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

9.7 Searching

We just saw how if we have one standard basis ket in mind, we flip the probability amplitude and then amplify the amplitude for that ket. When we repeat the process enough times, we are likely to measure the right ket with high probability.

In the last section I showed that the ket inline math, which I knew about, can be picked out of all the kets. So I found what I knew was there, and I even knew where it was beforehand. Here we put everything together to describe the famous quantum search algorithm discovered by Lov Kumar Grover, a computer scientist.

9.7.1 Grover’s search algorithm

Instead of using the magic gate matrix inline math, which flips the sign of the amplitude of the given ket, we instead employ Uf, which is related to the oracle f.

In essence, I have an oracle which I can call but I cannot see. I create Uf and then by repeating Uf Uϕ enough times, I can find the special element for which f returns 1. How many times is enough?

In subsection...