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 Making my peace with the Y-Gate issue. The Bloch sphere shows

us we are in a geometrical perspective:

 Applying an X-gate:                                                 

Applying a Y-gate:

                                                      

                                     

Requesting a positive 180 rotation around the y-axis:

Two y-gates in a row:

A y-gate following a Hadamard gate; the phase shift appears.

Indeed, the phase shift was always there. 

                                                                

Sharma explanation...

                                                                        

                    

                                                                         *     *     *

                                                                              

Gemini:

In the context of the Bloch sphere and your quantum circuit, the phase refers to an additional property of the qubit's state along with its probability of being in |0⟩ or |1⟩. Here's a breakdown:

1. Chance Amplitude and Probability: The Bloch sphere uses complex numbers to represent the qubit's state. The absolute value squared of this complex number gives the probability of finding the qubit in the state |0⟩ or |1⟩ when measured. In your example, the chance amplitude for |1⟩ was smaller, resulting in a lower probability (around 14.6%) of finding the qubit in the |1⟩ state.

2. Phase and Interference: The complex number representing the state also has a phase term, which doesn't directly affect the probability of measurement. This phase information becomes crucial when considering superpositions and interference between different states.

Imagine two waves (representing two possible qubit states) overlapping. Their peaks and troughs can line up constructively (reinforcing each other) or destructively (canceling each other). The phase difference between the waves determines this interference behavior.

3. Phase in Your Circuit: The 22.5° phase reading indicates a specific rotation of the qubit's state vector on the Bloch sphere. This rotation, caused by the Y-axis rotation gate, influences how the qubit would interfere with other qubits in a multi-qubit system.

While the individual phase itself might not hold a physical meaning on its own (since it doesn't affect the immediate measurement probability), it becomes significant when considering the relative phases of multiple qubits and their combined behavior in a quantum circuit. These relative phases can be manipulated by quantum gates to achieve specific desired outcomes in quantum computations.