Is China leading the quantum computing race?
- A Chinese quantum computer succeeded in performing a calculation 100 trillion times faster than a conventional computer could — surpassing Google’s achievement by a factor of 10 billion
- China has invested heavily in quantum computing, with Xi Jinping’s government spending US$10 billion on the country’s National Laboratory for Quantum Information Sciences
Just last year a team from Google achieved what it called “quantum supremacy” when its quantum computer performed a calculation faster than a conventional computer could. Google’s John Martinis and Sergio Boixo in a blog post said “Our machine performed the target computation in 200 seconds, and from measurements in our experiment, we determined that it would take the world’s fastest supercomputer 10,000 years to produce a similar output.”
And earlier this month, a team under the direction of Pan Jianwei at the University of Science and Technology in China (USTC), said its quantum computer succeeded in performing a calculation 100 trillion times faster than a conventional computer could — surpassing Google’s achievement by a factor of 10 billion, according to the Xinhua.
The state-run news agency said the researchers have built a quantum computer prototype that is able to detect up to 76 photons through Gaussian boson sampling, a standard simulation algorithm, citing research published in Science magazine. That’s exponentially faster than existing supercomputers.
It is important to note that all computing systems rely on a fundamental ability to store and manipulate information. Quantum computers leverage quantum mechanical phenomena to manipulate information. To do this, they rely on quantum bits, or qubits, whereas current computers manipulate individual bits, which store information as binary 0 and 1 states. Qubits are synonymous with binary bits of classical computers, but unlike binary bits, it can exist in many states simultaneously.
China’s quantum supremacy
Having understood the race to quantum supremacy, researchers from USTC explained that this quantum computer prototype named Jiuzhang delivered results in minutes calculated to take more than 2 billion years of effort by the world’s third-most-powerful supercomputer. This achievement marks China’s first milestone on its mission to attain full-scale quantum computing.
According to reports, Lu Chaoyang, a professor in charge of the experiment at USTC stated that Jiuzhang achieved the breakthrough by manipulating particles of light. The approach is different than the one used by Google, which used super cold, superconducting metal, to build quantum circuits to manipulate qubits.
IBM too leveraged on a similar approach. In fact, both tech giants have invested large sums of money into superconducting circuits to push quantum computing research. On the other hand, Honeywell and IonQ have been developing alternative quantum computing architectures that involve trapping ions. Moreover, Australia’s Silicon Quantum Computing uses spin-based silicon qubits for its quantum systems. As for Google’s Sycamore, 54 qubits were used, which were cooled to fractions of a degree above absolute zero. Only one qubit didn’t work but the remaining 53 were enough to demonstrate supremacy over conventional computers on a carefully chosen statistical problem.
In comparison, for Jiuzhang the research team led by quantum physicist Jian-Wei Pa built a large tabletop setup consisting of lasers as the light source and beam splitters to help create the individual photons, along with hundreds of prisms and dozens of mirrors to provide the randomized paths for the photons to travel. Wired mentions that each photon read out at the end of the process can be thought of as is roughly equivalent to reading out a qubit on a processor like Google’s, revealing the result of a calculation.
The researchers equipped Jiuzhang with 300 beam splitters and 75 mirrors. Up to 76 output photon-clicks were observed while the average detected photon number by the prototype is 43, during experimental runs lasting 200 seconds. Comparatively, the Chinese supercomputer, TaihuLight, would have taken 2.5 billion years to arrive at the same result.
However, Jiuzhang cannot be used immediately in real-life applications. It will need to work with a programmable chip to perform various calculations. On rumors about the threat, it poses to cryptocurrency, or any encryption used by finance, communication, and government systems currently; Jiuzhang is reported to be unable to solve the factoring problem that is crucial to decoding encrypted information.
To date, China has invested heavily in quantum computing, with Xi Jinping’s government spending US$10 billion on the country’s National Laboratory for Quantum Information Sciences.