Product Vectors in Quantum Computing

Matrix theory play a fundamental role in classical and quantum computing. Among this paper, we study the fundamental concepts of some matrices including unitary matrix and Hermitian matrix, which may convert some initial qubits into various kinds of qubits. We also explore the fundamental concept of eigenvalues. Furthermore, we input the concept of product vectors. Finally we use above-mentioned concepts examing the entanglement witness for verifying the entanglement in quantum computing and circuits.