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This content is taken from the Keio University's online course, Understanding Quantum Computers. Join the course to learn more.

Skip to 0 minutes and 4 secondsWelcome to "Understanding Quantum Computers." I'm Rodney D. Van Meter, of Keio University's Faculty of Environment and Information Studies. I'm Takahiko Satoh, of Keio University's Graduate School of Media and Governance. We are going to be your educators for this fascinating topic and we hope to get you through it using almost no math. By now, you have heard about quantum computers. Quantum computers have appeared quite a bit in recent science fiction. ‘Self-Reference Engine’, by Toh Enjoe, is one of my favorites, so is ‘Death's End’, by Liu Cixin. They have appeared in many others, including manga such as Eden. The representations aren't always accurate, but at least they heighten interest in the topic.

Skip to 0 minutes and 44 secondsOne of these may even be the reason that you are here. The story often goes something like this. Brilliant scientists in exotic labs are using the spookiest, most obscure effects of quantum mechanics to build science fiction computers, capable of practically anything. Quantum computers are going to break your encrypted internet connection. They are going to create an artificial intelligence that thinks at warp speed. Quantum networks are going to help us communicate faster than the speed of light and teleport objects, like, the transporter in ‘Star Trek’. Well, that's not quite true.

Skip to 1 minute and 17 secondsIn fact, faster-than-light communication is still impossible even using quantum mechanics and teleportation of objects looks to be impractical, though we do know how to teleport quantum information, still not faster than the speed of light, of course. Of all of these popular ideas, the only one that has some really solid basis is that quantum computers will impact the use of encryption. Quantum computing is going to change the world, and after three decades of research, practical systems may be just around the corner. We will discuss the motivation for building quantum computers, qualitatively cover the important principles in quantum computing and take a look at some of the most important quantum computing algorithms.

Skip to 1 minute and 54 secondsWe are going to learn how quantum computers can help chemists with their computations. Many companies need to optimize something. Their use of resources such as employee's time or material for manufacturing. Finding a route on a map is also an optimization problem. We will see where computers can and cannot help with problems like these. We will finish with a brief look at quantum computing hardware and the budding quantum computer information technology industry. This course is ideal for high school juniors and seniors and college freshmen and sophomores looking for a topic of study as well as practicing computer professionals interested in learning about one of technology's most exciting topics.

Skip to 2 minutes and 33 secondsLay people with an interest in popular science will have no problem keeping up. The field lies at the intersection of computer science, physics and mathematics. Being able to conduct research at the leading edge, as in any field, requires a lot of intense preparation but in this course, we will help you take the first steps in understanding the topic whether you hope to work in the area or are just curious. Fortunately, we won't go into the mathematics, beyond what you have already learned in high school. If you know what a sine wave is, can multiply to get powers of two, can add two vectors, and know enough probability to talk about rolling dice, you know enough to get through this course.

Skip to 3 minutes and 15 secondsImaginary numbers will make a cameo appearance, but you really don't need to know anything serious about them. On the computer science end, it is helpful if you know how to count in binary, but that's about it. No physics background is assumed beyond a rough idea of what photons, electrons and atoms are. So, let's get started!

Introduction

After twenty years as a subject of quiet academic research, suddenly talk about quantum computers is everywhere. You can use a quantum computer via the web, and perhaps soon buy one. Would you like to learn how they work?

Script and articles are available in Japanese and English in PDF format. Please find files in DOWNLOAD section at the bottom of this page. You can also turn on the subtitles in English or Japanese for all the videos.

[NOTE in JAPANESE] 全てのビデオは日本語字幕をオンにして視聴することができます。ビデオ開始後右下に出るピンクのマークで言語を選択してください。また、第1週のコンテンツの日本語版PDFは、このページの一番下にある DOWNLOAD というセクションにございますのでご利用ください。

[NOTE in Thai] เนื้อหาในวิดีโอทั้งหมดมีคำบรรยายภาษาไทย ผู้เรียนสามารถเลือกคำบรรยายภาษาไทยได้จากเครื่องหมายด้านขวาล่างของวิดีโอ หลังจากที่วิดีโอเริ่มเล่น สำหรับเนื้อหาภาษาไทยของสัปดาห์ที่ 1 ผู้เรียนสามารถดาวน์โหลดได้จากหน้าโฮมเพจ Step 1.1 ในส่วน DOWNLOAD

What’s a quantum computer?

Okay, maybe we should pause to tell you what a quantum computer is. Simply put, it’s a computer that uses quantum effects to calculate the results of some functions far faster than an ordinary (classical) computer can. That’s really not a lot of help, though.

You have probably heard that, in quantum mechanics, an electron or a photon sometimes behaves like a particle, and sometimes like a wave. Light makes beautiful patterns on a soap bubble thanks to waves, but we can also count photons one by one. Researchers all around the world are investigating a bunch of different ways to build quantum computers, but they all have this in common: a quantum computer takes advantage of both the wave nature and particle nature, using interference and quantum entanglement, to reduce the number of times we have to perform some calculation.

The excitement comes from their behavior as problems get harder: maybe increasing the size of a problem (for example, boosting the number of cities you are planning to visit on a trip by one) doubles the amount of time it would take a regular computer to find your best route, but only raises the time on a quantum computer by, say, twenty seconds. The actual size of the advantage a quantum computer has depends on a lot of factors, though, and you will learn about some of them in this course.

A four week journey

In this course, we will dive into quantum computing head first, but not without preparing. In Week 1, we will study the key concepts, beginning with how waves interfere with each other and leading toward quantum entanglement, which Einstein called “spooky action at a distance”. In Week 2, we move into the heart of quantum computing. The week is divided into four major Activities: Qubits, Entanglement, Basic Algorithm Idea, and State Variables. Across those Activities, you will learn about the seven key concepts needed to grasp quantum computing. In Week 3, we will examine some of the important quantum algorithms in detail. And in the final week, we will talk about devices that can make and control each kind of state variable, and meet some of the people and companies building real quantum computers.

Each week, you will watch videos and read articles, answer quizzes and discuss with your fellow learners. Some quizzes will use interactive applications to help you understand concepts and answer questions, and designs for several 3-D printable objects are provided both for fun and to help vision-impaired learners.

At the end, please check your understanding in the final Test step.

Join us on our four-week journey into one of the twenty-first century’s most exciting technologies!

Further study

Of course, in just a few weeks of a few hours a week, you can take only the first steps into this exciting new computational paradigm. If you want to learn more, the course ends with an Article on Further Study. If, during the course, you want to dig deeper into any individual topic, feel free to leap ahead to that step and follow the links there.

Video Communication Trial (BANSOU Videos)

In addition to the course lecture, we will upload short video clips on YouTube. The videos will include Interviews (of lead educators as well as mentors, etc.), Discussions (among the educators), Tips and Feedback.

BANSOU (伴走/伴奏) is a Japanese word, meaning that we ‘run together’ towards the goal. The focus of this trial is to support creating a sense of ‘connectedness’ and ‘empathy’ between the educators and learners, and we hope you enjoy watching the videos alongside the course.

Organizing team

This course will be led by Professor Rodney Van Meter and Project Research Associate Takahiko Satoh from Keio University.

Educators and Organizers From the left: Rodney Van Meter and Takahiko Satoh.

During the course, three students from Rod’s Lab - Takaaki Matsuo and Shin Nishio will assist you in addition to Professor Keiko Okawa and Motoki Yasui from Keio FutureLean supporting team.

Follow the team to read their responses to learners throughout the course.

Important notes

  • All videos have English and Japanese subtitles. You can choose one of those by clicking the bubble mark at the right cover of the video.
  • All steps have English and Japanese text of articles and video scripts which you can find as PDFs under the “DOWNLOADS” section at the bottom of the first step of each week.
  • We have included a glossary for your reference. You can consult the glossary by downloading the PDF version which is available from the “DOWNLOADS” section below. If you come across other words that you would like us to add to the glossary, please tell us in the comments section.
  • When you complete each step, select the Mark as complete button before selecting the forwarded arrow to move on.
  • If you are new to FutureLearn, take a look at the Using Futurelearn section for information on how to get the best out of the course.

Get extra benefits, upgrade your course

You can now get extra benefits by upgrading this course, including:

Unlimited access to the course: Go at your own pace with unlimited access to the course for as long as it exists on FutureLearn.

A Certificate of Achievement or Statement of Participation: To help you demonstrate your learning we’ll send you a Certificate of Achievement or Statement of Participation when you become eligible.

Find out more




イントロダクション

量子コンピュータは、20年前は比較的穏やかであった研究分野ですが、最近になって突如活発に研究されるようになりました。現在はWeb上で量子コンピュータを使う事ができ、やがて購入することができる時代がくることでしょう。では量子コンピュータがどのように成り立っているか興味ありませんか?

全てのビデオは日本語字幕をオンにして視聴することができます。ビデオ開始後右下に出るピンクのマークで言語を選択してください。また、第1週のコンテンツの日本語版PDFは、このページの一番下にある DOWNLOAD というセクションにございますのでご利用ください。

量子コンピュータとはなんでしょう?

簡単に言うと量子コンピュータとは計算に量子力学を応用する事で、古典コンピュータでは到底実現できないような高速な計算が可能なコンピュータです。

もしかしたら耳にした事があるかもしれませんが、量子力学では電子や光子は時に粒子として振る舞い時には波として振る舞います。光子の波としての性質によりシャボン玉に綺麗な模様を作る事などが可能になりますが、光子を一粒一粒数えることも可能です。世界中の研究者たちは様々な方法で量子コンピュータの設計を試みていますが、量子の粒子という性質による量子もつれと、波動という性質による干渉の両方を組み合わせて、計算処理を減らしているという共通点が存在します。

量子コンピュータの最大の魅力の一つは、計算問題が難しい場合における振る舞いにあります。問題(例えば大量の町の中から一箇所ずつ旅行する場合の町の数など)が大きくなれば大きくなるほど古典コンピュータは、最適な道のりを探すのに多くの時間がかかるようになりますが、量子コンピュータの場合は、言うとすれば20秒程度しか増えません。実際にどれだけ量子コンピュータが高速化するかは色々な要因によるのですが、コースではそれらのいくつかについて学習していきます。

量子コンピュータを学ぶ4週間の旅

まず、このコースでは、量子コンピュータについての知識を持たないことを前提に学習していきます。第1週では、アインシュタインが「奇妙な遠隔相互作用」と語った波の干渉について学習します。このことは、次の週で学ぶ量子もつれを理解するのに重要です。第2週では、量子コンピュータのとても重要な部分を学びます。この週は大きく量子ビット、量子もつれ、アルゴリズムの基礎、状態空間に分かれています。これを通して、量子コンピュータの理解の鍵となる7つの概念について学習します。第3週では、アルゴリズムの細かいところについて学習していきます。そして最終週には、状態空間を操作する機器に関して学び、実際に量子コンピュータの研究や開発に携わっている企業や人々にインタビューします。

コースでは、量子コンピュータに関する記事を読んだり、動画を視聴したり、また、クイズに答え、ほかの生徒と議論を重ね学習していきます。3-Dアプリケーションを使ってクイズに答えるといった、視覚的な学習も含まれています。

最後は自分がきちんと理解できているかを確認してください。

では21世紀で最もホットな技術について勉強していきましょう。

次のステップ

当然のことながら、週あたり数時間のこのコースだけでは、量子コンピュータの初歩的なところまでしか学習できません。コース終了後も更に学びたい方のための参考書籍や関連コースを、コース最後の記事「4.25 更に学びたい方へ」に準備しましたので、参照して下さい。コースの途中でより深く学習したくなった場合にも、いつでも参考にしてください。

講師紹介

このコースは慶應義塾大学のRodney Van Meter教授と佐藤貴彦助教が担当します。

Educators and Organizers 左からRodney Van Meterさんと佐藤 貴彦さんです。

コース中は慶應義塾大学の大川 恵子教授と慶應 Future Learnチームの安井 元規さんに加え、バンミーター研から松尾 賢明さん、西尾 真さんの2人の生徒がサポートしています。

チームメンバーを「フォロー」すると、メンバーの発言を常にウォッチできますので、ぜひご利用ください。

重要事項

  • 各週の最初のステップの__DOWNLOADS__から、その週の講義のPDFをダウンロードすることができます。
  • 用語集を用意しています。用語集は、このページの下部にある__DOWNLOADS__の部分から、PDFで取得することが可能です。もし用語集に存在しない単語で、追加してほしい単語がありましたら、そのセクションにその旨のコメントをお願いします。
  • 各ステップが終わるごとに、Mark as completeを押して、完了を報告してください。
  • 初めてFutureLearnを利用する方は、どのようにコースを進めていくのが良いのか、”Using Futurelearn”というページを見てみてください。

ビデオコミュニケーショントライアル(BANSOUビデオ)

私たちは、オンライン学習において教育者や学習者の人となり、背景を知ることで学習に対してどのような効果・影響が出るかということを研究しています。 これらのビデオはその研究の一部です。

コースをアップグレードすることのメリット

このコースを有料でアップグレードすると、以下のような利点があります。

永久にアクセス可能:無料の受講期間が終了しても、いつでもそのコースにアクセスして受講し直していただくことが可能となります。

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This video is from the free online course:

Understanding Quantum Computers

Keio University