quantum advantage

While often used interchangeably, quantum supremacy generally refers to a quantum computer solving a problem that is practically impossible for a classical computer. Quantum advantage is typically used in a more commercial sense, where a quantum computer performs a useful task faster or cheaper than classical supercomputers. Google famously claimed quantum supremacy in 2019 with its Sycamore processor.

Yes, in late 2019, Google announced it had achieved quantum advantage using its 53-qubit Sycamore processor. They claimed their quantum computer performed a specific random number generation task in 200 seconds, which they estimated would take the world's fastest supercomputer, Summit, over 10,000 years to complete. IBM quickly pushed back on this claim, arguing the classical supercomputer could do it much faster.

Once reliable quantum advantage is achieved, it will revolutionize industries that rely on complex molecular simulations and cryptography. Pharmaceutical companies will be able to simulate complex chemical reactions to discover new drugs instantly. Additionally, it will heavily impact logistics by optimizing global supply chain routing and breaking current cryptographic security protocols like RSA.

To achieve a practical, commercial quantum advantage for tasks like breaking RSA encryption, a machine would need thousands of logical, error-corrected qubits. Because current quantum systems are noisy, one logical qubit requires dozens or hundreds of physical qubits to maintain stability. This means a machine might need hundreds of thousands of physical qubits to reach a true, undeniable commercial quantum advantage.