Experimental Benchmarking of a 256-Qubit Room-Temperature NV-Diamond Quantum Processor with an Optically Programmable Biomolecular Quantum Bus

Abstract:We report Zeus-256, a room-temperature nitrogen-vacancy (NV) diamond processor with 256 simultaneously active processor-level logical qubits arranged in a 16 x 16 array. Each logical qubit combines an NV electron-spin ensemble with nuclear-spin memory and ancillary resources. OpenQASM 2.0 circuits are transpiled into RFSoC-controlled microwave, radio-frequency, optical, timing, measurement and bus-configuration sequences. An optically programmable proprietary protein-chromophore layer with an internal metastable-triplet spin mediator provides a reconfigurable biomolecular quantum bus for local and long-range interactions. Benchmarks cover QFT, GHZ entanglement, Grover search, arithmetic, variational, neural-network, graph-state and Shor-family circuits. Factor recovery is reported for 11 integers of 8-84 bits, with 10 attempts per instance; the 84-bit endpoint uses 256 qubits and 40,250,342 reported gates, with a reported execution time of 551.694 ms. Bell-CHSH measurements yield S = 2.8008 +/- 0.0446. Three-qubit Grover search returns the marked state in 958 of 1,024 shots (93.55%), compared with an ideal reference of 94.53%. A separate 30,000-shot population-and-parity protocol yields fixed-phase GHZ+ fidelity of 99.8960%, an estimated standard error of 0.2885 percentage points and a conservative physical 95% interval of [98.2342%, 100%]. Timing metrics are partial and do not establish quantum advantage. Scaling to 9,984 processor-level logical qubits is an engineering target, distinct from the demonstrated register.

arXiv:2610.18245 [quant-ph]

(or arXiv:2610.18245v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2610.18245 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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