Researchers at Google LLC claim that they have made a major breakthrough in Quantum Computing. According to a research paper published in SJN (Scientific Journal Nature), Google claimed that they used a quantum machine powered by their fully programmable ‘Sycamore Chip’ which consists of 54 qubits have successfully completed an experimental computation in 200 seconds (3 minutes 20 seconds) which, if were to be done on a super computer, would have taken about 10,000 years or more.
Quantum computing is on a whole different level than our current modern day computing where a sequence of bits exists in a state of either 0 or 1, rather uses qubits (quantum version of bits) which have no such restrictions and can be both, 0 and 1, simultaneously which is called as ‘Superposition’. This is what allows a Quantum Computer to solve problems and computations which are beyond the capabilities of the computers that are used right now.
However, IBM came forward and challenged Google’s claims of their accomplishment of Quantum supremacy. IBM published an official blog on the 21st of October in which IBM’s John Gunnels, Jay Gambetta, and Edwin Pednault questioned the approach used by Google to achieve quantum supremacy and claimed that the task performed by Google’s quantum computer can be performed by a current supercomputer in two and a half days or less, condition being, if all of its resources like high precision computation in hardware, software assets, hierarchy of memories, and the vast knowledge base of algorithms were to be leveraged properly.
The IBM blog talks about quantum systems as a feat of engineering and science, and claimed that benchmarking any quantum computer will be a colossal challenge in itself. Even though they praised Google’s experiment for the demonstration of the progress in quantum computing based on superconducting, they advised them to not see it as a proof verifying classical computers are inferior to quantum computers.
Google’s Chief Scientist Quantum Hardware, Sergio Boixo reacted to IBM’s claims and said that Google will be making the quantum simulations that were used to achieve this quantum supremacy available to public so that other groups and individuals can analyse and validate their results and methods.
In January 2019, IBM unveiled their first prototype of commercial quantum computers ‘Q system’ and last month even opened a quantum computation center in New York, there IBM give access to educators, developers, and researchers access to ten Q systems. IBM is considered as a pioneer in the field, yet, their prototypes are far away from solving complex problems on a commercial scale.
Google believes that this quantum supremacy is a huge milestone in quantum computing, but also recognizes this as a fact that it will take years to solve the real world problems using this technology. Sundar Pichai, Google’s CEO mentioned in a blog post ‘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’.
There is another limitation to quantum computers that cannot be overlooked, the computations that are carried out by any quantum computers which cannot be done by any existing supercomputer, there is no way to ascertain that the results are true or not. However, Urmina Mahadev, a US Berkley PHD student proposed a measurement protocol by which a classical computer will be able to verify the results of a quantum computer, this was proposed in October 2018.
Because of this, building a quantum computer which is error free has become a huge challenge, since practically there is no way to verify the results. Although Google claims that the ‘Sycamore Chip’ is designed in a two dimensional grid, wherein every individual qubit is connected to four other qubits. This allows quick interactions of qubits with the entire processor, which further enhance its capabilities to implement quantum error correction (it is a process that minimizes the scope of error in quantum computations).