New Technique: Symmetry Adjusted Classical Shadows

[purva-thakre]

Introduced in https://arxiv.org/abs/2310.03071

The technique uses Classical Shadows (especially Robust Shadows) to exploit the global symmetries inherent to a quantum system. It does not work if gate-dependent errors are considered at each circuit layer as the errors in the full quantum circuit are accounted for at once in post-processing.

Testing this new module with other mitigation techniques would be interesting as combining Classical Shadows with PEC led to better results. https://arxiv.org/abs/2305.04956

Note: Working on the implementation of this technique will also involve cleanup associated with the code and documentation of Classical Shadows in Mitiq. For more info, see #2110, #2129, and #2138.