At present days , reversible logic circuits have many applications in the field of optical information processing, digital signal processing , nano technology and quantum computing . Reversible logic plays an important role when computations with minimum energy dissipation are considered. The purpose of designing reversible logic is to decrease the number of area, power, garbage outputs , constant inputs, quantum cost, reversible gates, delay and hardware complexity . This paper reveals a review on some reversible logic gates, which is useful in designing more complex systems having reversible circuits and can do execution of more complex operations using quantum computers. In upcoming days digital technology will be using reversible logic gates in order to reduce the propagation delay and power consumption as it provides negligible loss of information in the circuit. Keywords: Reversible Gate, Garbage output, quantum cost, Reversible logic, Power dissipation
At present days , reversible logic circuits have many applications in the field of optical information processing, digital signal processing , nano technology and quantum computing . Reversible logic plays an important role when computations with minimum energy dissipation are considered. The purpose of designing reversible logic is to decrease the number of area, power, garbage outputs , constant inputs, quantum cost, reversible gates, delay and hardware complexity . This paper reveals a review on some reversible logic gates, which is useful in designing more complex systems having reversible circuits and can do execution of more complex operations using quantum computers. In upcoming days digital technology will be using reversible logic gates in order to reduce the propagation delay and power consumption as it provides negligible loss of information in the circuit. Keywords: Reversible Gate, Garbage output, quantum cost, Reversible logic, Power dissipation
In recent years, reversible logic circuits have applications in the emerging field of digital signal processing, optical information processing, quantum computing and nano technology. Reversibility plays an important role when computations with minimal energy dissipation are considered. The main purpose of designing reversible logic is to decrease the number of reversible gates, garbage outputs, constant inputs, quantum cost, area, power, delay and hardware complexity of the reversible circuits. This paper reveals a comparative review on various reversible logic gates. This paper provides some reversible logic gates, which can be used in designing more complex systems having reversible circuits and can execute more complicated operations using quantum computers. Future digital technology will use reversible logic gates in order to reduce the power consumption and propagation delay as it effectively provides negligible loss of information in the circuit. Keywords: Garbage output, Power dissipation, quantum cost, Reversible Gate, Reversible logic,
Abstract — Reversible logic is one of the most vital issue at present time and it has different areas for its application, those are low power CMOS, quantum computing, nanotechnology, cryptography, optical computing, DNA computing, digital signal processing (DSP), quantum dot cellular automata, communication, computer graphics. It is not possible to realize quantum computing without implementation of reversible logic. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. This paper provides the basic reversible logic gates, which in designing of more complex system having reversible circuits as a primitive component and which can execute more complicated operations using quantum computers. The reversible circuits form the basic building block of quantum computers as all quantum operations are reversible. This paper presents the data relating to the primitive reversible gates which are available in literature and helps researches in designing higher complex computing circuits using reversible gates.
This work presents the logical reversibility. The inputs and outputs of reversible logic gates can be uniquely retrievable from each other. The reversible logic operations can't erase information and dissipate zero heat. The circuit actually operates in a backward operation, allows reproducing the inputs from the outputs and consumes zero power. As the basic elements of any logic circuit, logic gates are used to realize Boolean functions. By combining reversible logic gates, reversible circuits can perform complex logical and arithmetic operations. A one-to-one mapping between inputs and outputs is realized. The logical operations run backwards by cascading a reversible logic gate with its dual (inverse). Reversible circuits are also called lossless circuits, as there is neither energy loss nor information loss. These circuits are very attractive for applications where extremely low power consumption, or heat dissipation, is desirable in areas ranging from communications, low power VLSI (very large-scale integration) technology, optical computing to nanotechnology. Reversible logic found to be very useful in quantum computing where the quantum evolution is inherently reversible.
Reversible logic is emerging as a promising computing paradigm with applications in ultralow power nanocomputing and emerging nanotechnologies such as quantum computing, quantum dot cellular automata (QCA), optical computing, etc. Reversible circuits are similar to conventional logic circuits except that they are built from reversible gates. In reversible gates, there is a unique, one-to-one mapping between the inputs and outputs, not the case with conventional logic. One of the primary motivations for adopting reversible logic lies in the fact that it can provide a logic design methodology for designing ultra-low power circuits beyond KTln2 limit for those emerging nanotechnologies in which the energy dissipated due to information destruction will be a significant factor of the overall heat dissipation. Further, logic circuits for quantum computers must be built from reversible logic components. Several important metrics need to be considered in the design of reversible circuits the importance of which needs to be discussed. Quantum computers of many qubits are extremely difficult to realize thus the number of qubits in the quantum circuits needs to be minimized. This sets the major objective of optimizing the number of ancilla inputs and the number of the garbage outputs in the reversible logic based quantum circuits. The constant input in the reversible quantum circuit is called the ancilla input, while the garbage output refers to the output which exists in the circuit just to maintain one-to-one mapping but is not a primary or a useful output. The reversible circuit has other important parameters of quantum cost and delay which need to be optimized.
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.
Abstract: Reversible logic is one of the most important issues at the moment and has a wide range of applications, such as low power CMOS, quantum computing, nanotechnol- ogy, cryptography, optical computing, DNA computing, and -digital signal processing (DSP), quantum Dot automata for mobile, communication, computer graphics. It is not possible to detect quantum computing without the implementation of a postponed brain operation. The main objectives of design are logical thinking to reduce quantum costs, circuit depths and the amount of waste disposal. This paper provides basic logical retrospective gates, which in the construction of a highly sophisticated system with retractable circuits as part of the old and unable to perform the most complex operations using quantum computers. Reversible circuits form the basic building block of quantum computers as all quantum functions are reversed. This paper presents data related to older retractable gates found in books and assists research in the design of complex computer circuits using retractable gates. Keywords: Defendable Logic, Portable Gate, Dismissal, Trash, Quantum Cost, Quantum-dot Cellular Automata, Reversible Computing, Reversible ALU, Flip Flop using Reversible Gates, Reversible Adder