Book Image

Dancing with Qubits

By : Robert S. Sutor
5 (1)
Book Image

Dancing with Qubits

5 (1)
By: Robert S. Sutor

Overview of this book

Quantum computing is making us change the way we think about computers. Quantum bits, a.k.a. qubits, can make it possible to solve problems that would otherwise be intractable with current computing technology. Dancing with Qubits is a quantum computing textbook that starts with an overview of why quantum computing is so different from classical computing and describes several industry use cases where it can have a major impact. From there it moves on to a fuller description of classical computing and the mathematical underpinnings necessary to understand such concepts as superposition, entanglement, and interference. Next up is circuits and algorithms, both basic and more sophisticated. It then nicely moves on to provide a survey of the physics and engineering ideas behind how quantum computing hardware is built. Finally, the book looks to the future and gives you guidance on understanding how further developments will affect you. Really understanding quantum computing requires a lot of math, and this book doesn't shy away from the necessary math concepts you'll need. Each topic is introduced and explained thoroughly, in clear English with helpful examples.
Table of Contents (16 chapters)
Preface
13
Afterword

11.1 That’s not logical

The qubits like those in the last two chapters are examples of ‘‘logical qubits.’’ We can use them indefinitely, they never lose state when they are not used, and we can apply as many gates to them as we wish.

When you build a quantum computer, the fundamental physical implementations of qubits aren’t as perfect as logical qubits. Such a qubit, called a ‘‘physical qubit,’’ starts to lose its ability to hold onto a state after what is called its ‘‘coherence time.’’ We also say that the qubit is decohering.

It’s a goal of quantum computing researchers and engineers to delay the decay of a physical qubit’s quantum state as long as possible. Since the decay is inevitable, a goal of fault tolerance and error correction is to handle and fix the effects of the qubits’ decoherence throughout the execution of a circuit.

Is it possible...