The Matrix Product Ansatz
The success of the DMRG for 1D systems is related to the fact that it is a variational method within the space of matrix product states. These are states of the form
where are the values of the e.g. z-component of the spin in a spin chain, and the Asi are matrices of arbitrary dimension m. As m → ∞, the representation becomes exact. This theory was exposed by S. Rommer and S. Ostlund in .
Read more about this topic: Density Matrix Renormalization Group
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