This simple yet practical first contact with quantum computing is well written, easy to read, and well structured. The authors state from the very beginning that they cannot cover all relevant topics of quantum computing, so instead they explain it from two appropriately chosen perspectives: theoretical computer science (CS) and quantum physics. I think the book is exceptionally interesting for people in CS who want to understand the basic notions behind quantum computing.
The book’s four core chapters cover “Bits and Qubits,” “Grover’s Algorithm for Unstructured Search in Quantum Computing,” ““Shor’s Algorithm for Integer Factorization,” and “Quantum Walks.” I have always wondered about quantum algorithms for both unstructured search and integer factorization, especially the latter because of the implications to cryptography and protocols. The book delivers a very good description of the algorithms for beginners. It also provides a full description of the algorithms using quantum physics formulas, a better presentation for an intermediate or expert reader. Furthermore, the book includes information on how to play with the algorithms using computer simulations provided by many software products, such as Mathematica, MATLAB, or Maple, or by coding them yourself in Python.
A particular characteristic of this book is to provide insights into many intricate elements of quantum computing: why reversible computing is essential to quantum computing; which different logical gates are associated to quantum computing; why all the logical gates can be reduced to a minimal set; how qubits are represented in quantum physics using spatial properties; the ecosystem of different functions applicable to qubits to represent a quantum computing program; and the differences between quantum walks and random walks.
The take-home message from this book is that amplitude amplification and quantum parallelism are the basis of unstructured search, and that the quantum version of the Fourier transform is the basis for integer factorization.
