Today's quantum computers have an official nickname: noisy. Here's why that's not actually an insult

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In 2018, physicist John Preskill needed a word to describe the specific, awkward moment quantum computing had reached, machines big enough to do something interesting, but nowhere near reliable enough to be trusted completely. He coined NISQ, short for Noisy Intermediate Scale Quantum, and the name stuck because it was simply honest. Intermediate scale means these devices carry somewhere from a few dozen to a few hundred qubits, large enough that a classical computer cannot easily simulate what they are doing, but nowhere near the scale eventually needed for a truly general purpose quantum computer

Noisy is the more important word though. These qubits are extremely sensitive to their surroundings, and even tiny disturbances, stray heat, electromagnetic interference, imperfect control signals, introduce errors into a calculation. Unlike the large, error corrected quantum computers researchers hope to eventually build, today's NISQ machines have no built in way to fully catch and fix those errors as they happen, so mistakes simply accumulate the longer and more complex a calculation runs

None of that makes NISQ machines useless though, just narrowly useful. Researchers use them for specific tasks like simulating small molecules, testing quantum algorithms in the real world, or exploring quantum machine learning, all careful to design experiments short enough that the noise does not overwhelm the result before it is even measured. NISQ is essentially quantum computing's teenage phase, genuinely capable of real things, just not yet mature enough to be handed the keys to the car

Nisq Noisy Intermediate Scale Quantum 7Ea1Bc3981Dfmedium.com

[BlackMamba]

The teenage phase analogy is a perfect way to describe where this technology actually sits right now, capable but not yet fully trustworthy