Back in 2019
In 2019, Google claimed that Sycamore had become the first to demonstrate “quantum supremacy” by performing a task that would be practically impossible on a classical machine. According to Google, Sycamore had completed a calculation in a few minutes that would have taken the world’s most powerful existing supercomputer, Summit, ten thousand years. The claim was disputed by IBM at that time.
A team of Chinese scientists has developed the most powerful quantum computer in the world, capable of performing at least one task 100 trillion times faster than the world’s fastest supercomputers.
Heavy Investments in Quantum Computing
China has reportedly invested heavily in quantum computing, with its government spending $10 billion on the country’s National Laboratory for Quantum Information Sciences. The country is also a world leader in quantum networking, where data encoded using quantum mechanics is transmitted across great distances.
The team, based primarily at the University of Science and Technology of China in Hefei, reported their quantum computer, named Jiuzhang (九章), is 10 billion times faster than Google’s.
The Light on the Path
To test Jiuzhang, the researchers assigned it a “Gaussian boson sampling” (GBS) task, where the computer calculates the output of a complex circuit that uses light.
“We performed Gaussian boson sampling by sending 50 indistinguishable single-mode squeezed states into a 100-mode ultralow-loss interferometer with full connectivity and random matrix—the whole optical setup is phase-locked—and sampling the output using 100 high-efficiency single-photon detectors. The samples obtained were validated against plausible hypotheses exploiting thermal states, distinguishable photons, and uniform distribution. The photonic quantum computer, Jiuzhang, generates up to 76 output photon clicks, which yields an output state-space dimension of 1030 and a sampling rate that is faster than using the state-of-the-art simulation strategy and supercomputers by a factor of ~1014.”
This success is measured in terms of the number of photons that were detected. Jiuzhang, which itself is an optical circuit, detected a maximum of 76 photons in one test and an average of 43 across several tests. Its calculation time to produce the list of numbers for each experimental run was about 200 seconds, while the fastest Chinese supercomputer, Sunway TaihuLight (神威·太湖之光), would have taken 2.5 billion years to arrive at the same result. That suggests the quantum computer can do GBS 100 trillion times faster than a classical supercomputer.
In comparison to Google’s Sycamore which uses superconducting materials on a chip and more nearly resembles the basic structure of classical computers, Jiuzhang makes its calculations using optical circuits.
Instantaneous Download Speed
The pace of such developments from both the east and the west suggests that the world is approaching a “Quantum era”. Instantaneous response from a mobile device is the prerequisite to consider for a purchase. You might even be able to download a multiple terabyte worth of information in a matter of microseconds.