To meet expectations of the futuristic technologies, thrust is on fast communication, low power, high computational speeds with delay intolerance. VLSI technology is laboring to meet the demands by incorporating low-power solutions to improve performance. Component size has come to Nano scales however, it has challenges of managing heat dissipation and physical limitations in fabrication. Reversible logic technology has gained momentum in research due to its prominence in Quantum computing and zero power dissipation. The arithmetic and Logic Unit is the significant component of any computing architecture, carrying out operations rigorously while consuming power for the endurance of performance. The proposed approach of designing the fault-tolerant Arithmetic and Logical Unit (ALU) in reversible logic for future computers. Analysis of the proposed design to existing designs is on the quantum cost (QC), garbage output (GO), ancilla input (AI), gate utilization (GC) and number of operations achieved. Improvements observed is at an average of 70% in AI and GC, 59% in QC , 53% in GO and operations are up by 33% to cater to the least power consumption applications.
To meet expectations of the futuristic technologies, thrust is on fast communication, low power, high computational speeds with delay intolerance. VLSI technology is laboring to meet the demands by incorporating low-power solutions to improve performance. Component size has come to Nano scales however, it has challenges of managing heat dissipation and physical limitations in fabrication. Reversible logic technology has gained momentum in research due to its prominence in Quantum computing and zero power dissipation. The arithmetic and Logic Unit is the significant component of any computing architecture, carrying out operations rigorously while consuming power for the endurance of performance. The proposed approach of designing the fault-tolerant Arithmetic and Logical Unit (ALU) in reversible logic for future computers. Analysis of the proposed design to existing designs is on the quantum cost (QC), garbage output (GO), ancilla input (AI), gate utilization (GC) and number of operations achieved. Improvements observed is at an average of 70% in AI and GC, 59% in QC , 53% in GO and operations are up by 33% to cater to the least power consumption applications.
Reduction in dimensions of CMOS technology has resulted in great increase in computing speeds but, at the same time, higher power consumption. Thus, a serious limitation arises since conventional approaches will eventually hit the physical limit [1], [2]. Reversible computing seems promising in the context of VLSI. In theory, it could operate without any energy loss due to lossless information processing [3], [4]. The paper presents development and implementation of a reversible Arithmetic Logic Unit (ALU) based on quantum logic gates working with qubits. The architecture is based on Fredkin gates (quantum cost 5) and CNOT gates (quantum cost 1), both preserving parity and being inherently reversible. The ALU can execute all arithmetic and logical operations and reconfigure operations dynamically according to system requirements. Also, the designed ALU possesses an inherent parity-preserving fault detection mechanism for reliable identification of single-bit faults. Overall the implemented ALU contains 9 CNOT and 7 Fredkin gates resulting in quantum cost equal to 44 and 12 garbage outputs. Thus, the quantum cost and garbage outputs are significantly lower than usual ones for the design of a reversible ALU, which generally amount to 48–65 and 16–20 correspondingly. The designed architecture is described in details through the application of Verilog HDL and simulation in Xilinx Vivado toolset. The work concentrates on optimization of such important parameters as the number of gates, quantum cost, garbage outputs, and constant inputs. Those design parameters are critical in order to develop scalable and sustainable quantum and low-power VLSI architectures.
Reversible computing has emerged as a promising solution for reducing energy dissipation in digital systems by addressing the fundamental limitations caused by information loss.Quaternary reversible logic, which uses multi-valued representations, provides higher information density, reduced interconnect complexity, and better scalability when compared to conventional binary logic.This work presents the design and implementation of a quaternary reversible Arithmetic Logic Unit (ALU) that integrates essential computational modules, including arithmetic units, logical units, memory units, decoders, and multiplexers.The proposed architecture supports efficient data routing and precise operation control through a scalable control unit and a selection-line-based design approach.The designed ALU demonstrates reduced quantum cost, fewer garbage outputs, and minimized constant inputs in comparison with existing reversible ALU designs, while remaining compatible with larger reversible and quantum computing architectures.Simulation results and comparative analysis validate the improved efficiency and low-power potential of the proposed system, making it suitable for next-generation computing applications.The complete design is implemented using Verilog HDL and synthesized and simulated using Xilinx Vivado Design Suite 2025.
Reversible logic is characterized by its feature of being a prominent application in low-power conventional computers and the most compatible logic in quantum computers. Quantum circuits executes quantum algorithms and are important in a new generation of advanced computing. However, they are highly error-prone and also subject to the use of limited and sensitive physical resources like qubits and quantum gates. This paper introduces a comprehensive fault tolerant quantum-based reversible circuit which can calculate a high variety number of arithmetic and logic operations. It uses both: parity preserving method for detecting one or an odd number of bit errors, and Clifford + T implementation for protecting circuits against decoherence faults. First, we propose a new fault-tolerant (parity preserving and Clifford + T) adder/subtractor and derive a quantum reversible Arithmetic and Logic Unit (ALU). These modules reach the most optimized extent of circuit line, ancilla inputs, and garbage outputs according to the logical analysis done in this work. This article focuses on reducing T-cost metrics in conjunction with enhancing the number of operations and quantum costs in proposed circuits compared to other counterparts. We propose 4-bit fault tolerant ALU derived from our proposed single-bit module to show the proposed circuit can be extended to any larger size. The proposed circuit is implemented in the Qiskit simulation tool, and output results confirm the accuracy of our design functionality. The proposed full adder/ subtractor achieves an average of 64% and 43%, and the proposed ALU circuit achieves an average of 38% and 27% improvement in T-count and T-depth, respectively compared to their counterparts. The proposed reversible quantum-optimized fault tolerant adder/subtractor and ALU units can be applied as the basic part of DSP systems and quantum processor units in quantum computing devices.
Reversible logic provides a foundation for nextgeneration computing systems, particularly in quantum and emerging nanotechnology-based architectures. Unlike conventional logic, reversible gates preserve information and support backward computation, making them crucial for designing quantum circuits. This paper introduces a reversible Arithmetic and Logic Unit (ALU) that performs eight fundamental operations-AND, OR, NOT, XOR, addition, subtraction, increment, and decrement-using Fredkin, Peres, TR, and modified Fredkin gates. A dedicated control unit manages operation selection, ensuring functional flexibility and circuit efficiency. The proposed design achieves significant improvements by minimizing ancilla inputs, quantum cost and garbage outputs, resulting in a total quantum cost of 71 and contains 16 reversible gates and 14 garbage outputs. The architecture was modeled and verified using Xilinx Vivado HLS and ISE 14.7, and implemented on the Nexys A7 (Artix-7) FPGA platform. Comparative analysis demonstrates better efficiency than existing reversible ALU designs, establishing the proposed circuit as a strong candidate for quantum computing and other advanced computing paradigms.
The NAND, NOT, and NOR logic gates which are utilised to realise the hardware modules of the system, are examples of basic classical logic gates that make up the hardware basics of electronic circuit systems. In addition to this, a useful system has been described for designing and implementing quantum processors by using reversible logic gates to analyse the performance of ALUs. Additionally, it shows that QCA might be used in quantum computers, assuming that the underlying technology can be made workable. When considering energy-efficient computations, reversible or information-lossless circuits are crucial for digital signal processing, communication, computer graphics, and cryptography. By preventing information loss, reversible logic is utilised to lessen the power dissipation that occurs in classical circuits, which is particularly promising because it allows for extremely low power computations like nano-computing for quantum processors. Because bits of information are lost during logic operations, typical digital circuits waste a lot of energy. It is well known that an Arithmetic and Logical Unit is one of the most fundamental operational units in the quantum processor (ALU). The design and implementation of an innovative r/q 16-bit ALU that improves the overall performance of quantum processors while carrying out the task in the digital signal processing domain are discussed in this study. When reversible gates were used in place of logic gates, the power dissipation in terms of information bit loss was significantly reduced. Simulation of these circuits is done by QCA Designer tool and language used for programming is very high-speed hardware integrated circuit hardware descriptive language, Verilog HDL. The power and delay analysis of the various sub modules is performed and a comparison with the traditional circuits is also carried out. The designed ALU has better efficiency as it has less power loses and reduction in power loss upto 39 % is obtained.
Quantum Arithmetic Logic Units (ALUs) serve as critical components in quantum processors, enabling both arithmetic and logical operations on qubits. However, the fragile nature of quantum systems makes them susceptible to errors and decoherence, necessitating fault-tolerant designs. In this work, we propose a fault-tolerant quantum ALU architecture constructed using the Clifford+ T gate set, which is widely recognized for its compatibility with error-correcting codes. The proposed design minimizes quantum resource overhead while maintaining computational accuracy under fault-prone conditions. Notably, the architecture requires zero ancilla and generates a single garbage output, optimizing the qubit space. Performance evaluations demonstrate significant improvements, achieving a 31.8% reduction in T-count and a 33.3% reduction in T-depth compared to existing designs. These enhancements contribute to more efficient and reliable quantum computation, paving the way for scalable quantum processor development.