In what could be one of the significant developments in the field of quantum computing, Chinese researchers suggest having achieved quantum supremacy with the capability of performing calculations 100 trillion times faster than the world’s most advanced supercomputer. Researchers from the University of Science and Technology of China, Hefei, believe that when put into practical use, it can carry calculations in minutes which would have otherwise taken two billion years to perform. The fastest supercomputers, before this, claimed to have achieved computational efficiency easing up to 10,000 years of calculations.
Jiuzhang, as the supercomputer is called, has outperformed Google’s supercomputer, which the company had claimed last year to have achieved quantum computing supremacy. The supercomputer by Google named Sycamore is a 54-qubit processor, consisting of high-fidelity quantum logic gates that could perform the target computation in 200 seconds.
How Jiuzhang Achieves Quantum Supremacy
The researchers explored Boson sampling, a task considered to be a strong candidate to demonstrate quantum computational advantage. As the researcher cited in the research paper, they performed Gaussian boson sampling (GBS), which is a new paradigm of boson sampling, one of the first feasible protocols for quantum computational advantage. In boson sampling and its variants, nonclassical light is injected into a linear optical network, which generates highly random photon-number, measured by single-photon detectors.
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Researchers sent 50 indistinguishable single-mode squeezed states into a 100-mode ultralow-loss interferometer with full connectivity and random matrix. They further shared that the whole optical setup is phase-locked and that the sampling of output was done using 100 high-efficiency single-photon detectors.
GSB has been identified as a highly-efficient approach to such large-scale implementations while offering potential applications in graph-based problems and quantum chemistry. “Instead of using single photons, GBS makes full use of the Gaussian nature of the PDC sources and utilises single-mode squeezed states (SMSS) as the input of nonclassical light sources, which can be deterministically prepared,” said researchers.
Following this method, researchers found that it took Jiuzhang approximately 200 seconds to provide an answer. It further obtained 3,097,810 events of 43-photon coincidence and a dimension of 1030 and a sampling rate that is ~1014 faster than using the state-of-the-art simulation strategy and supercomputers.
Researchers hope their findings will inspire new theoretical efforts in quantum computing while improving the classical simulation strategies.
How Does It Outperform Google’s Supercomputer
While Google builds quantum circuits using supercold, superconducting metal, the team of researchers from China, used photons — particles of light. As a matter of fact, the use of photons can prove to be the next big step in the application of large quantum fault-tolerant quantum computers.
While Google’s supercomputer could perform computation in 200 seconds, easing out calculations of about 10,000 years, Chinese researchers claim that their new prototype can process 10 billion times faster than Google’s prototype.
Google’s experiment used a superconducting chip with 54 qubits, cooled to fractions of a degree above absolute zero. Whereas, the Chinese team’s quantum data carriers take the form of photons travelling through optical circuits guided by mirrors.
The Future Of Supercomputers Is Highly Competitive
We have seen a deluge in supercomputers over the past few years with companies such as IBM, Microsoft, Intel, Nvidia and even startups looking to invest heavily into developing quantum computing hardware.
With the use of photons in making of a supercomputer, researchers are exploring newer avenues in quantum computing. The researchers believe that this new efficiency in quantum computers can help advance research in areas such as studying the properties of molecules, problems involving mathematical graphs, and more. Moreover, the fact that it is based on photons makes it easily scalable than supercomputing chips by other companies.
Read the complete paper here.