Possible Extension of dynamical DMRG in corvector.jl to InfiniteMPS

[zxm403089989]

The DDMRG algorithm in corvector.jl currently restricts its input type to finite MPS. In principle, can it be extended to support infinite MPS? If so, what modifications would be required?

[maartenvd]

Infinitemps is supported in a rather straightforward way - by using the same algorithms with a chain of site dependent mutable tensors embedded within an infinite mps chain. Such a state still subtypes abstractfinitemps, and is/was called windowMPS.

You should be able to prepare a windowmps psi for which you'd like to calculate (H-E)^-1 psi, and give it to that algorithm. E needs to be sufficiently complex, so that the inverse can again be well described by a windowmps.

You can even formulate these algorithms in momentumspace, though that isn't included in mpskit.