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A megaquop quantum computer is a system capable of executing roughly one million (mega) reliable quantum operations (quops) in a single computation. Reaching that scale requires error-corrected logical qubits with a logical error rate around 10⁻⁶ — about one error per million operations — which is far beyond what any uncorrected quantum hardware can achieve.
The term was popularized by physicist John Preskill as a way to mark the first stage of quantum computing beyond the NISQ (noisy intermediate-scale quantum) era. Where NISQ machines are limited to circuits of a few thousand operations before noise overwhelms the result, a megaquop machine can run computations three orders of magnitude deeper.
Why is a million operations the meaningful threshold?
Because that's roughly where scientifically and commercially interesting problems begin. Simulating quantum dynamics of lattice models relevant to materials science — spin-lattice Hamiltonians, or the Fermi-Hubbard model of interacting electrons — requires circuit depths that no NISQ machine can sustain, yet fits naturally within a megaquop budget. These are problems where classical methods like DMRG and quantum Monte Carlo hit fundamental walls.
What does it take to build one?
Three things must come together:
Logical qubits, not just physical qubits. A megaquop machine computes on error-corrected logical qubits. QuEra's Libra system encodes up to 256 logical qubits from more than 10,000 physical qubits using high-rate error-correcting codes.
A 10⁻⁶ logical error rate. Executing a million operations reliably means each logical operation must fail less than one time in a million. This requires below-threshold error correction — demonstrated by QuEra and collaborators in peer-reviewed work — plus real-time decoding that corrects errors as the computation runs.
Continuous operation. Deep circuits take time, and atoms are inevitably lost along the way. Libra continuously reloads fresh atoms from a dedicated reservoir mid-computation — QuEra has already commissioned a prototype delivering roughly 20,000 atoms per second — so the machine keeps running without resetting.
When will megaquop machines exist?
QuEra's Libra, launching on Amazon Braket in 2028, is designed as a megaquop-class system: 256 logical qubits, a 10⁻⁶ logical error rate, and about one million reliable logical operations per computation, all in a machine that runs at room temperature and consumes less than 40 kW. It is under construction today, and every architectural element — from magic state distillation to continuous atom reloading — is grounded in published, peer-reviewed research.
What comes after megaquop?
Gigaquop: a billion reliable operations, requiring logical error rates near 10⁻⁹. QuEra's roadmap targets a gigaquop-class system in 2028/29 with more than 1,000 logical qubits, unlocking applications in quantum chemistry, nuclear dynamics, and advanced materials that even megaquop systems cannot reach.
