Friday, June 28, 2024

Precision

 In the case of non_pauli gates, the exponentials do not commute:

                                               


                                                              


Gemini's explanation:
srix (a key element in quantum computing) using non-Pauli gates. Let's break it down:

 
The Problem:

* You're trying to create a unitary matrix U that represents a quantum operation.
* Unitary matrices are essential in quantum computing because they preserve the probabilities of quantum states.
* Pauli gates are a fundamental set of gates in quantum computing, but you're looking at a method that doesn't rely solely on them.

The Solution:

* The core idea is to approximate the desired unitary matrix using a series of exponentials of non-Pauli gates.
* **Exponentiation:** In quantum mechanics, the exponential of a Hamiltonian (which describes the energy of a system) is used to evolve a quantum state over time.  Here, we're using exponentials of non-Pauli gates to create a desired evolution.
* **Slices:** The method divides the desired evolution into "slices" of smaller steps. The approximation gets better as the number of slices increases.
* **Approximation:** For each slice, the exponential of the non-Pauli gate is approximated as if the gate's effect were spread out over the slice.
* **Limit:** As the number of slices (n) approaches infinity, the approximation gets arbitrarily close to the actual unitary matrix U.

Why This Matters:

* **Flexibility:** This method allows you to build complex unitary matrices using a wider range of gates than just Pauli gates.
* **Efficiency:** While the approximation with a finite number of slices introduces some error, this error can be controlled by increasing the number of slices. This can be a more efficient way to implement certain quantum operations than using only Pauli gates.

Example:

Imagine you want to create a unitary matrix U that rotates a qubit by a certain angle.  You could break this rotation into many smaller rotations, each represented by an exponential of a non-Pauli gate. As you increase the number of these small rotations, you get closer and closer to the desired overall rotation.

**Important Note:** This method is a powerful tool, but it's essential to understand the limitations of the approximation and how to control the error.  

Let me know if you'd like me to elaborate on any specific part of this explanation! 
 


Thursday, June 27, 2024

Phase

 Trying to see how phase differences influence things:





  Using the S-gate to navavigate between the x and y axis:                                                                               


                                                                                        

Creating stable clone qubits:

                                                                                  


Propagating a phase shift:




Wednesday, June 26, 2024

The Cliffords

 In quantum computing, the so-called Clifford gates are the hard workers, transforming

gates into other gates.

These are : the Hadamard, the phase S, and the CNOT. Only the Hadamard is hermitian.

The Hadamard as an outer product:

                                                             


The Hadamard snadwiching a Pauli gate. Here it transforms an X-gate into a z-gate;

 and a z-gate into an X-gate.



                                                                      

https://www.perplexity.ai/search/Quantum-computing-how-RNsm9Kd9QDuPZc2P5nRNsw

                                                                                 









                                                      

Tuesday, June 25, 2024

Error Correction

 Getting ahead of myself; a peek at error correction:

https://www.cl.cam.ac.uk/teaching/1920/QuantComp/Quantum_Computing_Lecture_13.pdf


Everything is as expected:                                                                        


Qubit 1 has flipped:


Qubit 2 has flipped:


Qubit 3 has flipped:



                                                                                                   ... and so forth


Bottom line: the outcomes are different than expected when a flip has occured!!

Correcting this will require delving into Shor's code, to be seen later in this series.





Monday, June 24, 2024

Clifford Gates

                                                                    



                                                                            *     *     *

Turns out it makes no difference if the identity gated  is placebefore or after our 

chosen gates.


As well, the CNOT is Hermitian so that CNOT† is the same as CNOT.

                                                                   


Sunday, June 23, 2024

Yaow

 Researchers in Japan have found a way to make teeth grow

back in adultood. 

Faire repousser les dents: un traitement révolutionnaire (msn.com)

                                                           *     *     *


Happy FĂȘte Nationale to All!

Continuation

 Continuing...

Sill using my initial outer-product matrices:

                                                                         


                                                                                     


Conjugation:

Conjugation on a rotational gate (non-Hermitian). Allows one to change the axis 

of rotation: