Recently design of reversible logic circuits draw much attention in nanotechnology and quantum computing. Conventional logic circuits are not reversible. A reversible circuit maps each input vector, into a unique output vector and vice versa. In this paper, we propose a novel scheme of Toffoli and Feynman gates in all-optical domain using terahertz optical asymmetric demultiplexer (TOAD). Both the realizations are supported through proper flowchart followed by simulation in Macad-7. Simulation results verify the functionality of both the gates along with verified reversibility. Toffoli and Feynman gates can be used to implement Boolean expressions and arithmetic operations.
Recently design of reversible logic circuits draw much attention in nanotechnology and quantum computing. Conventional logic circuits are not reversible. A reversible circuit maps each input vector, into a unique output vector and vice versa. In this paper, we propose a novel scheme of Toffoli and Feynman gates in all-optical domain using terahertz optical asymmetric demultiplexer (TOAD). Both the realizations are supported through proper flowchart followed by simulation in Macad-7. Simulation results verify the functionality of both the gates along with verified reversibility. Toffoli and Feynman gates can be used to implement Boolean expressions and arithmetic operations.
Quantum phase slip junction (QPSJ) can offer very low power switching operation and represent near adiabatic switching operation for using in designing of the reversible logic gates. The reversible gates have logical reversibility, where the inputs can be logically reconstructed from the outputs and no data is lost, and physical (adiabatic) reversibility, where the energy dissipation can be decreased even below the Landauer limit. In this manuscript, for the first time, designing of the QPSJ-based basic reversible gates, namely Feynman, Toffoli, Peres and Fredkin, from the logical reversibility point of view is represented. The main logic function in these gates is the XOR function. First, a new two-input QPSJ-based XOR gate with simple circuit is designed in which the outputs of the previous gate can be connected directly to its inputs without the need for splitter lines. Second, the proposed XOR gate is used to design the Feynman and Toffoli gates. Further, the Peres and Fredkin gates are designed by using the proposed Feynman and Toffoli gates. Proper operation of the proposed gates are verified by simulation results. Logical reversibility of the Feynman and Toffoli gates is verified by cascading them and operating their logical function two times, i.e.f(f(x))=x.
The reversible logic has promising applications in emerging computing paradigms, such as quantum computing, quantum dot cellular automata, optical computing, etc. In reversible logic gates, there is a unique one-to-one mapping between the inputs and outputs. To generate a useful gate function, the reversible gates require some constant ancillary inputs called ancilla inputs. Also to maintain the reversibility of the circuits some additional unused outputs are required that are referred to as the garbage outputs. The number of ancilla inputs, the number of garbage outputs and quantum cost plays an important role in the evaluation of reversible circuits. Thus minimizing these parameters are important for designing an efficient reversible circuit. Reversible circuits are of highest interest in optical computing, quantum dot cellular automata and quantum computing. The quantum gates perform an elementary unitary operation on one, two or more two-state quantum systems called qubits. Any unitary operation is reversible in nature, and hence, quantum networks are also reversible, to conclude the quantum computers must be built from reversible logic components. The main contribution of this dissertation is the design exploration and application of reversible circuits in emerging nanotechnologies. The emerging technologies explored in this work are 1) Optical quantum computing 2) Quantum computing. The first contribution of this dissertation is Mach-Zehnder interferometer based design of all optical reversible binary adder. The all optical reversible adder design is based on two new optical reversible gates referred as optical reversible gate I (ORG-I) and optical reversible gate II (ORG-II) and the existing all optical Feynman gate. The two new reversible gates ORG-I and ORGI-II have been proposed and can implement a reversible adder with a reduced optical cost which is equal to the number of MZI switches required, less propagation delay, and with zero overhead in terms of number of ancilla inputs and the garbage outputs. The proposed all optical reversible adder design based on the ORG-I and ORG-II reversible gates are compared and shown to be better than the other existing designs of reversible adder proposed in the non-optical domain in terms of number of MZI switches, delay, the number of ancilla inputs and the garbage outputs. The proposed all optical reversible adder will be a key component of an all optical reversible arithmetic logical unit (ALU), that is a quite essential component in a wide variety of optical signal processing applications. In the existing literature, the NAND logic based implementation is the only known implementation available for reversible gates and its functions. There is a lack of research in the direction of NOR logic based implementation of reversible gates and functions. The second contribution of this dissertation is the design of NOR logic based n-input and n-output reversible gates, one of which can be efficiently mapped into optical computing using the Mach-Zehnder interferometer (MZI), while the other can be mapped efficiently in optical computing using the linear optical quantum gates. The proposed reversible NOR gates work as a corresponding NOR counterpart of NAND logic based Toffoli gates. The proposed optical reversible NOR logic gates can implement the reversible boolean logic functions with less number of linear optical quantum logic gates with reduced optical cost and propagation delay compared to the implementation using existing optical reversible NAND gates. It is illustrated that an optical reversible gate library having both optical Toffoli gate and the proposed optical reversible NOR gate is superior compared to the library containing only the optical Toffoli gate: (i) in terms of number of linear optical quantum gates when implemented using linear optical quantum computing (LOQC), (ii) in terms of optical cost and delay when implemented using the Mach-Zehnder interferometer. The third contribution of this dissertation is a binary tree-based design methodology for a NxN reversible multiplier. The proposed binary tree-based design methodology for a NxN reversible multiplier performs the addition of partial products in parallel using the reversible ripple adders with zero ancilla bit and zero garbage bit; thereby, minimizing the number of ancilla and garbage bits used in the design. The proposed design methodology shows improvements in terms of number of ancilla inputs and garbage outputs compared to all the existing reversible multiplier designs. The methodology is also extended to the design of NxN reversible signed multiplier based on modified Baugh-Wooley multiplication methodology.
Quantum is an emerging technology in future computers. Reversibility is the main advantage of quantum computers. In conventional computers, the computation is irreversible i.e. the input bits are lost once the logic block generates the output and input bits cannot be restored but it can be done in reversible computation because in reversible computation the inputs and outputs have a one-to-one correspondence. Therefore, a reversible gate input could even be uniquely determined from their output which leads to less power consumption. Hence the complexity of the digital circuits can be reduced by using reversible computing. In quantum computer to perform reversible operations, we need to implement the reversible gates using quantum gates. In this paper, we discussed various reversible logic gates like Feynman, Toffoli, R, Peres and TR gates using basic quantum gates like CNOT, Pauli, Swap gates and their implementation using IBM quantum experience.
Considering the benefits of Quantum and Optics, if the logic gates in the quantum field and electronic structure are implemented using optical elements, then it will be benefited from advantages of Quantum and design, and these processing circuits can be used in optical computing and quantum computing, genetic processes, and other useful nanotechnology applications. Advantages of reversible logic systems and circuits have drawn a significant interest in recent years as a promising computing paradigm having application in low power CMOS, quantum computing, nanotechnology, and optical computing. In this study, we have introduced reversible optical Double Feynman gate using optical Mach-Zehnder interferometer (MZI) switches with new design. The proposed optical Double Feynman gate will be optical logic gate and reversible. As the proposed gate is a complete one, it can implement all the MZI-based quantum circuits.
Reversible logic, also known as information lossless logic, is a promising technology that allows embedded data within circuits to be retrieved in case of failure.This study explores the use of reversible gates, such as Feynman gates, Toffoli gates, Fredkin gates, Peres gates, Double Feynman gates, NFT gates, DKG gates, and DFT gates, to construct logic circuits.These reversible logic gates can be effectively used for the implementation of any higher logic circuits-based applications.In the proposed paper the Arithmetic logic unit based on reversible logic hates is implemented in Verilog as well as IBM quantum software.The major applications of reversible logic gates include quantum computing, low power circuits, nano and CMOS technologies, photonics.In the last part of the paper the circuits implemented using Verilog and IBM quantum a chip level design using Cadance layout is implemented.
In the context of modern Very Large-Scale Integration (VLSI) technology, information loss has been a major concern. Logic gates (LG) such as AND, OR, and NOT have been found to result in information loss during their operations. To address this issue, reversible LGs have been created. The development and implementation of a high-speed, efficient full adder circuit employing reversible LGs like Feynman, Toffoli, and Peres gates. The design aims to improve computational and thermal efficiencies. The circuit refarding quantum costs (QC), garbage outputs, and ancillary inputs. The implemented the suggested design in Verilog and verified the entire adder's functionality and efficiency through simulations using the Xilinx Vivado and Xilinx ISE tools. The circuit has a quantum cost of 10 with two outputs of useless and one auxiliary input, according to the researchers, highlighting its opportunities for usage in quantum computing applications andlow-power (dec 84%), high-performance computing systems.