Functional renormalization group without functional integrals: Implementing Hilbert space projections for strongly correlated electrons via Hubbard X-operators

Andreas Rückriegel, Jonas Arnold, Rüdiger Krämer +1 more

arXiv:2305.06928Physical review. B./Physical review. BSep 5, 20232 citations

Physica A Statistical Mechanics and its Applications

Application of the functional integral method to the classical and quantum spin models

R. Micnas

Published Oct 1, 1979• 21 citations

Publisher

DOI: 10.1016/0378-4371(79)90146-8

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Functional renormalization group without functional integrals: Implementing Hilbert space projections for strongly correlated electrons via Hubbard X-operators

Andreas Rückriegel, Jonas Arnold, Rüdiger Krämer +1 more

The authors show here that exact functional renormalization group flow (FRG) equations for quantum systems can be derived directly within an operator formalism without using functional integrals. This simple insight opens new possibilities for applying FRG methods to models for strongly correlated electrons with projected Hilbert spaces, such as quantum spin models, the $t$ - $J$ model, or the Hubbard model at infinite on-site repulsion. By representing these models in terms of Hubbard X-operators, various applications of this approach are explored.The authors show here that exact functional renormalization group flow (FRG) equations for quantum systems can be derived directly within an operator formalism without using functional integrals. This simple insight opens new possibilities for applying FRG methods to models for strongly correlated electrons with projected Hilbert spaces, such as quantum spin models, the $t$-$J$ model, or the Hubbard model at infinite on-site repulsion. By representing these models in terms of Hubbard X-operators, various applications of this approach are explored.

arXiv:2305.06928Physical review. B./Physical review. BSep 5, 20232 citations

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model, or the Hubbard model at infinite on-site repulsion. By representing these models in terms of Hubbard X-operators, various applications of this approach are explored.