Design and analysis of efficient QCA reversible adders

Quantum-dot cellular automata (QCA) as an emerging nanotechnology are envisioned to overcome the scaling and the heat dissipation issues of the current CMOS technology. In a QCA structure, information destruction plays an essential role in the overall heat dissipation, and in turn in the power consumption of the system. Therefore, reversible logic, which significantly controls the information flow of the system, is deemed suitable to achieve ultra-low-power structures. In order to benefit from the opportunities QCA and reversible logic provide, in this paper, we first review and implement prior reversible full-adder art in QCA. We then propose a novel reversible design based on three- and five-input majority gates, and a robust one-layer crossover scheme. The new full-adder significantly advances previous designs in terms of the optimization metrics, namely cell count, area, and delay. The proposed efficient full-adder is then used to design reversible ripple-carry adders (RCAs) with different sizes (i.e., 4, 8, and 16 bits). It is demonstrated that the new RCAs lead to 33% less garbage outputs, which can be essential in terms of lowering power consumption. This along with the achieved improvements in area, complexity, and delay introduces an ultra-efficient reversible QCA adder that can be beneficial in developing future computer arithmetic circuits and architecture

Quantum-dot Cellular Automata: Review Paper

Quantum-dot Cellular Automata (QCA) is one of the most important discoveries that will be the successful alternative for CMOS technology in the near future. An important feature of this technique, which has attracted the attention of many researchers, is that it is characterized by its low energy consumption, high speed and small size compared with CMOS.  Inverter and majority gate are the basic building blocks for QCA circuits where it can design the most logical circuit using these gates with help of QCA wire. Due to the lack of availability of review papers, this paper will be a destination for many people who are interested in the QCA field and to know how it works and why it had taken lots of attention recentl

Restoring and non-restoring array divider designs in quantum-dot cellular automata

Quantum-dot Cellular Automata (QCA) is a very high speed, extra low power and extremely dense technology for implementing computing architectures which encodes binary logics through configuration of charges amongst quantum dots. Several studies of adders and multipliers in QCA have been proposed, whereas QCA divider design and implementation is a rather unexplored research area. In this paper the earliest designs for QCA dividers, which explore the restoring and non-restoring array dividers, considered as the best possible dividers, are introduced. These designs use well-organized arithmetic components as their basic construction parts and take some design rules into consideration which make them reliable and more robust against noise. These dividers with their design considerations and constraints are introduced step by step. Moreover, these designs are probed in terms of complexity, clocking and latency. QCADesigner, a simulation tool for QCA circuits, is used to check circuits' layout and functionality