How I Learn Quantum Computing

Christophe Pere

Published in

The Startup

7 min readNov 2, 2020

A deep dive into the quantum world and AI

Introduction

I love quantum mechanics, something is fascinating about the perception of how QM explains the world. How different it is than the reality we can see and live in.

Everything we call real is made of things that cannot be regarded as real.
Niels Bohr

This quotation was a revelation to me when I was a student. Looking at the matter isn’t the good way because all of the elements are just waves. Why reality models itself when present to an observer?

I like to think the moon is there even if I am not looking at it.
Albert Einstein

The debate between microscopic effects and macroscopic effects is also very exciting. Why the infinity small doesn’t act like the macroscopic world? Why my table is still here if I’m not looking at it? A lot of strange effects populate quantum mechanics and your conception of the world will change if you look closer to them.

The way we have to describe Nature is generally incomprehensible to us. Richard Feynman.

Richard Feynman described the fact Nature isn’t classical and to study it, we need a quantum computer. Here it is, the Revolution just born in the brain of an imminent physician.

When I speak about Quantum Computing (QC), I generally receive the same answers:

Why?
This why is more “why do we need to have an interest in QC?”. As you think, this question is from companies I worked with. Most of the time people are just afraid to change. And they prefer to ignore the possibility that what they actually know can be irrelevant in several years. So why QC? In terms of simulation, artificial intelligence, computation, optimization it’s just the future. We will soon break the frontier, the quantum supremacy, and prove that this technology allows us to reach the actual impossible (to infinity and beyond like my son loves to say). IBM has a plan to build a Quantum Computer with more than 1,000 qubits (300 qubits represent 2³⁰⁰ states in superposition so more than atoms in the Universe, qubits is the name of the quantum bits used to compute) in 3 years. So the question is not why, but when? and How?

The technology is not ready!
I still laugh at this answer. The technology is not ready for what? D-Wave builds QC since 1999, the latest release is a quantum annealer with more than 5000 qubits. 1Qbit works with quantum solutions since 2012. IBM launched the IBM Q Experience in 2016 where you can use real QC in the cloud. Since, Microsoft via Azure launch his quantum platform, Google, Rigetti, etc. are also in the Cloud. So, the technology is here, but it depends on what you think. If it is “Can I have a QC at home?” the response is no for 99.999% of the population because the cost of a QC is around 10 million dollars. But, if the question is “Can I work and do research in real QC?” the answer is yes. If you ask “Can I have a QC to put applications in production?” the answer is, it depends.

What are the advantages?
They are many, but they are many disadvantages also. The advantages, you could compute 2^n (n is the number of qubits) states in superposition. Superposition allows you to compute 2^n computations at the same time, without looping into infinity. The problem is you need to understand interference to obtain and select the best results. The consumption of energy is constant, just need to refrigerate the qubits at almost absolute zero temperature to be stable. And many other things.

Too complicated!
I would say, if it’s easy it’s not interesting, we learn nothing. If you permit me a quotation of JFK when he speaks about the journey to the Moon:

We choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win, and the others, too. JFK

For me, interesting things come with challenges. So is QC complicated? Yes and no, is it because it’s something new, it’s something for which we need to change our thinking. Is it really complicated? No, it’s like a new thing, you need to learn and apply.

Ok, It’s a big introduction, but how to learn what is a quantum computer and what is quantum computing?

Formations

I was lucky recently in this field and was accepted in a training provided by IBM and The Coding School. The formation is Qubit by Qubit’s Introduction To Quantum Computing and it’s provided between October 2020 and May 2021.

I was also accepted in the IBM Quantum Challenge, 3 weeks of intense formation on Qiskit, and the IBM Quantum Experience.

But before that, I was just a young passionate about the field and looking for textbooks, tutorials, etc. just exploring different resources and going forward.

Resources

But, without this, how to learn Quantum Computing? Several good resources are available.

You can find lots of resources on youtube, explaining every part or every block of quantum mechanics. You can find lots and lots of resources on the internet. I just provide here some that I think are more useful or I appreciated the most. We begin with YouTube channels:

Videos

Qiskit, Youtube
Introduction to Quantum Computing and Quantum Hardware, Qiskit
Conference Quantum Computing Paris Saclay, YouTube

They are very interesting and the two first provided a very good introduction and useful information to study and use Qiskit, the IBM library to code Quantum Computers in Python. They are others like Pennylane, Cirq, TensorFlow-quantum but, I let you explore these ways and give me feedback.

Textbooks

I love books, so for me, it is one of the best ways to acquire knowledge about something. There aren’t tons of books about quantum computing, so when you look at “best books” or “reading list” for quantum computing you reach globally the same books, there, I provide a list of my favorites:

Dancing with Qubits, Robert Sutor, 2019, Packt
Quantum Information and Quantum Computation, 10th anniversary, Nielsen and Chuand, 2012, Cambridge University Press
Programming Quantum Computing, Jonhston et al. 2019, O’Reilly
Dance of the Photons: From Einstein to Quantum Teleportation, Anton Zeilinger, 2010
Quantum Mechanics: The Theoretical Minimum, Leonard Susskind & Art Freidman, 2014
Quantum Computing: An Applied Approach, Jack D. Hidary, 2019

Blogs / Articles

You also have very good resources through blogs and scientific papers. Here, are just a few:

Quantum Computing for the Very Curious, Andy Mathushak & Micheal Nielsen
Qiskit textbook, IBM
Guide to Quantum Computing, WIRED
Quantum Computing, IBM
Quantum-Computation and Applications, Bhupesh Bishnoi, 2020, arXiv preprint
Quantum Computing: Lecture Notes, Ronald de Wolf, 2019
A Gentle Introduction to Quantum Computing Algorithms with Applications to Universal Prediction, Elliot Catt and Marcus Hutter, 2020
Quantum computing from a mathematical perspective: a description of the quantum circuit model, J. Ossorio-Castillo and José M. Tornero, 2018
A course in Quantum Computing, Michael Loceff, 2015

MOOCs

MOOCs in QC are not many. The technology is too young and there aren’t many resources to use easily. But, I found three relevant:

Quantum Computing, edx
The Introduction to Quantum Computing, Coursera
Quantum Computing, Brilliant

Quantum Machine Learning

Yeah, next frontier, Quantum Machine Learning, or QML. Quantum Computing masters the art of computation especially with superposition (relevant in optimization). The natural way led to the field of Artificial Intelligence with the domain of machine learning. This is why I learn QC. I want to use QC in my day to day work as an AI researcher. Few resources:

Quantum Machine Learning, edx
Quantum machine learning, Biamonte et al. 2017, Nature
Quantum Machine Learning: a classical perspective, Ciliberto et al., 2017, arXiv preprint
Classification with Quantum Machine Learning: A Survey, Abohashima et al. 2020, arXiv preprint
Quantum Machine Learning for Data Scientists, Kopczyk, 2018, arXiv preprint
Advances in Quantum Deep Learning: An Overview, Garg & Ramakrishnan, 2020, arXiv paper

GitHub repositories

How to go deeper? Good question, I think the most interesting way is to practice and to look at Github repositories. Especially those entitled awesome-something.

Awesome Quantum Machine Learning, krishnakumarsekar
Awesome Quantum ML, artix41
Awesome Quantum Computing, desireevl

Conclusion

Yeah, I know, lots of materials but, it’s a shortlist. Even if the domain is pretty young, the number of resources is growing exponentially. Quantum Computing is the new oil, IBM is on a crusade to teach QC to every student in high school.

I’m always learning about QC because it will replace classical computing in different areas like chemistry, artificial intelligence, finance, optimization. I recently read that, the advice for companies was to hire a Quantum Computing officer to write the strategy of the migration. It is inevitable for the future of companies to avoid this technology. The number of quantum computers is only increasing and will soon make it possible to manage applications in production.

Many learners turn to this technology to learn the concepts and how to use them in order to be ready. Currently, most of the work of QC is at the research stage, but tomorrow will arrive very quickly. Don’t learn too late.