jaaborot

jaaborot

Quantum Computing: Assigned rotations for 0 qubelets and 1 qubelets are inconsistent across several pages (pages 400, 402, 406, 407, 413)

Title: Quantum Computing: The angle of rotation of the 0 qubelets and 1 qubelets are inconsistent across several pages (pages 400, 402, 406, 407, 413)

Example:

  • 0 qubelets are assigned with 20 degrees rotation, 1 qubelets are assigned with -30 degress rotation - (page 400)
  • 0 qubelets are assigned with 20 degrees rotation, 1 qubelets are assigned with -30 degrees rotation - (page 402)
  • 0 qubelets are assigned with 30 degrees rotation, 1 qubelets are assigned with 20 degrees rotation - (page 406)
  • 0 qubelets are assigned with 20 degrees rotation, 1 qubelets are assigned with 30 degrees rotation - (page 407)
  • 0 qubelets are assigned with 20 degrees rotation, 1 qubelets are assigned with -30 degrees rotation - (page 413)

First Post!

nihal.mehta

nihal.mehta

Author of Quantum Computing

Hi,

  • Not quite. What’s shown is that starting with qubelets that initially have no orientation, we move the entire qubit (the qubelet orientations are still 0 degrees) through a series of rotations (actually just 2), so that it ends up at any point on the unit sphere we choose. The difference between the 2 rotations we moved the qubit is then shown as the orientation of the triangle |1> qubelets. The latitude on the Bloch sphere tells us the relation between the number of the pentagon |0> qubelets and the triangle |1> qubelets (for example, states near the North Pole have more pentagon |0> qubelets than triangle |1> qubelets). And, the longitude indicates the relative difference in orientations between the pentagon |0> and triangle |1> qubelets. The intent is just to illustrate that any point on the Bloch sphere is equivalently represented as pentagon |0> and triangle |1> qubelets oriented in a mathematically precise way.
  • Don’t think of starting with qubelets in a specific orientation.
  • The Try Your Hand exercises on Page 156 should shed more light on the relationship between a point on the Bloch sphere (a specific quantum state) and the pentagon |0> and triangle |1> qubelets.
  • Not sure if it helps, but think of a solved Rubik’s Cube. When you twist and turn its faces, you are moving the entire face containing the tiny cubies at once. After a few such twists, the tiny cubies end up with different orientations. We are doing something similar here but with with just 2 “faces” each representing the pentagon |0> and triangle |1> qubelets respectively. We rotate the entire face as a unit just as in the Rubik’s Cube. And, the state we end up in is a specific combination of the number of pentagon |0> and triangle |1> qubelets their respective orientations.

Thanks again for your comments. This is a difficult topic and hard to wrap your head around. I find the Bloch sphere highly confusing when designing quantum algorithms.
But, since the qubelets in a qubit are equivalent to quantum states on the Bloch sphere, we can instead use the qubelets model to build quantum circuits that take a qubit from one quantum state. I find this more intuitive than grappling with the Bloch sphere.

Thanks,
Nihal

Where Next?

Popular Pragmatic Bookshelf topics Top

jeffmcompsci
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list) Typo:...
New
simonpeter
When I try the command to create a pair of migration files I get an error. user=> (create-migration "guestbook") Execution error (Ill...
New
mikecargal
Title: Hands-on Rust: question about get_component (page 295) (feel free to respond. “You dug you’re own hole… good luck”) I have somet...
New
cro
I am working on the “Your Turn” for chapter one and building out the restart button talked about on page 27. It recommends looking into ...
New
AndyDavis3416
@noelrappin Running the webpack dev server, I receive the following warning: ERROR in tsconfig.json TS18003: No inputs were found in c...
New
adamwoolhether
I’m not quite sure what’s going on here, but I’m unable to have to containers successfully complete the Readiness/Liveness checks. I’m im...
New
New
jwandekoken
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below: d...
New
davetron5000
Hello faithful readers! If you have tried to follow along in the book, you are asked to start up the dev environment via dx/build and ar...
New
dachristenson
I’ve got to the end of Ch. 11, and the app runs, with all tabs displaying what they should – at first. After switching around between St...
New

Other popular topics Top

PragmaticBookshelf
Brace yourself for a fun challenge: build a photorealistic 3D renderer from scratch! In just a couple of weeks, build a ray tracer that r...
New
AstonJ
I’ve been hearing quite a lot of comments relating to the sound of a keyboard, with one of the most desirable of these called ‘thock’, he...
New
AstonJ
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...
New
New
PragmaticBookshelf
Create efficient, elegant software tests in pytest, Python's most powerful testing framework. Brian Okken @brianokken Edited by Kat...
New
PragmaticBookshelf
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
New
PragmaticBookshelf
Author Spotlight: Peter Ullrich @PJUllrich Data is at the core of every business, but it is useless if nobody can access and analyze ...
New
AnfaengerAlex
Hello, I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
RobertRichards
Hair Salon Games for Girls Fun Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
New
xiji2646-netizen
Woke up to this today: Claude Code’s complete source code exposed via npm source map. Not a snippet. All 512,000 lines. 1,900 TypeScript ...
New

Sub Categories: