Simulating continuous-space systems with quantum-classical wave functions

Fuente: arXiv
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Main Authors: Metz, Friederike, Pescia, Gabriel, Carleo, Giuseppe
Format: Preprint
Published: 2024
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author Metz, Friederike
Pescia, Gabriel
Carleo, Giuseppe
author_facet Metz, Friederike
Pescia, Gabriel
Carleo, Giuseppe
contents Most non-relativistic interacting quantum many-body systems, such as atomic and molecular ensembles or materials, are naturally described in terms of continuous-space Hamiltonians. The simulation of their ground-state properties on digital quantum computers is challenging because current algorithms require discretization, which usually amounts to choosing a finite basis set, inevitably introducing errors. In this work, we propose an alternative, discretization-free approach that combines classical and quantum resources in a global variational ansatz, optimized using the framework of variational Monte Carlo. We introduce both purely quantum as well as hybrid quantum-classical ansatze and benchmark them on three paradigmatic continuous-space systems that are either very challenging or beyond the reach of current quantum approaches: the one-dimensional quantum rotor model, a system of Helium-3 particles in one and two dimensions, and the two-dimensional homogeneous electron gas. We embed relevant constraints such as the antisymmetry of fermionic wave functions directly into the ansatz. Many-body correlations are introduced via backflow transformations represented by parameterized quantum circuits. We demonstrate that the accuracy of the simulation can be systematically improved by increasing the number of circuit parameters and study the effects of shot noise. Furthermore, we show that the hybrid ansatz improves the ground-state energies obtained using the purely classical wave function.
format Preprint
id arxiv_https___arxiv_org_abs_2409_06415
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Simulating continuous-space systems with quantum-classical wave functions
Metz, Friederike
Pescia, Gabriel
Carleo, Giuseppe
Quantum Physics
Strongly Correlated Electrons
Nuclear Theory
Computational Physics
Most non-relativistic interacting quantum many-body systems, such as atomic and molecular ensembles or materials, are naturally described in terms of continuous-space Hamiltonians. The simulation of their ground-state properties on digital quantum computers is challenging because current algorithms require discretization, which usually amounts to choosing a finite basis set, inevitably introducing errors. In this work, we propose an alternative, discretization-free approach that combines classical and quantum resources in a global variational ansatz, optimized using the framework of variational Monte Carlo. We introduce both purely quantum as well as hybrid quantum-classical ansatze and benchmark them on three paradigmatic continuous-space systems that are either very challenging or beyond the reach of current quantum approaches: the one-dimensional quantum rotor model, a system of Helium-3 particles in one and two dimensions, and the two-dimensional homogeneous electron gas. We embed relevant constraints such as the antisymmetry of fermionic wave functions directly into the ansatz. Many-body correlations are introduced via backflow transformations represented by parameterized quantum circuits. We demonstrate that the accuracy of the simulation can be systematically improved by increasing the number of circuit parameters and study the effects of shot noise. Furthermore, we show that the hybrid ansatz improves the ground-state energies obtained using the purely classical wave function.
title Simulating continuous-space systems with quantum-classical wave functions
topic Quantum Physics
Strongly Correlated Electrons
Nuclear Theory
Computational Physics
url https://arxiv.org/abs/2409.06415