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.
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.
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,
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.
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.
It has been realized that quantum computing is one of the latest technologies using reversible logic. It is observed that increasing growth of transistor density, power consumption will reach their limits in conventional technologies. In conventional Circuits during the logic operations bits of information is erased resulting dissipation of energy in significant amount. Thus, if Circuits are designed so that information bits can be preserved, the power use can be reduced. In case of reversible logic computation, the information bits are not lost. We can use reversible logic technology for minimizing the power consumption, heat dissipation, increasing speed etc. This paper describes various logic gates based on reversible logic like Toffoli, Peres, Fredkin, and Feynman etc. A comparative between classical and quantum logic gates is also given on various parameters along with limitations of conventional computing.
Energy can neither be created nor be destroyed but it can be conserved. The processors of present day computers are designed using conventional logic circuits which are irreversible in nature. They suffer from loss of information during computation, leading to energy dissipation in the form of heat affecting the performance and life of the circuits. These limitations of conventional logic circuits can be overcome by the reversible logic circuits designed using quantum gates, the essential elements for quantum computing. Quantum computing is an emerging area of research which finds application in optical computing, DNA computing, cryptography, low power CMOS design, digital signal processing and nanotechnology.