”

The breakthrough study was published today in the journal APL Photonics.