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4 months ago in Quantum Computing By Shreya K

Does a fully working, practical quantum computer exist today?

My committee keeps pressing me to ground my algorithm simulations in the reality of current hardware. I understand the difference between theoretical qubits and fault-tolerant machines, but the hype cycle makes it difficult to discern what actually exists in a lab today versus what's still on the whiteboard. I need an honest, practitioner-level snapshot.

 

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By Pranav Answered 2 months ago

The answer is both yes and no. Today, prototype quantum computers with tens to hundreds of physical qubits exist and are actively used by organizations like IBM and Google for research and experimentation. However, a fault-tolerant, general-purpose quantum computer capable of reliably solving commercially valuable problems beyond classical supercomputers does not yet exist. Current machines are noisy and error-prone, placing us in the Noisy Intermediate-Scale Quantum (NISQ) era, where quantum devices are functional but limited research tools rather than fully practical computing systems.

By AnthonyEngix Answered 2 months ago

I appreciate you cutting through the noise. The honest answer is no not if we define "practical" as reliably solving useful problems faster or cheaper than a classical supercomputer. What we have today are impressive, but fundamentally limited, NISQ devices. I have seen 50-100 qubit processors perform specific, contrived sampling tasks that classical computers struggle with that's quantum supremacy. But these machines cannot sustain long coherence times or correct their inherent errors. I would recommend framing your work around what these noisy devices might soon do for quantum chemistry or optimization, while acknowledging fault-tolerance is still years away.

 

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