2024/08/19 by Richard Jozsa, Jozsa, Richard, Soumik Ghosh +3 · 1 citation
Computer Science · Physics and Astronomy · #Advanced Frequency and Time Standards #Electromagnetic Scattering and Analysis #FOS: Physical sciences #Matrix Theory and Algorithms #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2408.10093
openalex publication_date 2024/08/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider the computational model of IQP circuits (in which all computational steps are X basis diagonal gates), supplemented by intermediate X or Z basis measurements. We show that if we allow non-adaptive or adaptive X basis measurements, or allow non-adaptive Z basis measurements, then the computational power remains the same as that of the original IQP model; and with adaptive Z basis measurements the model becomes quantum universal. Furthermore we show that the computational model having circuits of only CZ gates and adaptive X basis measurements, with input states that are tensor products of 1-qubit states from the set \ |+⟩, |1⟩,(1)/(√(2))(|0⟩+i|1⟩), (1)/(√(2))(|0⟩+eiπ/4|1⟩) \ , is quantum universal. In contrast to the relation of IQP to PH collapse, all our results here are manifestly stable under small additive implementational errors.