Quantum Computing: Qubits, Quantum Circuits and Algorithms

Quantum computing emerged from the meeting of computer science and quantum mechanics, with the aim of determining whether physical resources described by quantum theory—such as superposition, interference, and entanglement—can be harnessed to construct computational models more powerful than their classical counterparts. The answer, developed from the 1980s to the present day, is affirmative for certain classes of problems, including integer factorization, the discrete logarithm problem, the simulation of quantum systems, and unstructured search.

This book provides an introductory yet substantial treatment of the subject. It begins with the qubit and the Bloch sphere, then moves to multi-qubit systems, tensor products, and entanglement; develops quantum logic gates and the circuit model; presents the paradigmatic algorithms ranging from Deutsch–Jozsa to Shor and Grover; and finally addresses the issues that make quantum computation physically realizable: noise, quantum channels, error-correcting codes, and models alternative to the standard circuit model.

Aimed at undergraduate students of Computer Science, Physics, Mathematics, and Engineering, the book includes more than one hundred exercises, each accompanied by its result, with detailed solutions provided in a concluding chapter.