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| Format: | Recurso digital |
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Zenodo
2025
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| Online Access: | https://doi.org/10.5281/zenodo.18109751 |
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Table of Contents:
- <p>Quantum random access memory (qRAM) remains a persistent bottleneck---not because the lookup specification is unclear, but because implementing a single coherent query can demand deep active control, long-range routing, or unrealistic unit-cost oracle assumptions. We address this tension through a universal, data-independent lookup unitary (U-QRAM) in which the database resides in memory qubits and functions as quantum control. Our first contribution is a hardware-explicit reformulation: U-QRAM equals time evolution under a single time-independent Hamiltonian that is a sum of mutually commuting projector terms---one per memory cell. Because these terms commute, the order of application is irrelevant: they may be executed sequentially or in parallel without changing the target unitary. Our second contribution identifies the most direct path to constant-locality interactions: when addresses are encoded in a unary (one-hot, mode-addressed) register, each Hamiltonian term reduces to 3-local form, replacing the usual (log N)-controlled fan-in barrier with spatial or modal selectivity. We maintain conservative claims: constant latency requires explicit hardware assumptions (global buses, all-to-all connectivity, or native multi-body interactions), and we provide compiled circuit baselines for when such assumptions do not hold.</p>