Dbi non classical simulation

[shangtai]

Hi,

This is an implementation of the scenario where classical simulation is not possible for first order product formula.

Scenario B: Classical simulation is not possible.

We may use the bound $$||Q(s) - U(s) || = \sum_{i=1}^N ||[hi,h{i+1}|| s^2 \le C_h s^2 N$$ where $C_h = max_i ||[hi,h{i+1}||$

Set $N = \epsilon / (C_h s^2)$

Checklist:

• [ ] Reviewers confirm new code works as expected.
• [ ] Tests are passing.
• [ ] Coverage does not decrease.
• [ ] Documentation is updated.