All Post-Quantum, PQC Posts
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Post-Quantum
Capability 3.3: Continuous Operation (Long-Duration Stability)
One of the most critical requirements for a cryptographically relevant quantum computer (CRQC) is continuous operation - the ability to run a complex quantum algorithm non-stop for an extended period (on the order of days) without losing quantum coherence or needing a reset. In practical terms, the entire quantum computing stack - qubits, control electronics, error-correction processes, cooling systems - must sustain stable performance for…
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Post-Quantum
Capability 3.1: Full Fault-Tolerant Algorithm Integration
Imagine a quantum computer that can execute an entire algorithm start-to-finish with errors actively corrected throughout. Full fault-tolerant algorithm integration is exactly that: the orchestration of all components - stable logical qubits, high-fidelity gates, error-correction cycles, ancilla factories, measurements, and real-time feedback - to run a useful quantum algorithm reliably from beginning to end. This capability is essentially the “system integration” of quantum computing, bringing…
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Post-Quantum
Capability 3.2: Decoder Performance (Real‑Time Error Correction Processing)
In a fault-tolerant quantum computer, qubits are continuously monitored via stabilizer measurements (producing “syndrome” bits) to detect errors. The decoder is a classical algorithm (running on specialized hardware) that takes this rapid stream of syndrome data and figures out which qubits have experienced errors, so that corrections can be applied immediately. Achieving real-time decoding at scale is enormously challenging: a CRQC may need to handle…
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Post-Quantum
Capability 2.2: Magic State Production & Injection (Non-Clifford Gates)
Magic states are an essential “extra ingredient” for universal quantum computing, often metaphorically likened to a magic catalyst enabling otherwise impossible operations. Quantum algorithms require not only robust qubits and error correction, but also a way to perform non-Clifford gates - operations outside the easy Clifford group. These non-Clifford gates (like the T gate or controlled-controlled-Z) are the key to achieving universal quantum computation, yet…
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Post-Quantum
Capability 2.1: High-Fidelity Logical Clifford Gates
Cryptographically Relevant Quantum Computers (CRQCs) will rely on a suite of core capabilities - and high-fidelity logical Clifford gates are among the most essential. This capability refers to performing the fundamental set of quantum logic operations (the Clifford gates: Pauli X, Y, Z flips; the Hadamard (H); the phase gate (S); and the controlled-NOT (CNOT), among others) on logical qubits with speed and reliability. In…
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Post-Quantum
Capability 1.3: Below-Threshold Operation & Scaling
“Below-threshold operation” refers to running a quantum processor at error rates below the critical threshold of a quantum error-correcting code. In simple terms, there is a tipping point in error rates: if each quantum gate and qubit has an error probability lower than this threshold, adding more qubits and more error-correction actually reduces the overall error rate of the computation. If error rates are above…
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Post-Quantum
Capability 1.2: Syndrome Extraction (Error Syndrome Measurement)
Quantum syndrome extraction - also called error syndrome measurement - is the process of measuring collective properties of qubits to detect errors without destroying the encoded quantum information. It is essentially the sensor mechanism of a quantum error-correcting code, analogous to measuring parity checks in a classical error-correcting code. In a stabilizer code (the leading framework for quantum error correction, introduced by Gottesman in the…
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Post-Quantum
Capability 1.1: Quantum Error Correction (QEC)
Quantum Error Correction (QEC) is the first and arguably most critical capability in the roadmap toward a cryptographically relevant quantum computer (CRQC). Without QEC, a large-scale quantum computer cannot reliably perform the billions of operations needed to break modern encryption - no matter how many qubits we build. In essence, QEC is what allows many noisy physical qubits to behave like a single near-perfect qubit.…
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