# Quantum Monte Carlo diagonalization for many-fermion systems - Condensed Matter > Strongly Correlated Electrons

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Abstract: In this study we present an optimization method based on the quantum MonteCarlo diagonalization for many-fermion systems. Using the Hubbard-Stratonovichtransformation, employed to decompose the interactions in terms of auxiliaryfields, we expand the true ground-state wave function. The ground-state wavefunction is written as a linear combination of the basis wave functions. TheHamiltonian is diagonalized to obtain the lowest energy state, using thevariational principle within the selected subspace of the basis functions. Thismethod is free from the difficulty known as the negative sign problem. We canoptimize a wave function using two procedures. The first procedure is toincrease the number of basis functions. The second improves each basis functionthrough the operators, $e^{-\Delta\tau H}$, using the Hubbard-Stratonovichdecomposition. We present an algorithm for the Quantum Monte Carlodiagonalization method using a genetic algorithm and the renormalizationmethod. We compute the ground-state energy and correlation functions of smallclusters to compare with available data.

Autor: Takashi Yanagisawa

Fuente: https://arxiv.org/