China's Researchers Said that They Are The First To Achieve 'Quantum Supremacy'


When common computers require data to be encoded into binary digits (bits), which is either 0 or 1, quantum computation uses quantum bits, or qubits for short, which can be in superpositions of states.

These qubits can be constructed in various ways, many of which involve super-cooled superconductors to take advantage of the quantum mechanics. As a result, a qubit can represent both 0 and 1 simultaneously. And, whereas the status of each conventional bit is independent of all the other bits in a computer, qubits influence one another.

In theory, this could make quantum computers solve a a problem in milliseconds that it would take a normal computers thousands of years to solve.

Back in 2011, D-Wave One was considered by many as the the world's first commercially available quantum computer.

Fast forward, researchers from the University of Science and Technology of China (USTC), headed by the renowned Chinese quantum physicist Pan Jianwei, published a paper indicating they’ve created a quantum computer that’s one million times faster than Google’s 53 qubits Sycamore machine.

Jiuzhang 2.0
The "Jiuzhang 2.0" quantum supercomputer uses photonics quantum computing technology to achieve what its creators said, "quantum supremacy." (Credit: University of Science and Technology of China)

The first Chinese computer system in the research, is called "Zuchongzhi 2.1," named after the noted 5th century Chinese mathematician and astronomer.

The researchers in China built the machine using 66-qubit quantum processor that uses superconducting material to perform calculation through the flow of electrons.

This computer is similar to Google's Sycamore.

The team then ran specific algorithms at a scale which would supposedly be too complex for a classical computer to accomplish, and said that the system is 10 million times faster than the current fastest supercomputers.

The main highlight is that the team also built another machine, which replaces the superconducting material with an optical circuit quantum processor in order to perform calculations using photons, rather electrons.

This machine uses 113 photon in what the researchers called the "Nine Chapter 2" quantum computing prototype (Chinese: 九章二号).

Called the "Jiuzhang 2.0," the publication said that the computer could "carry out large-scale GBS (Gaussian boson sampling) 100 trillion times faster than the world's fastest existing supercomputer.".

Another way of saying it, it is reported that Jiuzhang 2.0 can take 1 millisecond to perform a task that would take a conventional computer 30 trillion years.

This is a significant jump from "just" some "tens of thousands of years."

Jiuzhang 2.0
The "Jiuzhang 2.0" quantum supercomputer was inspired by the concept of laser-"stimulated emission light amplification", which significantly improved the yield, quality and collection efficiency of the quantum light source. (Credit: University of Science and Technology of China)

Writing for APS Physics, the researchers said:

"The two major results by the … group push experimental quantum computing to far larger problem sizes, making it much harder to find classical algorithms and classical computers that can keep up. The results take us further toward trusting claims that we have indeed reached the age of computational quantum primacy."

Based on these two computers, China becomes the first, and this time, the only country to have achieved quantum computational advantage in two mainstream technical routes.

China achieved milestones in both photonic and superconducting technological paradigms.

In the paper, it is argued that their device reached “quantum supremacy.”

According to Yuan Lanfeng, a researcher at the Hefei National Laboratory for Physical Sciences at USTC, quantum supremacy is a scientific concept that states a quantum computer can do things in some fields beyond the capability of non-quantum or classical computers.

In other words, the term that was first coined by John Preskill in 2012, refers to the goal of demonstrating that a programmable quantum device can solve a problem that no classical computer can solve in any feasible amount of time.

But still, said Yuan Lanfeng, quantum computers will never replace classical computers.

Further reading: Pentagon's Chief Software Officer Quits Because China's AI Is Superior