Quantum logic gate is a circuit, which performs a fixed unitary operation on selected qubits in a fixed period of time. The aim of this paper is to propose a simulator - Quantum Circuit Simulator (QCS) that simulates the quantum logic gates. This is a hardware-based simulator. Normally the quantum computers use quantum gates, which perform the arithmetic operations by means of Quantum Arithmetic And Logic Unit (QALU), which is similar to ALU in conventional computers. This paper presents the structure of quantum gates and their simulation result along with their run time calculation.
Quantum logic gate is a circuit, which performs a fixed unitary operation on selected qubits in a fixed period of time. The aim of this paper is to propose a simulator - Quantum Circuit Simulator (QCS) that simulates the quantum logic gates. This is a hardware-based simulator. Normally the quantum computers use quantum gates, which perform the arithmetic operations by means of Quantum Arithmetic And Logic Unit (QALU), which is similar to ALU in conventional computers. This paper presents the structure of quantum gates and their simulation result along with their run time calculation.
A quantum gate is the quantum analog of the classical logic gate of digital computers. It is a basic structural unit of a quantum circuit which operates on a small number of qubits to deliver a predefined output. A quantum circuit is a graphical representation of the sequence of the quantum gates used and the measurements performed in a quantum computation. Various quantum logic gates, namely, the Hadamard, T phase, NOT, Pauli-X, controlled NOT (CNOT), controlled-Z, SWAP and controlled phase gates as well as higher-level Toffoli and Fredkin gates are described. Conventions of reading quantum circuit diagrams are explained. Operation of a quantum full adder consisting of registers and gates is discussed, elaborating the role of the NOT gate, the sum calculation with CNOTgates and the carry C-out calculation with Toffoli gates. A primary tool used for performing arithmetic operations on a quantum computer is the quantum Fourier transform (QFT). The QFT adder and multiplier circuits are presented.
We show that a quantum version of a classical arithmetic-logic unit (ALU) can be implemented on a quantum circuit. It would perform the same functions as a classical ALU, with the possibility of adding quantum functions in conjunction. To create the quantum ALU, we utilized IBM's Python package Qiskit and JupyterLab. We believe that a quantum ALU has the potential to be faster than its classical counterpart and the ability to calculate quantum specific operations. The simple classical functions translated to a quantum circuit show a promising future for the development of a full quantum ALU with unique quantum operations.
Abstract-Quantum theory of computation establishes that there are problems for which quantum algorithms are far more efficient than their classical counterpart. Advances in quantum computing have initiated the design of systems based on quantum logic gates. Quantum computer hardware being primarily available in research laboratories at present, it mandates the ability to design, develop and test quantum logic operations by simulation of quantum logic circuits on classical computers. In this paper, we have defined a programming model for the design of a quantum circuit simulator, which can simulate a given quantum circuit obeying the rules of quantum gate operations. The quantum gate operations on both pure and superposed quantum states are being done with the help of effective data structures. The proposed quantum circuit simulator also incorporates the simulation of quantum circuit error under the action of certain quantum faults.
The quantum computer has attracted much attention since it can reduce running time of many tasks such as factorization and search compared to classical computers. However, the actual quantum computer is difficult to get access, and the classical computer has a problem of calculation time and computation cost grows exponentially with increasing the number of qubits. In this paper, we address an efficient quantum circuit simulator including quantum circuit emulation hardware and its software framework using classical bit. Also, the proposed quantum circuit simulator operates the same as the conventional quantum software framework and shows a fast operation speed.
A quantum computer is a device for computation that makes direct use of distinctively quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. In a classical (or conventional) computer, the amount of data is measured by bits, in a quantum computer; it is measured by quantum of bits (qubits). This work describes, and implements the universal quantum logic gates, the terminology is introduced with two well known quantum gates, the quantum NOT, and the quantum XOR gates. The NOT and XOR gates have already been described in classical reversible logic. This work gives the implementation of the quantum circuits, such as the Quantum Half-Adder Circuits, which consists of quantum control control not gate (CCNot) and quantum control not gate (CNot). Also, it describes and implements the Quantum Full-Adder Circuits, which consists of two Quantum Half-Adder Circuits and one control not gate (CNot). Depending on the quantum circuits, one can implement the quantum basic arithmetic operations such as (addition, subtraction, multiplication and division). After each implementation, the computational complexity of each step is calculated. Key words:
Quantum computing represents a paradigm shift in computation by leveraging the principles of quantum mechanics such as superposition, entanglement, and interference to perform operations beyond classical limitations. Unlike classical computing systems that rely on irreversible logic operations and suffer from energy dissipation due to information loss, quantum systems utilize reversible unitary transformations that preserve information and improve computational efficiency. This paper presents a comprehensive framework for the design, simulation, and validation of quantum gates and reversible arithmetic circuits, including half adders and half subtractors. The proposed approach systematically maps classical arithmetic logic into quantum circuits using fundamental quantum gates such as Pauli-X, Hadamard, Controlled-NOT (CNOT), and Toffoli gates. The circuits are implemented and simulated using the Qiskit Aer framework, enabling detailed analysis of quantum state evolution and measurement outputs. The results obtained from simulation include program-level outputs, state vector representations, measurement counts, and probability distributions, all of which demonstrate strong agreement with classical truth tables. The analysis confirms the correctness, reversibility, and scalability of the proposed designs. Furthermore, a comparative performance evaluation highlights the advantages of quantum computing over classical approaches in terms of parallelism and energy efficiency. The proposed framework establishes a robust foundation for future implementation of complex Boolean logic and arithmetic operations in quantum systems.