Google's quantum chip, named Sycamore, made headlines in 2019 when the company claimed it had achieved quantum supremacy. This is a milestone in quantum computing where a quantum computer performs a specific calculation that is effectively impossible for a classical supercomputer to solve in a reasonable amount of time.

What It Did 🤯
Google's Sycamore processor, which at the time had 53 operational qubits (the quantum equivalent of a classical bit), performed a specific calculation in 200 seconds that the company estimated would have taken the world's most powerful classical supercomputer at the time, Summit, approximately 10,000 years to complete.  The task involved a random sampling problem, specifically designed to demonstrate the unique computational power of a quantum system without being a useful, real-world application.

The Controversy and What It Proved 🤔
The claim of quantum supremacy was a significant milestone, but it was also met with some debate. IBM, a major competitor in the quantum space, argued that a different classical approach could have solved the same problem on a supercomputer in just 2.5 days, not 10,000 years.

Despite the controversy over the specific time estimates, the experiment was a landmark achievement because it was the first time a quantum device had definitively and experimentally outperformed a classical computer for a defined computational task. The experiment showed that a quantum computer could maintain quantum coherence and entanglement on a large enough scale to perform a computation that was beyond the reach of the best known classical algorithms at the time.

How It Defied Reality 🌌
The chip's abilities stem from the principles of quantum mechanics. Unlike a classical computer's bits, which can only be a 0 or a 1, a qubit can be both a 0 and a 1 at the same time through a property called superposition. As more qubits are added, the number of possible states the system can explore simultaneously grows exponentially. This allows a quantum computer to solve certain complex problems, like factoring large numbers or simulating molecular interactions, far faster than any classical machine.

This video shows a short overview of how Google's quantum computer works.

Google's Quantum Computer Achieves Quantum Supremacy Again