Circuit-Based Quantum Random Access Memory for Classical Data with Continuous Amplitudes

Loading data in a quantum device is required in several quantum computing applications. Without an efficient loading procedure, the cost to initialize the algorithms can dominate the overall computational cost. A circuit-based quantum random access memory named FF-QRAM can load $M$M $n$n-bit patterns with computational cost $O(CMn)$O(CMn) to load continuous data where $C$C depends on the data distribution. In this article, we propose a strategy to load continuous data without post-selection with computational cost $O(Mn$O(Mn). The proposed method is based on the probabilistic quantum memory, a strategy to load binary data in quantum devices, and the FF-QRAM using standard quantum gates, and is suitable for noisy intermediate-scale quantum computers.