Prepare Matrix Product States on a Quantum Computer

[henrik-dreyer]

What is the expected behavior?

Given a set of matrices, create a circuit that prepares the corresponding Matrix Product State. Currently, variational forms start from a product state (or a Hartree-Fock state). Instead of starting from zero entanglement, one could have a relatively cheap preparation of a slightly entangled state (MPS with moderate bond dimension) so the variational form has to do less heavy lifting. In chemistry, for example, people routinely do DMRG either in the full space or in a Complete Active Space. One could then apply further entangling gates on the quantum computer.

This code does that.