Renormalization of States and Quasiparticles in Many-body Downfolding

Fuente: arXiv
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Auteurs principaux: Canestraight, Annabelle, Huang, Zhen, Vlcek, Vojtech
Format: Preprint
Publié: 2024
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author Canestraight, Annabelle
Huang, Zhen
Vlcek, Vojtech
author_facet Canestraight, Annabelle
Huang, Zhen
Vlcek, Vojtech
contents We explore the principles of many-body Hamiltonian complexity reduction via downfolding on an effective low-dimensional representation. We present a unique measure of fidelity between the effective (reduced-rank) description and the full many-body treatment for arbitrary (i.e., ground and excited) states. When the entire problem is mapped on a system of interacting quasiparticles [npj Computational Materials 9 (1), 126, 2023], the effective Hamiltonians can faithfully reproduce the physics only when a clear energy scale separation exists between the subsystems and its environment. We also demonstrate that it is necessary to include quasiparticle renormalization at distinct energy scales, capturing the distinct interaction between subsystems and their surrounding environments. Numerical results from simple, exactly solvable models highlight the limitations and strengths of this approach, particularly for ground and low-lying excited states. This work lays the groundwork for applying dynamical downfolding techniques to problems concerned with (quantum) interfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2411_13725
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Renormalization of States and Quasiparticles in Many-body Downfolding
Canestraight, Annabelle
Huang, Zhen
Vlcek, Vojtech
Computational Physics
Materials Science
We explore the principles of many-body Hamiltonian complexity reduction via downfolding on an effective low-dimensional representation. We present a unique measure of fidelity between the effective (reduced-rank) description and the full many-body treatment for arbitrary (i.e., ground and excited) states. When the entire problem is mapped on a system of interacting quasiparticles [npj Computational Materials 9 (1), 126, 2023], the effective Hamiltonians can faithfully reproduce the physics only when a clear energy scale separation exists between the subsystems and its environment. We also demonstrate that it is necessary to include quasiparticle renormalization at distinct energy scales, capturing the distinct interaction between subsystems and their surrounding environments. Numerical results from simple, exactly solvable models highlight the limitations and strengths of this approach, particularly for ground and low-lying excited states. This work lays the groundwork for applying dynamical downfolding techniques to problems concerned with (quantum) interfaces.
title Renormalization of States and Quasiparticles in Many-body Downfolding
topic Computational Physics
Materials Science
url https://arxiv.org/abs/2411.13725