PragProg Customers

Quantum Computing: QuBit state from a multi-QuBit register (page 99)

DoLed

DoLed

Quantum Computing: QuBit state from a multi-QuBit register (page 99)

the statement “The quantum state of a qubit is obtained by reading across a row … |0011>” seems quite problematic to me.
First, the quantum (pure) state of the considered qubit is a priori not well defined any more at this stage, the global state of the 7-qubits register must be considered as a whole because of entanglement (see next chapter)
Second, even if we could assign this qubit a well defined quantum state, using the notation “0011>” for it is very misleading, as this is used also for the tensor product of qubit states…

8 comments
#errata/book-quantum-computing
0 1200 8

First Post!

nihal.mehta

nihal.mehta

Author of Quantum Computing

Hi Dominique,
All that the statement you referenced is saying is that the quantum state of the first qubit, q[0], is in a superposition of 4 states: |0>, |0>, |1>, |1>. This is simply abbreviated for ease of reading to |0011>.

You are right that that the entire state must be considered as a whole. This is precisely the mega-qubit.

Hope this helps.

Regards,
Nihal

Post #2

Where Next?

View thread on forum
View Quantum Computing's book portal
Post errata for this book
Post a suggestion for this book
Post a question about this book
Post a review about this book
Home PragProg Customers
#errata/book-quantum-computing
0 1200 8
Last post

Popular Pragmatic Bookshelf topics Top

telemachus
PragProg Customers

Warnings in Python Testing With Pytest Chapter 2
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks” While running the smoke tests in Chapter 2, I get these...
#pragprog#errata/book-python-testing-with-pytest
5 2081 1
New
ianwillie
PragProg Customers

Build Websites with Hugo: Code will not run in a working Hugo setup
Hello Brian, I have some problems with running the code in your book. I like the style of the book very much and I have learnt a lot as...
#question/book-build-websites-with-hugo
0 1501 3
New
mikecargal
PragProg Customers

Hands-on Rust: can_place logic is "inside out"
Title: Hands-On Rust (Chapter 11: prefab) Just played a couple of amulet-less games. With a bit of debugging, I believe that your can_p...
#errata/book-hands-on-rust
22 1628 20
New
jdufour
PragProg Customers

The Cucumber for Java Book:
Hello! On page xix of the preface, it says there is a community forum "… for help if your’re stuck on one of the exercises in this book… ...
#question/book-the-cucumber-for-java-book
3 1143 1
New
JohnS
PragProg Customers

Modern CSS with Tailwind: can’t setup the Rails source code
I can’t setup the Rails source code. This happens in a working directory containing multiple (postgres) Rails apps. With: ruby-3.0.0 s...
#question/book-modern-css-with-tailwind
0 1280 3
New
gilesdotcodes
PragProg Customers

Modern CSS with Tailwind: setting up Rails app
In case this helps anyone, I’ve had issues setting up the rails source code. Here were the solutions: In Gemfile, change gem 'rails' t...
#errata/book-modern-css-with-tailwind
3 1278 2
New
jskubick
PragProg Customers

Kotlin and Android Development featuring Jetpack: $kotlin_version ? (page 8)
I’m running Android Studio “Arctic Fox” 2020.3.1 Patch 2, and I’m embarrassed to admit that I only made it to page 8 before running into ...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 1698 3
New
nicoatridge
PragProg Customers

Kotlin and Android Development: Could not get unknown property ‘kotlin_version’…
Hi, I have just acquired Michael Fazio’s “Kotlin and Android Development” to learn about game programming for Android. I have a game in p...
/book-kotlin-and-android-development-featuring-jetpack
0 8095 6
New
taguniversalmachine
PragProg Customers

Real-Time Phoenix: ProductChannelTest - undefined function describe/2 (pg 203)
Hi, I am getting an error I cannot figure out on my test. I have what I think is the exact code from the book, other than I changed “us...
#question/book-real-time-phoenix
0 1775 6
New
dachristenson
PragProg Customers

Kotlin and Android Development featuring Jetpack: No activity_main.xml anymore
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 2172 6
New

Other popular topics Top

Exadra37
Linux>Questions

AMD or Intel for Programming with Linux as the OS?
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
#mobile#android#web-development#linux#desktop-computer#mobile-development
36 6006 10
New
dasdom
General Dev>Dev Chat

Standing Desks
No chair. I have a standing desk. This post was split into a dedicated thread from our thread about chairs :slight_smile:
#workspace#opinions
177 9886 77
New
AstonJ
General Dev>Hardware

Planck vs Preonic vs Subatomic (Keyboards)
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me. I think the Planck and the Preonic (o...
/keyboards#mechanical-keyboards#ortholinear#planck#preonic
105 17596 47
New
AstonJ
Backend>Chat

How to install Ruby 3 with ASDF
In case anyone else is wondering why Ruby 3 doesn’t show when you do asdf list-all ruby :man_facepalming: do this first: asdf plugin-upd...
/ruby#asdf
11 5961 4
New
mafinar
Backend>Chat

Data Structures and Algorithms with Elixir
This is going to be a long an frequently posted thread. While talking to a friend of mine who has taken data structure and algorithm cou...
/elixir#algorithms#data-structures
108 11869 31
New
PragmaticBookshelf
Backend>Learning Resources

Agile Web Development with Rails 7
Rails 7 completely redefines what it means to produce fantastic user experiences and provides a way to achieve all the benefits of single...
pragprog.com
#pragprog#web-development/ruby/rails#published-book/book-agile-web-development-with-rails-7
32 6600 9
New
husaindevelop
Android>Questions

Clipboard readtext not working in android webview
Inside our android webview app, we are trying to paste the copied content from another app eg (notes) using navigator.clipboard.readtext ...
#android#clipboard
1 5651 0
New
hilfordjames
Windows>Chat

Taskbar Overflow Menu (NOT System Tray Overflow)
There appears to have been an update that has changed the terminology for what has previously been known as the Taskbar Overflow - this h...
#taskbar-overflow-win-11
3 3715 2
New
PragmaticBookshelf
Backend>Learning Resources

Engineering Elixir Applications
Develop, deploy, and debug BEAM applications using BEAMOps: a new paradigm that focuses on scalability, fault tolerance, and owning each ...
pragprog.com
#pragprog/elixir#published-book/book-engineering-elixir-applications
40 7136 21
New
PragmaticBookshelf
Backend>Learning Resources

Simplicity
Fight complexity and reclaim the original spirit of agility by learning to simplify how you develop software. The result: a more humane a...
pragprog.com
#pragprog#published-book/book-simplicity
10 6553 8
New
Back to top

Latest in Quantum Computing

Quantum Computing Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap