Book Image

Dancing with Python

By : Robert S. Sutor
Book Image

Dancing with Python

By: Robert S. Sutor

Overview of this book

Dancing with Python helps you learn Python and quantum computing in a practical way. It will help you explore how to work with numbers, strings, collections, iterators, and files. The book goes beyond functions and classes and teaches you to use Python and Qiskit to create gates and circuits for classical and quantum computing. Learn how quantum extends traditional techniques using the Grover Search Algorithm and the code that implements it. Dive into some advanced and widely used applications of Python and revisit strings with more sophisticated tools, such as regular expressions and basic natural language processing (NLP). The final chapters introduce you to data analysis, visualizations, and supervised and unsupervised machine learning. By the end of the book, you will be proficient in programming the latest and most powerful quantum computers, the Pythonic way.
Table of Contents (29 chapters)
Part I: Getting to Know Python
PART II: Algorithms and Circuits
PART III: Advanced Features and Libraries
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Appendix C: The Complete UniPoly Class
Appendix D: The Complete Guitar Class Hierarchy
Appendix F: Production Notes

11.5 Amplitude amplification

I now stop talking about “data values” and call them what they are for Grover search: amplitudes. In this section, we work with three qubits and begin by placing them in a balanced superposition:

Three qubits in a balanced superposition

These are the same quantum states we saw with the light bulbs in section 11.2. The qubits being in balanced superposition translates to the light bulbs all being in the half-dimmed state.

When I apply the oracle for |000⟩, the amplitude for that ket becomes negative:

Three qubits in a balanced superposition, first sign flipped

Figure 11.8 shows these two sets of amplitudes. The mean on the left-hand side is 1/√8, which is approximately 0.354.

Amplitudes for three qubits: Original and sign flipped for |000>
Figure 11.8: Amplitudes for three qubits: Original and sign flipped for |000⟩

If we measure the quantum states...