Quantum supremacy: Who will win the race--Google or IBM?3 min read . Updated: 24 Oct 2019, 02:23 PM IST
- Google claims to have used a quantum machine powered by their fully programmable Sycamore chip consisting of 54 qubits to successfully carry out an experimental computation in 200 seconds
- Quantum supremacy would solve those problems which are beyond the computational capabilities of a present day computer
NEW DELHI : Researchers at Google say they have landed a major breakthrough in the field of quantum computing to achieve the haloed quantum supremacy. In a research paper published in scientific journal Nature, Google claims to have used a quantum machine powered by their fully programmable Sycamore chip consisting of 54 qubits to successfully carry out an experimental computation in 200 seconds. Google claims, to carry out the same computation a supercomputer would take thousands of years .
A quantum computing is very unlike the traditional computer. Unlike modern day computing where a sequence of bits (binary digits used as fundamental unit of computing) can exist in a state of either 0 or 1, qubits (quantum version of bits used by quantum computers) are not restricted to be in one of the two states, and can be both 0 and 1 simultaneously. Also known as superposition, it is this process which lies at the heart of quantum computing and would allow it to solve those problems which are beyond the computational capabilities of a present day computer.
However, Google’s claims to Quantum supremacy has been challenged by IBM. In an official blog post published on 21 October, IBM’s Edwin Pednault, John Gunnels, and Jay Gambetta have questioned the methods used by Google to achieve quantum supremacy and argue that an ideal simulation of the same task can be performed by a classical supercomputer in 2.5 days or lesser time if all their resources such as hierarchy of memories, high-precision computations in hardware, various software assets, and a vast knowledge base of algorithms had been leveraged properly.
The IBM blog hails quantum systems as a feat of science and engineering, and also point out that benchmarking them is an enormous challenge. They called Google’s experiment an excellent demonstration of the progress in superconducting-based quantum computing, but cautioned against seeing it as proof that quantum computers are superior to classical computers.
IBM showed a prototype of its first commercial quantum computer called Q system One in January 2019 and went on to open a quantum computation centre in New York in Sep 2019, giving researchers, educators and developers access to 10 quantum systems. While IBM is widely regarded as a pioneer in the field, its prototypes are still far from ready to solve the complex problems at a commercial level.
Reacting to IBM's claims, Sergio Boixo, Chief Scientist Quantum Hardware, pointed out that Google will open source the quantum simulations used to achieve the quantum supremacy in order to facilitate other groups to analyse and validate their data and techniques.
While Google believes that quantum supremacy is a major milestone in quantum computing, the company also acknowledges the fact that they are still many years away from using the technology to solve real world problems. In a blog post, Google CEO Sundar Pichai notes, “We have a long way to go between today’s lab experiments and tomorrow’s practical applications. It will be many years before we can implement a broader set of real-world applications."
Another limitation of quantum computer is that once it carries out a computation that an existing supercomputer cannot, there is no way to determine if the results are correct or not. In October 2018, a UC Berkley PHD student Urmila Mahadev presented a measurement protocol which would allow a classical computer to interactively verify the result of a quantum computation.
Building an error free quantum computer is another challenge as there is no way to validate the results. Google on its part, claims the Sycamore chip has been designed in a two-dimensional grid where each qubit is connected to four other qubits. This allows the qubit states to quickly interact throughout the entire processor. This is what makes it forward compatible for the implementation of quantum error-correction (a process which minimises scope of error in quantum computation).
IBM’s reservations about Google’ claim on quantum supremacy can be seen as a classical tete-e-tete between two major technology giants where one is trying to take the limelight away from the other. However, it also draws attention to the fact that the technology is still in a very nascent stage and whether it can actually take over from existing computers without causing any major disruption, is yet to be seen. The sheer fact that quantum computer can carry out million times faster calculations than modern day computers can have significant impact on the cryptographic system we rely on to encrypt and secure our data.