Bounding the fidelity of quantum many-body states from partial information
Bounding the fidelity of quantum many-body states from partial information
We formulate an algorithm to lower bound the fidelity between quantum many-body states only from partial information, such as the one accessible by few-body observables. Our method is especially tailored to permutationally invariant states, but it gives nontrivial results in all situations where this symmetry is even partial. This property …