Explained | What is ‘quantum supremacy’?

The story so far: Tech websites and theoretical computer-science outlets were aflame earlier this week after a story in the U.K.-based Financial Times said Google had claimed to have achieved ‘quantum supremacy’. Because of quantum superposition, a quantum computer — if it works to plan — can mimic several classical computers working in parallel. Quantum supremacy refers to quantum computers being able to solve a problem that a classical computer cannot. Google’s quantum computer, named Sycamore, claimed ‘supremacy’ because it reportedly did the task in 200 seconds that would have apparently taken a supercomputer 10,000 years to complete. Scott Aaronson, a theoretical computer scientist who has written on Google’s feat, opines that current encryption standards would require a quantum computer to have “several thousand logical qubits” working in tandem perfectly.