With the advent of nanotechnology, transistors are getting smaller and growing in number according to Moore's Law. With this, the issue of heat dissipation is becoming of greater concern to researchers as the transistor heat dissipation reaches the Land Auer limit. Reversible logic is predicted to be an alternative to conventional computing due to lesser energy dissipation and exponentially faster problem-solving capacity. This paper introduces the design of a reversible ripple-carry adder using a mix of the well-known NCV library and the recently introduced NCV-|v1> library, with the assumption of a four-level quantum system. The results for the proposed adder are compared with previous ripple-carry adder designs. It then explores the design of a cost-optimized reversible ALU by modifying the above adder. Finally, a comparison of the proposed ALU is made with one of the latest reversible ALU designs.
With the advent of nanotechnology, transistors are getting smaller and growing in number according to Moore's Law. With this, the issue of heat dissipation is becoming of greater concern to researchers as the transistor heat dissipation reaches the Land Auer limit. Reversible logic is predicted to be an alternative to conventional computing due to lesser energy dissipation and exponentially faster problem-solving capacity. This paper introduces the design of a reversible ripple-carry adder using a mix of the well-known NCV library and the recently introduced NCV-|v1> library, with the assumption of a four-level quantum system. The results for the proposed adder are compared with previous ripple-carry adder designs. It then explores the design of a cost-optimized reversible ALU by modifying the above adder. Finally, a comparison of the proposed ALU is made with one of the latest reversible ALU designs.
In recent years, reversible logic has emerged as a promising technology withapplications spanning low-power CMOS, quantum computing, nanotechnology, andoptical computing. Quantum computing, in particular, relies on reversible logic for itsrealization. The construction of low-power and low-loss computational structures iscrucial for developing arithmetic circuits used in quantum computation, nanotechnology,and other low-power digital circuits. This work presents optimized one-digit BCD addersand carries skip BCD adders using new reversible logic gates. The proposed approachaims to minimize quantum cost and optimize performance compared to existing circuits,focusing on reducing the number of reversible gates used and minimizing garbage outputsproduced. The objective is to design faster BCD adders and provide a foundation forbuilding the decimal Arithmetic Logic Unit (ALU) of a Quantum CPU. The work isimplemented using Hardware Description Language (HDL), with Simulation & Synthesisconducted on Xilinx ISE. The design targets the Xilinx Spartan 3E FPGA device. Thisresearch contributes to the advancement of efficient and high-performance arithmeticcircuits suitable for emerging technologies such as quantum computing andnanotechnology.
Abstract: Compared to classical computing implementations, reversible arithmetic adders offer a valuable platform for implementing quantum computation models in digital systems and specific applications, such as cryptography and natural language processing. Reversible logic efficiently prevents energy wastage through thermal dissipation. This study presents a comprehensive exploration introducing new carry-select adders (CSLA) based on quantum and reversible logic. Five reversible CSLA designs are proposed and compared, evaluating various criteria, including speed, quantum cost, and area, compared to previously published schemes. These comparative metrics are formulated for arbitrary n-bit size blocks. Each design type is described generically, capable of implementing carry-select adders of any size.. Introduction: one of the critical factors in designing VLSI circuits and digital systems is power consumption and energy dissipation. Energy dissipation increases due to many transistors in circuits, shrinking the feature size. In the early 1960s, Landauer introduced a novel power dissipation principle in digital circuits. He issued his theory about power dissipation based on information loss during computation in digital systems. From his perspective, designing digital and logical circuits based on conventional logic, also known as irreversible logic, leads to inevitable power dissipation. The motive is that digital circuits designed based on irreversible logic contain more input lines
This paper presents the design, optimization, and simulation of arithmetic circuits using reversible logic for quantum computing applications. The motivation behind this work is to achieve resource-efficient computation through reduced quantum cost, minimized garbage outputs, and lower ancilla requirements. The methodology involves implementing Half Adders, Full Adders, Multiplexers, and Ripple Carry Adders (RCAs) using Toffoli and Peres gates. The proposed 8-bit RCA achieves a quantum cost of 58 using 24 qubits, 8 garbage outputs, and 6 ancilla inputs—showing a significant improvement over conventional Toffoli-based designs that require higher quantum cost and resources. Simulations were conducted on IBM Qiskit and Google Colab using the Qiskit SDK to validate circuit correctness and scalability. The obtained results demonstrate superior resource efficiency and confirm the feasibility of reversible-logic-based quantum arithmetic as a foundation for scalable quantum arithmetic logic units (ALUs) and processors.
Reversible logic is one of the emerging technologies having promising applications in quantum computing. In this work, we present new design of the reversible BCD adder that has been primarily optimized for the number of ancilla input bits and the number of garbage outputs. The number of ancilla input bits and the garbage outputs is primarily considered as an optimization criteria as it is extremely difficult to realize a quantum computer with many qubits. As the optimization of ancilla input bits and the garbage outputs may degrade the design in terms of the quantum cost and the delay, thus the quantum cost and the delay parameters are also considered for optimization with primary focus towards the optimization of the number of ancilla input bits and the garbage outputs. Firstly, we propose a new design of the reversible ripple carry adder having the input carry Co and is designed with no ancilla input bits. The proposed reversible ripple carry adder design with no ancilla input bits has less quantum cost and the logic depth (delay) compared to its existing counterparts. The existing reversible Peres gate and a new reversible gate called the TR gate is efficiently utilized to improve the quantum cost and the delay of the reversible ripple carry adder. The improved quantum design of the TR gate is also illustrated. Finally, the reversible design of the BCD adder is presented which is based on a 4 bit reversible binary adder to add the BCD number, and finally the conversion of the binary result to the BCD format using a reversible binary to BCD converter.
The design of fast arithmetic logic circuits is an important research topic for reversible and quantum computing. A special challenge in this setting is the computation of standard arithmetical functions without the generation of garbage. Here, we present a novel parallelization scheme wherein m parallel k-bit reversible ripple-carry adders are combined to form a reversible mk-bit ripple-block carry adder with logic depth [Formula: see text] for a minimal logic depth [Formula: see text], thus improving on the mk-bit ripple-carry adder logic depth [Formula: see text]. The underlying mechanisms of the parallelization scheme are formally proven correct. We also show designs for garbage-less reversible comparison circuits. We compare the circuit costs of the resulting ripple-block carry adder with known optimized reversible ripple-carry adders in measures of circuit delay, width, gate, transistor count, and relative power efficiency, and find that the parallelized adder offers significant speedups at realistic word sizes with modest parallelization overhead.
Reversible logic has represented itself as a prominent technology which plays an important role in Quantum Computing. Theoretically Quantum Computers operates at high speed and consumes less power. Furthermore, Reversible logic can break the conventional speed of power trade-off. To prove this we are implementing Ripple Carry Adder and Carry Look Ahead Adder using reversible logic gates. The paper presents efficient adder circuits using Peres gate, New fault Tolerant gate and Double Feyman gate. The complexity, simulated outputs and the speed parameters for the adder circuit have been indicated using the Quartus II 9.1 edition and Modelsim tool. Moreover, the quantum algorithms can potentially solve NP-complete problems. Furthermore, doing high performance functions beyond the limit of deterministic computer systems is possible by only reversible logic. Quantum operations are unitary in nature which is reversible and hence the arithmetic operations like adders can be implemented using the reversible logic. Likewise, optimized block size, minimum ancillary bits, and one to one mappings of inputs and outputs are obtained in the reversible adder circuit, giving fan out as 1. Hence, the Ripple Carry Adder and Carry look Ahead Adder is providing complexity reduction and high speed, proving to be an efficient and important part in the development of arithmetic blocks of Quantum Computers.