Google Claims “Quantum Supremacy”

Andrew Gu ‘23

Google’s state-of-the-art quantum computer, dubbed “Sycamore,” has solved a problem deemed virtually impossible for normal machines. Sycamore completed what would have taken the most powerful supercomputers about 10,000 years in a record-breaking 200 seconds. The completed task consisted of generating a long list of random numbers and checking their values millions of times.


One key feature of a quantum computer like Sycamore is the usage of qubits instead of bits. Normal computers complete tasks using bits, which have two possible values, 1 and 0, and act as an on/off switch, 1 being “on” and 0 being “off.” Qubits, which are used by quantum computers, have the ability to hold both values at once.


This is a state known as superposition, which is the key advantage quantum computers have over classical computers. For example, a pair of bits can only yield four different combinations of on/off values, while a pair of qubits can hold all 4 combinations at the same time. This is what makes Google’s computer so powerful—according to Live Science, “Google’s new computer with 53 qubits can store 253 values, or more than 10,000,000,000,000,000 (10 quadrillion) combinations.”


IBM, another competitor in the quantum computing race, quickly posted an article disputing Google’s claims to quantum supremacy after the news of the successful completion of the task broke. The company disputed that Google’s task was a technological breakthrough, citing possible errors in Google’s calculation of how long it would take a classical computer to complete the same task. 


The article argued that, “an ideal simulation of the same task can be performed on a classical system in 2.5 days and with far greater fidelity. This is, in fact, a conservative, worst-case estimate, and we expect that with additional refinements the classical cost of the simulation can be further reduced.” 


Even though Google completing the task was certainly considered a technological advancement by some, the article pushed the idea that Google had not yet attained quantum supremacy, defined by John Preskill, an American physicist at the California Institute of Technology, as the threshold where, “quantum computers can do things that classical computers can’t.”


As the debate over quantum supremacy rages on, it remains to be seen whether or not Google has claimed quantum supremacy with Sycamore. Nevertheless, this has sparked the race to create the most advanced quantum computers, reminiscent of how Ed Roberts’ 1975 introduction of a revolutionary personal computer, the Altair 8800, sparked a new era of advanced personal computer manufacture.