Study of the triangular-lattice Hubbard model with constrained-path quantum Monte Carlo

Fuente: arXiv
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Autores principales: Ung, Shu Fay, Mahajan, Ankit, Reichman, David R.
Formato: Preprint
Publicado: 2026
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author Ung, Shu Fay
Mahajan, Ankit
Reichman, David R.
author_facet Ung, Shu Fay
Mahajan, Ankit
Reichman, David R.
contents We benchmark constrained-path Monte Carlo (CPMC) on the triangular-lattice Hubbard model for several fillings and $U$ values and show that symmetry-adapted trial wave functions are essential for quantitative accuracy. Away from half-filling, simple free-electron-based trials that preserve the ground state symmetry yield energy deviations $\lesssim 1\%$ from exact diagonalization and density matrix renormalization group results. At half-filling, strong frustration in the intermediate to large $U$ regimes necessitates symmetry-projected trials to reach comparable accuracy, where both free-electron and symmetry-broken Hartree-Fock trials incur substantial constraint bias. Since the computational cost of CPMC with symmetry projection scales polynomially with system size, our results motivate its use as a practical route for studying competing ground states in strongly correlated, frustrated systems.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14808
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Study of the triangular-lattice Hubbard model with constrained-path quantum Monte Carlo
Ung, Shu Fay
Mahajan, Ankit
Reichman, David R.
Strongly Correlated Electrons
Quantum Physics
We benchmark constrained-path Monte Carlo (CPMC) on the triangular-lattice Hubbard model for several fillings and $U$ values and show that symmetry-adapted trial wave functions are essential for quantitative accuracy. Away from half-filling, simple free-electron-based trials that preserve the ground state symmetry yield energy deviations $\lesssim 1\%$ from exact diagonalization and density matrix renormalization group results. At half-filling, strong frustration in the intermediate to large $U$ regimes necessitates symmetry-projected trials to reach comparable accuracy, where both free-electron and symmetry-broken Hartree-Fock trials incur substantial constraint bias. Since the computational cost of CPMC with symmetry projection scales polynomially with system size, our results motivate its use as a practical route for studying competing ground states in strongly correlated, frustrated systems.
title Study of the triangular-lattice Hubbard model with constrained-path quantum Monte Carlo
topic Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2603.14808