QCA-Based Secure RAM Cell Structure Using Logic Transformation and Cell Interaction with Signal Reliability and Energy Dissipation in Quantum Computing

A RAM cell, one of the components that greatly affects the performance of quantum computing, outputs mostly stored values on quantum-dot cellular automata (QCA) as they are. Currently, a problem is that the stored value may be initialized according to the selection input. To solve this problem, circuits that separate the stored value from the output value have recently been designed, but most of them have long latency, large areas, and many plane structure intersections, resulting in unstable signals. Therefore, in this paper, we propose a new secure QRAM (QCA-based RAM) cell logic by analyzing and modifying the existing cell logic in nanotechnology. We initially propose 2-to-1 multiplexers based on cell interaction, and a QRAM cell is proposed based on our multiplexer and an optimized QRAM cell logic diagram. Compared with existing designs, the proposed circuits produce superior results in terms of circuit performance and energy dissipation. Additionally, the operation of our multiplexers is verified mathematically using physical proof. The secure QRAM cell proposed in this paper does not have the initialization problem based on the selection input that is present in some existing circuits, thus it is very easy to design an extension to N × N RAM, and it has high signal stability, reliability, connectivity, and scalability because there is no intersection.