Ground-State-Based Model Reduction with Unitary Circuits
arXiv:2504.10774 · doi:10.1103/h1pt-v5kz
Abstract
We present a method to numerically obtain low-energy effective models based on a unitary transformation of the ground state. The algorithm finds a unitary circuit that transforms the ground state of the original model to a projected wavefunction with only the low-energy degrees of freedom. The effective model can then be derived using the unitary transformation encoded in the circuit. We test our method on the one-dimensional and two-dimensional square-lattice Hubbard model at half-filling, and obtain more accurate effective spin models than the standard perturbative approach.
5 pages, 4 figures; published version with minor revisions
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